6 @documentencoding UTF-8
7 @settitle GNU Guix Reference Manual
12 @c Identifier of the OpenPGP key used to sign tarballs and such.
13 @set OPENPGP-SIGNING-KEY-ID BCA689B636553801C3C62150197A5888235FACAC
16 Copyright @copyright{} 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès@*
17 Copyright @copyright{} 2013, 2014, 2016 Andreas Enge@*
18 Copyright @copyright{} 2013 Nikita Karetnikov@*
19 Copyright @copyright{} 2014, 2015, 2016 Alex Kost@*
20 Copyright @copyright{} 2015, 2016 Mathieu Lirzin@*
21 Copyright @copyright{} 2014 Pierre-Antoine Rault@*
22 Copyright @copyright{} 2015 Taylan Ulrich Bayırlı/Kammer@*
23 Copyright @copyright{} 2015, 2016, 2017 Leo Famulari@*
24 Copyright @copyright{} 2015, 2016 Ricardo Wurmus@*
25 Copyright @copyright{} 2016 Ben Woodcroft@*
26 Copyright @copyright{} 2016 Chris Marusich@*
27 Copyright @copyright{} 2016, 2017 Efraim Flashner@*
28 Copyright @copyright{} 2016 John Darrington@*
29 Copyright @copyright{} 2016 ng0@*
30 Copyright @copyright{} 2016 Jan Nieuwenhuizen@*
31 Copyright @copyright{} 2016 Julien Lepiller@*
32 Copyright @copyright{} 2016 Alex ter Weele@*
33 Copyright @copyright{} 2017 Clément Lassieur@*
34 Copyright @copyright{} 2017 Mathieu Othacehe@*
35 Copyright @copyright{} 2017 Federico Beffa@*
36 Copyright @copyright{} 2017 Carlo Zancanaro@*
37 Copyright @copyright{} 2017 Thomas Danckaert
39 Permission is granted to copy, distribute and/or modify this document
40 under the terms of the GNU Free Documentation License, Version 1.3 or
41 any later version published by the Free Software Foundation; with no
42 Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
43 copy of the license is included in the section entitled ``GNU Free
44 Documentation License''.
47 @dircategory System administration
49 * Guix: (guix). Manage installed software and system configuration.
50 * guix package: (guix)Invoking guix package. Installing, removing, and upgrading packages.
51 * guix gc: (guix)Invoking guix gc. Reclaiming unused disk space.
52 * guix pull: (guix)Invoking guix pull. Update the list of available packages.
53 * guix system: (guix)Invoking guix system. Manage the operating system configuration.
56 @dircategory Software development
58 * guix environment: (guix)Invoking guix environment. Building development environments with Guix.
59 * guix build: (guix)Invoking guix build. Building packages.
60 * guix pack: (guix)Invoking guix pack. Creating binary bundles.
64 @title GNU Guix Reference Manual
65 @subtitle Using the GNU Guix Functional Package Manager
66 @author The GNU Guix Developers
69 @vskip 0pt plus 1filll
70 Edition @value{EDITION} @*
78 @c *********************************************************************
82 This document describes GNU Guix version @value{VERSION}, a functional
83 package management tool written for the GNU system.
86 * Introduction:: What is Guix about?
87 * Installation:: Installing Guix.
88 * Package Management:: Package installation, upgrade, etc.
89 * Programming Interface:: Using Guix in Scheme.
90 * Utilities:: Package management commands.
91 * GNU Distribution:: Software for your friendly GNU system.
92 * Contributing:: Your help needed!
94 * Acknowledgments:: Thanks!
95 * GNU Free Documentation License:: The license of this manual.
96 * Concept Index:: Concepts.
97 * Programming Index:: Data types, functions, and variables.
100 --- The Detailed Node Listing ---
104 * Binary Installation:: Getting Guix running in no time!
105 * Requirements:: Software needed to build and run Guix.
106 * Running the Test Suite:: Testing Guix.
107 * Setting Up the Daemon:: Preparing the build daemon's environment.
108 * Invoking guix-daemon:: Running the build daemon.
109 * Application Setup:: Application-specific setup.
111 Setting Up the Daemon
113 * Build Environment Setup:: Preparing the isolated build environment.
114 * Daemon Offload Setup:: Offloading builds to remote machines.
118 * Features:: How Guix will make your life brighter.
119 * Invoking guix package:: Package installation, removal, etc.
120 * Substitutes:: Downloading pre-built binaries.
121 * Packages with Multiple Outputs:: Single source package, multiple outputs.
122 * Invoking guix gc:: Running the garbage collector.
123 * Invoking guix pull:: Fetching the latest Guix and distribution.
124 * Invoking guix pack:: Creating software bundles.
125 * Invoking guix archive:: Exporting and importing store files.
127 Programming Interface
129 * Defining Packages:: Defining new packages.
130 * Build Systems:: Specifying how packages are built.
131 * The Store:: Manipulating the package store.
132 * Derivations:: Low-level interface to package derivations.
133 * The Store Monad:: Purely functional interface to the store.
134 * G-Expressions:: Manipulating build expressions.
138 * package Reference:: The package data type.
139 * origin Reference:: The origin data type.
143 * Invoking guix build:: Building packages from the command line.
144 * Invoking guix edit:: Editing package definitions.
145 * Invoking guix download:: Downloading a file and printing its hash.
146 * Invoking guix hash:: Computing the cryptographic hash of a file.
147 * Invoking guix import:: Importing package definitions.
148 * Invoking guix refresh:: Updating package definitions.
149 * Invoking guix lint:: Finding errors in package definitions.
150 * Invoking guix size:: Profiling disk usage.
151 * Invoking guix graph:: Visualizing the graph of packages.
152 * Invoking guix environment:: Setting up development environments.
153 * Invoking guix publish:: Sharing substitutes.
154 * Invoking guix challenge:: Challenging substitute servers.
155 * Invoking guix copy:: Copying to and from a remote store.
156 * Invoking guix container:: Process isolation.
158 Invoking @command{guix build}
160 * Common Build Options:: Build options for most commands.
161 * Package Transformation Options:: Creating variants of packages.
162 * Additional Build Options:: Options specific to 'guix build'.
166 * System Installation:: Installing the whole operating system.
167 * System Configuration:: Configuring the operating system.
168 * Documentation:: Browsing software user manuals.
169 * Installing Debugging Files:: Feeding the debugger.
170 * Security Updates:: Deploying security fixes quickly.
171 * Package Modules:: Packages from the programmer's viewpoint.
172 * Packaging Guidelines:: Growing the distribution.
173 * Bootstrapping:: GNU/Linux built from scratch.
174 * Porting:: Targeting another platform or kernel.
178 * Limitations:: What you can expect.
179 * Hardware Considerations:: Supported hardware.
180 * USB Stick Installation:: Preparing the installation medium.
181 * Preparing for Installation:: Networking, partitioning, etc.
182 * Proceeding with the Installation:: The real thing.
183 * Installing GuixSD in a VM:: GuixSD playground.
184 * Building the Installation Image:: How this comes to be.
188 * Using the Configuration System:: Customizing your GNU system.
189 * operating-system Reference:: Detail of operating-system declarations.
190 * File Systems:: Configuring file system mounts.
191 * Mapped Devices:: Block device extra processing.
192 * User Accounts:: Specifying user accounts.
193 * Locales:: Language and cultural convention settings.
194 * Services:: Specifying system services.
195 * Setuid Programs:: Programs running with root privileges.
196 * X.509 Certificates:: Authenticating HTTPS servers.
197 * Name Service Switch:: Configuring libc's name service switch.
198 * Initial RAM Disk:: Linux-Libre bootstrapping.
199 * GRUB Configuration:: Configuring the boot loader.
200 * Invoking guix system:: Instantiating a system configuration.
201 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
202 * Defining Services:: Adding new service definitions.
206 * Base Services:: Essential system services.
207 * Scheduled Job Execution:: The mcron service.
208 * Log Rotation:: The rottlog service.
209 * Networking Services:: Network setup, SSH daemon, etc.
210 * X Window:: Graphical display.
211 * Printing Services:: Local and remote printer support.
212 * Desktop Services:: D-Bus and desktop services.
213 * Database Services:: SQL databases.
214 * Mail Services:: IMAP, POP3, SMTP, and all that.
215 * Messaging Services:: Messaging services.
216 * Kerberos Services:: Kerberos services.
217 * Web Services:: Web servers.
218 * VPN Services:: VPN daemons.
219 * Network File System:: NFS related services.
220 * Continuous Integration:: The Cuirass service.
221 * Power management Services:: The TLP tool.
222 * Miscellaneous Services:: Other services.
226 * Service Composition:: The model for composing services.
227 * Service Types and Services:: Types and services.
228 * Service Reference:: API reference.
229 * Shepherd Services:: A particular type of service.
233 * Software Freedom:: What may go into the distribution.
234 * Package Naming:: What's in a name?
235 * Version Numbers:: When the name is not enough.
236 * Synopses and Descriptions:: Helping users find the right package.
237 * Python Modules:: A touch of British comedy.
238 * Perl Modules:: Little pearls.
239 * Java Packages:: Coffee break.
240 * Fonts:: Fond of fonts.
244 * Building from Git:: The latest and greatest.
245 * Running Guix Before It Is Installed:: Hacker tricks.
246 * The Perfect Setup:: The right tools.
247 * Coding Style:: Hygiene of the contributor.
248 * Submitting Patches:: Share your work.
252 * Programming Paradigm:: How to compose your elements.
253 * Modules:: Where to store your code?
254 * Data Types and Pattern Matching:: Implementing data structures.
255 * Formatting Code:: Writing conventions.
260 @c *********************************************************************
262 @chapter Introduction
265 GNU Guix@footnote{``Guix'' is pronounced like ``geeks'', or ``ɡiːks''
266 using the international phonetic alphabet (IPA).} is a package
267 management tool for the GNU system. Guix makes it easy for unprivileged
268 users to install, upgrade, or remove packages, to roll back to a
269 previous package set, to build packages from source, and generally
270 assists with the creation and maintenance of software environments.
272 @cindex user interfaces
273 Guix provides a command-line package management interface
274 (@pxref{Invoking guix package}), a set of command-line utilities
275 (@pxref{Utilities}), as well as Scheme programming interfaces
276 (@pxref{Programming Interface}).
278 Its @dfn{build daemon} is responsible for building packages on behalf of
279 users (@pxref{Setting Up the Daemon}) and for downloading pre-built
280 binaries from authorized sources (@pxref{Substitutes}).
282 @cindex extensibility of the distribution
283 @cindex customization, of packages
284 Guix includes package definitions for many GNU and non-GNU packages, all
285 of which @uref{https://www.gnu.org/philosophy/free-sw.html, respect the
286 user's computing freedom}. It is @emph{extensible}: users can write
287 their own package definitions (@pxref{Defining Packages}) and make them
288 available as independent package modules (@pxref{Package Modules}). It
289 is also @emph{customizable}: users can @emph{derive} specialized package
290 definitions from existing ones, including from the command line
291 (@pxref{Package Transformation Options}).
293 @cindex Guix System Distribution
295 You can install GNU@tie{}Guix on top of an existing GNU/Linux system
296 where it complements the available tools without interference
297 (@pxref{Installation}), or you can use it as part of the standalone
298 @dfn{Guix System Distribution} or GuixSD (@pxref{GNU Distribution}).
299 With GNU@tie{}GuixSD, you @emph{declare} all aspects of the operating
300 system configuration and Guix takes care of instantiating the
301 configuration in a transactional, reproducible, and stateless fashion
302 (@pxref{System Configuration}).
304 @cindex functional package management
305 Under the hood, Guix implements the @dfn{functional package management}
306 discipline pioneered by Nix (@pxref{Acknowledgments}).
307 In Guix, the package build and installation process is seen
308 as a @emph{function}, in the mathematical sense. That function takes inputs,
309 such as build scripts, a compiler, and libraries, and
310 returns an installed package. As a pure function, its result depends
311 solely on its inputs---for instance, it cannot refer to software or
312 scripts that were not explicitly passed as inputs. A build function
313 always produces the same result when passed a given set of inputs. It
314 cannot alter the environment of the running system in
315 any way; for instance, it cannot create, modify, or delete files outside
316 of its build and installation directories. This is achieved by running
317 build processes in isolated environments (or @dfn{containers}), where only their
318 explicit inputs are visible.
321 The result of package build functions is @dfn{cached} in the file
322 system, in a special directory called @dfn{the store} (@pxref{The
323 Store}). Each package is installed in a directory of its own in the
324 store---by default under @file{/gnu/store}. The directory name contains
325 a hash of all the inputs used to build that package; thus, changing an
326 input yields a different directory name.
328 This approach is the foundation for the salient features of Guix: support
329 for transactional package upgrade and rollback, per-user installation, and
330 garbage collection of packages (@pxref{Features}).
333 @c *********************************************************************
335 @chapter Installation
337 @cindex installing Guix
338 GNU Guix is available for download from its website at
339 @url{http://www.gnu.org/software/guix/}. This section describes the
340 software requirements of Guix, as well as how to install it and get
343 Note that this section is concerned with the installation of the package
344 manager, which can be done on top of a running GNU/Linux system. If,
345 instead, you want to install the complete GNU operating system,
346 @pxref{System Installation}.
348 @cindex foreign distro
349 When installed on a running GNU/Linux system---thereafter called a
350 @dfn{foreign distro}---GNU@tie{}Guix complements the available tools
351 without interference. Its data lives exclusively in two directories,
352 usually @file{/gnu/store} and @file{/var/guix}; other files on your
353 system, such as @file{/etc}, are left untouched.
355 Once installed, Guix can be updated by running @command{guix pull}
356 (@pxref{Invoking guix pull}).
359 * Binary Installation:: Getting Guix running in no time!
360 * Requirements:: Software needed to build and run Guix.
361 * Running the Test Suite:: Testing Guix.
362 * Setting Up the Daemon:: Preparing the build daemon's environment.
363 * Invoking guix-daemon:: Running the build daemon.
364 * Application Setup:: Application-specific setup.
367 @node Binary Installation
368 @section Binary Installation
370 @cindex installing Guix from binaries
371 This section describes how to install Guix on an arbitrary system from a
372 self-contained tarball providing binaries for Guix and for all its
373 dependencies. This is often quicker than installing from source, which
374 is described in the next sections. The only requirement is to have
377 Installing goes along these lines:
381 @cindex downloading Guix binary
382 Download the binary tarball from
383 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz},
384 where @var{system} is @code{x86_64-linux} for an @code{x86_64} machine
385 already running the kernel Linux, and so on.
387 @c The following is somewhat duplicated in ``System Installation''.
388 Make sure to download the associated @file{.sig} file and to verify the
389 authenticity of the tarball against it, along these lines:
392 $ wget ftp://alpha.gnu.org/gnu/guix/guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
393 $ gpg --verify guix-binary-@value{VERSION}.@var{system}.tar.xz.sig
396 If that command fails because you do not have the required public key,
397 then run this command to import it:
400 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
404 and rerun the @code{gpg --verify} command.
405 @c end authentication part
412 # tar --warning=no-timestamp -xf \
413 guix-binary-@value{VERSION}.@var{system}.tar.xz
414 # mv var/guix /var/ && mv gnu /
417 This creates @file{/gnu/store} (@pxref{The Store}) and @file{/var/guix}.
418 The latter contains a ready-to-use profile for @code{root} (see next
421 Do @emph{not} unpack the tarball on a working Guix system since that
422 would overwrite its own essential files.
424 The @code{--warning=no-timestamp} option makes sure GNU@tie{}tar does
425 not emit warnings about ``implausibly old time stamps'' (such
426 warnings were triggered by GNU@tie{}tar 1.26 and older; recent
428 They stem from the fact that all the
429 files in the archive have their modification time set to zero (which
430 means January 1st, 1970.) This is done on purpose to make sure the
431 archive content is independent of its creation time, thus making it
435 Make @code{root}'s profile available under @file{~/.guix-profile}:
438 # ln -sf /var/guix/profiles/per-user/root/guix-profile \
442 Source @file{etc/profile} to augment @code{PATH} and other relevant
443 environment variables:
446 # GUIX_PROFILE=$HOME/.guix-profile \
447 source $GUIX_PROFILE/etc/profile
451 Create the group and user accounts for build users as explained below
452 (@pxref{Build Environment Setup}).
455 Run the daemon, and set it to automatically start on boot.
457 If your host distro uses the systemd init system, this can be achieved
460 @c Versions of systemd that supported symlinked service files are not
461 @c yet widely deployed, so we should suggest that users copy the service
464 @c See this thread for more information:
465 @c http://lists.gnu.org/archive/html/guix-devel/2017-01/msg01199.html
468 # cp ~root/.guix-profile/lib/systemd/system/guix-daemon.service \
470 # systemctl start guix-daemon && systemctl enable guix-daemon
473 If your host distro uses the Upstart init system:
476 # initctl reload-configuration
477 # cp ~root/.guix-profile/lib/upstart/system/guix-daemon.conf /etc/init/
481 Otherwise, you can still start the daemon manually with:
484 # ~root/.guix-profile/bin/guix-daemon --build-users-group=guixbuild
488 Make the @command{guix} command available to other users on the machine,
492 # mkdir -p /usr/local/bin
494 # ln -s /var/guix/profiles/per-user/root/guix-profile/bin/guix
497 It is also a good idea to make the Info version of this manual available
501 # mkdir -p /usr/local/share/info
502 # cd /usr/local/share/info
503 # for i in /var/guix/profiles/per-user/root/guix-profile/share/info/* ;
507 That way, assuming @file{/usr/local/share/info} is in the search path,
508 running @command{info guix} will open this manual (@pxref{Other Info
509 Directories,,, texinfo, GNU Texinfo}, for more details on changing the
513 @cindex substitutes, authorization thereof
514 To use substitutes from @code{hydra.gnu.org} or one of its mirrors
515 (@pxref{Substitutes}), authorize them:
518 # guix archive --authorize < ~root/.guix-profile/share/guix/hydra.gnu.org.pub
522 Each user may need to perform a few additional steps to make their Guix
523 environment ready for use, @pxref{Application Setup}.
526 Voilà, the installation is complete!
528 You can confirm that Guix is working by installing a sample package into
532 # guix package -i hello
535 The @code{guix} package must remain available in @code{root}'s profile,
536 or it would become subject to garbage collection---in which case you
537 would find yourself badly handicapped by the lack of the @command{guix}
538 command. In other words, do not remove @code{guix} by running
539 @code{guix package -r guix}.
541 The binary installation tarball can be (re)produced and verified simply
542 by running the following command in the Guix source tree:
545 make guix-binary.@var{system}.tar.xz
549 ... which, in turn, runs:
552 guix pack -s @var{system} --localstatedir guix
555 @xref{Invoking guix pack}, for more info on this handy tool.
558 @section Requirements
560 This section lists requirements when building Guix from source. The
561 build procedure for Guix is the same as for other GNU software, and is
562 not covered here. Please see the files @file{README} and @file{INSTALL}
563 in the Guix source tree for additional details.
565 GNU Guix depends on the following packages:
568 @item @url{http://gnu.org/software/guile/, GNU Guile}, version 2.0.9 or
569 later, including 2.2.x;
570 @item @url{http://gnupg.org/, GNU libgcrypt};
572 @uref{http://gnutls.org/, GnuTLS}, specifically its Guile bindings
573 (@pxref{Guile Preparations, how to install the GnuTLS bindings for
574 Guile,, gnutls-guile, GnuTLS-Guile});
575 @item @url{http://www.gnu.org/software/make/, GNU Make}.
578 The following dependencies are optional:
583 @url{http://savannah.nongnu.org/projects/guile-json/, Guile-JSON} will
584 allow you to use the @command{guix import pypi} command (@pxref{Invoking
585 guix import}). It is of
586 interest primarily for developers and not for casual users.
589 @c Note: We need at least 0.10.2 for 'channel-send-eof'.
590 Support for build offloading (@pxref{Daemon Offload Setup}) and
591 @command{guix copy} (@pxref{Invoking guix copy}) depends on
592 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH},
593 version 0.10.2 or later.
596 When @url{http://zlib.net, zlib} is available, @command{guix publish}
597 can compress build byproducts (@pxref{Invoking guix publish}).
600 Unless @code{--disable-daemon} was passed to @command{configure}, the
601 following packages are also needed:
604 @item @url{http://sqlite.org, SQLite 3};
605 @item @url{http://www.bzip.org, libbz2};
606 @item @url{http://gcc.gnu.org, GCC's g++}, with support for the
610 @cindex state directory
611 When configuring Guix on a system that already has a Guix installation,
612 be sure to specify the same state directory as the existing installation
613 using the @code{--localstatedir} option of the @command{configure}
614 script (@pxref{Directory Variables, @code{localstatedir},, standards,
615 GNU Coding Standards}). The @command{configure} script protects against
616 unintended misconfiguration of @var{localstatedir} so you do not
617 inadvertently corrupt your store (@pxref{The Store}).
619 @cindex Nix, compatibility
620 When a working installation of @url{http://nixos.org/nix/, the Nix package
621 manager} is available, you
622 can instead configure Guix with @code{--disable-daemon}. In that case,
623 Nix replaces the three dependencies above.
625 Guix is compatible with Nix, so it is possible to share the same store
626 between both. To do so, you must pass @command{configure} not only the
627 same @code{--with-store-dir} value, but also the same
628 @code{--localstatedir} value. The latter is essential because it
629 specifies where the database that stores metadata about the store is
630 located, among other things. The default values for Nix are
631 @code{--with-store-dir=/nix/store} and @code{--localstatedir=/nix/var}.
632 Note that @code{--disable-daemon} is not required if
633 your goal is to share the store with Nix.
635 @node Running the Test Suite
636 @section Running the Test Suite
639 After a successful @command{configure} and @code{make} run, it is a good
640 idea to run the test suite. It can help catch issues with the setup or
641 environment, or bugs in Guix itself---and really, reporting test
642 failures is a good way to help improve the software. To run the test
649 Test cases can run in parallel: you can use the @code{-j} option of
650 GNU@tie{}make to speed things up. The first run may take a few minutes
651 on a recent machine; subsequent runs will be faster because the store
652 that is created for test purposes will already have various things in
655 It is also possible to run a subset of the tests by defining the
656 @code{TESTS} makefile variable as in this example:
659 make check TESTS="tests/store.scm tests/cpio.scm"
662 By default, tests results are displayed at a file level. In order to
663 see the details of every individual test cases, it is possible to define
664 the @code{SCM_LOG_DRIVER_FLAGS} makefile variable as in this example:
667 make check TESTS="tests/base64.scm" SCM_LOG_DRIVER_FLAGS="--brief=no"
670 Upon failure, please email @email{bug-guix@@gnu.org} and attach the
671 @file{test-suite.log} file. Please specify the Guix version being used
672 as well as version numbers of the dependencies (@pxref{Requirements}) in
675 Guix also comes with a whole-system test suite that tests complete
676 GuixSD operating system instances. It can only run on systems where
677 Guix is already installed, using:
684 or, again, by defining @code{TESTS} to select a subset of tests to run:
687 make check-system TESTS="basic mcron"
690 These system tests are defined in the @code{(gnu tests @dots{})}
691 modules. They work by running the operating systems under test with
692 lightweight instrumentation in a virtual machine (VM). They can be
693 computationally intensive or rather cheap, depending on whether
694 substitutes are available for their dependencies (@pxref{Substitutes}).
695 Some of them require a lot of storage space to hold VM images.
697 Again in case of test failures, please send @email{bug-guix@@gnu.org}
700 @node Setting Up the Daemon
701 @section Setting Up the Daemon
704 Operations such as building a package or running the garbage collector
705 are all performed by a specialized process, the @dfn{build daemon}, on
706 behalf of clients. Only the daemon may access the store and its
707 associated database. Thus, any operation that manipulates the store
708 goes through the daemon. For instance, command-line tools such as
709 @command{guix package} and @command{guix build} communicate with the
710 daemon (@i{via} remote procedure calls) to instruct it what to do.
712 The following sections explain how to prepare the build daemon's
713 environment. See also @ref{Substitutes}, for information on how to allow
714 the daemon to download pre-built binaries.
717 * Build Environment Setup:: Preparing the isolated build environment.
718 * Daemon Offload Setup:: Offloading builds to remote machines.
721 @node Build Environment Setup
722 @subsection Build Environment Setup
724 @cindex build environment
725 In a standard multi-user setup, Guix and its daemon---the
726 @command{guix-daemon} program---are installed by the system
727 administrator; @file{/gnu/store} is owned by @code{root} and
728 @command{guix-daemon} runs as @code{root}. Unprivileged users may use
729 Guix tools to build packages or otherwise access the store, and the
730 daemon will do it on their behalf, ensuring that the store is kept in a
731 consistent state, and allowing built packages to be shared among users.
734 When @command{guix-daemon} runs as @code{root}, you may not want package
735 build processes themselves to run as @code{root} too, for obvious
736 security reasons. To avoid that, a special pool of @dfn{build users}
737 should be created for use by build processes started by the daemon.
738 These build users need not have a shell and a home directory: they will
739 just be used when the daemon drops @code{root} privileges in build
740 processes. Having several such users allows the daemon to launch
741 distinct build processes under separate UIDs, which guarantees that they
742 do not interfere with each other---an essential feature since builds are
743 regarded as pure functions (@pxref{Introduction}).
745 On a GNU/Linux system, a build user pool may be created like this (using
746 Bash syntax and the @code{shadow} commands):
748 @c See http://lists.gnu.org/archive/html/bug-guix/2013-01/msg00239.html
749 @c for why `-G' is needed.
751 # groupadd --system guixbuild
752 # for i in `seq -w 1 10`;
754 useradd -g guixbuild -G guixbuild \
755 -d /var/empty -s `which nologin` \
756 -c "Guix build user $i" --system \
762 The number of build users determines how many build jobs may run in
763 parallel, as specified by the @option{--max-jobs} option
764 (@pxref{Invoking guix-daemon, @option{--max-jobs}}). To use
765 @command{guix system vm} and related commands, you may need to add the
766 build users to the @code{kvm} group so they can access @file{/dev/kvm},
767 using @code{-G guixbuild,kvm} instead of @code{-G guixbuild}
768 (@pxref{Invoking guix system}).
770 The @code{guix-daemon} program may then be run as @code{root} with the
771 following command@footnote{If your machine uses the systemd init system,
772 dropping the @file{@var{prefix}/lib/systemd/system/guix-daemon.service}
773 file in @file{/etc/systemd/system} will ensure that
774 @command{guix-daemon} is automatically started. Similarly, if your
775 machine uses the Upstart init system, drop the
776 @file{@var{prefix}/lib/upstart/system/guix-daemon.conf}
777 file in @file{/etc/init}.}:
780 # guix-daemon --build-users-group=guixbuild
785 This way, the daemon starts build processes in a chroot, under one of
786 the @code{guixbuilder} users. On GNU/Linux, by default, the chroot
787 environment contains nothing but:
789 @c Keep this list in sync with libstore/build.cc! -----------------------
792 a minimal @code{/dev} directory, created mostly independently from the
793 host @code{/dev}@footnote{``Mostly'', because while the set of files
794 that appear in the chroot's @code{/dev} is fixed, most of these files
795 can only be created if the host has them.};
798 the @code{/proc} directory; it only shows the processes of the container
799 since a separate PID name space is used;
802 @file{/etc/passwd} with an entry for the current user and an entry for
806 @file{/etc/group} with an entry for the user's group;
809 @file{/etc/hosts} with an entry that maps @code{localhost} to
813 a writable @file{/tmp} directory.
816 You can influence the directory where the daemon stores build trees
817 @i{via} the @code{TMPDIR} environment variable. However, the build tree
818 within the chroot is always called @file{/tmp/guix-build-@var{name}.drv-0},
819 where @var{name} is the derivation name---e.g., @code{coreutils-8.24}.
820 This way, the value of @code{TMPDIR} does not leak inside build
821 environments, which avoids discrepancies in cases where build processes
822 capture the name of their build tree.
825 The daemon also honors the @code{http_proxy} environment variable for
826 HTTP downloads it performs, be it for fixed-output derivations
827 (@pxref{Derivations}) or for substitutes (@pxref{Substitutes}).
829 If you are installing Guix as an unprivileged user, it is still possible
830 to run @command{guix-daemon} provided you pass @code{--disable-chroot}.
831 However, build processes will not be isolated from one another, and not
832 from the rest of the system. Thus, build processes may interfere with
833 each other, and may access programs, libraries, and other files
834 available on the system---making it much harder to view them as
835 @emph{pure} functions.
838 @node Daemon Offload Setup
839 @subsection Using the Offload Facility
843 When desired, the build daemon can @dfn{offload} derivation builds to
844 other machines running Guix, using the @code{offload} @dfn{build
845 hook}@footnote{This feature is available only when
846 @uref{https://github.com/artyom-poptsov/guile-ssh, Guile-SSH} is
848 feature is enabled, a list of user-specified build machines is read from
849 @file{/etc/guix/machines.scm}; every time a build is requested, for
850 instance via @code{guix build}, the daemon attempts to offload it to one
851 of the machines that satisfy the constraints of the derivation, in
852 particular its system type---e.g., @file{x86_64-linux}. Missing
853 prerequisites for the build are copied over SSH to the target machine,
854 which then proceeds with the build; upon success the output(s) of the
855 build are copied back to the initial machine.
857 The @file{/etc/guix/machines.scm} file typically looks like this:
861 (name "eightysix.example.org")
862 (system "x86_64-linux")
863 (host-key "ssh-ed25519 AAAAC3Nza@dots{}")
865 (speed 2.)) ;incredibly fast!
868 (name "meeps.example.org")
869 (system "mips64el-linux")
870 (host-key "ssh-rsa AAAAB3Nza@dots{}")
873 (string-append (getenv "HOME")
874 "/.ssh/identity-for-guix"))))
878 In the example above we specify a list of two build machines, one for
879 the @code{x86_64} architecture and one for the @code{mips64el}
882 In fact, this file is---not surprisingly!---a Scheme file that is
883 evaluated when the @code{offload} hook is started. Its return value
884 must be a list of @code{build-machine} objects. While this example
885 shows a fixed list of build machines, one could imagine, say, using
886 DNS-SD to return a list of potential build machines discovered in the
887 local network (@pxref{Introduction, Guile-Avahi,, guile-avahi, Using
888 Avahi in Guile Scheme Programs}). The @code{build-machine} data type is
891 @deftp {Data Type} build-machine
892 This data type represents build machines to which the daemon may offload
893 builds. The important fields are:
898 The host name of the remote machine.
901 The system type of the remote machine---e.g., @code{"x86_64-linux"}.
904 The user account to use when connecting to the remote machine over SSH.
905 Note that the SSH key pair must @emph{not} be passphrase-protected, to
906 allow non-interactive logins.
909 This must be the machine's SSH @dfn{public host key} in OpenSSH format.
910 This is used to authenticate the machine when we connect to it. It is a
911 long string that looks like this:
914 ssh-ed25519 AAAAC3NzaC@dots{}mde+UhL hint@@example.org
917 If the machine is running the OpenSSH daemon, @command{sshd}, the host
918 key can be found in a file such as
919 @file{/etc/ssh/ssh_host_ed25519_key.pub}.
921 If the machine is running the SSH daemon of GNU@tie{}lsh,
922 @command{lshd}, the host key is in @file{/etc/lsh/host-key.pub} or a
923 similar file. It can be converted to the OpenSSH format using
924 @command{lsh-export-key} (@pxref{Converting keys,,, lsh, LSH Manual}):
927 $ lsh-export-key --openssh < /etc/lsh/host-key.pub
928 ssh-rsa AAAAB3NzaC1yc2EAAAAEOp8FoQAAAQEAs1eB46LV@dots{}
933 A number of optional fields may be specified:
937 @item @code{port} (default: @code{22})
938 Port number of SSH server on the machine.
940 @item @code{private-key} (default: @file{~/.ssh/id_rsa})
941 The SSH private key file to use when connecting to the machine, in
944 @item @code{compression} (default: @code{"zlib@@openssh.com,zlib"})
945 @itemx @code{compression-level} (default: @code{3})
946 The SSH-level compression methods and compression level requested.
948 Note that offloading relies on SSH compression to reduce bandwidth usage
949 when transferring files to and from build machines.
951 @item @code{daemon-socket} (default: @code{"/var/guix/daemon-socket/socket"})
952 File name of the Unix-domain socket @command{guix-daemon} is listening
955 @item @code{parallel-builds} (default: @code{1})
956 The number of builds that may run in parallel on the machine.
958 @item @code{speed} (default: @code{1.0})
959 A ``relative speed factor''. The offload scheduler will tend to prefer
960 machines with a higher speed factor.
962 @item @code{features} (default: @code{'()})
963 A list of strings denoting specific features supported by the machine.
964 An example is @code{"kvm"} for machines that have the KVM Linux modules
965 and corresponding hardware support. Derivations can request features by
966 name, and they will be scheduled on matching build machines.
971 The @code{guile} command must be in the search path on the build
972 machines. In addition, the Guix modules must be in
973 @code{$GUILE_LOAD_PATH} on the build machine---you can check whether
974 this is the case by running:
977 ssh build-machine guile -c "'(use-modules (guix config))'"
980 There is one last thing to do once @file{machines.scm} is in place. As
981 explained above, when offloading, files are transferred back and forth
982 between the machine stores. For this to work, you first need to
983 generate a key pair on each machine to allow the daemon to export signed
984 archives of files from the store (@pxref{Invoking guix archive}):
987 # guix archive --generate-key
991 Each build machine must authorize the key of the master machine so that
992 it accepts store items it receives from the master:
995 # guix archive --authorize < master-public-key.txt
999 Likewise, the master machine must authorize the key of each build machine.
1001 All the fuss with keys is here to express pairwise mutual trust
1002 relations between the master and the build machines. Concretely, when
1003 the master receives files from a build machine (and @i{vice versa}), its
1004 build daemon can make sure they are genuine, have not been tampered
1005 with, and that they are signed by an authorized key.
1007 @cindex offload test
1008 To test whether your setup is operational, run this command on the
1015 This will attempt to connect to each of the build machines specified in
1016 @file{/etc/guix/machines.scm}, make sure Guile and the Guix modules are
1017 available on each machine, attempt to export to the machine and import
1018 from it, and report any error in the process.
1020 If you want to test a different machine file, just specify it on the
1024 # guix offload test machines-qualif.scm
1027 Last, you can test the subset of the machines whose name matches a
1028 regular expression like this:
1031 # guix offload test machines.scm '\.gnu\.org$'
1034 @node Invoking guix-daemon
1035 @section Invoking @command{guix-daemon}
1037 The @command{guix-daemon} program implements all the functionality to
1038 access the store. This includes launching build processes, running the
1039 garbage collector, querying the availability of a build result, etc. It
1040 is normally run as @code{root} like this:
1043 # guix-daemon --build-users-group=guixbuild
1047 For details on how to set it up, @pxref{Setting Up the Daemon}.
1050 @cindex container, build environment
1051 @cindex build environment
1052 @cindex reproducible builds
1053 By default, @command{guix-daemon} launches build processes under
1054 different UIDs, taken from the build group specified with
1055 @code{--build-users-group}. In addition, each build process is run in a
1056 chroot environment that only contains the subset of the store that the
1057 build process depends on, as specified by its derivation
1058 (@pxref{Programming Interface, derivation}), plus a set of specific
1059 system directories. By default, the latter contains @file{/dev} and
1060 @file{/dev/pts}. Furthermore, on GNU/Linux, the build environment is a
1061 @dfn{container}: in addition to having its own file system tree, it has
1062 a separate mount name space, its own PID name space, network name space,
1063 etc. This helps achieve reproducible builds (@pxref{Features}).
1065 When the daemon performs a build on behalf of the user, it creates a
1066 build directory under @file{/tmp} or under the directory specified by
1067 its @code{TMPDIR} environment variable; this directory is shared with
1068 the container for the duration of the build. Be aware that using a
1069 directory other than @file{/tmp} can affect build results---for example,
1070 with a longer directory name, a build process that uses Unix-domain
1071 sockets might hit the name length limitation for @code{sun_path}, which
1072 it would otherwise not hit.
1074 The build directory is automatically deleted upon completion, unless the
1075 build failed and the client specified @option{--keep-failed}
1076 (@pxref{Invoking guix build, @option{--keep-failed}}).
1078 The following command-line options are supported:
1081 @item --build-users-group=@var{group}
1082 Take users from @var{group} to run build processes (@pxref{Setting Up
1083 the Daemon, build users}).
1085 @item --no-substitutes
1087 Do not use substitutes for build products. That is, always build things
1088 locally instead of allowing downloads of pre-built binaries
1089 (@pxref{Substitutes}).
1091 By default substitutes are used, unless the client---such as the
1092 @command{guix package} command---is explicitly invoked with
1093 @code{--no-substitutes}.
1095 When the daemon runs with @code{--no-substitutes}, clients can still
1096 explicitly enable substitution @i{via} the @code{set-build-options}
1097 remote procedure call (@pxref{The Store}).
1099 @item --substitute-urls=@var{urls}
1100 @anchor{daemon-substitute-urls}
1101 Consider @var{urls} the default whitespace-separated list of substitute
1102 source URLs. When this option is omitted,
1103 @indicateurl{https://mirror.hydra.gnu.org https://hydra.gnu.org} is used
1104 (@code{mirror.hydra.gnu.org} is a mirror of @code{hydra.gnu.org}).
1106 This means that substitutes may be downloaded from @var{urls}, as long
1107 as they are signed by a trusted signature (@pxref{Substitutes}).
1110 @item --no-build-hook
1111 Do not use the @dfn{build hook}.
1113 The build hook is a helper program that the daemon can start and to
1114 which it submits build requests. This mechanism is used to offload
1115 builds to other machines (@pxref{Daemon Offload Setup}).
1117 @item --cache-failures
1118 Cache build failures. By default, only successful builds are cached.
1120 When this option is used, @command{guix gc --list-failures} can be used
1121 to query the set of store items marked as failed; @command{guix gc
1122 --clear-failures} removes store items from the set of cached failures.
1123 @xref{Invoking guix gc}.
1125 @item --cores=@var{n}
1127 Use @var{n} CPU cores to build each derivation; @code{0} means as many
1130 The default value is @code{0}, but it may be overridden by clients, such
1131 as the @code{--cores} option of @command{guix build} (@pxref{Invoking
1134 The effect is to define the @code{NIX_BUILD_CORES} environment variable
1135 in the build process, which can then use it to exploit internal
1136 parallelism---for instance, by running @code{make -j$NIX_BUILD_CORES}.
1138 @item --max-jobs=@var{n}
1140 Allow at most @var{n} build jobs in parallel. The default value is
1141 @code{1}. Setting it to @code{0} means that no builds will be performed
1142 locally; instead, the daemon will offload builds (@pxref{Daemon Offload
1143 Setup}), or simply fail.
1145 @item --rounds=@var{N}
1146 Build each derivation @var{n} times in a row, and raise an error if
1147 consecutive build results are not bit-for-bit identical. Note that this
1148 setting can be overridden by clients such as @command{guix build}
1149 (@pxref{Invoking guix build}).
1151 When used in conjunction with @option{--keep-failed}, the differing
1152 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
1153 This makes it easy to look for differences between the two results.
1156 Produce debugging output.
1158 This is useful to debug daemon start-up issues, but then it may be
1159 overridden by clients, for example the @code{--verbosity} option of
1160 @command{guix build} (@pxref{Invoking guix build}).
1162 @item --chroot-directory=@var{dir}
1163 Add @var{dir} to the build chroot.
1165 Doing this may change the result of build processes---for instance if
1166 they use optional dependencies found in @var{dir} when it is available,
1167 and not otherwise. For that reason, it is not recommended to do so.
1168 Instead, make sure that each derivation declares all the inputs that it
1171 @item --disable-chroot
1172 Disable chroot builds.
1174 Using this option is not recommended since, again, it would allow build
1175 processes to gain access to undeclared dependencies. It is necessary,
1176 though, when @command{guix-daemon} is running under an unprivileged user
1179 @item --disable-log-compression
1180 Disable compression of the build logs.
1182 Unless @code{--lose-logs} is used, all the build logs are kept in the
1183 @var{localstatedir}. To save space, the daemon automatically compresses
1184 them with bzip2 by default. This option disables that.
1186 @item --disable-deduplication
1187 @cindex deduplication
1188 Disable automatic file ``deduplication'' in the store.
1190 By default, files added to the store are automatically ``deduplicated'':
1191 if a newly added file is identical to another one found in the store,
1192 the daemon makes the new file a hard link to the other file. This can
1193 noticeably reduce disk usage, at the expense of slightly increased
1194 input/output load at the end of a build process. This option disables
1197 @item --gc-keep-outputs[=yes|no]
1198 Tell whether the garbage collector (GC) must keep outputs of live
1201 When set to ``yes'', the GC will keep the outputs of any live derivation
1202 available in the store---the @code{.drv} files. The default is ``no'',
1203 meaning that derivation outputs are kept only if they are GC roots.
1205 @item --gc-keep-derivations[=yes|no]
1206 Tell whether the garbage collector (GC) must keep derivations
1207 corresponding to live outputs.
1209 When set to ``yes'', as is the case by default, the GC keeps
1210 derivations---i.e., @code{.drv} files---as long as at least one of their
1211 outputs is live. This allows users to keep track of the origins of
1212 items in their store. Setting it to ``no'' saves a bit of disk space.
1214 Note that when both @code{--gc-keep-derivations} and
1215 @code{--gc-keep-outputs} are used, the effect is to keep all the build
1216 prerequisites (the sources, compiler, libraries, and other build-time
1217 tools) of live objects in the store, regardless of whether these
1218 prerequisites are live. This is convenient for developers since it
1219 saves rebuilds or downloads.
1221 @item --impersonate-linux-2.6
1222 On Linux-based systems, impersonate Linux 2.6. This means that the
1223 kernel's @code{uname} system call will report 2.6 as the release number.
1225 This might be helpful to build programs that (usually wrongfully) depend
1226 on the kernel version number.
1229 Do not keep build logs. By default they are kept under
1230 @code{@var{localstatedir}/guix/log}.
1232 @item --system=@var{system}
1233 Assume @var{system} as the current system type. By default it is the
1234 architecture/kernel pair found at configure time, such as
1235 @code{x86_64-linux}.
1237 @item --listen=@var{socket}
1238 Listen for connections on @var{socket}, the file name of a Unix-domain
1239 socket. The default socket is
1240 @file{@var{localstatedir}/daemon-socket/socket}. This option is only
1241 useful in exceptional circumstances, such as if you need to run several
1242 daemons on the same machine.
1246 @node Application Setup
1247 @section Application Setup
1249 @cindex foreign distro
1250 When using Guix on top of GNU/Linux distribution other than GuixSD---a
1251 so-called @dfn{foreign distro}---a few additional steps are needed to
1252 get everything in place. Here are some of them.
1256 @anchor{locales-and-locpath}
1257 @cindex locales, when not on GuixSD
1259 @vindex GUIX_LOCPATH
1260 Packages installed @i{via} Guix will not use the locale data of the
1261 host system. Instead, you must first install one of the locale packages
1262 available with Guix and then define the @code{GUIX_LOCPATH} environment
1266 $ guix package -i glibc-locales
1267 $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
1270 Note that the @code{glibc-locales} package contains data for all the
1271 locales supported by the GNU@tie{}libc and weighs in at around
1272 110@tie{}MiB. Alternatively, the @code{glibc-utf8-locales} is smaller but
1273 limited to a few UTF-8 locales.
1275 The @code{GUIX_LOCPATH} variable plays a role similar to @code{LOCPATH}
1276 (@pxref{Locale Names, @code{LOCPATH},, libc, The GNU C Library Reference
1277 Manual}). There are two important differences though:
1281 @code{GUIX_LOCPATH} is honored only by the libc in Guix, and not by the libc
1282 provided by foreign distros. Thus, using @code{GUIX_LOCPATH} allows you
1283 to make sure the programs of the foreign distro will not end up loading
1284 incompatible locale data.
1287 libc suffixes each entry of @code{GUIX_LOCPATH} with @code{/X.Y}, where
1288 @code{X.Y} is the libc version---e.g., @code{2.22}. This means that,
1289 should your Guix profile contain a mixture of programs linked against
1290 different libc version, each libc version will only try to load locale
1291 data in the right format.
1294 This is important because the locale data format used by different libc
1295 versions may be incompatible.
1297 @subsection Name Service Switch
1299 @cindex name service switch, glibc
1300 @cindex NSS (name service switch), glibc
1301 @cindex nscd (name service caching daemon)
1302 @cindex name service caching daemon (nscd)
1303 When using Guix on a foreign distro, we @emph{strongly recommend} that
1304 the system run the GNU C library's @dfn{name service cache daemon},
1305 @command{nscd}, which should be listening on the
1306 @file{/var/run/nscd/socket} socket. Failing to do that, applications
1307 installed with Guix may fail to look up host names or user accounts, or
1308 may even crash. The next paragraphs explain why.
1310 @cindex @file{nsswitch.conf}
1311 The GNU C library implements a @dfn{name service switch} (NSS), which is
1312 an extensible mechanism for ``name lookups'' in general: host name
1313 resolution, user accounts, and more (@pxref{Name Service Switch,,, libc,
1314 The GNU C Library Reference Manual}).
1316 @cindex Network information service (NIS)
1317 @cindex NIS (Network information service)
1318 Being extensible, the NSS supports @dfn{plugins}, which provide new name
1319 lookup implementations: for example, the @code{nss-mdns} plugin allow
1320 resolution of @code{.local} host names, the @code{nis} plugin allows
1321 user account lookup using the Network information service (NIS), and so
1322 on. These extra ``lookup services'' are configured system-wide in
1323 @file{/etc/nsswitch.conf}, and all the programs running on the system
1324 honor those settings (@pxref{NSS Configuration File,,, libc, The GNU C
1327 When they perform a name lookup---for instance by calling the
1328 @code{getaddrinfo} function in C---applications first try to connect to
1329 the nscd; on success, nscd performs name lookups on their behalf. If
1330 the nscd is not running, then they perform the name lookup by
1331 themselves, by loading the name lookup services into their own address
1332 space and running it. These name lookup services---the
1333 @file{libnss_*.so} files---are @code{dlopen}'d, but they may come from
1334 the host system's C library, rather than from the C library the
1335 application is linked against (the C library coming from Guix).
1337 And this is where the problem is: if your application is linked against
1338 Guix's C library (say, glibc 2.24) and tries to load NSS plugins from
1339 another C library (say, @code{libnss_mdns.so} for glibc 2.22), it will
1340 likely crash or have its name lookups fail unexpectedly.
1342 Running @command{nscd} on the system, among other advantages, eliminates
1343 this binary incompatibility problem because those @code{libnss_*.so}
1344 files are loaded in the @command{nscd} process, not in applications
1347 @subsection X11 Fonts
1350 The majority of graphical applications use Fontconfig to locate and
1351 load fonts and perform X11-client-side rendering. The @code{fontconfig}
1352 package in Guix looks for fonts in @file{$HOME/.guix-profile}
1353 by default. Thus, to allow graphical applications installed with Guix
1354 to display fonts, you have to install fonts with Guix as well.
1355 Essential font packages include @code{gs-fonts}, @code{font-dejavu}, and
1356 @code{font-gnu-freefont-ttf}.
1358 To display text written in Chinese languages, Japanese, or Korean in
1359 graphical applications, consider installing
1360 @code{font-adobe-source-han-sans} or @code{font-wqy-zenhei}. The former
1361 has multiple outputs, one per language family (@pxref{Packages with
1362 Multiple Outputs}). For instance, the following command installs fonts
1363 for Chinese languages:
1366 guix package -i font-adobe-source-han-sans:cn
1369 @cindex @code{xterm}
1370 Older programs such as @command{xterm} do not use Fontconfig and instead
1371 rely on server-side font rendering. Such programs require to specify a
1372 full name of a font using XLFD (X Logical Font Description), like this:
1375 -*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
1378 To be able to use such full names for the TrueType fonts installed in
1379 your Guix profile, you need to extend the font path of the X server:
1382 xset +fp ~/.guix-profile/share/fonts/truetype
1385 @cindex @code{xlsfonts}
1386 After that, you can run @code{xlsfonts} (from @code{xlsfonts} package)
1387 to make sure your TrueType fonts are listed there.
1389 @subsection X.509 Certificates
1391 @cindex @code{nss-certs}
1392 The @code{nss-certs} package provides X.509 certificates, which allow
1393 programs to authenticate Web servers accessed over HTTPS.
1395 When using Guix on a foreign distro, you can install this package and
1396 define the relevant environment variables so that packages know where to
1397 look for certificates. @xref{X.509 Certificates}, for detailed
1400 @subsection Emacs Packages
1402 @cindex @code{emacs}
1403 When you install Emacs packages with Guix, the elisp files may be placed
1404 either in @file{$HOME/.guix-profile/share/emacs/site-lisp/} or in
1406 @file{$HOME/.guix-profile/share/emacs/site-lisp/guix.d/}. The latter
1407 directory exists because potentially there may exist thousands of Emacs
1408 packages and storing all their files in a single directory may be not
1409 reliable (because of name conflicts). So we think using a separate
1410 directory for each package is a good idea. It is very similar to how
1411 the Emacs package system organizes the file structure (@pxref{Package
1412 Files,,, emacs, The GNU Emacs Manual}).
1414 By default, Emacs (installed with Guix) ``knows'' where these packages
1415 are placed, so you do not need to perform any configuration. If, for
1416 some reason, you want to avoid auto-loading Emacs packages installed
1417 with Guix, you can do so by running Emacs with @code{--no-site-file}
1418 option (@pxref{Init File,,, emacs, The GNU Emacs Manual}).
1422 @c *********************************************************************
1423 @node Package Management
1424 @chapter Package Management
1427 The purpose of GNU Guix is to allow users to easily install, upgrade, and
1428 remove software packages, without having to know about their build
1429 procedures or dependencies. Guix also goes beyond this obvious set of
1432 This chapter describes the main features of Guix, as well as the package
1433 management tools it provides. Along with the command-line interface
1434 described below (@pxref{Invoking guix package, @code{guix package}}),
1435 you may also use Emacs Interface, after installing @code{emacs-guix}
1436 package (run @kbd{M-x guix-help} command to start with it):
1439 guix package -i emacs-guix
1443 * Features:: How Guix will make your life brighter.
1444 * Invoking guix package:: Package installation, removal, etc.
1445 * Substitutes:: Downloading pre-built binaries.
1446 * Packages with Multiple Outputs:: Single source package, multiple outputs.
1447 * Invoking guix gc:: Running the garbage collector.
1448 * Invoking guix pull:: Fetching the latest Guix and distribution.
1449 * Invoking guix pack:: Creating software bundles.
1450 * Invoking guix archive:: Exporting and importing store files.
1456 When using Guix, each package ends up in the @dfn{package store}, in its
1457 own directory---something that resembles
1458 @file{/gnu/store/xxx-package-1.2}, where @code{xxx} is a base32 string.
1460 Instead of referring to these directories, users have their own
1461 @dfn{profile}, which points to the packages that they actually want to
1462 use. These profiles are stored within each user's home directory, at
1463 @code{$HOME/.guix-profile}.
1465 For example, @code{alice} installs GCC 4.7.2. As a result,
1466 @file{/home/alice/.guix-profile/bin/gcc} points to
1467 @file{/gnu/store/@dots{}-gcc-4.7.2/bin/gcc}. Now, on the same machine,
1468 @code{bob} had already installed GCC 4.8.0. The profile of @code{bob}
1469 simply continues to point to
1470 @file{/gnu/store/@dots{}-gcc-4.8.0/bin/gcc}---i.e., both versions of GCC
1471 coexist on the same system without any interference.
1473 The @command{guix package} command is the central tool to manage
1474 packages (@pxref{Invoking guix package}). It operates on the per-user
1475 profiles, and can be used @emph{with normal user privileges}.
1477 @cindex transactions
1478 The command provides the obvious install, remove, and upgrade
1479 operations. Each invocation is actually a @emph{transaction}: either
1480 the specified operation succeeds, or nothing happens. Thus, if the
1481 @command{guix package} process is terminated during the transaction,
1482 or if a power outage occurs during the transaction, then the user's
1483 profile remains in its previous state, and remains usable.
1485 In addition, any package transaction may be @emph{rolled back}. So, if,
1486 for example, an upgrade installs a new version of a package that turns
1487 out to have a serious bug, users may roll back to the previous instance
1488 of their profile, which was known to work well. Similarly, the global
1489 system configuration on GuixSD is subject to
1490 transactional upgrades and roll-back
1491 (@pxref{Using the Configuration System}).
1493 All packages in the package store may be @emph{garbage-collected}.
1494 Guix can determine which packages are still referenced by user
1495 profiles, and remove those that are provably no longer referenced
1496 (@pxref{Invoking guix gc}). Users may also explicitly remove old
1497 generations of their profile so that the packages they refer to can be
1500 @cindex reproducibility
1501 @cindex reproducible builds
1502 Finally, Guix takes a @dfn{purely functional} approach to package
1503 management, as described in the introduction (@pxref{Introduction}).
1504 Each @file{/gnu/store} package directory name contains a hash of all the
1505 inputs that were used to build that package---compiler, libraries, build
1506 scripts, etc. This direct correspondence allows users to make sure a
1507 given package installation matches the current state of their
1508 distribution. It also helps maximize @dfn{build reproducibility}:
1509 thanks to the isolated build environments that are used, a given build
1510 is likely to yield bit-identical files when performed on different
1511 machines (@pxref{Invoking guix-daemon, container}).
1514 This foundation allows Guix to support @dfn{transparent binary/source
1515 deployment}. When a pre-built binary for a @file{/gnu/store} item is
1516 available from an external source---a @dfn{substitute}, Guix just
1517 downloads it and unpacks it;
1518 otherwise, it builds the package from source, locally
1519 (@pxref{Substitutes}). Because build results are usually bit-for-bit
1520 reproducible, users do not have to trust servers that provide
1521 substitutes: they can force a local build and @emph{challenge} providers
1522 (@pxref{Invoking guix challenge}).
1524 Control over the build environment is a feature that is also useful for
1525 developers. The @command{guix environment} command allows developers of
1526 a package to quickly set up the right development environment for their
1527 package, without having to manually install the dependencies of the
1528 package into their profile (@pxref{Invoking guix environment}).
1530 @node Invoking guix package
1531 @section Invoking @command{guix package}
1533 @cindex installing packages
1534 @cindex removing packages
1535 @cindex package installation
1536 @cindex package removal
1537 The @command{guix package} command is the tool that allows users to
1538 install, upgrade, and remove packages, as well as rolling back to
1539 previous configurations. It operates only on the user's own profile,
1540 and works with normal user privileges (@pxref{Features}). Its syntax
1544 guix package @var{options}
1546 @cindex transactions
1547 Primarily, @var{options} specifies the operations to be performed during
1548 the transaction. Upon completion, a new profile is created, but
1549 previous @dfn{generations} of the profile remain available, should the user
1552 For example, to remove @code{lua} and install @code{guile} and
1553 @code{guile-cairo} in a single transaction:
1556 guix package -r lua -i guile guile-cairo
1559 @command{guix package} also supports a @dfn{declarative approach}
1560 whereby the user specifies the exact set of packages to be available and
1561 passes it @i{via} the @option{--manifest} option
1562 (@pxref{profile-manifest, @option{--manifest}}).
1565 For each user, a symlink to the user's default profile is automatically
1566 created in @file{$HOME/.guix-profile}. This symlink always points to the
1567 current generation of the user's default profile. Thus, users can add
1568 @file{$HOME/.guix-profile/bin} to their @code{PATH} environment
1569 variable, and so on.
1570 @cindex search paths
1571 If you are not using the Guix System Distribution, consider adding the
1572 following lines to your @file{~/.bash_profile} (@pxref{Bash Startup
1573 Files,,, bash, The GNU Bash Reference Manual}) so that newly-spawned
1574 shells get all the right environment variable definitions:
1577 GUIX_PROFILE="$HOME/.guix-profile" \
1578 source "$HOME/.guix-profile/etc/profile"
1581 In a multi-user setup, user profiles are stored in a place registered as
1582 a @dfn{garbage-collector root}, which @file{$HOME/.guix-profile} points
1583 to (@pxref{Invoking guix gc}). That directory is normally
1584 @code{@var{localstatedir}/profiles/per-user/@var{user}}, where
1585 @var{localstatedir} is the value passed to @code{configure} as
1586 @code{--localstatedir}, and @var{user} is the user name. The
1587 @file{per-user} directory is created when @command{guix-daemon} is
1588 started, and the @var{user} sub-directory is created by @command{guix
1591 The @var{options} can be among the following:
1595 @item --install=@var{package} @dots{}
1596 @itemx -i @var{package} @dots{}
1597 Install the specified @var{package}s.
1599 Each @var{package} may specify either a simple package name, such as
1600 @code{guile}, or a package name followed by an at-sign and version number,
1601 such as @code{guile@@1.8.8} or simply @code{guile@@1.8} (in the latter
1602 case, the newest version prefixed by @code{1.8} is selected.)
1604 If no version number is specified, the
1605 newest available version will be selected. In addition, @var{package}
1606 may contain a colon, followed by the name of one of the outputs of the
1607 package, as in @code{gcc:doc} or @code{binutils@@2.22:lib}
1608 (@pxref{Packages with Multiple Outputs}). Packages with a corresponding
1609 name (and optionally version) are searched for among the GNU
1610 distribution modules (@pxref{Package Modules}).
1612 @cindex propagated inputs
1613 Sometimes packages have @dfn{propagated inputs}: these are dependencies
1614 that automatically get installed along with the required package
1615 (@pxref{package-propagated-inputs, @code{propagated-inputs} in
1616 @code{package} objects}, for information about propagated inputs in
1617 package definitions).
1619 @anchor{package-cmd-propagated-inputs}
1620 An example is the GNU MPC library: its C header files refer to those of
1621 the GNU MPFR library, which in turn refer to those of the GMP library.
1622 Thus, when installing MPC, the MPFR and GMP libraries also get installed
1623 in the profile; removing MPC also removes MPFR and GMP---unless they had
1624 also been explicitly installed by the user.
1626 Besides, packages sometimes rely on the definition of environment
1627 variables for their search paths (see explanation of
1628 @code{--search-paths} below). Any missing or possibly incorrect
1629 environment variable definitions are reported here.
1631 @item --install-from-expression=@var{exp}
1633 Install the package @var{exp} evaluates to.
1635 @var{exp} must be a Scheme expression that evaluates to a
1636 @code{<package>} object. This option is notably useful to disambiguate
1637 between same-named variants of a package, with expressions such as
1638 @code{(@@ (gnu packages base) guile-final)}.
1640 Note that this option installs the first output of the specified
1641 package, which may be insufficient when needing a specific output of a
1642 multiple-output package.
1644 @item --install-from-file=@var{file}
1645 @itemx -f @var{file}
1646 Install the package that the code within @var{file} evaluates to.
1648 As an example, @var{file} might contain a definition like this
1649 (@pxref{Defining Packages}):
1652 @verbatiminclude package-hello.scm
1655 Developers may find it useful to include such a @file{guix.scm} file
1656 in the root of their project source tree that can be used to test
1657 development snapshots and create reproducible development environments
1658 (@pxref{Invoking guix environment}).
1660 @item --remove=@var{package} @dots{}
1661 @itemx -r @var{package} @dots{}
1662 Remove the specified @var{package}s.
1664 As for @code{--install}, each @var{package} may specify a version number
1665 and/or output name in addition to the package name. For instance,
1666 @code{-r glibc:debug} would remove the @code{debug} output of
1669 @item --upgrade[=@var{regexp} @dots{}]
1670 @itemx -u [@var{regexp} @dots{}]
1671 @cindex upgrading packages
1672 Upgrade all the installed packages. If one or more @var{regexp}s are
1673 specified, upgrade only installed packages whose name matches a
1674 @var{regexp}. Also see the @code{--do-not-upgrade} option below.
1676 Note that this upgrades package to the latest version of packages found
1677 in the distribution currently installed. To update your distribution,
1678 you should regularly run @command{guix pull} (@pxref{Invoking guix
1681 @item --do-not-upgrade[=@var{regexp} @dots{}]
1682 When used together with the @code{--upgrade} option, do @emph{not}
1683 upgrade any packages whose name matches a @var{regexp}. For example, to
1684 upgrade all packages in the current profile except those containing the
1685 substring ``emacs'':
1688 $ guix package --upgrade . --do-not-upgrade emacs
1691 @item @anchor{profile-manifest}--manifest=@var{file}
1692 @itemx -m @var{file}
1693 @cindex profile declaration
1694 @cindex profile manifest
1695 Create a new generation of the profile from the manifest object
1696 returned by the Scheme code in @var{file}.
1698 This allows you to @emph{declare} the profile's contents rather than
1699 constructing it through a sequence of @code{--install} and similar
1700 commands. The advantage is that @var{file} can be put under version
1701 control, copied to different machines to reproduce the same profile, and
1704 @c FIXME: Add reference to (guix profile) documentation when available.
1705 @var{file} must return a @dfn{manifest} object, which is roughly a list
1708 @findex packages->manifest
1710 (use-package-modules guile emacs)
1715 ;; Use a specific package output.
1716 (list guile-2.0 "debug")))
1719 @findex specification->package+output
1720 In this example we have to know which modules define the @code{emacs}
1721 and @code{guile-2.0} variables to provide the right
1722 @code{use-package-modules} line, which can be cumbersome. We can
1723 instead provide regular package specifications and let
1724 @code{specification->package-output} look up the corresponding package
1729 (map (compose list specification->package+output)
1730 '("emacs" "guile@@2.0" "guile@@2.0:debug")))
1734 @cindex rolling back
1735 @cindex undoing transactions
1736 @cindex transactions, undoing
1737 Roll back to the previous @dfn{generation} of the profile---i.e., undo
1738 the last transaction.
1740 When combined with options such as @code{--install}, roll back occurs
1741 before any other actions.
1743 When rolling back from the first generation that actually contains
1744 installed packages, the profile is made to point to the @dfn{zeroth
1745 generation}, which contains no files apart from its own metadata.
1747 After having rolled back, installing, removing, or upgrading packages
1748 overwrites previous future generations. Thus, the history of the
1749 generations in a profile is always linear.
1751 @item --switch-generation=@var{pattern}
1752 @itemx -S @var{pattern}
1754 Switch to a particular generation defined by @var{pattern}.
1756 @var{pattern} may be either a generation number or a number prefixed
1757 with ``+'' or ``-''. The latter means: move forward/backward by a
1758 specified number of generations. For example, if you want to return to
1759 the latest generation after @code{--roll-back}, use
1760 @code{--switch-generation=+1}.
1762 The difference between @code{--roll-back} and
1763 @code{--switch-generation=-1} is that @code{--switch-generation} will
1764 not make a zeroth generation, so if a specified generation does not
1765 exist, the current generation will not be changed.
1767 @item --search-paths[=@var{kind}]
1768 @cindex search paths
1769 Report environment variable definitions, in Bash syntax, that may be
1770 needed in order to use the set of installed packages. These environment
1771 variables are used to specify @dfn{search paths} for files used by some
1772 of the installed packages.
1774 For example, GCC needs the @code{CPATH} and @code{LIBRARY_PATH}
1775 environment variables to be defined so it can look for headers and
1776 libraries in the user's profile (@pxref{Environment Variables,,, gcc,
1777 Using the GNU Compiler Collection (GCC)}). If GCC and, say, the C
1778 library are installed in the profile, then @code{--search-paths} will
1779 suggest setting these variables to @code{@var{profile}/include} and
1780 @code{@var{profile}/lib}, respectively.
1782 The typical use case is to define these environment variables in the
1786 $ eval `guix package --search-paths`
1789 @var{kind} may be one of @code{exact}, @code{prefix}, or @code{suffix},
1790 meaning that the returned environment variable definitions will either
1791 be exact settings, or prefixes or suffixes of the current value of these
1792 variables. When omitted, @var{kind} defaults to @code{exact}.
1794 This option can also be used to compute the @emph{combined} search paths
1795 of several profiles. Consider this example:
1798 $ guix package -p foo -i guile
1799 $ guix package -p bar -i guile-json
1800 $ guix package -p foo -p bar --search-paths
1803 The last command above reports about the @code{GUILE_LOAD_PATH}
1804 variable, even though, taken individually, neither @file{foo} nor
1805 @file{bar} would lead to that recommendation.
1808 @item --profile=@var{profile}
1809 @itemx -p @var{profile}
1810 Use @var{profile} instead of the user's default profile.
1813 Produce verbose output. In particular, emit the build log of the
1814 environment on the standard error port.
1817 Use the bootstrap Guile to build the profile. This option is only
1818 useful to distribution developers.
1822 In addition to these actions, @command{guix package} supports the
1823 following options to query the current state of a profile, or the
1824 availability of packages:
1828 @item --search=@var{regexp}
1829 @itemx -s @var{regexp}
1830 @cindex searching for packages
1831 List the available packages whose name, synopsis, or description matches
1832 @var{regexp}. Print all the metadata of matching packages in
1833 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils,
1834 GNU recutils manual}).
1836 This allows specific fields to be extracted using the @command{recsel}
1837 command, for instance:
1840 $ guix package -s malloc | recsel -p name,version
1848 Similarly, to show the name of all the packages available under the
1849 terms of the GNU@tie{}LGPL version 3:
1852 $ guix package -s "" | recsel -p name -e 'license ~ "LGPL 3"'
1859 It is also possible to refine search results using several @code{-s}
1860 flags. For example, the following command returns a list of board
1864 $ guix package -s '\<board\>' -s game | recsel -p name
1869 If we were to omit @code{-s game}, we would also get software packages
1870 that deal with printed circuit boards; removing the angle brackets
1871 around @code{board} would further add packages that have to do with
1874 And now for a more elaborate example. The following command searches
1875 for cryptographic libraries, filters out Haskell, Perl, Python, and Ruby
1876 libraries, and prints the name and synopsis of the matching packages:
1879 $ guix package -s crypto -s library | \
1880 recsel -e '! (name ~ "^(ghc|perl|python|ruby)")' -p name,synopsis
1884 @xref{Selection Expressions,,, recutils, GNU recutils manual}, for more
1885 information on @dfn{selection expressions} for @code{recsel -e}.
1887 @item --show=@var{package}
1888 Show details about @var{package}, taken from the list of available packages, in
1889 @code{recutils} format (@pxref{Top, GNU recutils databases,, recutils, GNU
1893 $ guix package --show=python | recsel -p name,version
1901 You may also specify the full name of a package to only get details about a
1902 specific version of it:
1904 $ guix package --show=python@@3.4 | recsel -p name,version
1911 @item --list-installed[=@var{regexp}]
1912 @itemx -I [@var{regexp}]
1913 List the currently installed packages in the specified profile, with the
1914 most recently installed packages shown last. When @var{regexp} is
1915 specified, list only installed packages whose name matches @var{regexp}.
1917 For each installed package, print the following items, separated by
1918 tabs: the package name, its version string, the part of the package that
1919 is installed (for instance, @code{out} for the default output,
1920 @code{include} for its headers, etc.), and the path of this package in
1923 @item --list-available[=@var{regexp}]
1924 @itemx -A [@var{regexp}]
1925 List packages currently available in the distribution for this system
1926 (@pxref{GNU Distribution}). When @var{regexp} is specified, list only
1927 installed packages whose name matches @var{regexp}.
1929 For each package, print the following items separated by tabs: its name,
1930 its version string, the parts of the package (@pxref{Packages with
1931 Multiple Outputs}), and the source location of its definition.
1933 @item --list-generations[=@var{pattern}]
1934 @itemx -l [@var{pattern}]
1936 Return a list of generations along with their creation dates; for each
1937 generation, show the installed packages, with the most recently
1938 installed packages shown last. Note that the zeroth generation is never
1941 For each installed package, print the following items, separated by
1942 tabs: the name of a package, its version string, the part of the package
1943 that is installed (@pxref{Packages with Multiple Outputs}), and the
1944 location of this package in the store.
1946 When @var{pattern} is used, the command returns only matching
1947 generations. Valid patterns include:
1950 @item @emph{Integers and comma-separated integers}. Both patterns denote
1951 generation numbers. For instance, @code{--list-generations=1} returns
1954 And @code{--list-generations=1,8,2} outputs three generations in the
1955 specified order. Neither spaces nor trailing commas are allowed.
1957 @item @emph{Ranges}. @code{--list-generations=2..9} prints the
1958 specified generations and everything in between. Note that the start of
1959 a range must be smaller than its end.
1961 It is also possible to omit the endpoint. For example,
1962 @code{--list-generations=2..}, returns all generations starting from the
1965 @item @emph{Durations}. You can also get the last @emph{N}@tie{}days, weeks,
1966 or months by passing an integer along with the first letter of the
1967 duration. For example, @code{--list-generations=20d} lists generations
1968 that are up to 20 days old.
1971 @item --delete-generations[=@var{pattern}]
1972 @itemx -d [@var{pattern}]
1973 When @var{pattern} is omitted, delete all generations except the current
1976 This command accepts the same patterns as @option{--list-generations}.
1977 When @var{pattern} is specified, delete the matching generations. When
1978 @var{pattern} specifies a duration, generations @emph{older} than the
1979 specified duration match. For instance, @code{--delete-generations=1m}
1980 deletes generations that are more than one month old.
1982 If the current generation matches, it is @emph{not} deleted. Also, the
1983 zeroth generation is never deleted.
1985 Note that deleting generations prevents rolling back to them.
1986 Consequently, this command must be used with care.
1990 Finally, since @command{guix package} may actually start build
1991 processes, it supports all the common build options (@pxref{Common Build
1992 Options}). It also supports package transformation options, such as
1993 @option{--with-source} (@pxref{Package Transformation Options}).
1994 However, note that package transformations are lost when upgrading; to
1995 preserve transformations across upgrades, you should define your own
1996 package variant in a Guile module and add it to @code{GUIX_PACKAGE_PATH}
1997 (@pxref{Defining Packages}).
2001 @section Substitutes
2004 @cindex pre-built binaries
2005 Guix supports transparent source/binary deployment, which means that it
2006 can either build things locally, or download pre-built items from a
2007 server. We call these pre-built items @dfn{substitutes}---they are
2008 substitutes for local build results. In many cases, downloading a
2009 substitute is much faster than building things locally.
2011 Substitutes can be anything resulting from a derivation build
2012 (@pxref{Derivations}). Of course, in the common case, they are
2013 pre-built package binaries, but source tarballs, for instance, which
2014 also result from derivation builds, can be available as substitutes.
2016 The @code{hydra.gnu.org} server is a front-end to a build farm that
2017 builds packages from the GNU distribution continuously for some
2018 architectures, and makes them available as substitutes. This is the
2019 default source of substitutes; it can be overridden by passing the
2020 @option{--substitute-urls} option either to @command{guix-daemon}
2021 (@pxref{daemon-substitute-urls,, @code{guix-daemon --substitute-urls}})
2022 or to client tools such as @command{guix package}
2023 (@pxref{client-substitute-urls,, client @option{--substitute-urls}
2026 Substitute URLs can be either HTTP or HTTPS.
2027 HTTPS is recommended because communications are encrypted; conversely,
2028 using HTTP makes all communications visible to an eavesdropper, who
2029 could use the information gathered to determine, for instance, whether
2030 your system has unpatched security vulnerabilities.
2033 @cindex digital signatures
2034 @cindex substitutes, authorization thereof
2035 To allow Guix to download substitutes from @code{hydra.gnu.org} or a
2037 must add its public key to the access control list (ACL) of archive
2038 imports, using the @command{guix archive} command (@pxref{Invoking guix
2039 archive}). Doing so implies that you trust @code{hydra.gnu.org} to not
2040 be compromised and to serve genuine substitutes.
2042 This public key is installed along with Guix, in
2043 @code{@var{prefix}/share/guix/hydra.gnu.org.pub}, where @var{prefix} is
2044 the installation prefix of Guix. If you installed Guix from source,
2045 make sure you checked the GPG signature of
2046 @file{guix-@value{VERSION}.tar.gz}, which contains this public key file.
2047 Then, you can run something like this:
2050 # guix archive --authorize < hydra.gnu.org.pub
2053 Once this is in place, the output of a command like @code{guix build}
2054 should change from something like:
2057 $ guix build emacs --dry-run
2058 The following derivations would be built:
2059 /gnu/store/yr7bnx8xwcayd6j95r2clmkdl1qh688w-emacs-24.3.drv
2060 /gnu/store/x8qsh1hlhgjx6cwsjyvybnfv2i37z23w-dbus-1.6.4.tar.gz.drv
2061 /gnu/store/1ixwp12fl950d15h2cj11c73733jay0z-alsa-lib-1.0.27.1.tar.bz2.drv
2062 /gnu/store/nlma1pw0p603fpfiqy7kn4zm105r5dmw-util-linux-2.21.drv
2070 $ guix build emacs --dry-run
2071 The following files would be downloaded:
2072 /gnu/store/pk3n22lbq6ydamyymqkkz7i69wiwjiwi-emacs-24.3
2073 /gnu/store/2ygn4ncnhrpr61rssa6z0d9x22si0va3-libjpeg-8d
2074 /gnu/store/71yz6lgx4dazma9dwn2mcjxaah9w77jq-cairo-1.12.16
2075 /gnu/store/7zdhgp0n1518lvfn8mb96sxqfmvqrl7v-libxrender-0.9.7
2080 This indicates that substitutes from @code{hydra.gnu.org} are usable and
2081 will be downloaded, when possible, for future builds.
2083 Guix ignores substitutes that are not signed, or that are not signed by
2084 one of the keys listed in the ACL. It also detects and raises an error
2085 when attempting to use a substitute that has been tampered with.
2088 Substitutes are downloaded over HTTP or HTTPS.
2089 The @code{http_proxy} environment
2090 variable can be set in the environment of @command{guix-daemon} and is
2091 honored for downloads of substitutes. Note that the value of
2092 @code{http_proxy} in the environment where @command{guix build},
2093 @command{guix package}, and other client commands are run has
2094 @emph{absolutely no effect}.
2096 When using HTTPS, the server's X.509 certificate is @emph{not} validated
2097 (in other words, the server is not authenticated), contrary to what
2098 HTTPS clients such as Web browsers usually do. This is because Guix
2099 authenticates substitute information itself, as explained above, which
2100 is what we care about (whereas X.509 certificates are about
2101 authenticating bindings between domain names and public keys.)
2103 The substitute mechanism can be disabled globally by running
2104 @code{guix-daemon} with @code{--no-substitutes} (@pxref{Invoking
2105 guix-daemon}). It can also be disabled temporarily by passing the
2106 @code{--no-substitutes} option to @command{guix package}, @command{guix
2107 build}, and other command-line tools.
2110 @unnumberedsubsec On Trusting Binaries
2112 Today, each individual's control over their own computing is at the
2113 mercy of institutions, corporations, and groups with enough power and
2114 determination to subvert the computing infrastructure and exploit its
2115 weaknesses. While using @code{hydra.gnu.org} substitutes can be
2116 convenient, we encourage users to also build on their own, or even run
2117 their own build farm, such that @code{hydra.gnu.org} is less of an
2118 interesting target. One way to help is by publishing the software you
2119 build using @command{guix publish} so that others have one more choice
2120 of server to download substitutes from (@pxref{Invoking guix publish}).
2122 Guix has the foundations to maximize build reproducibility
2123 (@pxref{Features}). In most cases, independent builds of a given
2124 package or derivation should yield bit-identical results. Thus, through
2125 a diverse set of independent package builds, we can strengthen the
2126 integrity of our systems. The @command{guix challenge} command aims to
2127 help users assess substitute servers, and to assist developers in
2128 finding out about non-deterministic package builds (@pxref{Invoking guix
2129 challenge}). Similarly, the @option{--check} option of @command{guix
2130 build} allows users to check whether previously-installed substitutes
2131 are genuine by rebuilding them locally (@pxref{build-check,
2132 @command{guix build --check}}).
2134 In the future, we want Guix to have support to publish and retrieve
2135 binaries to/from other users, in a peer-to-peer fashion. If you would
2136 like to discuss this project, join us on @email{guix-devel@@gnu.org}.
2139 @node Packages with Multiple Outputs
2140 @section Packages with Multiple Outputs
2142 @cindex multiple-output packages
2143 @cindex package outputs
2146 Often, packages defined in Guix have a single @dfn{output}---i.e., the
2147 source package leads to exactly one directory in the store. When running
2148 @command{guix package -i glibc}, one installs the default output of the
2149 GNU libc package; the default output is called @code{out}, but its name
2150 can be omitted as shown in this command. In this particular case, the
2151 default output of @code{glibc} contains all the C header files, shared
2152 libraries, static libraries, Info documentation, and other supporting
2155 Sometimes it is more appropriate to separate the various types of files
2156 produced from a single source package into separate outputs. For
2157 instance, the GLib C library (used by GTK+ and related packages)
2158 installs more than 20 MiB of reference documentation as HTML pages.
2159 To save space for users who do not need it, the documentation goes to a
2160 separate output, called @code{doc}. To install the main GLib output,
2161 which contains everything but the documentation, one would run:
2164 guix package -i glib
2167 @cindex documentation
2168 The command to install its documentation is:
2171 guix package -i glib:doc
2174 Some packages install programs with different ``dependency footprints''.
2175 For instance, the WordNet package installs both command-line tools and
2176 graphical user interfaces (GUIs). The former depend solely on the C
2177 library, whereas the latter depend on Tcl/Tk and the underlying X
2178 libraries. In this case, we leave the command-line tools in the default
2179 output, whereas the GUIs are in a separate output. This allows users
2180 who do not need the GUIs to save space. The @command{guix size} command
2181 can help find out about such situations (@pxref{Invoking guix size}).
2182 @command{guix graph} can also be helpful (@pxref{Invoking guix graph}).
2184 There are several such multiple-output packages in the GNU distribution.
2185 Other conventional output names include @code{lib} for libraries and
2186 possibly header files, @code{bin} for stand-alone programs, and
2187 @code{debug} for debugging information (@pxref{Installing Debugging
2188 Files}). The outputs of a packages are listed in the third column of
2189 the output of @command{guix package --list-available} (@pxref{Invoking
2193 @node Invoking guix gc
2194 @section Invoking @command{guix gc}
2196 @cindex garbage collector
2198 Packages that are installed, but not used, may be @dfn{garbage-collected}.
2199 The @command{guix gc} command allows users to explicitly run the garbage
2200 collector to reclaim space from the @file{/gnu/store} directory. It is
2201 the @emph{only} way to remove files from @file{/gnu/store}---removing
2202 files or directories manually may break it beyond repair!
2204 The garbage collector has a set of known @dfn{roots}: any file under
2205 @file{/gnu/store} reachable from a root is considered @dfn{live} and
2206 cannot be deleted; any other file is considered @dfn{dead} and may be
2207 deleted. The set of garbage collector roots includes default user
2208 profiles, and may be augmented with @command{guix build --root}, for
2209 example (@pxref{Invoking guix build}).
2211 Prior to running @code{guix gc --collect-garbage} to make space, it is
2212 often useful to remove old generations from user profiles; that way, old
2213 package builds referenced by those generations can be reclaimed. This
2214 is achieved by running @code{guix package --delete-generations}
2215 (@pxref{Invoking guix package}).
2217 The @command{guix gc} command has three modes of operation: it can be
2218 used to garbage-collect any dead files (the default), to delete specific
2219 files (the @code{--delete} option), to print garbage-collector
2220 information, or for more advanced queries. The garbage collection
2221 options are as follows:
2224 @item --collect-garbage[=@var{min}]
2225 @itemx -C [@var{min}]
2226 Collect garbage---i.e., unreachable @file{/gnu/store} files and
2227 sub-directories. This is the default operation when no option is
2230 When @var{min} is given, stop once @var{min} bytes have been collected.
2231 @var{min} may be a number of bytes, or it may include a unit as a
2232 suffix, such as @code{MiB} for mebibytes and @code{GB} for gigabytes
2233 (@pxref{Block size, size specifications,, coreutils, GNU Coreutils}).
2235 When @var{min} is omitted, collect all the garbage.
2237 @item --free-space=@var{free}
2238 @itemx -F @var{free}
2239 Collect garbage until @var{free} space is available under
2240 @file{/gnu/store}, if possible; @var{free} denotes storage space, such
2241 as @code{500MiB}, as described above.
2243 When @var{free} or more is already available in @file{/gnu/store}, do
2244 nothing and exit immediately.
2248 Attempt to delete all the store files and directories specified as
2249 arguments. This fails if some of the files are not in the store, or if
2250 they are still live.
2252 @item --list-failures
2253 List store items corresponding to cached build failures.
2255 This prints nothing unless the daemon was started with
2256 @option{--cache-failures} (@pxref{Invoking guix-daemon,
2257 @option{--cache-failures}}).
2259 @item --clear-failures
2260 Remove the specified store items from the failed-build cache.
2262 Again, this option only makes sense when the daemon is started with
2263 @option{--cache-failures}. Otherwise, it does nothing.
2266 Show the list of dead files and directories still present in the
2267 store---i.e., files and directories no longer reachable from any root.
2270 Show the list of live store files and directories.
2274 In addition, the references among existing store files can be queried:
2280 @cindex package dependencies
2281 List the references (respectively, the referrers) of store files given
2287 List the requisites of the store files passed as arguments. Requisites
2288 include the store files themselves, their references, and the references
2289 of these, recursively. In other words, the returned list is the
2290 @dfn{transitive closure} of the store files.
2292 @xref{Invoking guix size}, for a tool to profile the size of the closure
2293 of an element. @xref{Invoking guix graph}, for a tool to visualize
2294 the graph of references.
2298 Lastly, the following options allow you to check the integrity of the
2299 store and to control disk usage.
2303 @item --verify[=@var{options}]
2304 @cindex integrity, of the store
2305 @cindex integrity checking
2306 Verify the integrity of the store.
2308 By default, make sure that all the store items marked as valid in the
2309 database of the daemon actually exist in @file{/gnu/store}.
2311 When provided, @var{options} must be a comma-separated list containing one
2312 or more of @code{contents} and @code{repair}.
2314 When passing @option{--verify=contents}, the daemon computes the
2315 content hash of each store item and compares it against its hash in the
2316 database. Hash mismatches are reported as data corruptions. Because it
2317 traverses @emph{all the files in the store}, this command can take a
2318 long time, especially on systems with a slow disk drive.
2320 @cindex repairing the store
2321 @cindex corruption, recovering from
2322 Using @option{--verify=repair} or @option{--verify=contents,repair}
2323 causes the daemon to try to repair corrupt store items by fetching
2324 substitutes for them (@pxref{Substitutes}). Because repairing is not
2325 atomic, and thus potentially dangerous, it is available only to the
2326 system administrator. A lightweight alternative, when you know exactly
2327 which items in the store are corrupt, is @command{guix build --repair}
2328 (@pxref{Invoking guix build}).
2331 @cindex deduplication
2332 Optimize the store by hard-linking identical files---this is
2333 @dfn{deduplication}.
2335 The daemon performs deduplication after each successful build or archive
2336 import, unless it was started with @code{--disable-deduplication}
2337 (@pxref{Invoking guix-daemon, @code{--disable-deduplication}}). Thus,
2338 this option is primarily useful when the daemon was running with
2339 @code{--disable-deduplication}.
2343 @node Invoking guix pull
2344 @section Invoking @command{guix pull}
2346 @cindex upgrading Guix
2347 @cindex updating Guix
2348 @cindex @command{guix pull}
2350 Packages are installed or upgraded to the latest version available in
2351 the distribution currently available on your local machine. To update
2352 that distribution, along with the Guix tools, you must run @command{guix
2353 pull}: the command downloads the latest Guix source code and package
2354 descriptions, and deploys it.
2356 On completion, @command{guix package} will use packages and package
2357 versions from this just-retrieved copy of Guix. Not only that, but all
2358 the Guix commands and Scheme modules will also be taken from that latest
2359 version. New @command{guix} sub-commands added by the update also
2362 Any user can update their Guix copy using @command{guix pull}, and the
2363 effect is limited to the user who run @command{guix pull}. For
2364 instance, when user @code{root} runs @command{guix pull}, this has no
2365 effect on the version of Guix that user @code{alice} sees, and vice
2366 versa@footnote{Under the hood, @command{guix pull} updates the
2367 @file{~/.config/guix/latest} symbolic link to point to the latest Guix,
2368 and the @command{guix} command loads code from there. Currently, the
2369 only way to roll back an invocation of @command{guix pull} is to
2370 manually update this symlink to point to the previous Guix.}.
2372 The @command{guix pull} command is usually invoked with no arguments,
2373 but it supports the following options:
2377 Produce verbose output, writing build logs to the standard error output.
2379 @item --url=@var{url}
2380 Download the source tarball of Guix from @var{url}.
2382 By default, the tarball is taken from its canonical address at
2383 @code{gnu.org}, for the stable branch of Guix.
2385 With some Git servers, this can be used to deploy any version of Guix.
2386 For example, to download and deploy version 0.12.0 of Guix from the
2390 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/v0.12.0.tar.gz
2393 It can also be used to deploy arbitrary Git revisions:
2396 guix pull --url=http://git.savannah.gnu.org/cgit/guix.git/snapshot/74d862e8a.tar.gz
2400 Use the bootstrap Guile to build the latest Guix. This option is only
2401 useful to Guix developers.
2405 @node Invoking guix pack
2406 @section Invoking @command{guix pack}
2408 Occasionally you want to pass software to people who are not (yet!)
2409 lucky enough to be using Guix. You'd tell them to run @command{guix
2410 package -i @var{something}}, but that's not possible in this case. This
2411 is where @command{guix pack} comes in.
2415 @cindex application bundle
2416 @cindex software bundle
2417 The @command{guix pack} command creates a shrink-wrapped @dfn{pack} or
2418 @dfn{software bundle}: it creates a tarball or some other archive
2419 containing the binaries of the software you're interested in, and all
2420 its dependencies. The resulting archive can be used on any machine that
2421 does not have Guix, and people can run the exact same binaries as those
2422 you have with Guix. The pack itself is created in a bit-reproducible
2423 fashion, so anyone can verify that it really contains the build results
2424 that you pretend to be shipping.
2426 For example, to create a bundle containing Guile, Emacs, Geiser, and all
2427 their dependencies, you can run:
2430 $ guix pack guile emacs geiser
2432 /gnu/store/@dots{}-pack.tar.gz
2435 The result here is a tarball containing a @file{/gnu/store} directory
2436 with all the relevant packages. The resulting tarball contains a
2437 @dfn{profile} with the three packages of interest; the profile is the
2438 same as would be created by @command{guix package -i}. It is this
2439 mechanism that is used to create Guix's own standalone binary tarball
2440 (@pxref{Binary Installation}).
2442 Users of this pack would have to run
2443 @file{/gnu/store/@dots{}-profile/bin/guile} to run Guile, which you may
2444 find inconvenient. To work around it, you can create, say, a
2445 @file{/opt/gnu/bin} symlink to the profile:
2448 guix pack -S /opt/gnu/bin=bin guile emacs geiser
2452 That way, users can happily type @file{/opt/gnu/bin/guile} and enjoy.
2454 Alternatively, you can produce a pack in the Docker image format using
2455 the following command:
2458 guix pack -f docker guile emacs geiser
2462 The result is a tarball that can be passed to the @command{docker load}
2464 @uref{https://docs.docker.com/engine/reference/commandline/load/, Docker
2465 documentation} for more information.
2467 Several command-line options allow you to customize your pack:
2470 @item --format=@var{format}
2471 @itemx -f @var{format}
2472 Produce a pack in the given @var{format}.
2474 The available formats are:
2478 This is the default format. It produces a tarball containing all the
2479 specifies binaries and symlinks.
2482 This produces a tarball that follows the
2483 @uref{https://github.com/docker/docker/blob/master/image/spec/v1.2.md,
2484 Docker Image Specification}.
2487 @item --expression=@var{expr}
2488 @itemx -e @var{expr}
2489 Consider the package @var{expr} evaluates to.
2491 This has the same purpose as the same-named option in @command{guix
2492 build} (@pxref{Additional Build Options, @code{--expression} in
2493 @command{guix build}}).
2495 @item --system=@var{system}
2496 @itemx -s @var{system}
2497 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
2498 the system type of the build host.
2500 @item --target=@var{triplet}
2501 @cindex cross-compilation
2502 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
2503 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
2504 configuration triplets,, autoconf, Autoconf}).
2506 @item --compression=@var{tool}
2507 @itemx -C @var{tool}
2508 Compress the resulting tarball using @var{tool}---one of @code{gzip},
2509 @code{bzip2}, @code{xz}, or @code{lzip}.
2511 @item --symlink=@var{spec}
2512 @itemx -S @var{spec}
2513 Add the symlinks specified by @var{spec} to the pack. This option can
2514 appear several times.
2516 @var{spec} has the form @code{@var{source}=@var{target}}, where
2517 @var{source} is the symlink that will be created and @var{target} is the
2520 For instance, @code{-S /opt/gnu/bin=bin} creates a @file{/opt/gnu/bin}
2521 symlink pointing to the @file{bin} sub-directory of the profile.
2523 @item --localstatedir
2524 Include the ``local state directory'', @file{/var/guix}, in the
2527 @file{/var/guix} contains the store database (@pxref{The Store}) as well
2528 as garbage-collector roots (@pxref{Invoking guix gc}). Providing it in
2529 the pack means that the store is ``complete'' and manageable by Guix;
2530 not providing it pack means that the store is ``dead'': items cannot be
2531 added to it or removed from it after extraction of the pack.
2533 One use case for this is the Guix self-contained binary tarball
2534 (@pxref{Binary Installation}).
2537 In addition, @command{guix pack} supports all the common build options
2538 (@pxref{Common Build Options}) and all the package transformation
2539 options (@pxref{Package Transformation Options}).
2542 @node Invoking guix archive
2543 @section Invoking @command{guix archive}
2545 @cindex @command{guix archive}
2547 The @command{guix archive} command allows users to @dfn{export} files
2548 from the store into a single archive, and to later @dfn{import} them.
2549 In particular, it allows store files to be transferred from one machine
2550 to the store on another machine.
2552 @cindex exporting store items
2553 To export store files as an archive to standard output, run:
2556 guix archive --export @var{options} @var{specifications}...
2559 @var{specifications} may be either store file names or package
2560 specifications, as for @command{guix package} (@pxref{Invoking guix
2561 package}). For instance, the following command creates an archive
2562 containing the @code{gui} output of the @code{git} package and the main
2563 output of @code{emacs}:
2566 guix archive --export git:gui /gnu/store/...-emacs-24.3 > great.nar
2569 If the specified packages are not built yet, @command{guix archive}
2570 automatically builds them. The build process may be controlled with the
2571 common build options (@pxref{Common Build Options}).
2573 To transfer the @code{emacs} package to a machine connected over SSH,
2577 guix archive --export -r emacs | ssh the-machine guix archive --import
2581 Similarly, a complete user profile may be transferred from one machine
2582 to another like this:
2585 guix archive --export -r $(readlink -f ~/.guix-profile) | \
2586 ssh the-machine guix-archive --import
2590 However, note that, in both examples, all of @code{emacs} and the
2591 profile as well as all of their dependencies are transferred (due to
2592 @code{-r}), regardless of what is already available in the store on the
2593 target machine. The @code{--missing} option can help figure out which
2594 items are missing from the target store. The @command{guix copy}
2595 command simplifies and optimizes this whole process, so this is probably
2596 what you should use in this case (@pxref{Invoking guix copy}).
2598 @cindex nar, archive format
2599 @cindex normalized archive (nar)
2600 Archives are stored in the ``normalized archive'' or ``nar'' format, which is
2601 comparable in spirit to `tar', but with differences
2602 that make it more appropriate for our purposes. First, rather than
2603 recording all Unix metadata for each file, the nar format only mentions
2604 the file type (regular, directory, or symbolic link); Unix permissions
2605 and owner/group are dismissed. Second, the order in which directory
2606 entries are stored always follows the order of file names according to
2607 the C locale collation order. This makes archive production fully
2610 When exporting, the daemon digitally signs the contents of the archive,
2611 and that digital signature is appended. When importing, the daemon
2612 verifies the signature and rejects the import in case of an invalid
2613 signature or if the signing key is not authorized.
2614 @c FIXME: Add xref to daemon doc about signatures.
2616 The main options are:
2620 Export the specified store files or packages (see below.) Write the
2621 resulting archive to the standard output.
2623 Dependencies are @emph{not} included in the output, unless
2624 @code{--recursive} is passed.
2628 When combined with @code{--export}, this instructs @command{guix
2629 archive} to include dependencies of the given items in the archive.
2630 Thus, the resulting archive is self-contained: it contains the closure
2631 of the exported store items.
2634 Read an archive from the standard input, and import the files listed
2635 therein into the store. Abort if the archive has an invalid digital
2636 signature, or if it is signed by a public key not among the authorized
2637 keys (see @code{--authorize} below.)
2640 Read a list of store file names from the standard input, one per line,
2641 and write on the standard output the subset of these files missing from
2644 @item --generate-key[=@var{parameters}]
2645 @cindex signing, archives
2646 Generate a new key pair for the daemon. This is a prerequisite before
2647 archives can be exported with @code{--export}. Note that this operation
2648 usually takes time, because it needs to gather enough entropy to
2649 generate the key pair.
2651 The generated key pair is typically stored under @file{/etc/guix}, in
2652 @file{signing-key.pub} (public key) and @file{signing-key.sec} (private
2653 key, which must be kept secret.) When @var{parameters} is omitted,
2654 an ECDSA key using the Ed25519 curve is generated, or, for Libgcrypt
2655 versions before 1.6.0, it is a 4096-bit RSA key.
2656 Alternatively, @var{parameters} can specify
2657 @code{genkey} parameters suitable for Libgcrypt (@pxref{General
2658 public-key related Functions, @code{gcry_pk_genkey},, gcrypt, The
2659 Libgcrypt Reference Manual}).
2662 @cindex authorizing, archives
2663 Authorize imports signed by the public key passed on standard input.
2664 The public key must be in ``s-expression advanced format''---i.e., the
2665 same format as the @file{signing-key.pub} file.
2667 The list of authorized keys is kept in the human-editable file
2668 @file{/etc/guix/acl}. The file contains
2669 @url{http://people.csail.mit.edu/rivest/Sexp.txt, ``advanced-format
2670 s-expressions''} and is structured as an access-control list in the
2671 @url{http://theworld.com/~cme/spki.txt, Simple Public-Key Infrastructure
2674 @item --extract=@var{directory}
2675 @itemx -x @var{directory}
2676 Read a single-item archive as served by substitute servers
2677 (@pxref{Substitutes}) and extract it to @var{directory}. This is a
2678 low-level operation needed in only very narrow use cases; see below.
2680 For example, the following command extracts the substitute for Emacs
2681 served by @code{hydra.gnu.org} to @file{/tmp/emacs}:
2685 https://hydra.gnu.org/nar/@dots{}-emacs-24.5 \
2686 | bunzip2 | guix archive -x /tmp/emacs
2689 Single-item archives are different from multiple-item archives produced
2690 by @command{guix archive --export}; they contain a single store item,
2691 and they do @emph{not} embed a signature. Thus this operation does
2692 @emph{no} signature verification and its output should be considered
2695 The primary purpose of this operation is to facilitate inspection of
2696 archive contents coming from possibly untrusted substitute servers.
2700 @c *********************************************************************
2701 @node Programming Interface
2702 @chapter Programming Interface
2704 GNU Guix provides several Scheme programming interfaces (APIs) to
2705 define, build, and query packages. The first interface allows users to
2706 write high-level package definitions. These definitions refer to
2707 familiar packaging concepts, such as the name and version of a package,
2708 its build system, and its dependencies. These definitions can then be
2709 turned into concrete build actions.
2711 Build actions are performed by the Guix daemon, on behalf of users. In a
2712 standard setup, the daemon has write access to the store---the
2713 @file{/gnu/store} directory---whereas users do not. The recommended
2714 setup also has the daemon perform builds in chroots, under a specific
2715 build users, to minimize interference with the rest of the system.
2718 Lower-level APIs are available to interact with the daemon and the
2719 store. To instruct the daemon to perform a build action, users actually
2720 provide it with a @dfn{derivation}. A derivation is a low-level
2721 representation of the build actions to be taken, and the environment in
2722 which they should occur---derivations are to package definitions what
2723 assembly is to C programs. The term ``derivation'' comes from the fact
2724 that build results @emph{derive} from them.
2726 This chapter describes all these APIs in turn, starting from high-level
2727 package definitions.
2730 * Defining Packages:: Defining new packages.
2731 * Build Systems:: Specifying how packages are built.
2732 * The Store:: Manipulating the package store.
2733 * Derivations:: Low-level interface to package derivations.
2734 * The Store Monad:: Purely functional interface to the store.
2735 * G-Expressions:: Manipulating build expressions.
2738 @node Defining Packages
2739 @section Defining Packages
2741 The high-level interface to package definitions is implemented in the
2742 @code{(guix packages)} and @code{(guix build-system)} modules. As an
2743 example, the package definition, or @dfn{recipe}, for the GNU Hello
2744 package looks like this:
2747 (define-module (gnu packages hello)
2748 #:use-module (guix packages)
2749 #:use-module (guix download)
2750 #:use-module (guix build-system gnu)
2751 #:use-module (guix licenses)
2752 #:use-module (gnu packages gawk))
2754 (define-public hello
2760 (uri (string-append "mirror://gnu/hello/hello-" version
2764 "0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i"))))
2765 (build-system gnu-build-system)
2766 (arguments '(#:configure-flags '("--enable-silent-rules")))
2767 (inputs `(("gawk" ,gawk)))
2768 (synopsis "Hello, GNU world: An example GNU package")
2769 (description "Guess what GNU Hello prints!")
2770 (home-page "http://www.gnu.org/software/hello/")
2775 Without being a Scheme expert, the reader may have guessed the meaning
2776 of the various fields here. This expression binds the variable
2777 @code{hello} to a @code{<package>} object, which is essentially a record
2778 (@pxref{SRFI-9, Scheme records,, guile, GNU Guile Reference Manual}).
2779 This package object can be inspected using procedures found in the
2780 @code{(guix packages)} module; for instance, @code{(package-name hello)}
2781 returns---surprise!---@code{"hello"}.
2783 With luck, you may be able to import part or all of the definition of
2784 the package you are interested in from another repository, using the
2785 @code{guix import} command (@pxref{Invoking guix import}).
2787 In the example above, @var{hello} is defined in a module of its own,
2788 @code{(gnu packages hello)}. Technically, this is not strictly
2789 necessary, but it is convenient to do so: all the packages defined in
2790 modules under @code{(gnu packages @dots{})} are automatically known to
2791 the command-line tools (@pxref{Package Modules}).
2793 There are a few points worth noting in the above package definition:
2797 The @code{source} field of the package is an @code{<origin>} object
2798 (@pxref{origin Reference}, for the complete reference).
2799 Here, the @code{url-fetch} method from @code{(guix download)} is used,
2800 meaning that the source is a file to be downloaded over FTP or HTTP.
2802 The @code{mirror://gnu} prefix instructs @code{url-fetch} to use one of
2803 the GNU mirrors defined in @code{(guix download)}.
2805 The @code{sha256} field specifies the expected SHA256 hash of the file
2806 being downloaded. It is mandatory, and allows Guix to check the
2807 integrity of the file. The @code{(base32 @dots{})} form introduces the
2808 base32 representation of the hash. You can obtain this information with
2809 @code{guix download} (@pxref{Invoking guix download}) and @code{guix
2810 hash} (@pxref{Invoking guix hash}).
2813 When needed, the @code{origin} form can also have a @code{patches} field
2814 listing patches to be applied, and a @code{snippet} field giving a
2815 Scheme expression to modify the source code.
2818 @cindex GNU Build System
2819 The @code{build-system} field specifies the procedure to build the
2820 package (@pxref{Build Systems}). Here, @var{gnu-build-system}
2821 represents the familiar GNU Build System, where packages may be
2822 configured, built, and installed with the usual @code{./configure &&
2823 make && make check && make install} command sequence.
2826 The @code{arguments} field specifies options for the build system
2827 (@pxref{Build Systems}). Here it is interpreted by
2828 @var{gnu-build-system} as a request run @file{configure} with the
2829 @code{--enable-silent-rules} flag.
2835 What about these quote (@code{'}) characters? They are Scheme syntax to
2836 introduce a literal list; @code{'} is synonymous with @code{quote}.
2837 @xref{Expression Syntax, quoting,, guile, GNU Guile Reference Manual},
2838 for details. Here the value of the @code{arguments} field is a list of
2839 arguments passed to the build system down the road, as with @code{apply}
2840 (@pxref{Fly Evaluation, @code{apply},, guile, GNU Guile Reference
2843 The hash-colon (@code{#:}) sequence defines a Scheme @dfn{keyword}
2844 (@pxref{Keywords,,, guile, GNU Guile Reference Manual}), and
2845 @code{#:configure-flags} is a keyword used to pass a keyword argument
2846 to the build system (@pxref{Coding With Keywords,,, guile, GNU Guile
2850 The @code{inputs} field specifies inputs to the build process---i.e.,
2851 build-time or run-time dependencies of the package. Here, we define an
2852 input called @code{"gawk"} whose value is that of the @var{gawk}
2853 variable; @var{gawk} is itself bound to a @code{<package>} object.
2855 @cindex backquote (quasiquote)
2858 @cindex comma (unquote)
2862 @findex unquote-splicing
2863 Again, @code{`} (a backquote, synonymous with @code{quasiquote}) allows
2864 us to introduce a literal list in the @code{inputs} field, while
2865 @code{,} (a comma, synonymous with @code{unquote}) allows us to insert a
2866 value in that list (@pxref{Expression Syntax, unquote,, guile, GNU Guile
2869 Note that GCC, Coreutils, Bash, and other essential tools do not need to
2870 be specified as inputs here. Instead, @var{gnu-build-system} takes care
2871 of ensuring that they are present (@pxref{Build Systems}).
2873 However, any other dependencies need to be specified in the
2874 @code{inputs} field. Any dependency not specified here will simply be
2875 unavailable to the build process, possibly leading to a build failure.
2878 @xref{package Reference}, for a full description of possible fields.
2880 Once a package definition is in place, the
2881 package may actually be built using the @code{guix build} command-line
2882 tool (@pxref{Invoking guix build}). You can easily jump back to the
2883 package definition using the @command{guix edit} command
2884 (@pxref{Invoking guix edit}).
2885 @xref{Packaging Guidelines}, for
2886 more information on how to test package definitions, and
2887 @ref{Invoking guix lint}, for information on how to check a definition
2888 for style conformance.
2890 Finally, updating the package definition to a new upstream version
2891 can be partly automated by the @command{guix refresh} command
2892 (@pxref{Invoking guix refresh}).
2894 Behind the scenes, a derivation corresponding to the @code{<package>}
2895 object is first computed by the @code{package-derivation} procedure.
2896 That derivation is stored in a @code{.drv} file under @file{/gnu/store}.
2897 The build actions it prescribes may then be realized by using the
2898 @code{build-derivations} procedure (@pxref{The Store}).
2900 @deffn {Scheme Procedure} package-derivation @var{store} @var{package} [@var{system}]
2901 Return the @code{<derivation>} object of @var{package} for @var{system}
2902 (@pxref{Derivations}).
2904 @var{package} must be a valid @code{<package>} object, and @var{system}
2905 must be a string denoting the target system type---e.g.,
2906 @code{"x86_64-linux"} for an x86_64 Linux-based GNU system. @var{store}
2907 must be a connection to the daemon, which operates on the store
2908 (@pxref{The Store}).
2912 @cindex cross-compilation
2913 Similarly, it is possible to compute a derivation that cross-builds a
2914 package for some other system:
2916 @deffn {Scheme Procedure} package-cross-derivation @var{store} @
2917 @var{package} @var{target} [@var{system}]
2918 Return the @code{<derivation>} object of @var{package} cross-built from
2919 @var{system} to @var{target}.
2921 @var{target} must be a valid GNU triplet denoting the target hardware
2922 and operating system, such as @code{"mips64el-linux-gnu"}
2923 (@pxref{Configuration Names, GNU configuration triplets,, configure, GNU
2924 Configure and Build System}).
2927 @cindex package transformations
2928 @cindex input rewriting
2929 @cindex dependency tree rewriting
2930 Packages can be manipulated in arbitrary ways. An example of a useful
2931 transformation is @dfn{input rewriting}, whereby the dependency tree of
2932 a package is rewritten by replacing specific inputs by others:
2934 @deffn {Scheme Procedure} package-input-rewriting @var{replacements} @
2935 [@var{rewrite-name}]
2936 Return a procedure that, when passed a package, replaces its direct and
2937 indirect dependencies (but not its implicit inputs) according to
2938 @var{replacements}. @var{replacements} is a list of package pairs; the
2939 first element of each pair is the package to replace, and the second one
2942 Optionally, @var{rewrite-name} is a one-argument procedure that takes
2943 the name of a package and returns its new name after rewrite.
2947 Consider this example:
2950 (define libressl-instead-of-openssl
2951 ;; This is a procedure to replace OPENSSL by LIBRESSL,
2953 (package-input-rewriting `((,openssl . ,libressl))))
2955 (define git-with-libressl
2956 (libressl-instead-of-openssl git))
2960 Here we first define a rewriting procedure that replaces @var{openssl}
2961 with @var{libressl}. Then we use it to define a @dfn{variant} of the
2962 @var{git} package that uses @var{libressl} instead of @var{openssl}.
2963 This is exactly what the @option{--with-input} command-line option does
2964 (@pxref{Package Transformation Options, @option{--with-input}}).
2966 A more generic procedure to rewrite a package dependency graph is
2967 @code{package-mapping}: it supports arbitrary changes to nodes in the
2970 @deffn {Scheme Procedure} package-mapping @var{proc} [@var{cut?}]
2971 Return a procedure that, given a package, applies @var{proc} to all the packages
2972 depended on and returns the resulting package. The procedure stops recursion
2973 when @var{cut?} returns true for a given package.
2977 * package Reference :: The package data type.
2978 * origin Reference:: The origin data type.
2982 @node package Reference
2983 @subsection @code{package} Reference
2985 This section summarizes all the options available in @code{package}
2986 declarations (@pxref{Defining Packages}).
2988 @deftp {Data Type} package
2989 This is the data type representing a package recipe.
2993 The name of the package, as a string.
2995 @item @code{version}
2996 The version of the package, as a string.
2999 An object telling how the source code for the package should be
3000 acquired. Most of the time, this is an @code{origin} object, which
3001 denotes a file fetched from the Internet (@pxref{origin Reference}). It
3002 can also be any other ``file-like'' object such as a @code{local-file},
3003 which denotes a file from the local file system (@pxref{G-Expressions,
3004 @code{local-file}}).
3006 @item @code{build-system}
3007 The build system that should be used to build the package (@pxref{Build
3010 @item @code{arguments} (default: @code{'()})
3011 The arguments that should be passed to the build system. This is a
3012 list, typically containing sequential keyword-value pairs.
3014 @item @code{inputs} (default: @code{'()})
3015 @itemx @code{native-inputs} (default: @code{'()})
3016 @itemx @code{propagated-inputs} (default: @code{'()})
3017 @cindex inputs, of packages
3018 These fields list dependencies of the package. Each one is a list of
3019 tuples, where each tuple has a label for the input (a string) as its
3020 first element, a package, origin, or derivation as its second element,
3021 and optionally the name of the output thereof that should be used, which
3022 defaults to @code{"out"} (@pxref{Packages with Multiple Outputs}, for
3023 more on package outputs). For example, the list below specifies three
3027 `(("libffi" ,libffi)
3028 ("libunistring" ,libunistring)
3029 ("glib:bin" ,glib "bin")) ;the "bin" output of Glib
3032 @cindex cross compilation, package dependencies
3033 The distinction between @code{native-inputs} and @code{inputs} is
3034 necessary when considering cross-compilation. When cross-compiling,
3035 dependencies listed in @code{inputs} are built for the @emph{target}
3036 architecture; conversely, dependencies listed in @code{native-inputs}
3037 are built for the architecture of the @emph{build} machine.
3039 @code{native-inputs} is typically used to list tools needed at
3040 build time, but not at run time, such as Autoconf, Automake, pkg-config,
3041 Gettext, or Bison. @command{guix lint} can report likely mistakes in
3042 this area (@pxref{Invoking guix lint}).
3044 @anchor{package-propagated-inputs}
3045 Lastly, @code{propagated-inputs} is similar to @code{inputs}, but the
3046 specified packages will be automatically installed alongside the package
3047 they belong to (@pxref{package-cmd-propagated-inputs, @command{guix
3048 package}}, for information on how @command{guix package} deals with
3051 For example this is necessary when a C/C++ library needs headers of
3052 another library to compile, or when a pkg-config file refers to another
3053 one @i{via} its @code{Requires} field.
3055 Another example where @code{propagated-inputs} is useful is for languages
3056 that lack a facility to record the run-time search path akin to the
3057 @code{RUNPATH} of ELF files; this includes Guile, Python, Perl, and
3058 more. To ensure that libraries written in those languages can find
3059 library code they depend on at run time, run-time dependencies must be
3060 listed in @code{propagated-inputs} rather than @code{inputs}.
3062 @item @code{self-native-input?} (default: @code{#f})
3063 This is a Boolean field telling whether the package should use itself as
3064 a native input when cross-compiling.
3066 @item @code{outputs} (default: @code{'("out")})
3067 The list of output names of the package. @xref{Packages with Multiple
3068 Outputs}, for typical uses of additional outputs.
3070 @item @code{native-search-paths} (default: @code{'()})
3071 @itemx @code{search-paths} (default: @code{'()})
3072 A list of @code{search-path-specification} objects describing
3073 search-path environment variables honored by the package.
3075 @item @code{replacement} (default: @code{#f})
3076 This must be either @code{#f} or a package object that will be used as a
3077 @dfn{replacement} for this package. @xref{Security Updates, grafts},
3080 @item @code{synopsis}
3081 A one-line description of the package.
3083 @item @code{description}
3084 A more elaborate description of the package.
3086 @item @code{license}
3087 @cindex license, of packages
3088 The license of the package; a value from @code{(guix licenses)},
3089 or a list of such values.
3091 @item @code{home-page}
3092 The URL to the home-page of the package, as a string.
3094 @item @code{supported-systems} (default: @var{%supported-systems})
3095 The list of systems supported by the package, as strings of the form
3096 @code{architecture-kernel}, for example @code{"x86_64-linux"}.
3098 @item @code{maintainers} (default: @code{'()})
3099 The list of maintainers of the package, as @code{maintainer} objects.
3101 @item @code{location} (default: source location of the @code{package} form)
3102 The source location of the package. It is useful to override this when
3103 inheriting from another package, in which case this field is not
3104 automatically corrected.
3109 @node origin Reference
3110 @subsection @code{origin} Reference
3112 This section summarizes all the options available in @code{origin}
3113 declarations (@pxref{Defining Packages}).
3115 @deftp {Data Type} origin
3116 This is the data type representing a source code origin.
3120 An object containing the URI of the source. The object type depends on
3121 the @code{method} (see below). For example, when using the
3122 @var{url-fetch} method of @code{(guix download)}, the valid @code{uri}
3123 values are: a URL represented as a string, or a list thereof.
3126 A procedure that handles the URI.
3131 @item @var{url-fetch} from @code{(guix download)}
3132 download a file from the HTTP, HTTPS, or FTP URL specified in the
3136 @item @var{git-fetch} from @code{(guix git-download)}
3137 clone the Git version control repository, and check out the revision
3138 specified in the @code{uri} field as a @code{git-reference} object; a
3139 @code{git-reference} looks like this:
3143 (url "git://git.debian.org/git/pkg-shadow/shadow")
3144 (commit "v4.1.5.1"))
3149 A bytevector containing the SHA-256 hash of the source. Typically the
3150 @code{base32} form is used here to generate the bytevector from a
3153 You can obtain this information using @code{guix download}
3154 (@pxref{Invoking guix download}) or @code{guix hash} (@pxref{Invoking
3157 @item @code{file-name} (default: @code{#f})
3158 The file name under which the source code should be saved. When this is
3159 @code{#f}, a sensible default value will be used in most cases. In case
3160 the source is fetched from a URL, the file name from the URL will be
3161 used. For version control checkouts, it is recommended to provide the
3162 file name explicitly because the default is not very descriptive.
3164 @item @code{patches} (default: @code{'()})
3165 A list of file names containing patches to be applied to the source.
3167 This list of patches must be unconditional. In particular, it cannot
3168 depend on the value of @code{%current-system} or
3169 @code{%current-target-system}.
3171 @item @code{snippet} (default: @code{#f})
3172 A G-expression (@pxref{G-Expressions}) or S-expression that will be run
3173 in the source directory. This is a convenient way to modify the source,
3174 sometimes more convenient than a patch.
3176 @item @code{patch-flags} (default: @code{'("-p1")})
3177 A list of command-line flags that should be passed to the @code{patch}
3180 @item @code{patch-inputs} (default: @code{#f})
3181 Input packages or derivations to the patching process. When this is
3182 @code{#f}, the usual set of inputs necessary for patching are provided,
3183 such as GNU@tie{}Patch.
3185 @item @code{modules} (default: @code{'()})
3186 A list of Guile modules that should be loaded during the patching
3187 process and while running the code in the @code{snippet} field.
3189 @item @code{patch-guile} (default: @code{#f})
3190 The Guile package that should be used in the patching process. When
3191 this is @code{#f}, a sensible default is used.
3197 @section Build Systems
3199 @cindex build system
3200 Each package definition specifies a @dfn{build system} and arguments for
3201 that build system (@pxref{Defining Packages}). This @code{build-system}
3202 field represents the build procedure of the package, as well as implicit
3203 dependencies of that build procedure.
3205 Build systems are @code{<build-system>} objects. The interface to
3206 create and manipulate them is provided by the @code{(guix build-system)}
3207 module, and actual build systems are exported by specific modules.
3209 @cindex bag (low-level package representation)
3210 Under the hood, build systems first compile package objects to
3211 @dfn{bags}. A @dfn{bag} is like a package, but with less
3212 ornamentation---in other words, a bag is a lower-level representation of
3213 a package, which includes all the inputs of that package, including some
3214 that were implicitly added by the build system. This intermediate
3215 representation is then compiled to a derivation (@pxref{Derivations}).
3217 Build systems accept an optional list of @dfn{arguments}. In package
3218 definitions, these are passed @i{via} the @code{arguments} field
3219 (@pxref{Defining Packages}). They are typically keyword arguments
3220 (@pxref{Optional Arguments, keyword arguments in Guile,, guile, GNU
3221 Guile Reference Manual}). The value of these arguments is usually
3222 evaluated in the @dfn{build stratum}---i.e., by a Guile process launched
3223 by the daemon (@pxref{Derivations}).
3225 The main build system is @var{gnu-build-system}, which implements the
3226 standard build procedure for GNU and many other packages. It
3227 is provided by the @code{(guix build-system gnu)} module.
3229 @defvr {Scheme Variable} gnu-build-system
3230 @var{gnu-build-system} represents the GNU Build System, and variants
3231 thereof (@pxref{Configuration, configuration and makefile conventions,,
3232 standards, GNU Coding Standards}).
3234 @cindex build phases
3235 In a nutshell, packages using it are configured, built, and installed with
3236 the usual @code{./configure && make && make check && make install}
3237 command sequence. In practice, a few additional steps are often needed.
3238 All these steps are split up in separate @dfn{phases},
3239 notably@footnote{Please see the @code{(guix build gnu-build-system)}
3240 modules for more details about the build phases.}:
3244 Unpack the source tarball, and change the current directory to the
3245 extracted source tree. If the source is actually a directory, copy it
3246 to the build tree, and enter that directory.
3248 @item patch-source-shebangs
3249 Patch shebangs encountered in source files so they refer to the right
3250 store file names. For instance, this changes @code{#!/bin/sh} to
3251 @code{#!/gnu/store/@dots{}-bash-4.3/bin/sh}.
3254 Run the @file{configure} script with a number of default options, such
3255 as @code{--prefix=/gnu/store/@dots{}}, as well as the options specified
3256 by the @code{#:configure-flags} argument.
3259 Run @code{make} with the list of flags specified with
3260 @code{#:make-flags}. If the @code{#:parallel-build?} argument is true
3261 (the default), build with @code{make -j}.
3264 Run @code{make check}, or some other target specified with
3265 @code{#:test-target}, unless @code{#:tests? #f} is passed. If the
3266 @code{#:parallel-tests?} argument is true (the default), run @code{make
3270 Run @code{make install} with the flags listed in @code{#:make-flags}.
3272 @item patch-shebangs
3273 Patch shebangs on the installed executable files.
3276 Strip debugging symbols from ELF files (unless @code{#:strip-binaries?}
3277 is false), copying them to the @code{debug} output when available
3278 (@pxref{Installing Debugging Files}).
3281 @vindex %standard-phases
3282 The build-side module @code{(guix build gnu-build-system)} defines
3283 @var{%standard-phases} as the default list of build phases.
3284 @var{%standard-phases} is a list of symbol/procedure pairs, where the
3285 procedure implements the actual phase.
3287 The list of phases used for a particular package can be changed with the
3288 @code{#:phases} parameter. For instance, passing:
3291 #:phases (modify-phases %standard-phases (delete 'configure))
3294 means that all the phases described above will be used, except the
3295 @code{configure} phase.
3297 In addition, this build system ensures that the ``standard'' environment
3298 for GNU packages is available. This includes tools such as GCC, libc,
3299 Coreutils, Bash, Make, Diffutils, grep, and sed (see the @code{(guix
3300 build-system gnu)} module for a complete list). We call these the
3301 @dfn{implicit inputs} of a package, because package definitions do not
3302 have to mention them.
3305 Other @code{<build-system>} objects are defined to support other
3306 conventions and tools used by free software packages. They inherit most
3307 of @var{gnu-build-system}, and differ mainly in the set of inputs
3308 implicitly added to the build process, and in the list of phases
3309 executed. Some of these build systems are listed below.
3311 @defvr {Scheme Variable} ant-build-system
3312 This variable is exported by @code{(guix build-system ant)}. It
3313 implements the build procedure for Java packages that can be built with
3314 @url{http://ant.apache.org/, Ant build tool}.
3316 It adds both @code{ant} and the @dfn{Java Development Kit} (JDK) as
3317 provided by the @code{icedtea} package to the set of inputs. Different
3318 packages can be specified with the @code{#:ant} and @code{#:jdk}
3319 parameters, respectively.
3321 When the original package does not provide a suitable Ant build file,
3322 the parameter @code{#:jar-name} can be used to generate a minimal Ant
3323 build file @file{build.xml} with tasks to build the specified jar
3326 The parameter @code{#:build-target} can be used to specify the Ant task
3327 that should be run during the @code{build} phase. By default the
3328 ``jar'' task will be run.
3332 @defvr {Scheme Variable} asdf-build-system/source
3333 @defvrx {Scheme Variable} asdf-build-system/sbcl
3334 @defvrx {Scheme Variable} asdf-build-system/ecl
3336 These variables, exported by @code{(guix build-system asdf)}, implement
3337 build procedures for Common Lisp packages using
3338 @url{https://common-lisp.net/project/asdf/, ``ASDF''}. ASDF is a system
3339 definition facility for Common Lisp programs and libraries.
3341 The @code{asdf-build-system/source} system installs the packages in
3342 source form, and can be loaded using any common lisp implementation, via
3343 ASDF. The others, such as @code{asdf-build-system/sbcl}, install binary
3344 systems in the format which a particular implementation understands.
3345 These build systems can also be used to produce executable programs, or
3346 lisp images which contain a set of packages pre-loaded.
3348 The build system uses naming conventions. For binary packages, the
3349 package itself as well as its run-time dependencies should begin their
3350 name with the lisp implementation, such as @code{sbcl-} for
3351 @code{asdf-build-system/sbcl}. Beginning the input name with this
3352 prefix will allow the build system to encode its location into the
3353 resulting library, so that the input can be found at run-time.
3355 If dependencies are used only for tests, it is convenient to use a
3356 different prefix in order to avoid having a run-time dependency on such
3357 systems. For example,
3360 (define-public sbcl-bordeaux-threads
3363 (native-inputs `(("tests:cl-fiveam" ,sbcl-fiveam)))
3367 Additionally, the corresponding source package should be labeled using
3368 the same convention as python packages (see @ref{Python Modules}), using
3369 the @code{cl-} prefix.
3371 For binary packages, each system should be defined as a Guix package.
3372 If one package @code{origin} contains several systems, package variants
3373 can be created in order to build all the systems. Source packages,
3374 which use @code{asdf-build-system/source}, may contain several systems.
3376 In order to create executable programs and images, the build-side
3377 procedures @code{build-program} and @code{build-image} can be used.
3378 They should be called in a build phase after the @code{create-symlinks}
3379 phase, so that the system which was just built can be used within the
3380 resulting image. @code{build-program} requires a list of Common Lisp
3381 expressions to be passed as the @code{#:entry-program} argument.
3383 If the system is not defined within its own @code{.asd} file of the same
3384 name, then the @code{#:asd-file} parameter should be used to specify
3385 which file the system is defined in.
3389 @defvr {Scheme Variable} cargo-build-system
3390 @cindex Rust programming language
3391 @cindex Cargo (Rust build system)
3392 This variable is exported by @code{(guix build-system cargo)}. It
3393 supports builds of packages using Cargo, the build tool of the
3394 @uref{https://www.rust-lang.org, Rust programming language}.
3396 In its @code{configure} phase, this build system replaces dependencies
3397 specified in the @file{Carto.toml} file with inputs to the Guix package.
3398 The @code{install} phase installs the binaries, and it also installs the
3399 source code and @file{Cargo.toml} file.
3402 @defvr {Scheme Variable} cmake-build-system
3403 This variable is exported by @code{(guix build-system cmake)}. It
3404 implements the build procedure for packages using the
3405 @url{http://www.cmake.org, CMake build tool}.
3407 It automatically adds the @code{cmake} package to the set of inputs.
3408 Which package is used can be specified with the @code{#:cmake}
3411 The @code{#:configure-flags} parameter is taken as a list of flags
3412 passed to the @command{cmake} command. The @code{#:build-type}
3413 parameter specifies in abstract terms the flags passed to the compiler;
3414 it defaults to @code{"RelWithDebInfo"} (short for ``release mode with
3415 debugging information''), which roughly means that code is compiled with
3416 @code{-O2 -g}, as is the case for Autoconf-based packages by default.
3419 @defvr {Scheme Variable} glib-or-gtk-build-system
3420 This variable is exported by @code{(guix build-system glib-or-gtk)}. It
3421 is intended for use with packages making use of GLib or GTK+.
3423 This build system adds the following two phases to the ones defined by
3424 @var{gnu-build-system}:
3427 @item glib-or-gtk-wrap
3428 The phase @code{glib-or-gtk-wrap} ensures that programs in
3429 @file{bin/} are able to find GLib ``schemas'' and
3430 @uref{https://developer.gnome.org/gtk3/stable/gtk-running.html, GTK+
3431 modules}. This is achieved by wrapping the programs in launch scripts
3432 that appropriately set the @code{XDG_DATA_DIRS} and @code{GTK_PATH}
3433 environment variables.
3435 It is possible to exclude specific package outputs from that wrapping
3436 process by listing their names in the
3437 @code{#:glib-or-gtk-wrap-excluded-outputs} parameter. This is useful
3438 when an output is known not to contain any GLib or GTK+ binaries, and
3439 where wrapping would gratuitously add a dependency of that output on
3442 @item glib-or-gtk-compile-schemas
3443 The phase @code{glib-or-gtk-compile-schemas} makes sure that all
3444 @uref{https://developer.gnome.org/gio/stable/glib-compile-schemas.html,
3445 GSettings schemas} of GLib are compiled. Compilation is performed by the
3446 @command{glib-compile-schemas} program. It is provided by the package
3447 @code{glib:bin} which is automatically imported by the build system.
3448 The @code{glib} package providing @command{glib-compile-schemas} can be
3449 specified with the @code{#:glib} parameter.
3452 Both phases are executed after the @code{install} phase.
3455 @defvr {Scheme Variable} ocaml-build-system
3456 This variable is exported by @code{(guix build-system ocaml)}. It implements
3457 a build procedure for @uref{https://ocaml.org, OCaml} packages, which consists
3458 of choosing the correct set of commands to run for each package. OCaml
3459 packages can expect many different commands to be run. This build system will
3462 When the package has a @file{setup.ml} file present at the top-level, it will
3463 run @code{ocaml setup.ml -configure}, @code{ocaml setup.ml -build} and
3464 @code{ocaml setup.ml -install}. The build system will assume that this file
3465 was generated by @uref{http://oasis.forge.ocamlcore.org/, OASIS} and will take
3466 care of setting the prefix and enabling tests if they are not disabled. You
3467 can pass configure and build flags with the @code{#:configure-flags} and
3468 @code{#:build-flags}. The @code{#:test-flags} key can be passed to change the
3469 set of flags used to enable tests. The @code{#:use-make?} key can be used to
3470 bypass this system in the build and install phases.
3472 When the package has a @file{configure} file, it is assumed that it is a
3473 hand-made configure script that requires a different argument format than
3474 in the @code{gnu-build-system}. You can add more flags with the
3475 @code{#:configure-flags} key.
3477 When the package has a @file{Makefile} file (or @code{#:use-make?} is
3478 @code{#t}), it will be used and more flags can be passed to the build and
3479 install phases with the @code{#:make-flags} key.
3481 Finally, some packages do not have these files and use a somewhat standard
3482 location for its build system. In that case, the build system will run
3483 @code{ocaml pkg/pkg.ml} or @code{ocaml pkg/build.ml} and take care of
3484 providing the path to the required findlib module. Additional flags can
3485 be passed via the @code{#:build-flags} key. Install is taken care of by
3486 @command{opam-installer}. In this case, the @code{opam} package must
3487 be added to the @code{native-inputs} field of the package definition.
3489 Note that most OCaml packages assume they will be installed in the same
3490 directory as OCaml, which is not what we want in guix. In particular, they
3491 will install @file{.so} files in their module's directory, which is usually
3492 fine because it is in the OCaml compiler directory. In guix though, these
3493 libraries cannot be found and we use @code{CAML_LD_LIBRARY_PATH}. This
3494 variable points to @file{lib/ocaml/site-lib/stubslibs} and this is where
3495 @file{.so} libraries should be installed.
3498 @defvr {Scheme Variable} python-build-system
3499 This variable is exported by @code{(guix build-system python)}. It
3500 implements the more or less standard build procedure used by Python
3501 packages, which consists in running @code{python setup.py build} and
3502 then @code{python setup.py install --prefix=/gnu/store/@dots{}}.
3504 For packages that install stand-alone Python programs under @code{bin/},
3505 it takes care of wrapping these programs so that their @code{PYTHONPATH}
3506 environment variable points to all the Python libraries they depend on.
3508 Which Python package is used to perform the build can be specified with
3509 the @code{#:python} parameter. This is a useful way to force a package
3510 to be built for a specific version of the Python interpreter, which
3511 might be necessary if the package is only compatible with a single
3512 interpreter version.
3514 By default guix calls @code{setup.py} under control of
3515 @code{setuptools}, much like @command{pip} does. Some packages are not
3516 compatible with setuptools (and pip), thus you can disable this by
3517 setting the @code{#:use-setuptools} parameter to @code{#f}.
3520 @defvr {Scheme Variable} perl-build-system
3521 This variable is exported by @code{(guix build-system perl)}. It
3522 implements the standard build procedure for Perl packages, which either
3523 consists in running @code{perl Build.PL --prefix=/gnu/store/@dots{}},
3524 followed by @code{Build} and @code{Build install}; or in running
3525 @code{perl Makefile.PL PREFIX=/gnu/store/@dots{}}, followed by
3526 @code{make} and @code{make install}, depending on which of
3527 @code{Build.PL} or @code{Makefile.PL} is present in the package
3528 distribution. Preference is given to the former if both @code{Build.PL}
3529 and @code{Makefile.PL} exist in the package distribution. This
3530 preference can be reversed by specifying @code{#t} for the
3531 @code{#:make-maker?} parameter.
3533 The initial @code{perl Makefile.PL} or @code{perl Build.PL} invocation
3534 passes flags specified by the @code{#:make-maker-flags} or
3535 @code{#:module-build-flags} parameter, respectively.
3537 Which Perl package is used can be specified with @code{#:perl}.
3540 @defvr {Scheme Variable} r-build-system
3541 This variable is exported by @code{(guix build-system r)}. It
3542 implements the build procedure used by @uref{http://r-project.org, R}
3543 packages, which essentially is little more than running @code{R CMD
3544 INSTALL --library=/gnu/store/@dots{}} in an environment where
3545 @code{R_LIBS_SITE} contains the paths to all R package inputs. Tests
3546 are run after installation using the R function
3547 @code{tools::testInstalledPackage}.
3550 @defvr {Scheme Variable} ruby-build-system
3551 This variable is exported by @code{(guix build-system ruby)}. It
3552 implements the RubyGems build procedure used by Ruby packages, which
3553 involves running @code{gem build} followed by @code{gem install}.
3555 The @code{source} field of a package that uses this build system
3556 typically references a gem archive, since this is the format that Ruby
3557 developers use when releasing their software. The build system unpacks
3558 the gem archive, potentially patches the source, runs the test suite,
3559 repackages the gem, and installs it. Additionally, directories and
3560 tarballs may be referenced to allow building unreleased gems from Git or
3561 a traditional source release tarball.
3563 Which Ruby package is used can be specified with the @code{#:ruby}
3564 parameter. A list of additional flags to be passed to the @command{gem}
3565 command can be specified with the @code{#:gem-flags} parameter.
3568 @defvr {Scheme Variable} waf-build-system
3569 This variable is exported by @code{(guix build-system waf)}. It
3570 implements a build procedure around the @code{waf} script. The common
3571 phases---@code{configure}, @code{build}, and @code{install}---are
3572 implemented by passing their names as arguments to the @code{waf}
3575 The @code{waf} script is executed by the Python interpreter. Which
3576 Python package is used to run the script can be specified with the
3577 @code{#:python} parameter.
3580 @defvr {Scheme Variable} haskell-build-system
3581 This variable is exported by @code{(guix build-system haskell)}. It
3582 implements the Cabal build procedure used by Haskell packages, which
3583 involves running @code{runhaskell Setup.hs configure
3584 --prefix=/gnu/store/@dots{}} and @code{runhaskell Setup.hs build}.
3585 Instead of installing the package by running @code{runhaskell Setup.hs
3586 install}, to avoid trying to register libraries in the read-only
3587 compiler store directory, the build system uses @code{runhaskell
3588 Setup.hs copy}, followed by @code{runhaskell Setup.hs register}. In
3589 addition, the build system generates the package documentation by
3590 running @code{runhaskell Setup.hs haddock}, unless @code{#:haddock? #f}
3591 is passed. Optional Haddock parameters can be passed with the help of
3592 the @code{#:haddock-flags} parameter. If the file @code{Setup.hs} is
3593 not found, the build system looks for @code{Setup.lhs} instead.
3595 Which Haskell compiler is used can be specified with the @code{#:haskell}
3596 parameter which defaults to @code{ghc}.
3599 @defvr {Scheme Variable} dub-build-system
3600 This variable is exported by @code{(guix build-system dub)}. It
3601 implements the Dub build procedure used by D packages, which
3602 involves running @code{dub build} and @code{dub run}.
3603 Installation is done by copying the files manually.
3605 Which D compiler is used can be specified with the @code{#:ldc}
3606 parameter which defaults to @code{ldc}.
3609 @defvr {Scheme Variable} emacs-build-system
3610 This variable is exported by @code{(guix build-system emacs)}. It
3611 implements an installation procedure similar to the packaging system
3612 of Emacs itself (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
3614 It first creates the @code{@var{package}-autoloads.el} file, then it
3615 byte compiles all Emacs Lisp files. Differently from the Emacs
3616 packaging system, the Info documentation files are moved to the standard
3617 documentation directory and the @file{dir} file is deleted. Each
3618 package is installed in its own directory under
3619 @file{share/emacs/site-lisp/guix.d}.
3622 Lastly, for packages that do not need anything as sophisticated, a
3623 ``trivial'' build system is provided. It is trivial in the sense that
3624 it provides basically no support: it does not pull any implicit inputs,
3625 and does not have a notion of build phases.
3627 @defvr {Scheme Variable} trivial-build-system
3628 This variable is exported by @code{(guix build-system trivial)}.
3630 This build system requires a @code{#:builder} argument. This argument
3631 must be a Scheme expression that builds the package output(s)---as
3632 with @code{build-expression->derivation} (@pxref{Derivations,
3633 @code{build-expression->derivation}}).
3643 Conceptually, the @dfn{store} is the place where derivations that have
3644 been built successfully are stored---by default, @file{/gnu/store}.
3645 Sub-directories in the store are referred to as @dfn{store items} or
3646 sometimes @dfn{store paths}. The store has an associated database that
3647 contains information such as the store paths referred to by each store
3648 path, and the list of @emph{valid} store items---results of successful
3649 builds. This database resides in @file{@var{localstatedir}/guix/db},
3650 where @var{localstatedir} is the state directory specified @i{via}
3651 @option{--localstatedir} at configure time, usually @file{/var}.
3653 The store is @emph{always} accessed by the daemon on behalf of its clients
3654 (@pxref{Invoking guix-daemon}). To manipulate the store, clients
3655 connect to the daemon over a Unix-domain socket, send requests to it,
3656 and read the result---these are remote procedure calls, or RPCs.
3659 Users must @emph{never} modify files under @file{/gnu/store} directly.
3660 This would lead to inconsistencies and break the immutability
3661 assumptions of Guix's functional model (@pxref{Introduction}).
3663 @xref{Invoking guix gc, @command{guix gc --verify}}, for information on
3664 how to check the integrity of the store and attempt recovery from
3665 accidental modifications.
3668 The @code{(guix store)} module provides procedures to connect to the
3669 daemon, and to perform RPCs. These are described below. By default,
3670 @code{open-connection}, and thus all the @command{guix} commands,
3671 connect to the local daemon or to the URI specified by the
3672 @code{GUIX_DAEMON_SOCKET} environment variable.
3674 @defvr {Environment Variable} GUIX_DAEMON_SOCKET
3675 When set, the value of this variable should be a file name or a URI
3676 designating the daemon endpoint. When it is a file name, it denotes a
3677 Unix-domain socket to connect to. In addition to file names, the
3678 supported URI schemes are:
3683 These are for Unix-domain sockets.
3684 @code{file:///var/guix/daemon-socket/socket} is equivalent to
3685 @file{/var/guix/daemon-socket/socket}.
3688 These URIs denote connections over TCP/IP, without encryption nor
3689 authentication of the remote host. The URI must always specify both the
3690 host name and port number:
3693 guix://master.guix.example.org:1234
3696 This setup is suitable on local networks, such as clusters, where only
3697 trusted nodes may connect to the build daemon at
3698 @code{master.guix.example.org}.
3701 @cindex SSH access to build daemons
3702 These URIs allow you to connect to a remote daemon over
3703 SSH@footnote{This feature requires Guile-SSH (@pxref{Requirements}).}.
3704 A typical URL might look like this:
3707 ssh://charlie@@guix.example.org:22
3710 As for @command{guix copy}, the usual OpenSSH client configuration files
3711 are honored (@pxref{Invoking guix copy}).
3714 Additional URI schemes may be supported in the future.
3716 @c XXX: Remove this note when the protocol incurs fewer round trips
3717 @c and when (guix derivations) no longer relies on file system access.
3719 The ability to connect to remote build daemons is considered
3720 experimental as of @value{VERSION}. Please get in touch with us to
3721 share any problems or suggestions you may have (@pxref{Contributing}).
3725 @deffn {Scheme Procedure} open-connection [@var{uri}] [#:reserve-space? #t]
3726 Connect to the daemon over the Unix-domain socket at @var{uri} (a string). When
3727 @var{reserve-space?} is true, instruct it to reserve a little bit of
3728 extra space on the file system so that the garbage collector can still
3729 operate should the disk become full. Return a server object.
3731 @var{file} defaults to @var{%default-socket-path}, which is the normal
3732 location given the options that were passed to @command{configure}.
3735 @deffn {Scheme Procedure} close-connection @var{server}
3736 Close the connection to @var{server}.
3739 @defvr {Scheme Variable} current-build-output-port
3740 This variable is bound to a SRFI-39 parameter, which refers to the port
3741 where build and error logs sent by the daemon should be written.
3744 Procedures that make RPCs all take a server object as their first
3747 @deffn {Scheme Procedure} valid-path? @var{server} @var{path}
3748 @cindex invalid store items
3749 Return @code{#t} when @var{path} designates a valid store item and
3750 @code{#f} otherwise (an invalid item may exist on disk but still be
3751 invalid, for instance because it is the result of an aborted or failed
3754 A @code{&nix-protocol-error} condition is raised if @var{path} is not
3755 prefixed by the store directory (@file{/gnu/store}).
3758 @deffn {Scheme Procedure} add-text-to-store @var{server} @var{name} @var{text} [@var{references}]
3759 Add @var{text} under file @var{name} in the store, and return its store
3760 path. @var{references} is the list of store paths referred to by the
3761 resulting store path.
3764 @deffn {Scheme Procedure} build-derivations @var{server} @var{derivations}
3765 Build @var{derivations} (a list of @code{<derivation>} objects or
3766 derivation paths), and return when the worker is done building them.
3767 Return @code{#t} on success.
3770 Note that the @code{(guix monads)} module provides a monad as well as
3771 monadic versions of the above procedures, with the goal of making it
3772 more convenient to work with code that accesses the store (@pxref{The
3776 @i{This section is currently incomplete.}
3779 @section Derivations
3782 Low-level build actions and the environment in which they are performed
3783 are represented by @dfn{derivations}. A derivation contains the
3784 following pieces of information:
3788 The outputs of the derivation---derivations produce at least one file or
3789 directory in the store, but may produce more.
3792 The inputs of the derivations, which may be other derivations or plain
3793 files in the store (patches, build scripts, etc.)
3796 The system type targeted by the derivation---e.g., @code{x86_64-linux}.
3799 The file name of a build script in the store, along with the arguments
3803 A list of environment variables to be defined.
3807 @cindex derivation path
3808 Derivations allow clients of the daemon to communicate build actions to
3809 the store. They exist in two forms: as an in-memory representation,
3810 both on the client- and daemon-side, and as files in the store whose
3811 name end in @code{.drv}---these files are referred to as @dfn{derivation
3812 paths}. Derivations paths can be passed to the @code{build-derivations}
3813 procedure to perform the build actions they prescribe (@pxref{The
3816 The @code{(guix derivations)} module provides a representation of
3817 derivations as Scheme objects, along with procedures to create and
3818 otherwise manipulate derivations. The lowest-level primitive to create
3819 a derivation is the @code{derivation} procedure:
3821 @deffn {Scheme Procedure} derivation @var{store} @var{name} @var{builder} @
3822 @var{args} [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3823 [#:recursive? #f] [#:inputs '()] [#:env-vars '()] @
3824 [#:system (%current-system)] [#:references-graphs #f] @
3825 [#:allowed-references #f] [#:disallowed-references #f] @
3826 [#:leaked-env-vars #f] [#:local-build? #f] @
3827 [#:substitutable? #t]
3828 Build a derivation with the given arguments, and return the resulting
3829 @code{<derivation>} object.
3831 When @var{hash} and @var{hash-algo} are given, a
3832 @dfn{fixed-output derivation} is created---i.e., one whose result is
3833 known in advance, such as a file download. If, in addition,
3834 @var{recursive?} is true, then that fixed output may be an executable
3835 file or a directory and @var{hash} must be the hash of an archive
3836 containing this output.
3838 When @var{references-graphs} is true, it must be a list of file
3839 name/store path pairs. In that case, the reference graph of each store
3840 path is exported in the build environment in the corresponding file, in
3841 a simple text format.
3843 When @var{allowed-references} is true, it must be a list of store items
3844 or outputs that the derivation's output may refer to. Likewise,
3845 @var{disallowed-references}, if true, must be a list of things the
3846 outputs may @emph{not} refer to.
3848 When @var{leaked-env-vars} is true, it must be a list of strings
3849 denoting environment variables that are allowed to ``leak'' from the
3850 daemon's environment to the build environment. This is only applicable
3851 to fixed-output derivations---i.e., when @var{hash} is true. The main
3852 use is to allow variables such as @code{http_proxy} to be passed to
3853 derivations that download files.
3855 When @var{local-build?} is true, declare that the derivation is not a
3856 good candidate for offloading and should rather be built locally
3857 (@pxref{Daemon Offload Setup}). This is the case for small derivations
3858 where the costs of data transfers would outweigh the benefits.
3860 When @var{substitutable?} is false, declare that substitutes of the
3861 derivation's output should not be used (@pxref{Substitutes}). This is
3862 useful, for instance, when building packages that capture details of the
3863 host CPU instruction set.
3867 Here's an example with a shell script as its builder, assuming
3868 @var{store} is an open connection to the daemon, and @var{bash} points
3869 to a Bash executable in the store:
3872 (use-modules (guix utils)
3876 (let ((builder ; add the Bash script to the store
3877 (add-text-to-store store "my-builder.sh"
3878 "echo hello world > $out\n" '())))
3879 (derivation store "foo"
3880 bash `("-e" ,builder)
3881 #:inputs `((,bash) (,builder))
3882 #:env-vars '(("HOME" . "/homeless"))))
3883 @result{} #<derivation /gnu/store/@dots{}-foo.drv => /gnu/store/@dots{}-foo>
3886 As can be guessed, this primitive is cumbersome to use directly. A
3887 better approach is to write build scripts in Scheme, of course! The
3888 best course of action for that is to write the build code as a
3889 ``G-expression'', and to pass it to @code{gexp->derivation}. For more
3890 information, @pxref{G-Expressions}.
3892 Once upon a time, @code{gexp->derivation} did not exist and constructing
3893 derivations with build code written in Scheme was achieved with
3894 @code{build-expression->derivation}, documented below. This procedure
3895 is now deprecated in favor of the much nicer @code{gexp->derivation}.
3897 @deffn {Scheme Procedure} build-expression->derivation @var{store} @
3898 @var{name} @var{exp} @
3899 [#:system (%current-system)] [#:inputs '()] @
3900 [#:outputs '("out")] [#:hash #f] [#:hash-algo #f] @
3901 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
3902 [#:references-graphs #f] [#:allowed-references #f] @
3903 [#:disallowed-references #f] @
3904 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
3905 Return a derivation that executes Scheme expression @var{exp} as a
3906 builder for derivation @var{name}. @var{inputs} must be a list of
3907 @code{(name drv-path sub-drv)} tuples; when @var{sub-drv} is omitted,
3908 @code{"out"} is assumed. @var{modules} is a list of names of Guile
3909 modules from the current search path to be copied in the store,
3910 compiled, and made available in the load path during the execution of
3911 @var{exp}---e.g., @code{((guix build utils) (guix build
3912 gnu-build-system))}.
3914 @var{exp} is evaluated in an environment where @code{%outputs} is bound
3915 to a list of output/path pairs, and where @code{%build-inputs} is bound
3916 to a list of string/output-path pairs made from @var{inputs}.
3917 Optionally, @var{env-vars} is a list of string pairs specifying the name
3918 and value of environment variables visible to the builder. The builder
3919 terminates by passing the result of @var{exp} to @code{exit}; thus, when
3920 @var{exp} returns @code{#f}, the build is considered to have failed.
3922 @var{exp} is built using @var{guile-for-build} (a derivation). When
3923 @var{guile-for-build} is omitted or is @code{#f}, the value of the
3924 @code{%guile-for-build} fluid is used instead.
3926 See the @code{derivation} procedure for the meaning of
3927 @var{references-graphs}, @var{allowed-references},
3928 @var{disallowed-references}, @var{local-build?}, and
3929 @var{substitutable?}.
3933 Here's an example of a single-output derivation that creates a directory
3934 containing one file:
3937 (let ((builder '(let ((out (assoc-ref %outputs "out")))
3938 (mkdir out) ; create /gnu/store/@dots{}-goo
3939 (call-with-output-file (string-append out "/test")
3941 (display '(hello guix) p))))))
3942 (build-expression->derivation store "goo" builder))
3944 @result{} #<derivation /gnu/store/@dots{}-goo.drv => @dots{}>
3948 @node The Store Monad
3949 @section The Store Monad
3953 The procedures that operate on the store described in the previous
3954 sections all take an open connection to the build daemon as their first
3955 argument. Although the underlying model is functional, they either have
3956 side effects or depend on the current state of the store.
3958 The former is inconvenient: the connection to the build daemon has to be
3959 carried around in all those functions, making it impossible to compose
3960 functions that do not take that parameter with functions that do. The
3961 latter can be problematic: since store operations have side effects
3962 and/or depend on external state, they have to be properly sequenced.
3964 @cindex monadic values
3965 @cindex monadic functions
3966 This is where the @code{(guix monads)} module comes in. This module
3967 provides a framework for working with @dfn{monads}, and a particularly
3968 useful monad for our uses, the @dfn{store monad}. Monads are a
3969 construct that allows two things: associating ``context'' with values
3970 (in our case, the context is the store), and building sequences of
3971 computations (here computations include accesses to the store). Values
3972 in a monad---values that carry this additional context---are called
3973 @dfn{monadic values}; procedures that return such values are called
3974 @dfn{monadic procedures}.
3976 Consider this ``normal'' procedure:
3979 (define (sh-symlink store)
3980 ;; Return a derivation that symlinks the 'bash' executable.
3981 (let* ((drv (package-derivation store bash))
3982 (out (derivation->output-path drv))
3983 (sh (string-append out "/bin/bash")))
3984 (build-expression->derivation store "sh"
3985 `(symlink ,sh %output))))
3988 Using @code{(guix monads)} and @code{(guix gexp)}, it may be rewritten
3989 as a monadic function:
3992 (define (sh-symlink)
3993 ;; Same, but return a monadic value.
3994 (mlet %store-monad ((drv (package->derivation bash)))
3995 (gexp->derivation "sh"
3996 #~(symlink (string-append #$drv "/bin/bash")
4000 There are several things to note in the second version: the @code{store}
4001 parameter is now implicit and is ``threaded'' in the calls to the
4002 @code{package->derivation} and @code{gexp->derivation} monadic
4003 procedures, and the monadic value returned by @code{package->derivation}
4004 is @dfn{bound} using @code{mlet} instead of plain @code{let}.
4006 As it turns out, the call to @code{package->derivation} can even be
4007 omitted since it will take place implicitly, as we will see later
4008 (@pxref{G-Expressions}):
4011 (define (sh-symlink)
4012 (gexp->derivation "sh"
4013 #~(symlink (string-append #$bash "/bin/bash")
4018 @c <https://syntaxexclamation.wordpress.com/2014/06/26/escaping-continuations/>
4019 @c for the funny quote.
4020 Calling the monadic @code{sh-symlink} has no effect. As someone once
4021 said, ``you exit a monad like you exit a building on fire: by running''.
4022 So, to exit the monad and get the desired effect, one must use
4023 @code{run-with-store}:
4026 (run-with-store (open-connection) (sh-symlink))
4027 @result{} /gnu/store/...-sh-symlink
4030 Note that the @code{(guix monad-repl)} module extends the Guile REPL with
4031 new ``meta-commands'' to make it easier to deal with monadic procedures:
4032 @code{run-in-store}, and @code{enter-store-monad}. The former is used
4033 to ``run'' a single monadic value through the store:
4036 scheme@@(guile-user)> ,run-in-store (package->derivation hello)
4037 $1 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4040 The latter enters a recursive REPL, where all the return values are
4041 automatically run through the store:
4044 scheme@@(guile-user)> ,enter-store-monad
4045 store-monad@@(guile-user) [1]> (package->derivation hello)
4046 $2 = #<derivation /gnu/store/@dots{}-hello-2.9.drv => @dots{}>
4047 store-monad@@(guile-user) [1]> (text-file "foo" "Hello!")
4048 $3 = "/gnu/store/@dots{}-foo"
4049 store-monad@@(guile-user) [1]> ,q
4050 scheme@@(guile-user)>
4054 Note that non-monadic values cannot be returned in the
4055 @code{store-monad} REPL.
4057 The main syntactic forms to deal with monads in general are provided by
4058 the @code{(guix monads)} module and are described below.
4060 @deffn {Scheme Syntax} with-monad @var{monad} @var{body} ...
4061 Evaluate any @code{>>=} or @code{return} forms in @var{body} as being
4065 @deffn {Scheme Syntax} return @var{val}
4066 Return a monadic value that encapsulates @var{val}.
4069 @deffn {Scheme Syntax} >>= @var{mval} @var{mproc} ...
4070 @dfn{Bind} monadic value @var{mval}, passing its ``contents'' to monadic
4071 procedures @var{mproc}@dots{}@footnote{This operation is commonly
4072 referred to as ``bind'', but that name denotes an unrelated procedure in
4073 Guile. Thus we use this somewhat cryptic symbol inherited from the
4074 Haskell language.}. There can be one @var{mproc} or several of them, as
4079 (with-monad %state-monad
4081 (lambda (x) (return (+ 1 x)))
4082 (lambda (x) (return (* 2 x)))))
4086 @result{} some-state
4090 @deffn {Scheme Syntax} mlet @var{monad} ((@var{var} @var{mval}) ...) @
4092 @deffnx {Scheme Syntax} mlet* @var{monad} ((@var{var} @var{mval}) ...) @
4094 Bind the variables @var{var} to the monadic values @var{mval} in
4095 @var{body}, which is a sequence of expressions. As with the bind
4096 operator, this can be thought of as ``unpacking'' the raw, non-monadic
4097 value ``contained'' in @var{mval} and making @var{var} refer to that
4098 raw, non-monadic value within the scope of the @var{body}. The form
4099 (@var{var} -> @var{val}) binds @var{var} to the ``normal'' value
4100 @var{val}, as per @code{let}. The binding operations occur in sequence
4101 from left to right. The last expression of @var{body} must be a monadic
4102 expression, and its result will become the result of the @code{mlet} or
4103 @code{mlet*} when run in the @var{monad}.
4105 @code{mlet*} is to @code{mlet} what @code{let*} is to @code{let}
4106 (@pxref{Local Bindings,,, guile, GNU Guile Reference Manual}).
4109 @deffn {Scheme System} mbegin @var{monad} @var{mexp} ...
4110 Bind @var{mexp} and the following monadic expressions in sequence,
4111 returning the result of the last expression. Every expression in the
4112 sequence must be a monadic expression.
4114 This is akin to @code{mlet}, except that the return values of the
4115 monadic expressions are ignored. In that sense, it is analogous to
4116 @code{begin}, but applied to monadic expressions.
4119 @deffn {Scheme System} mwhen @var{condition} @var{mexp0} @var{mexp*} ...
4120 When @var{condition} is true, evaluate the sequence of monadic
4121 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4122 @var{condition} is false, return @code{*unspecified*} in the current
4123 monad. Every expression in the sequence must be a monadic expression.
4126 @deffn {Scheme System} munless @var{condition} @var{mexp0} @var{mexp*} ...
4127 When @var{condition} is false, evaluate the sequence of monadic
4128 expressions @var{mexp0}..@var{mexp*} as in an @code{mbegin}. When
4129 @var{condition} is true, return @code{*unspecified*} in the current
4130 monad. Every expression in the sequence must be a monadic expression.
4134 The @code{(guix monads)} module provides the @dfn{state monad}, which
4135 allows an additional value---the state---to be @emph{threaded} through
4136 monadic procedure calls.
4138 @defvr {Scheme Variable} %state-monad
4139 The state monad. Procedures in the state monad can access and change
4140 the state that is threaded.
4142 Consider the example below. The @code{square} procedure returns a value
4143 in the state monad. It returns the square of its argument, but also
4144 increments the current state value:
4148 (mlet %state-monad ((count (current-state)))
4149 (mbegin %state-monad
4150 (set-current-state (+ 1 count))
4153 (run-with-state (sequence %state-monad (map square (iota 3))) 0)
4158 When ``run'' through @var{%state-monad}, we obtain that additional state
4159 value, which is the number of @code{square} calls.
4162 @deffn {Monadic Procedure} current-state
4163 Return the current state as a monadic value.
4166 @deffn {Monadic Procedure} set-current-state @var{value}
4167 Set the current state to @var{value} and return the previous state as a
4171 @deffn {Monadic Procedure} state-push @var{value}
4172 Push @var{value} to the current state, which is assumed to be a list,
4173 and return the previous state as a monadic value.
4176 @deffn {Monadic Procedure} state-pop
4177 Pop a value from the current state and return it as a monadic value.
4178 The state is assumed to be a list.
4181 @deffn {Scheme Procedure} run-with-state @var{mval} [@var{state}]
4182 Run monadic value @var{mval} starting with @var{state} as the initial
4183 state. Return two values: the resulting value, and the resulting state.
4186 The main interface to the store monad, provided by the @code{(guix
4187 store)} module, is as follows.
4189 @defvr {Scheme Variable} %store-monad
4190 The store monad---an alias for @var{%state-monad}.
4192 Values in the store monad encapsulate accesses to the store. When its
4193 effect is needed, a value of the store monad must be ``evaluated'' by
4194 passing it to the @code{run-with-store} procedure (see below.)
4197 @deffn {Scheme Procedure} run-with-store @var{store} @var{mval} [#:guile-for-build] [#:system (%current-system)]
4198 Run @var{mval}, a monadic value in the store monad, in @var{store}, an
4199 open store connection.
4202 @deffn {Monadic Procedure} text-file @var{name} @var{text} [@var{references}]
4203 Return as a monadic value the absolute file name in the store of the file
4204 containing @var{text}, a string. @var{references} is a list of store items that the
4205 resulting text file refers to; it defaults to the empty list.
4208 @deffn {Monadic Procedure} interned-file @var{file} [@var{name}] @
4209 [#:recursive? #t] [#:select? (const #t)]
4210 Return the name of @var{file} once interned in the store. Use
4211 @var{name} as its store name, or the basename of @var{file} if
4212 @var{name} is omitted.
4214 When @var{recursive?} is true, the contents of @var{file} are added
4215 recursively; if @var{file} designates a flat file and @var{recursive?}
4216 is true, its contents are added, and its permission bits are kept.
4218 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4219 @var{stat})} for each directory entry, where @var{file} is the entry's
4220 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4221 entries for which @var{select?} does not return true.
4223 The example below adds a file to the store, under two different names:
4226 (run-with-store (open-connection)
4227 (mlet %store-monad ((a (interned-file "README"))
4228 (b (interned-file "README" "LEGU-MIN")))
4229 (return (list a b))))
4231 @result{} ("/gnu/store/rwm@dots{}-README" "/gnu/store/44i@dots{}-LEGU-MIN")
4236 The @code{(guix packages)} module exports the following package-related
4239 @deffn {Monadic Procedure} package-file @var{package} [@var{file}] @
4240 [#:system (%current-system)] [#:target #f] @
4243 value in the absolute file name of @var{file} within the @var{output}
4244 directory of @var{package}. When @var{file} is omitted, return the name
4245 of the @var{output} directory of @var{package}. When @var{target} is
4246 true, use it as a cross-compilation target triplet.
4249 @deffn {Monadic Procedure} package->derivation @var{package} [@var{system}]
4250 @deffnx {Monadic Procedure} package->cross-derivation @var{package} @
4251 @var{target} [@var{system}]
4252 Monadic version of @code{package-derivation} and
4253 @code{package-cross-derivation} (@pxref{Defining Packages}).
4258 @section G-Expressions
4260 @cindex G-expression
4261 @cindex build code quoting
4262 So we have ``derivations'', which represent a sequence of build actions
4263 to be performed to produce an item in the store (@pxref{Derivations}).
4264 These build actions are performed when asking the daemon to actually
4265 build the derivations; they are run by the daemon in a container
4266 (@pxref{Invoking guix-daemon}).
4268 @cindex strata of code
4269 It should come as no surprise that we like to write these build actions
4270 in Scheme. When we do that, we end up with two @dfn{strata} of Scheme
4271 code@footnote{The term @dfn{stratum} in this context was coined by
4272 Manuel Serrano et al.@: in the context of their work on Hop. Oleg
4273 Kiselyov, who has written insightful
4274 @url{http://okmij.org/ftp/meta-programming/#meta-scheme, essays and code
4275 on this topic}, refers to this kind of code generation as
4276 @dfn{staging}.}: the ``host code''---code that defines packages, talks
4277 to the daemon, etc.---and the ``build code''---code that actually
4278 performs build actions, such as making directories, invoking
4279 @command{make}, etc.
4281 To describe a derivation and its build actions, one typically needs to
4282 embed build code inside host code. It boils down to manipulating build
4283 code as data, and the homoiconicity of Scheme---code has a direct
4284 representation as data---comes in handy for that. But we need more than
4285 the normal @code{quasiquote} mechanism in Scheme to construct build
4288 The @code{(guix gexp)} module implements @dfn{G-expressions}, a form of
4289 S-expressions adapted to build expressions. G-expressions, or
4290 @dfn{gexps}, consist essentially of three syntactic forms: @code{gexp},
4291 @code{ungexp}, and @code{ungexp-splicing} (or simply: @code{#~},
4292 @code{#$}, and @code{#$@@}), which are comparable to
4293 @code{quasiquote}, @code{unquote}, and @code{unquote-splicing},
4294 respectively (@pxref{Expression Syntax, @code{quasiquote},, guile,
4295 GNU Guile Reference Manual}). However, there are major differences:
4299 Gexps are meant to be written to a file and run or manipulated by other
4303 When a high-level object such as a package or derivation is unquoted
4304 inside a gexp, the result is as if its output file name had been
4308 Gexps carry information about the packages or derivations they refer to,
4309 and these dependencies are automatically added as inputs to the build
4310 processes that use them.
4313 @cindex lowering, of high-level objects in gexps
4314 This mechanism is not limited to package and derivation
4315 objects: @dfn{compilers} able to ``lower'' other high-level objects to
4316 derivations or files in the store can be defined,
4317 such that these objects can also be inserted
4318 into gexps. For example, a useful type of high-level objects that can be
4319 inserted in a gexp is ``file-like objects'', which make it easy to
4320 add files to the store and to refer to them in
4321 derivations and such (see @code{local-file} and @code{plain-file}
4324 To illustrate the idea, here is an example of a gexp:
4331 (symlink (string-append #$coreutils "/bin/ls")
4335 This gexp can be passed to @code{gexp->derivation}; we obtain a
4336 derivation that builds a directory containing exactly one symlink to
4337 @file{/gnu/store/@dots{}-coreutils-8.22/bin/ls}:
4340 (gexp->derivation "the-thing" build-exp)
4343 As one would expect, the @code{"/gnu/store/@dots{}-coreutils-8.22"} string is
4344 substituted to the reference to the @var{coreutils} package in the
4345 actual build code, and @var{coreutils} is automatically made an input to
4346 the derivation. Likewise, @code{#$output} (equivalent to @code{(ungexp
4347 output)}) is replaced by a string containing the directory name of the
4348 output of the derivation.
4350 @cindex cross compilation
4351 In a cross-compilation context, it is useful to distinguish between
4352 references to the @emph{native} build of a package---that can run on the
4353 host---versus references to cross builds of a package. To that end, the
4354 @code{#+} plays the same role as @code{#$}, but is a reference to a
4355 native package build:
4358 (gexp->derivation "vi"
4361 (system* (string-append #+coreutils "/bin/ln")
4363 (string-append #$emacs "/bin/emacs")
4364 (string-append #$output "/bin/vi")))
4365 #:target "mips64el-linux-gnu")
4369 In the example above, the native build of @var{coreutils} is used, so
4370 that @command{ln} can actually run on the host; but then the
4371 cross-compiled build of @var{emacs} is referenced.
4373 @cindex imported modules, for gexps
4374 @findex with-imported-modules
4375 Another gexp feature is @dfn{imported modules}: sometimes you want to be
4376 able to use certain Guile modules from the ``host environment'' in the
4377 gexp, so those modules should be imported in the ``build environment''.
4378 The @code{with-imported-modules} form allows you to express that:
4381 (let ((build (with-imported-modules '((guix build utils))
4383 (use-modules (guix build utils))
4384 (mkdir-p (string-append #$output "/bin"))))))
4385 (gexp->derivation "empty-dir"
4388 (display "success!\n")
4393 In this example, the @code{(guix build utils)} module is automatically
4394 pulled into the isolated build environment of our gexp, such that
4395 @code{(use-modules (guix build utils))} works as expected.
4397 @cindex module closure
4398 @findex source-module-closure
4399 Usually you want the @emph{closure} of the module to be imported---i.e.,
4400 the module itself and all the modules it depends on---rather than just
4401 the module; failing to do that, attempts to use the module will fail
4402 because of missing dependent modules. The @code{source-module-closure}
4403 procedure computes the closure of a module by looking at its source file
4404 headers, which comes in handy in this case:
4407 (use-modules (guix modules)) ;for 'source-module-closure'
4409 (with-imported-modules (source-module-closure
4410 '((guix build utils)
4412 (gexp->derivation "something-with-vms"
4414 (use-modules (guix build utils)
4419 The syntactic form to construct gexps is summarized below.
4421 @deffn {Scheme Syntax} #~@var{exp}
4422 @deffnx {Scheme Syntax} (gexp @var{exp})
4423 Return a G-expression containing @var{exp}. @var{exp} may contain one
4424 or more of the following forms:
4428 @itemx (ungexp @var{obj})
4429 Introduce a reference to @var{obj}. @var{obj} may have one of the
4430 supported types, for example a package or a
4431 derivation, in which case the @code{ungexp} form is replaced by its
4432 output file name---e.g., @code{"/gnu/store/@dots{}-coreutils-8.22}.
4434 If @var{obj} is a list, it is traversed and references to supported
4435 objects are substituted similarly.
4437 If @var{obj} is another gexp, its contents are inserted and its
4438 dependencies are added to those of the containing gexp.
4440 If @var{obj} is another kind of object, it is inserted as is.
4442 @item #$@var{obj}:@var{output}
4443 @itemx (ungexp @var{obj} @var{output})
4444 This is like the form above, but referring explicitly to the
4445 @var{output} of @var{obj}---this is useful when @var{obj} produces
4446 multiple outputs (@pxref{Packages with Multiple Outputs}).
4449 @itemx #+@var{obj}:output
4450 @itemx (ungexp-native @var{obj})
4451 @itemx (ungexp-native @var{obj} @var{output})
4452 Same as @code{ungexp}, but produces a reference to the @emph{native}
4453 build of @var{obj} when used in a cross compilation context.
4455 @item #$output[:@var{output}]
4456 @itemx (ungexp output [@var{output}])
4457 Insert a reference to derivation output @var{output}, or to the main
4458 output when @var{output} is omitted.
4460 This only makes sense for gexps passed to @code{gexp->derivation}.
4463 @itemx (ungexp-splicing @var{lst})
4464 Like the above, but splices the contents of @var{lst} inside the
4468 @itemx (ungexp-native-splicing @var{lst})
4469 Like the above, but refers to native builds of the objects listed in
4474 G-expressions created by @code{gexp} or @code{#~} are run-time objects
4475 of the @code{gexp?} type (see below.)
4478 @deffn {Scheme Syntax} with-imported-modules @var{modules} @var{body}@dots{}
4479 Mark the gexps defined in @var{body}@dots{} as requiring @var{modules}
4480 in their execution environment.
4482 Each item in @var{modules} can be the name of a module, such as
4483 @code{(guix build utils)}, or it can be a module name, followed by an
4484 arrow, followed by a file-like object:
4487 `((guix build utils)
4489 ((guix config) => ,(scheme-file "config.scm"
4490 #~(define-module @dots{}))))
4494 In the example above, the first two modules are taken from the search
4495 path, and the last one is created from the given file-like object.
4497 This form has @emph{lexical} scope: it has an effect on the gexps
4498 directly defined in @var{body}@dots{}, but not on those defined, say, in
4499 procedures called from @var{body}@dots{}.
4502 @deffn {Scheme Procedure} gexp? @var{obj}
4503 Return @code{#t} if @var{obj} is a G-expression.
4506 G-expressions are meant to be written to disk, either as code building
4507 some derivation, or as plain files in the store. The monadic procedures
4508 below allow you to do that (@pxref{The Store Monad}, for more
4509 information about monads.)
4511 @deffn {Monadic Procedure} gexp->derivation @var{name} @var{exp} @
4512 [#:system (%current-system)] [#:target #f] [#:graft? #t] @
4513 [#:hash #f] [#:hash-algo #f] @
4514 [#:recursive? #f] [#:env-vars '()] [#:modules '()] @
4515 [#:module-path @var{%load-path}] @
4516 [#:references-graphs #f] [#:allowed-references #f] @
4517 [#:disallowed-references #f] @
4518 [#:leaked-env-vars #f] @
4519 [#:script-name (string-append @var{name} "-builder")] @
4520 [#:local-build? #f] [#:substitutable? #t] [#:guile-for-build #f]
4521 Return a derivation @var{name} that runs @var{exp} (a gexp) with
4522 @var{guile-for-build} (a derivation) on @var{system}; @var{exp} is
4523 stored in a file called @var{script-name}. When @var{target} is true,
4524 it is used as the cross-compilation target triplet for packages referred
4527 @var{modules} is deprecated in favor of @code{with-imported-modules}.
4529 make @var{modules} available in the evaluation context of @var{exp};
4530 @var{modules} is a list of names of Guile modules searched in
4531 @var{module-path} to be copied in the store, compiled, and made available in
4532 the load path during the execution of @var{exp}---e.g., @code{((guix
4533 build utils) (guix build gnu-build-system))}.
4535 @var{graft?} determines whether packages referred to by @var{exp} should be grafted when
4538 When @var{references-graphs} is true, it must be a list of tuples of one of the
4542 (@var{file-name} @var{package})
4543 (@var{file-name} @var{package} @var{output})
4544 (@var{file-name} @var{derivation})
4545 (@var{file-name} @var{derivation} @var{output})
4546 (@var{file-name} @var{store-item})
4549 The right-hand-side of each element of @var{references-graphs} is automatically made
4550 an input of the build process of @var{exp}. In the build environment, each
4551 @var{file-name} contains the reference graph of the corresponding item, in a simple
4554 @var{allowed-references} must be either @code{#f} or a list of output names and packages.
4555 In the latter case, the list denotes store items that the result is allowed to
4556 refer to. Any reference to another store item will lead to a build error.
4557 Similarly for @var{disallowed-references}, which can list items that must not be
4558 referenced by the outputs.
4560 The other arguments are as for @code{derivation} (@pxref{Derivations}).
4563 @cindex file-like objects
4564 The @code{local-file}, @code{plain-file}, @code{computed-file},
4565 @code{program-file}, and @code{scheme-file} procedures below return
4566 @dfn{file-like objects}. That is, when unquoted in a G-expression,
4567 these objects lead to a file in the store. Consider this G-expression:
4570 #~(system* #$(file-append glibc "/sbin/nscd") "-f"
4571 #$(local-file "/tmp/my-nscd.conf"))
4574 The effect here is to ``intern'' @file{/tmp/my-nscd.conf} by copying it
4575 to the store. Once expanded, for instance @i{via}
4576 @code{gexp->derivation}, the G-expression refers to that copy under
4577 @file{/gnu/store}; thus, modifying or removing the file in @file{/tmp}
4578 does not have any effect on what the G-expression does.
4579 @code{plain-file} can be used similarly; it differs in that the file
4580 content is directly passed as a string.
4582 @deffn {Scheme Procedure} local-file @var{file} [@var{name}] @
4583 [#:recursive? #f] [#:select? (const #t)]
4584 Return an object representing local file @var{file} to add to the store; this
4585 object can be used in a gexp. If @var{file} is a relative file name, it is looked
4586 up relative to the source file where this form appears. @var{file} will be added to
4587 the store under @var{name}--by default the base name of @var{file}.
4589 When @var{recursive?} is true, the contents of @var{file} are added recursively; if @var{file}
4590 designates a flat file and @var{recursive?} is true, its contents are added, and its
4591 permission bits are kept.
4593 When @var{recursive?} is true, call @code{(@var{select?} @var{file}
4594 @var{stat})} for each directory entry, where @var{file} is the entry's
4595 absolute file name and @var{stat} is the result of @code{lstat}; exclude
4596 entries for which @var{select?} does not return true.
4598 This is the declarative counterpart of the @code{interned-file} monadic
4599 procedure (@pxref{The Store Monad, @code{interned-file}}).
4602 @deffn {Scheme Procedure} plain-file @var{name} @var{content}
4603 Return an object representing a text file called @var{name} with the given
4604 @var{content} (a string) to be added to the store.
4606 This is the declarative counterpart of @code{text-file}.
4609 @deffn {Scheme Procedure} computed-file @var{name} @var{gexp} @
4610 [#:options '(#:local-build? #t)]
4611 Return an object representing the store item @var{name}, a file or
4612 directory computed by @var{gexp}. @var{options}
4613 is a list of additional arguments to pass to @code{gexp->derivation}.
4615 This is the declarative counterpart of @code{gexp->derivation}.
4618 @deffn {Monadic Procedure} gexp->script @var{name} @var{exp}
4619 Return an executable script @var{name} that runs @var{exp} using
4620 @var{guile}, with @var{exp}'s imported modules in its search path.
4622 The example below builds a script that simply invokes the @command{ls}
4626 (use-modules (guix gexp) (gnu packages base))
4628 (gexp->script "list-files"
4629 #~(execl #$(file-append coreutils "/bin/ls")
4633 When ``running'' it through the store (@pxref{The Store Monad,
4634 @code{run-with-store}}), we obtain a derivation that produces an
4635 executable file @file{/gnu/store/@dots{}-list-files} along these lines:
4638 #!/gnu/store/@dots{}-guile-2.0.11/bin/guile -ds
4640 (execl "/gnu/store/@dots{}-coreutils-8.22"/bin/ls" "ls")
4644 @deffn {Scheme Procedure} program-file @var{name} @var{exp} @
4646 Return an object representing the executable store item @var{name} that
4647 runs @var{gexp}. @var{guile} is the Guile package used to execute that
4650 This is the declarative counterpart of @code{gexp->script}.
4653 @deffn {Monadic Procedure} gexp->file @var{name} @var{exp} @
4654 [#:set-load-path? #t]
4655 Return a derivation that builds a file @var{name} containing @var{exp}.
4656 When @var{set-load-path?} is true, emit code in the resulting file to
4657 set @code{%load-path} and @code{%load-compiled-path} to honor
4658 @var{exp}'s imported modules.
4660 The resulting file holds references to all the dependencies of @var{exp}
4661 or a subset thereof.
4664 @deffn {Scheme Procedure} scheme-file @var{name} @var{exp}
4665 Return an object representing the Scheme file @var{name} that contains
4668 This is the declarative counterpart of @code{gexp->file}.
4671 @deffn {Monadic Procedure} text-file* @var{name} @var{text} @dots{}
4672 Return as a monadic value a derivation that builds a text file
4673 containing all of @var{text}. @var{text} may list, in addition to
4674 strings, objects of any type that can be used in a gexp: packages,
4675 derivations, local file objects, etc. The resulting store file holds
4676 references to all these.
4678 This variant should be preferred over @code{text-file} anytime the file
4679 to create will reference items from the store. This is typically the
4680 case when building a configuration file that embeds store file names,
4684 (define (profile.sh)
4685 ;; Return the name of a shell script in the store that
4686 ;; initializes the 'PATH' environment variable.
4687 (text-file* "profile.sh"
4688 "export PATH=" coreutils "/bin:"
4689 grep "/bin:" sed "/bin\n"))
4692 In this example, the resulting @file{/gnu/store/@dots{}-profile.sh} file
4693 will reference @var{coreutils}, @var{grep}, and @var{sed}, thereby
4694 preventing them from being garbage-collected during its lifetime.
4697 @deffn {Scheme Procedure} mixed-text-file @var{name} @var{text} @dots{}
4698 Return an object representing store file @var{name} containing
4699 @var{text}. @var{text} is a sequence of strings and file-like objects,
4703 (mixed-text-file "profile"
4704 "export PATH=" coreutils "/bin:" grep "/bin")
4707 This is the declarative counterpart of @code{text-file*}.
4710 @deffn {Scheme Procedure} file-append @var{obj} @var{suffix} @dots{}
4711 Return a file-like object that expands to the concatenation of @var{obj}
4712 and @var{suffix}, where @var{obj} is a lowerable object and each
4713 @var{suffix} is a string.
4715 As an example, consider this gexp:
4718 (gexp->script "run-uname"
4719 #~(system* #$(file-append coreutils
4723 The same effect could be achieved with:
4726 (gexp->script "run-uname"
4727 #~(system* (string-append #$coreutils
4731 There is one difference though: in the @code{file-append} case, the
4732 resulting script contains the absolute file name as a string, whereas in
4733 the second case, the resulting script contains a @code{(string-append
4734 @dots{})} expression to construct the file name @emph{at run time}.
4738 Of course, in addition to gexps embedded in ``host'' code, there are
4739 also modules containing build tools. To make it clear that they are
4740 meant to be used in the build stratum, these modules are kept in the
4741 @code{(guix build @dots{})} name space.
4743 @cindex lowering, of high-level objects in gexps
4744 Internally, high-level objects are @dfn{lowered}, using their compiler,
4745 to either derivations or store items. For instance, lowering a package
4746 yields a derivation, and lowering a @code{plain-file} yields a store
4747 item. This is achieved using the @code{lower-object} monadic procedure.
4749 @deffn {Monadic Procedure} lower-object @var{obj} [@var{system}] @
4751 Return as a value in @var{%store-monad} the derivation or store item
4752 corresponding to @var{obj} for @var{system}, cross-compiling for
4753 @var{target} if @var{target} is true. @var{obj} must be an object that
4754 has an associated gexp compiler, such as a @code{<package>}.
4758 @c *********************************************************************
4762 This section describes Guix command-line utilities. Some of them are
4763 primarily targeted at developers and users who write new package
4764 definitions, while others are more generally useful. They complement
4765 the Scheme programming interface of Guix in a convenient way.
4768 * Invoking guix build:: Building packages from the command line.
4769 * Invoking guix edit:: Editing package definitions.
4770 * Invoking guix download:: Downloading a file and printing its hash.
4771 * Invoking guix hash:: Computing the cryptographic hash of a file.
4772 * Invoking guix import:: Importing package definitions.
4773 * Invoking guix refresh:: Updating package definitions.
4774 * Invoking guix lint:: Finding errors in package definitions.
4775 * Invoking guix size:: Profiling disk usage.
4776 * Invoking guix graph:: Visualizing the graph of packages.
4777 * Invoking guix environment:: Setting up development environments.
4778 * Invoking guix publish:: Sharing substitutes.
4779 * Invoking guix challenge:: Challenging substitute servers.
4780 * Invoking guix copy:: Copying to and from a remote store.
4781 * Invoking guix container:: Process isolation.
4784 @node Invoking guix build
4785 @section Invoking @command{guix build}
4787 @cindex package building
4788 @cindex @command{guix build}
4789 The @command{guix build} command builds packages or derivations and
4790 their dependencies, and prints the resulting store paths. Note that it
4791 does not modify the user's profile---this is the job of the
4792 @command{guix package} command (@pxref{Invoking guix package}). Thus,
4793 it is mainly useful for distribution developers.
4795 The general syntax is:
4798 guix build @var{options} @var{package-or-derivation}@dots{}
4801 As an example, the following command builds the latest versions of Emacs
4802 and of Guile, displays their build logs, and finally displays the
4803 resulting directories:
4806 guix build emacs guile
4809 Similarly, the following command builds all the available packages:
4812 guix build --quiet --keep-going \
4813 `guix package -A | cut -f1,2 --output-delimiter=@@`
4816 @var{package-or-derivation} may be either the name of a package found in
4817 the software distribution such as @code{coreutils} or
4818 @code{coreutils@@8.20}, or a derivation such as
4819 @file{/gnu/store/@dots{}-coreutils-8.19.drv}. In the former case, a
4820 package with the corresponding name (and optionally version) is searched
4821 for among the GNU distribution modules (@pxref{Package Modules}).
4823 Alternatively, the @code{--expression} option may be used to specify a
4824 Scheme expression that evaluates to a package; this is useful when
4825 disambiguating among several same-named packages or package variants is
4828 There may be zero or more @var{options}. The available options are
4829 described in the subsections below.
4832 * Common Build Options:: Build options for most commands.
4833 * Package Transformation Options:: Creating variants of packages.
4834 * Additional Build Options:: Options specific to 'guix build'.
4837 @node Common Build Options
4838 @subsection Common Build Options
4840 A number of options that control the build process are common to
4841 @command{guix build} and other commands that can spawn builds, such as
4842 @command{guix package} or @command{guix archive}. These are the
4847 @item --load-path=@var{directory}
4848 @itemx -L @var{directory}
4849 Add @var{directory} to the front of the package module search path
4850 (@pxref{Package Modules}).
4852 This allows users to define their own packages and make them visible to
4853 the command-line tools.
4857 Keep the build tree of failed builds. Thus, if a build fails, its build
4858 tree is kept under @file{/tmp}, in a directory whose name is shown at
4859 the end of the build log. This is useful when debugging build issues.
4863 Keep going when some of the derivations fail to build; return only once
4864 all the builds have either completed or failed.
4866 The default behavior is to stop as soon as one of the specified
4867 derivations has failed.
4871 Do not build the derivations.
4874 When substituting a pre-built binary fails, fall back to building
4877 @item --substitute-urls=@var{urls}
4878 @anchor{client-substitute-urls}
4879 Consider @var{urls} the whitespace-separated list of substitute source
4880 URLs, overriding the default list of URLs of @command{guix-daemon}
4881 (@pxref{daemon-substitute-urls,, @command{guix-daemon} URLs}).
4883 This means that substitutes may be downloaded from @var{urls}, provided
4884 they are signed by a key authorized by the system administrator
4885 (@pxref{Substitutes}).
4887 When @var{urls} is the empty string, substitutes are effectively
4890 @item --no-substitutes
4891 Do not use substitutes for build products. That is, always build things
4892 locally instead of allowing downloads of pre-built binaries
4893 (@pxref{Substitutes}).
4896 Do not ``graft'' packages. In practice, this means that package updates
4897 available as grafts are not applied. @xref{Security Updates}, for more
4898 information on grafts.
4900 @item --rounds=@var{n}
4901 Build each derivation @var{n} times in a row, and raise an error if
4902 consecutive build results are not bit-for-bit identical.
4904 This is a useful way to detect non-deterministic builds processes.
4905 Non-deterministic build processes are a problem because they make it
4906 practically impossible for users to @emph{verify} whether third-party
4907 binaries are genuine. @xref{Invoking guix challenge}, for more.
4909 Note that, currently, the differing build results are not kept around,
4910 so you will have to manually investigate in case of an error---e.g., by
4911 stashing one of the build results with @code{guix archive --export}
4912 (@pxref{Invoking guix archive}), then rebuilding, and finally comparing
4915 @item --no-build-hook
4916 Do not attempt to offload builds @i{via} the ``build hook'' of the daemon
4917 (@pxref{Daemon Offload Setup}). That is, always build things locally
4918 instead of offloading builds to remote machines.
4920 @item --max-silent-time=@var{seconds}
4921 When the build or substitution process remains silent for more than
4922 @var{seconds}, terminate it and report a build failure.
4924 @item --timeout=@var{seconds}
4925 Likewise, when the build or substitution process lasts for more than
4926 @var{seconds}, terminate it and report a build failure.
4928 By default there is no timeout. This behavior can be restored with
4931 @item --verbosity=@var{level}
4932 Use the given verbosity level. @var{level} must be an integer between 0
4933 and 5; higher means more verbose output. Setting a level of 4 or more
4934 may be helpful when debugging setup issues with the build daemon.
4936 @item --cores=@var{n}
4938 Allow the use of up to @var{n} CPU cores for the build. The special
4939 value @code{0} means to use as many CPU cores as available.
4941 @item --max-jobs=@var{n}
4943 Allow at most @var{n} build jobs in parallel. @xref{Invoking
4944 guix-daemon, @code{--max-jobs}}, for details about this option and the
4945 equivalent @command{guix-daemon} option.
4949 Behind the scenes, @command{guix build} is essentially an interface to
4950 the @code{package-derivation} procedure of the @code{(guix packages)}
4951 module, and to the @code{build-derivations} procedure of the @code{(guix
4952 derivations)} module.
4954 In addition to options explicitly passed on the command line,
4955 @command{guix build} and other @command{guix} commands that support
4956 building honor the @code{GUIX_BUILD_OPTIONS} environment variable.
4958 @defvr {Environment Variable} GUIX_BUILD_OPTIONS
4959 Users can define this variable to a list of command line options that
4960 will automatically be used by @command{guix build} and other
4961 @command{guix} commands that can perform builds, as in the example
4965 $ export GUIX_BUILD_OPTIONS="--no-substitutes -c 2 -L /foo/bar"
4968 These options are parsed independently, and the result is appended to
4969 the parsed command-line options.
4973 @node Package Transformation Options
4974 @subsection Package Transformation Options
4976 @cindex package variants
4977 Another set of command-line options supported by @command{guix build}
4978 and also @command{guix package} are @dfn{package transformation
4979 options}. These are options that make it possible to define @dfn{package
4980 variants}---for instance, packages built from different source code.
4981 This is a convenient way to create customized packages on the fly
4982 without having to type in the definitions of package variants
4983 (@pxref{Defining Packages}).
4987 @item --with-source=@var{source}
4988 Use @var{source} as the source of the corresponding package.
4989 @var{source} must be a file name or a URL, as for @command{guix
4990 download} (@pxref{Invoking guix download}).
4992 The ``corresponding package'' is taken to be the one specified on the
4993 command line the name of which matches the base of @var{source}---e.g.,
4994 if @var{source} is @code{/src/guile-2.0.10.tar.gz}, the corresponding
4995 package is @code{guile}. Likewise, the version string is inferred from
4996 @var{source}; in the previous example, it is @code{2.0.10}.
4998 This option allows users to try out versions of packages other than the
4999 one provided by the distribution. The example below downloads
5000 @file{ed-1.7.tar.gz} from a GNU mirror and uses that as the source for
5001 the @code{ed} package:
5004 guix build ed --with-source=mirror://gnu/ed/ed-1.7.tar.gz
5007 As a developer, @code{--with-source} makes it easy to test release
5011 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
5014 @dots{} or to build from a checkout in a pristine environment:
5017 $ git clone git://git.sv.gnu.org/guix.git
5018 $ guix build guix --with-source=./guix
5021 @item --with-input=@var{package}=@var{replacement}
5022 Replace dependency on @var{package} by a dependency on
5023 @var{replacement}. @var{package} must be a package name, and
5024 @var{replacement} must be a package specification such as @code{guile}
5025 or @code{guile@@1.8}.
5027 For instance, the following command builds Guix, but replaces its
5028 dependency on the current stable version of Guile with a dependency on
5029 the legacy version of Guile, @code{guile@@2.0}:
5032 guix build --with-input=guile=guile@@2.0 guix
5035 This is a recursive, deep replacement. So in this example, both
5036 @code{guix} and its dependency @code{guile-json} (which also depends on
5037 @code{guile}) get rebuilt against @code{guile@@2.0}.
5039 This is implemented using the @code{package-input-rewriting} Scheme
5040 procedure (@pxref{Defining Packages, @code{package-input-rewriting}}).
5042 @item --with-graft=@var{package}=@var{replacement}
5043 This is similar to @code{--with-input} but with an important difference:
5044 instead of rebuilding the whole dependency chain, @var{replacement} is
5045 built and then @dfn{grafted} onto the binaries that were initially
5046 referring to @var{package}. @xref{Security Updates}, for more
5047 information on grafts.
5049 For example, the command below grafts version 3.5.4 of GnuTLS onto Wget
5050 and all its dependencies, replacing references to the version of GnuTLS
5051 they currently refer to:
5054 guix build --with-graft=gnutls=gnutls@@3.5.4 wget
5057 This has the advantage of being much faster than rebuilding everything.
5058 But there is a caveat: it works if and only if @var{package} and
5059 @var{replacement} are strictly compatible---for example, if they provide
5060 a library, the application binary interface (ABI) of those libraries
5061 must be compatible. If @var{replacement} is somehow incompatible with
5062 @var{package}, then the resulting package may be unusable. Use with
5067 @node Additional Build Options
5068 @subsection Additional Build Options
5070 The command-line options presented below are specific to @command{guix
5077 Build quietly, without displaying the build log. Upon completion, the
5078 build log is kept in @file{/var} (or similar) and can always be
5079 retrieved using the @option{--log-file} option.
5081 @item --file=@var{file}
5082 @itemx -f @var{file}
5084 Build the package or derivation that the code within @var{file}
5087 As an example, @var{file} might contain a package definition like this
5088 (@pxref{Defining Packages}):
5091 @verbatiminclude package-hello.scm
5094 @item --expression=@var{expr}
5095 @itemx -e @var{expr}
5096 Build the package or derivation @var{expr} evaluates to.
5098 For example, @var{expr} may be @code{(@@ (gnu packages guile)
5099 guile-1.8)}, which unambiguously designates this specific variant of
5100 version 1.8 of Guile.
5102 Alternatively, @var{expr} may be a G-expression, in which case it is used
5103 as a build program passed to @code{gexp->derivation}
5104 (@pxref{G-Expressions}).
5106 Lastly, @var{expr} may refer to a zero-argument monadic procedure
5107 (@pxref{The Store Monad}). The procedure must return a derivation as a
5108 monadic value, which is then passed through @code{run-with-store}.
5112 Build the source derivations of the packages, rather than the packages
5115 For instance, @code{guix build -S gcc} returns something like
5116 @file{/gnu/store/@dots{}-gcc-4.7.2.tar.bz2}, which is the GCC
5119 The returned source tarball is the result of applying any patches and
5120 code snippets specified in the package @code{origin} (@pxref{Defining
5124 Fetch and return the source of @var{package-or-derivation} and all their
5125 dependencies, recursively. This is a handy way to obtain a local copy
5126 of all the source code needed to build @var{packages}, allowing you to
5127 eventually build them even without network access. It is an extension
5128 of the @code{--source} option and can accept one of the following
5129 optional argument values:
5133 This value causes the @code{--sources} option to behave in the same way
5134 as the @code{--source} option.
5137 Build the source derivations of all packages, including any source that
5138 might be listed as @code{inputs}. This is the default value.
5141 $ guix build --sources tzdata
5142 The following derivations will be built:
5143 /gnu/store/@dots{}-tzdata2015b.tar.gz.drv
5144 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5148 Build the source derivations of all packages, as well of all transitive
5149 inputs to the packages. This can be used e.g. to
5150 prefetch package source for later offline building.
5153 $ guix build --sources=transitive tzdata
5154 The following derivations will be built:
5155 /gnu/store/@dots{}-tzcode2015b.tar.gz.drv
5156 /gnu/store/@dots{}-findutils-4.4.2.tar.xz.drv
5157 /gnu/store/@dots{}-grep-2.21.tar.xz.drv
5158 /gnu/store/@dots{}-coreutils-8.23.tar.xz.drv
5159 /gnu/store/@dots{}-make-4.1.tar.xz.drv
5160 /gnu/store/@dots{}-bash-4.3.tar.xz.drv
5166 @item --system=@var{system}
5167 @itemx -s @var{system}
5168 Attempt to build for @var{system}---e.g., @code{i686-linux}---instead of
5169 the system type of the build host.
5171 An example use of this is on Linux-based systems, which can emulate
5172 different personalities. For instance, passing
5173 @code{--system=i686-linux} on an @code{x86_64-linux} system allows users
5174 to build packages in a complete 32-bit environment.
5176 @item --target=@var{triplet}
5177 @cindex cross-compilation
5178 Cross-build for @var{triplet}, which must be a valid GNU triplet, such
5179 as @code{"mips64el-linux-gnu"} (@pxref{Specifying target triplets, GNU
5180 configuration triplets,, autoconf, Autoconf}).
5182 @anchor{build-check}
5184 @cindex determinism, checking
5185 @cindex reproducibility, checking
5186 Rebuild @var{package-or-derivation}, which are already available in the
5187 store, and raise an error if the build results are not bit-for-bit
5190 This mechanism allows you to check whether previously installed
5191 substitutes are genuine (@pxref{Substitutes}), or whether the build result
5192 of a package is deterministic. @xref{Invoking guix challenge}, for more
5193 background information and tools.
5195 When used in conjunction with @option{--keep-failed}, the differing
5196 output is kept in the store, under @file{/gnu/store/@dots{}-check}.
5197 This makes it easy to look for differences between the two results.
5200 @cindex repairing store items
5201 @cindex corruption, recovering from
5202 Attempt to repair the specified store items, if they are corrupt, by
5203 re-downloading or rebuilding them.
5205 This operation is not atomic and thus restricted to @code{root}.
5209 Return the derivation paths, not the output paths, of the given
5212 @item --root=@var{file}
5213 @itemx -r @var{file}
5214 Make @var{file} a symlink to the result, and register it as a garbage
5218 Return the build log file names or URLs for the given
5219 @var{package-or-derivation}, or raise an error if build logs are
5222 This works regardless of how packages or derivations are specified. For
5223 instance, the following invocations are equivalent:
5226 guix build --log-file `guix build -d guile`
5227 guix build --log-file `guix build guile`
5228 guix build --log-file guile
5229 guix build --log-file -e '(@@ (gnu packages guile) guile-2.0)'
5232 If a log is unavailable locally, and unless @code{--no-substitutes} is
5233 passed, the command looks for a corresponding log on one of the
5234 substitute servers (as specified with @code{--substitute-urls}.)
5236 So for instance, imagine you want to see the build log of GDB on MIPS,
5237 but you are actually on an @code{x86_64} machine:
5240 $ guix build --log-file gdb -s mips64el-linux
5241 https://hydra.gnu.org/log/@dots{}-gdb-7.10
5244 You can freely access a huge library of build logs!
5248 @node Invoking guix edit
5249 @section Invoking @command{guix edit}
5251 @cindex @command{guix edit}
5252 @cindex package definition, editing
5253 So many packages, so many source files! The @command{guix edit} command
5254 facilitates the life of users and packagers by pointing their editor at
5255 the source file containing the definition of the specified packages.
5259 guix edit gcc@@4.9 vim
5263 launches the program specified in the @code{VISUAL} or in the
5264 @code{EDITOR} environment variable to view the recipe of GCC@tie{}4.9.3
5267 If you are using a Guix Git checkout (@pxref{Building from Git}), or
5268 have created your own packages on @code{GUIX_PACKAGE_PATH}
5269 (@pxref{Defining Packages}), you will be able to edit the package
5270 recipes. Otherwise, you will be able to examine the read-only recipes
5271 for packages currently in the store.
5274 @node Invoking guix download
5275 @section Invoking @command{guix download}
5277 @cindex @command{guix download}
5278 @cindex downloading package sources
5279 When writing a package definition, developers typically need to download
5280 a source tarball, compute its SHA256 hash, and write that
5281 hash in the package definition (@pxref{Defining Packages}). The
5282 @command{guix download} tool helps with this task: it downloads a file
5283 from the given URI, adds it to the store, and prints both its file name
5284 in the store and its SHA256 hash.
5286 The fact that the downloaded file is added to the store saves bandwidth:
5287 when the developer eventually tries to build the newly defined package
5288 with @command{guix build}, the source tarball will not have to be
5289 downloaded again because it is already in the store. It is also a
5290 convenient way to temporarily stash files, which may be deleted
5291 eventually (@pxref{Invoking guix gc}).
5293 The @command{guix download} command supports the same URIs as used in
5294 package definitions. In particular, it supports @code{mirror://} URIs.
5295 @code{https} URIs (HTTP over TLS) are supported @emph{provided} the
5296 Guile bindings for GnuTLS are available in the user's environment; when
5297 they are not available, an error is raised. @xref{Guile Preparations,
5298 how to install the GnuTLS bindings for Guile,, gnutls-guile,
5299 GnuTLS-Guile}, for more information.
5301 @command{guix download} verifies HTTPS server certificates by loading
5302 the certificates of X.509 authorities from the directory pointed to by
5303 the @code{SSL_CERT_DIR} environment variable (@pxref{X.509
5304 Certificates}), unless @option{--no-check-certificate} is used.
5306 The following options are available:
5309 @item --format=@var{fmt}
5311 Write the hash in the format specified by @var{fmt}. For more
5312 information on the valid values for @var{fmt}, @pxref{Invoking guix hash}.
5314 @item --no-check-certificate
5315 Do not validate the X.509 certificates of HTTPS servers.
5317 When using this option, you have @emph{absolutely no guarantee} that you
5318 are communicating with the authentic server responsible for the given
5319 URL, which makes you vulnerable to ``man-in-the-middle'' attacks.
5321 @item --output=@var{file}
5322 @itemx -o @var{file}
5323 Save the downloaded file to @var{file} instead of adding it to the
5327 @node Invoking guix hash
5328 @section Invoking @command{guix hash}
5330 @cindex @command{guix hash}
5331 The @command{guix hash} command computes the SHA256 hash of a file.
5332 It is primarily a convenience tool for anyone contributing to the
5333 distribution: it computes the cryptographic hash of a file, which can be
5334 used in the definition of a package (@pxref{Defining Packages}).
5336 The general syntax is:
5339 guix hash @var{option} @var{file}
5342 When @var{file} is @code{-} (a hyphen), @command{guix hash} computes the
5343 hash of data read from standard input. @command{guix hash} has the
5348 @item --format=@var{fmt}
5350 Write the hash in the format specified by @var{fmt}.
5352 Supported formats: @code{nix-base32}, @code{base32}, @code{base16}
5353 (@code{hex} and @code{hexadecimal} can be used as well).
5355 If the @option{--format} option is not specified, @command{guix hash}
5356 will output the hash in @code{nix-base32}. This representation is used
5357 in the definitions of packages.
5361 Compute the hash on @var{file} recursively.
5363 In this case, the hash is computed on an archive containing @var{file},
5364 including its children if it is a directory. Some of the metadata of
5365 @var{file} is part of the archive; for instance, when @var{file} is a
5366 regular file, the hash is different depending on whether @var{file} is
5367 executable or not. Metadata such as time stamps has no impact on the
5368 hash (@pxref{Invoking guix archive}).
5369 @c FIXME: Replace xref above with xref to an ``Archive'' section when
5374 When combined with @option{--recursive}, exclude version control system
5375 directories (@file{.bzr}, @file{.git}, @file{.hg}, etc.)
5378 As an example, here is how you would compute the hash of a Git checkout,
5379 which is useful when using the @code{git-fetch} method (@pxref{origin
5383 $ git clone http://example.org/foo.git
5389 @node Invoking guix import
5390 @section Invoking @command{guix import}
5392 @cindex importing packages
5393 @cindex package import
5394 @cindex package conversion
5395 @cindex Invoking @command{guix import}
5396 The @command{guix import} command is useful for people who would like to
5397 add a package to the distribution with as little work as
5398 possible---a legitimate demand. The command knows of a few
5399 repositories from which it can ``import'' package metadata. The result
5400 is a package definition, or a template thereof, in the format we know
5401 (@pxref{Defining Packages}).
5403 The general syntax is:
5406 guix import @var{importer} @var{options}@dots{}
5409 @var{importer} specifies the source from which to import package
5410 metadata, and @var{options} specifies a package identifier and other
5411 options specific to @var{importer}. Currently, the available
5416 Import metadata for the given GNU package. This provides a template
5417 for the latest version of that GNU package, including the hash of its
5418 source tarball, and its canonical synopsis and description.
5420 Additional information such as the package dependencies and its
5421 license needs to be figured out manually.
5423 For example, the following command returns a package definition for
5427 guix import gnu hello
5430 Specific command-line options are:
5433 @item --key-download=@var{policy}
5434 As for @code{guix refresh}, specify the policy to handle missing OpenPGP
5435 keys when verifying the package signature. @xref{Invoking guix
5436 refresh, @code{--key-download}}.
5441 Import metadata from the @uref{https://pypi.python.org/, Python Package
5442 Index}@footnote{This functionality requires Guile-JSON to be installed.
5443 @xref{Requirements}.}. Information is taken from the JSON-formatted
5444 description available at @code{pypi.python.org} and usually includes all
5445 the relevant information, including package dependencies. For maximum
5446 efficiency, it is recommended to install the @command{unzip} utility, so
5447 that the importer can unzip Python wheels and gather data from them.
5449 The command below imports metadata for the @code{itsdangerous} Python
5453 guix import pypi itsdangerous
5458 Import metadata from @uref{https://rubygems.org/,
5459 RubyGems}@footnote{This functionality requires Guile-JSON to be
5460 installed. @xref{Requirements}.}. Information is taken from the
5461 JSON-formatted description available at @code{rubygems.org} and includes
5462 most relevant information, including runtime dependencies. There are
5463 some caveats, however. The metadata doesn't distinguish between
5464 synopses and descriptions, so the same string is used for both fields.
5465 Additionally, the details of non-Ruby dependencies required to build
5466 native extensions is unavailable and left as an exercise to the
5469 The command below imports metadata for the @code{rails} Ruby package:
5472 guix import gem rails
5477 Import metadata from @uref{https://www.metacpan.org/, MetaCPAN}@footnote{This
5478 functionality requires Guile-JSON to be installed.
5479 @xref{Requirements}.}.
5480 Information is taken from the JSON-formatted metadata provided through
5481 @uref{https://api.metacpan.org/, MetaCPAN's API} and includes most
5482 relevant information, such as module dependencies. License information
5483 should be checked closely. If Perl is available in the store, then the
5484 @code{corelist} utility will be used to filter core modules out of the
5485 list of dependencies.
5487 The command command below imports metadata for the @code{Acme::Boolean}
5491 guix import cpan Acme::Boolean
5496 @cindex Bioconductor
5497 Import metadata from @uref{http://cran.r-project.org/, CRAN}, the
5498 central repository for the @uref{http://r-project.org, GNU@tie{}R
5499 statistical and graphical environment}.
5501 Information is extracted from the @code{DESCRIPTION} file of the package.
5503 The command command below imports metadata for the @code{Cairo}
5507 guix import cran Cairo
5510 When @code{--recursive} is added, the importer will traverse the
5511 dependency graph of the given upstream package recursively and generate
5512 package expressions for all those packages that are not yet in Guix.
5514 When @code{--archive=bioconductor} is added, metadata is imported from
5515 @uref{http://www.bioconductor.org/, Bioconductor}, a repository of R
5516 packages for for the analysis and comprehension of high-throughput
5517 genomic data in bioinformatics.
5519 Information is extracted from the @code{DESCRIPTION} file of a package
5520 published on the web interface of the Bioconductor SVN repository.
5522 The command below imports metadata for the @code{GenomicRanges}
5526 guix import cran --archive=bioconductor GenomicRanges
5530 Import metadata from a local copy of the source of the
5531 @uref{http://nixos.org/nixpkgs/, Nixpkgs distribution}@footnote{This
5532 relies on the @command{nix-instantiate} command of
5533 @uref{http://nixos.org/nix/, Nix}.}. Package definitions in Nixpkgs are
5534 typically written in a mixture of Nix-language and Bash code. This
5535 command only imports the high-level package structure that is written in
5536 the Nix language. It normally includes all the basic fields of a
5539 When importing a GNU package, the synopsis and descriptions are replaced
5540 by their canonical upstream variant.
5542 Usually, you will first need to do:
5545 export NIX_REMOTE=daemon
5549 so that @command{nix-instantiate} does not try to open the Nix database.
5551 As an example, the command below imports the package definition of
5552 LibreOffice (more precisely, it imports the definition of the package
5553 bound to the @code{libreoffice} top-level attribute):
5556 guix import nix ~/path/to/nixpkgs libreoffice
5561 Import metadata from the Haskell community's central package archive
5562 @uref{https://hackage.haskell.org/, Hackage}. Information is taken from
5563 Cabal files and includes all the relevant information, including package
5566 Specific command-line options are:
5571 Read a Cabal file from standard input.
5572 @item --no-test-dependencies
5574 Do not include dependencies required only by the test suites.
5575 @item --cabal-environment=@var{alist}
5576 @itemx -e @var{alist}
5577 @var{alist} is a Scheme alist defining the environment in which the
5578 Cabal conditionals are evaluated. The accepted keys are: @code{os},
5579 @code{arch}, @code{impl} and a string representing the name of a flag.
5580 The value associated with a flag has to be either the symbol
5581 @code{true} or @code{false}. The value associated with other keys
5582 has to conform to the Cabal file format definition. The default value
5583 associated with the keys @code{os}, @code{arch} and @code{impl} is
5584 @samp{linux}, @samp{x86_64} and @samp{ghc}, respectively.
5587 The command below imports metadata for the latest version of the
5588 @code{HTTP} Haskell package without including test dependencies and
5589 specifying the value of the flag @samp{network-uri} as @code{false}:
5592 guix import hackage -t -e "'((\"network-uri\" . false))" HTTP
5595 A specific package version may optionally be specified by following the
5596 package name by an at-sign and a version number as in the following example:
5599 guix import hackage mtl@@2.1.3.1
5604 The @code{stackage} importer is a wrapper around the @code{hackage} one.
5605 It takes a package name, looks up the package version included in a
5606 long-term support (LTS) @uref{https://www.stackage.org, Stackage}
5607 release and uses the @code{hackage} importer to retrieve its metadata.
5608 Note that it is up to you to select an LTS release compatible with the
5609 GHC compiler used by Guix.
5611 Specific command-line options are:
5614 @item --no-test-dependencies
5616 Do not include dependencies required only by the test suites.
5617 @item --lts-version=@var{version}
5618 @itemx -r @var{version}
5619 @var{version} is the desired LTS release version. If omitted the latest
5623 The command below imports metadata for the @code{HTTP} Haskell package
5624 included in the LTS Stackage release version 7.18:
5627 guix import stackage --lts-version=7.18 HTTP
5632 Import metadata from an Emacs Lisp Package Archive (ELPA) package
5633 repository (@pxref{Packages,,, emacs, The GNU Emacs Manual}).
5635 Specific command-line options are:
5638 @item --archive=@var{repo}
5639 @itemx -a @var{repo}
5640 @var{repo} identifies the archive repository from which to retrieve the
5641 information. Currently the supported repositories and their identifiers
5645 @uref{http://elpa.gnu.org/packages, GNU}, selected by the @code{gnu}
5646 identifier. This is the default.
5648 Packages from @code{elpa.gnu.org} are signed with one of the keys
5649 contained in the GnuPG keyring at
5650 @file{share/emacs/25.1/etc/package-keyring.gpg} (or similar) in the
5651 @code{emacs} package (@pxref{Package Installation, ELPA package
5652 signatures,, emacs, The GNU Emacs Manual}).
5655 @uref{http://stable.melpa.org/packages, MELPA-Stable}, selected by the
5656 @code{melpa-stable} identifier.
5659 @uref{http://melpa.org/packages, MELPA}, selected by the @code{melpa}
5666 Import metadata from the crates.io Rust package repository
5667 @uref{https://crates.io, crates.io}.
5670 The structure of the @command{guix import} code is modular. It would be
5671 useful to have more importers for other package formats, and your help
5672 is welcome here (@pxref{Contributing}).
5674 @node Invoking guix refresh
5675 @section Invoking @command{guix refresh}
5677 @cindex @command {guix refresh}
5678 The primary audience of the @command{guix refresh} command is developers
5679 of the GNU software distribution. By default, it reports any packages
5680 provided by the distribution that are outdated compared to the latest
5681 upstream version, like this:
5685 gnu/packages/gettext.scm:29:13: gettext would be upgraded from 0.18.1.1 to 0.18.2.1
5686 gnu/packages/glib.scm:77:12: glib would be upgraded from 2.34.3 to 2.37.0
5689 Alternately, one can specify packages to consider, in which case a
5690 warning is emitted for packages that lack an updater:
5693 $ guix refresh coreutils guile guile-ssh
5694 gnu/packages/ssh.scm:205:2: warning: no updater for guile-ssh
5695 gnu/packages/guile.scm:136:12: guile would be upgraded from 2.0.12 to 2.0.13
5698 @command{guix refresh} browses the upstream repository of each package and determines
5699 the highest version number of the releases therein. The command
5700 knows how to update specific types of packages: GNU packages, ELPA
5701 packages, etc.---see the documentation for @option{--type} below. There
5702 are many packages, though, for which it lacks a method to determine
5703 whether a new upstream release is available. However, the mechanism is
5704 extensible, so feel free to get in touch with us to add a new method!
5706 When passed @code{--update}, it modifies distribution source files to
5707 update the version numbers and source tarball hashes of those package
5708 recipes (@pxref{Defining Packages}). This is achieved by downloading
5709 each package's latest source tarball and its associated OpenPGP
5710 signature, authenticating the downloaded tarball against its signature
5711 using @command{gpg}, and finally computing its hash. When the public
5712 key used to sign the tarball is missing from the user's keyring, an
5713 attempt is made to automatically retrieve it from a public key server;
5714 when this is successful, the key is added to the user's keyring; otherwise,
5715 @command{guix refresh} reports an error.
5717 The following options are supported:
5721 @item --expression=@var{expr}
5722 @itemx -e @var{expr}
5723 Consider the package @var{expr} evaluates to.
5725 This is useful to precisely refer to a package, as in this example:
5728 guix refresh -l -e '(@@@@ (gnu packages commencement) glibc-final)'
5731 This command lists the dependents of the ``final'' libc (essentially all
5736 Update distribution source files (package recipes) in place. This is
5737 usually run from a checkout of the Guix source tree (@pxref{Running
5738 Guix Before It Is Installed}):
5741 $ ./pre-inst-env guix refresh -s non-core -u
5744 @xref{Defining Packages}, for more information on package definitions.
5746 @item --select=[@var{subset}]
5747 @itemx -s @var{subset}
5748 Select all the packages in @var{subset}, one of @code{core} or
5751 The @code{core} subset refers to all the packages at the core of the
5752 distribution---i.e., packages that are used to build ``everything
5753 else''. This includes GCC, libc, Binutils, Bash, etc. Usually,
5754 changing one of these packages in the distribution entails a rebuild of
5755 all the others. Thus, such updates are an inconvenience to users in
5756 terms of build time or bandwidth used to achieve the upgrade.
5758 The @code{non-core} subset refers to the remaining packages. It is
5759 typically useful in cases where an update of the core packages would be
5762 @item --type=@var{updater}
5763 @itemx -t @var{updater}
5764 Select only packages handled by @var{updater} (may be a comma-separated
5765 list of updaters). Currently, @var{updater} may be one of:
5769 the updater for GNU packages;
5771 the updater for GNOME packages;
5773 the updater for KDE packages;
5775 the updater for X.org packages;
5777 the updater for packages hosted on kernel.org;
5779 the updater for @uref{http://elpa.gnu.org/, ELPA} packages;
5781 the updater for @uref{http://cran.r-project.org/, CRAN} packages;
5783 the updater for @uref{http://www.bioconductor.org/, Bioconductor} R packages;
5785 the updater for @uref{http://www.cpan.org/, CPAN} packages;
5787 the updater for @uref{https://pypi.python.org, PyPI} packages.
5789 the updater for @uref{https://rubygems.org, RubyGems} packages.
5791 the updater for @uref{https://github.com, GitHub} packages.
5793 the updater for @uref{https://hackage.haskell.org, Hackage} packages.
5795 the updater for @uref{https://www.stackage.org, Stackage} packages.
5797 the updater for @uref{https://crates.io, Crates} packages.
5800 For instance, the following command only checks for updates of Emacs
5801 packages hosted at @code{elpa.gnu.org} and for updates of CRAN packages:
5804 $ guix refresh --type=elpa,cran
5805 gnu/packages/statistics.scm:819:13: r-testthat would be upgraded from 0.10.0 to 0.11.0
5806 gnu/packages/emacs.scm:856:13: emacs-auctex would be upgraded from 11.88.6 to 11.88.9
5811 In addition, @command{guix refresh} can be passed one or more package
5812 names, as in this example:
5815 $ ./pre-inst-env guix refresh -u emacs idutils gcc@@4.8
5819 The command above specifically updates the @code{emacs} and
5820 @code{idutils} packages. The @code{--select} option would have no
5821 effect in this case.
5823 When considering whether to upgrade a package, it is sometimes
5824 convenient to know which packages would be affected by the upgrade and
5825 should be checked for compatibility. For this the following option may
5826 be used when passing @command{guix refresh} one or more package names:
5830 @item --list-updaters
5832 List available updaters and exit (see @option{--type} above.)
5834 For each updater, display the fraction of packages it covers; at the
5835 end, display the fraction of packages covered by all these updaters.
5837 @item --list-dependent
5839 List top-level dependent packages that would need to be rebuilt as a
5840 result of upgrading one or more packages.
5842 @xref{Invoking guix graph, the @code{reverse-package} type of
5843 @command{guix graph}}, for information on how to visualize the list of
5844 dependents of a package.
5848 Be aware that the @code{--list-dependent} option only
5849 @emph{approximates} the rebuilds that would be required as a result of
5850 an upgrade. More rebuilds might be required under some circumstances.
5853 $ guix refresh --list-dependent flex
5854 Building the following 120 packages would ensure 213 dependent packages are rebuilt:
5855 hop@@2.4.0 geiser@@0.4 notmuch@@0.18 mu@@0.9.9.5 cflow@@1.4 idutils@@4.6 @dots{}
5858 The command above lists a set of packages that could be built to check
5859 for compatibility with an upgraded @code{flex} package.
5861 The following options can be used to customize GnuPG operation:
5865 @item --gpg=@var{command}
5866 Use @var{command} as the GnuPG 2.x command. @var{command} is searched
5867 for in @code{$PATH}.
5869 @item --key-download=@var{policy}
5870 Handle missing OpenPGP keys according to @var{policy}, which may be one
5875 Always download missing OpenPGP keys from the key server, and add them
5876 to the user's GnuPG keyring.
5879 Never try to download missing OpenPGP keys. Instead just bail out.
5882 When a package signed with an unknown OpenPGP key is encountered, ask
5883 the user whether to download it or not. This is the default behavior.
5886 @item --key-server=@var{host}
5887 Use @var{host} as the OpenPGP key server when importing a public key.
5891 The @code{github} updater uses the
5892 @uref{https://developer.github.com/v3/, GitHub API} to query for new
5893 releases. When used repeatedly e.g. when refreshing all packages,
5894 GitHub will eventually refuse to answer any further API requests. By
5895 default 60 API requests per hour are allowed, and a full refresh on all
5896 GitHub packages in Guix requires more than this. Authentication with
5897 GitHub through the use of an API token alleviates these limits. To use
5898 an API token, set the environment variable @code{GUIX_GITHUB_TOKEN} to a
5899 token procured from @uref{https://github.com/settings/tokens} or
5903 @node Invoking guix lint
5904 @section Invoking @command{guix lint}
5906 @cindex @command{guix lint}
5907 @cindex package, checking for errors
5908 The @command{guix lint} command is meant to help package developers avoid
5909 common errors and use a consistent style. It runs a number of checks on
5910 a given set of packages in order to find common mistakes in their
5911 definitions. Available @dfn{checkers} include (see
5912 @code{--list-checkers} for a complete list):
5917 Validate certain typographical and stylistic rules about package
5918 descriptions and synopses.
5920 @item inputs-should-be-native
5921 Identify inputs that should most likely be native inputs.
5926 @itemx source-file-name
5927 Probe @code{home-page} and @code{source} URLs and report those that are
5928 invalid. Suggest a @code{mirror://} URL when applicable. Check that
5929 the source file name is meaningful, e.g. is not
5930 just a version number or ``git-checkout'', without a declared
5931 @code{file-name} (@pxref{origin Reference}).
5934 @cindex security vulnerabilities
5935 @cindex CVE, Common Vulnerabilities and Exposures
5936 Report known vulnerabilities found in the Common Vulnerabilities and
5937 Exposures (CVE) databases of the current and past year
5938 @uref{https://nvd.nist.gov/download.cfm#CVE_FEED, published by the US
5941 To view information about a particular vulnerability, visit pages such as:
5945 @indicateurl{https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-YYYY-ABCD}
5947 @indicateurl{https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-YYYY-ABCD}
5951 where @code{CVE-YYYY-ABCD} is the CVE identifier---e.g.,
5952 @code{CVE-2015-7554}.
5954 Package developers can specify in package recipes the
5955 @uref{https://nvd.nist.gov/cpe.cfm,Common Platform Enumeration (CPE)}
5956 name and version of the package when they differ from the name that Guix
5957 uses, as in this example:
5963 ;; CPE calls this package "grub2".
5964 (properties '((cpe-name . "grub2"))))
5968 Warn about obvious source code formatting issues: trailing white space,
5969 use of tabulations, etc.
5972 The general syntax is:
5975 guix lint @var{options} @var{package}@dots{}
5978 If no package is given on the command line, then all packages are checked.
5979 The @var{options} may be zero or more of the following:
5982 @item --list-checkers
5984 List and describe all the available checkers that will be run on packages
5989 Only enable the checkers specified in a comma-separated list using the
5990 names returned by @code{--list-checkers}.
5994 @node Invoking guix size
5995 @section Invoking @command{guix size}
5998 @cindex package size
6000 @cindex @command{guix size}
6001 The @command{guix size} command helps package developers profile the
6002 disk usage of packages. It is easy to overlook the impact of an
6003 additional dependency added to a package, or the impact of using a
6004 single output for a package that could easily be split (@pxref{Packages
6005 with Multiple Outputs}). Such are the typical issues that
6006 @command{guix size} can highlight.
6008 The command can be passed a package specification such as @code{gcc@@4.8}
6009 or @code{guile:debug}, or a file name in the store. Consider this
6013 $ guix size coreutils
6014 store item total self
6015 /gnu/store/@dots{}-coreutils-8.23 70.0 13.9 19.8%
6016 /gnu/store/@dots{}-gmp-6.0.0a 55.3 2.5 3.6%
6017 /gnu/store/@dots{}-acl-2.2.52 53.7 0.5 0.7%
6018 /gnu/store/@dots{}-attr-2.4.46 53.2 0.3 0.5%
6019 /gnu/store/@dots{}-gcc-4.8.4-lib 52.9 15.7 22.4%
6020 /gnu/store/@dots{}-glibc-2.21 37.2 37.2 53.1%
6024 The store items listed here constitute the @dfn{transitive closure} of
6025 Coreutils---i.e., Coreutils and all its dependencies, recursively---as
6026 would be returned by:
6029 $ guix gc -R /gnu/store/@dots{}-coreutils-8.23
6032 Here the output shows three columns next to store items. The first column,
6033 labeled ``total'', shows the size in mebibytes (MiB) of the closure of
6034 the store item---that is, its own size plus the size of all its
6035 dependencies. The next column, labeled ``self'', shows the size of the
6036 item itself. The last column shows the ratio of the size of the item
6037 itself to the space occupied by all the items listed here.
6039 In this example, we see that the closure of Coreutils weighs in at
6040 70@tie{}MiB, half of which is taken by libc. (That libc represents a
6041 large fraction of the closure is not a problem @i{per se} because it is
6042 always available on the system anyway.)
6044 When the package passed to @command{guix size} is available in the
6045 store, @command{guix size} queries the daemon to determine its
6046 dependencies, and measures its size in the store, similar to @command{du
6047 -ms --apparent-size} (@pxref{du invocation,,, coreutils, GNU
6050 When the given package is @emph{not} in the store, @command{guix size}
6051 reports information based on the available substitutes
6052 (@pxref{Substitutes}). This makes it possible it to profile disk usage of
6053 store items that are not even on disk, only available remotely.
6055 You can also specify several package names:
6058 $ guix size coreutils grep sed bash
6059 store item total self
6060 /gnu/store/@dots{}-coreutils-8.24 77.8 13.8 13.4%
6061 /gnu/store/@dots{}-grep-2.22 73.1 0.8 0.8%
6062 /gnu/store/@dots{}-bash-4.3.42 72.3 4.7 4.6%
6063 /gnu/store/@dots{}-readline-6.3 67.6 1.2 1.2%
6069 In this example we see that the combination of the four packages takes
6070 102.3@tie{}MiB in total, which is much less than the sum of each closure
6071 since they have a lot of dependencies in common.
6073 The available options are:
6077 @item --substitute-urls=@var{urls}
6078 Use substitute information from @var{urls}.
6079 @xref{client-substitute-urls, the same option for @code{guix build}}.
6081 @item --map-file=@var{file}
6082 Write a graphical map of disk usage in PNG format to @var{file}.
6084 For the example above, the map looks like this:
6086 @image{images/coreutils-size-map,5in,, map of Coreutils disk usage
6087 produced by @command{guix size}}
6089 This option requires that
6090 @uref{http://wingolog.org/software/guile-charting/, Guile-Charting} be
6091 installed and visible in Guile's module search path. When that is not
6092 the case, @command{guix size} fails as it tries to load it.
6094 @item --system=@var{system}
6095 @itemx -s @var{system}
6096 Consider packages for @var{system}---e.g., @code{x86_64-linux}.
6100 @node Invoking guix graph
6101 @section Invoking @command{guix graph}
6104 @cindex @command{guix graph}
6105 @cindex package dependencies
6106 Packages and their dependencies form a @dfn{graph}, specifically a
6107 directed acyclic graph (DAG). It can quickly become difficult to have a
6108 mental model of the package DAG, so the @command{guix graph} command
6109 provides a visual representation of the DAG. By default,
6110 @command{guix graph} emits a DAG representation in the input format of
6111 @uref{http://www.graphviz.org/, Graphviz}, so its output can be passed
6112 directly to the @command{dot} command of Graphviz. It can also emit an
6113 HTML page with embedded JavaScript code to display a ``chord diagram''
6114 in a Web browser, using the @uref{https://d3js.org/, d3.js} library.
6115 The general syntax is:
6118 guix graph @var{options} @var{package}@dots{}
6121 For example, the following command generates a PDF file representing the
6122 package DAG for the GNU@tie{}Core Utilities, showing its build-time
6126 guix graph coreutils | dot -Tpdf > dag.pdf
6129 The output looks like this:
6131 @image{images/coreutils-graph,2in,,Dependency graph of the GNU Coreutils}
6133 Nice little graph, no?
6135 But there is more than one graph! The one above is concise: it is the
6136 graph of package objects, omitting implicit inputs such as GCC, libc,
6137 grep, etc. It is often useful to have such a concise graph, but
6138 sometimes one may want to see more details. @command{guix graph} supports
6139 several types of graphs, allowing you to choose the level of detail:
6143 This is the default type used in the example above. It shows the DAG of
6144 package objects, excluding implicit dependencies. It is concise, but
6145 filters out many details.
6147 @item reverse-package
6148 This shows the @emph{reverse} DAG of packages. For example:
6151 guix graph --type=reverse-package ocaml
6154 ... yields the graph of packages that depend on OCaml.
6156 Note that for core packages this can yield huge graphs. If all you want
6157 is to know the number of packages that depend on a given package, use
6158 @command{guix refresh --list-dependent} (@pxref{Invoking guix refresh,
6159 @option{--list-dependent}}).
6162 This is the package DAG, @emph{including} implicit inputs.
6164 For instance, the following command:
6167 guix graph --type=bag-emerged coreutils | dot -Tpdf > dag.pdf
6170 ... yields this bigger graph:
6172 @image{images/coreutils-bag-graph,,5in,Detailed dependency graph of the GNU Coreutils}
6174 At the bottom of the graph, we see all the implicit inputs of
6175 @var{gnu-build-system} (@pxref{Build Systems, @code{gnu-build-system}}).
6177 Now, note that the dependencies of these implicit inputs---that is, the
6178 @dfn{bootstrap dependencies} (@pxref{Bootstrapping})---are not shown
6179 here, for conciseness.
6182 Similar to @code{bag-emerged}, but this time including all the bootstrap
6185 @item bag-with-origins
6186 Similar to @code{bag}, but also showing origins and their dependencies.
6189 This is the most detailed representation: It shows the DAG of
6190 derivations (@pxref{Derivations}) and plain store items. Compared to
6191 the above representation, many additional nodes are visible, including
6192 build scripts, patches, Guile modules, etc.
6194 For this type of graph, it is also possible to pass a @file{.drv} file
6195 name instead of a package name, as in:
6198 guix graph -t derivation `guix system build -d my-config.scm`
6202 All the types above correspond to @emph{build-time dependencies}. The
6203 following graph type represents the @emph{run-time dependencies}:
6207 This is the graph of @dfn{references} of a package output, as returned
6208 by @command{guix gc --references} (@pxref{Invoking guix gc}).
6210 If the given package output is not available in the store, @command{guix
6211 graph} attempts to obtain dependency information from substitutes.
6213 Here you can also pass a store file name instead of a package name. For
6214 example, the command below produces the reference graph of your profile
6215 (which can be big!):
6218 guix graph -t references `readlink -f ~/.guix-profile`
6222 This is the graph of the @dfn{referrers} of a store item, as returned by
6223 @command{guix gc --referrers} (@pxref{Invoking guix gc}).
6225 This relies exclusively on local information from your store. For
6226 instance, let us suppose that the current Inkscape is available in 10
6227 profiles on your machine; @command{guix graph -t referrers inkscape}
6228 will show a graph rooted at Inkscape and with those 10 profiles linked
6231 It can help determine what is preventing a store item from being garbage
6236 The available options are the following:
6239 @item --type=@var{type}
6240 @itemx -t @var{type}
6241 Produce a graph output of @var{type}, where @var{type} must be one of
6242 the values listed above.
6245 List the supported graph types.
6247 @item --backend=@var{backend}
6248 @itemx -b @var{backend}
6249 Produce a graph using the selected @var{backend}.
6251 @item --list-backends
6252 List the supported graph backends.
6254 Currently, the available backends are Graphviz and d3.js.
6256 @item --expression=@var{expr}
6257 @itemx -e @var{expr}
6258 Consider the package @var{expr} evaluates to.
6260 This is useful to precisely refer to a package, as in this example:
6263 guix graph -e '(@@@@ (gnu packages commencement) gnu-make-final)'
6268 @node Invoking guix environment
6269 @section Invoking @command{guix environment}
6271 @cindex reproducible build environments
6272 @cindex development environments
6273 @cindex @command{guix environment}
6274 @cindex environment, package build environment
6275 The purpose of @command{guix environment} is to assist hackers in
6276 creating reproducible development environments without polluting their
6277 package profile. The @command{guix environment} tool takes one or more
6278 packages, builds all of their inputs, and creates a shell
6279 environment to use them.
6281 The general syntax is:
6284 guix environment @var{options} @var{package}@dots{}
6287 The following example spawns a new shell set up for the development of
6291 guix environment guile
6294 If the needed dependencies are not built yet, @command{guix environment}
6295 automatically builds them. The environment of the new shell is an augmented
6296 version of the environment that @command{guix environment} was run in.
6297 It contains the necessary search paths for building the given package
6298 added to the existing environment variables. To create a ``pure''
6299 environment, in which the original environment variables have been unset,
6300 use the @code{--pure} option@footnote{Users sometimes wrongfully augment
6301 environment variables such as @code{PATH} in their @file{~/.bashrc}
6302 file. As a consequence, when @code{guix environment} launches it, Bash
6303 may read @file{~/.bashrc}, thereby introducing ``impurities'' in these
6304 environment variables. It is an error to define such environment
6305 variables in @file{.bashrc}; instead, they should be defined in
6306 @file{.bash_profile}, which is sourced only by log-in shells.
6307 @xref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}, for
6308 details on Bash start-up files.}.
6310 @vindex GUIX_ENVIRONMENT
6311 @command{guix environment} defines the @code{GUIX_ENVIRONMENT}
6312 variable in the shell it spawns; its value is the file name of the
6313 profile of this environment. This allows users to, say, define a
6314 specific prompt for development environments in their @file{.bashrc}
6315 (@pxref{Bash Startup Files,,, bash, The GNU Bash Reference Manual}):
6318 if [ -n "$GUIX_ENVIRONMENT" ]
6320 export PS1="\u@@\h \w [dev]\$ "
6325 ... or to browse the profile:
6328 $ ls "$GUIX_ENVIRONMENT/bin"
6331 Additionally, more than one package may be specified, in which case the
6332 union of the inputs for the given packages are used. For example, the
6333 command below spawns a shell where all of the dependencies of both Guile
6334 and Emacs are available:
6337 guix environment guile emacs
6340 Sometimes an interactive shell session is not desired. An arbitrary
6341 command may be invoked by placing the @code{--} token to separate the
6342 command from the rest of the arguments:
6345 guix environment guile -- make -j4
6348 In other situations, it is more convenient to specify the list of
6349 packages needed in the environment. For example, the following command
6350 runs @command{python} from an environment containing Python@tie{}2.7 and
6354 guix environment --ad-hoc python2-numpy python-2.7 -- python
6357 Furthermore, one might want the dependencies of a package and also some
6358 additional packages that are not build-time or runtime dependencies, but
6359 are useful when developing nonetheless. Because of this, the
6360 @code{--ad-hoc} flag is positional. Packages appearing before
6361 @code{--ad-hoc} are interpreted as packages whose dependencies will be
6362 added to the environment. Packages appearing after are interpreted as
6363 packages that will be added to the environment directly. For example,
6364 the following command creates a Guix development environment that
6365 additionally includes Git and strace:
6368 guix environment guix --ad-hoc git strace
6371 Sometimes it is desirable to isolate the environment as much as
6372 possible, for maximal purity and reproducibility. In particular, when
6373 using Guix on a host distro that is not GuixSD, it is desirable to
6374 prevent access to @file{/usr/bin} and other system-wide resources from
6375 the development environment. For example, the following command spawns
6376 a Guile REPL in a ``container'' where only the store and the current
6377 working directory are mounted:
6380 guix environment --ad-hoc --container guile -- guile
6384 The @code{--container} option requires Linux-libre 3.19 or newer.
6387 The available options are summarized below.
6390 @item --root=@var{file}
6391 @itemx -r @var{file}
6392 @cindex persistent environment
6393 @cindex garbage collector root, for environments
6394 Make @var{file} a symlink to the profile for this environment, and
6395 register it as a garbage collector root.
6397 This is useful if you want to protect your environment from garbage
6398 collection, to make it ``persistent''.
6400 When this option is omitted, the environment is protected from garbage
6401 collection only for the duration of the @command{guix environment}
6402 session. This means that next time you recreate the same environment,
6403 you could have to rebuild or re-download packages.
6405 @item --expression=@var{expr}
6406 @itemx -e @var{expr}
6407 Create an environment for the package or list of packages that
6408 @var{expr} evaluates to.
6410 For example, running:
6413 guix environment -e '(@@ (gnu packages maths) petsc-openmpi)'
6416 starts a shell with the environment for this specific variant of the
6422 guix environment --ad-hoc -e '(@@ (gnu) %base-packages)'
6425 starts a shell with all the GuixSD base packages available.
6427 The above commands only use the default output of the given packages.
6428 To select other outputs, two element tuples can be specified:
6431 guix environment --ad-hoc -e '(list (@ (gnu packages bash) bash) "include")'
6434 @item --load=@var{file}
6435 @itemx -l @var{file}
6436 Create an environment for the package or list of packages that the code
6437 within @var{file} evaluates to.
6439 As an example, @var{file} might contain a definition like this
6440 (@pxref{Defining Packages}):
6443 @verbatiminclude environment-gdb.scm
6447 Include all specified packages in the resulting environment, as if an
6448 @i{ad hoc} package were defined with them as inputs. This option is
6449 useful for quickly creating an environment without having to write a
6450 package expression to contain the desired inputs.
6452 For instance, the command:
6455 guix environment --ad-hoc guile guile-sdl -- guile
6458 runs @command{guile} in an environment where Guile and Guile-SDL are
6461 Note that this example implicitly asks for the default output of
6462 @code{guile} and @code{guile-sdl}, but it is possible to ask for a
6463 specific output---e.g., @code{glib:bin} asks for the @code{bin} output
6464 of @code{glib} (@pxref{Packages with Multiple Outputs}).
6466 This option may be composed with the default behavior of @command{guix
6467 environment}. Packages appearing before @code{--ad-hoc} are interpreted
6468 as packages whose dependencies will be added to the environment, the
6469 default behavior. Packages appearing after are interpreted as packages
6470 that will be added to the environment directly.
6473 Unset existing environment variables when building the new environment.
6474 This has the effect of creating an environment in which search paths
6475 only contain package inputs.
6477 @item --search-paths
6478 Display the environment variable definitions that make up the
6481 @item --system=@var{system}
6482 @itemx -s @var{system}
6483 Attempt to build for @var{system}---e.g., @code{i686-linux}.
6488 Run @var{command} within an isolated container. The current working
6489 directory outside the container is mapped inside the container.
6490 Additionally, a dummy home directory is created that matches the current
6491 user's home directory, and @file{/etc/passwd} is configured accordingly.
6492 The spawned process runs as the current user outside the container, but
6493 has root privileges in the context of the container.
6497 For containers, share the network namespace with the host system.
6498 Containers created without this flag only have access to the loopback
6501 @item --expose=@var{source}[=@var{target}]
6502 For containers, expose the file system @var{source} from the host system
6503 as the read-only file system @var{target} within the container. If
6504 @var{target} is not specified, @var{source} is used as the target mount
6505 point in the container.
6507 The example below spawns a Guile REPL in a container in which the user's
6508 home directory is accessible read-only via the @file{/exchange}
6512 guix environment --container --expose=$HOME=/exchange --ad-hoc guile -- guile
6515 @item --share=@var{source}[=@var{target}]
6516 For containers, share the file system @var{source} from the host system
6517 as the writable file system @var{target} within the container. If
6518 @var{target} is not specified, @var{source} is used as the target mount
6519 point in the container.
6521 The example below spawns a Guile REPL in a container in which the user's
6522 home directory is accessible for both reading and writing via the
6523 @file{/exchange} directory:
6526 guix environment --container --share=$HOME=/exchange --ad-hoc guile -- guile
6530 @command{guix environment}
6531 also supports all of the common build options that @command{guix
6532 build} supports (@pxref{Common Build Options}).
6535 @node Invoking guix publish
6536 @section Invoking @command{guix publish}
6538 @cindex @command{guix publish}
6539 The purpose of @command{guix publish} is to enable users to easily share
6540 their store with others, who can then use it as a substitute server
6541 (@pxref{Substitutes}).
6543 When @command{guix publish} runs, it spawns an HTTP server which allows
6544 anyone with network access to obtain substitutes from it. This means
6545 that any machine running Guix can also act as if it were a build farm,
6546 since the HTTP interface is compatible with Hydra, the software behind
6547 the @code{hydra.gnu.org} build farm.
6549 For security, each substitute is signed, allowing recipients to check
6550 their authenticity and integrity (@pxref{Substitutes}). Because
6551 @command{guix publish} uses the signing key of the system, which is only
6552 readable by the system administrator, it must be started as root; the
6553 @code{--user} option makes it drop root privileges early on.
6555 The signing key pair must be generated before @command{guix publish} is
6556 launched, using @command{guix archive --generate-key} (@pxref{Invoking
6559 The general syntax is:
6562 guix publish @var{options}@dots{}
6565 Running @command{guix publish} without any additional arguments will
6566 spawn an HTTP server on port 8080:
6572 Once a publishing server has been authorized (@pxref{Invoking guix
6573 archive}), the daemon may download substitutes from it:
6576 guix-daemon --substitute-urls=http://example.org:8080
6579 By default, @command{guix publish} compresses archives on the fly as it
6580 serves them. This ``on-the-fly'' mode is convenient in that it requires
6581 no setup and is immediately available. However, when serving lots of
6582 clients, we recommend using the @option{--cache} option, which enables
6583 caching of the archives before they are sent to clients---see below for
6586 As a bonus, @command{guix publish} also serves as a content-addressed
6587 mirror for source files referenced in @code{origin} records
6588 (@pxref{origin Reference}). For instance, assuming @command{guix
6589 publish} is running on @code{example.org}, the following URL returns the
6590 raw @file{hello-2.10.tar.gz} file with the given SHA256 hash
6591 (represented in @code{nix-base32} format, @pxref{Invoking guix hash}):
6594 http://example.org/file/hello-2.10.tar.gz/sha256/0ssi1@dots{}ndq1i
6597 Obviously, these URLs only work for files that are in the store; in
6598 other cases, they return 404 (``Not Found'').
6600 The following options are available:
6603 @item --port=@var{port}
6604 @itemx -p @var{port}
6605 Listen for HTTP requests on @var{port}.
6607 @item --listen=@var{host}
6608 Listen on the network interface for @var{host}. The default is to
6609 accept connections from any interface.
6611 @item --user=@var{user}
6612 @itemx -u @var{user}
6613 Change privileges to @var{user} as soon as possible---i.e., once the
6614 server socket is open and the signing key has been read.
6616 @item --compression[=@var{level}]
6617 @itemx -C [@var{level}]
6618 Compress data using the given @var{level}. When @var{level} is zero,
6619 disable compression. The range 1 to 9 corresponds to different gzip
6620 compression levels: 1 is the fastest, and 9 is the best (CPU-intensive).
6623 Unless @option{--cache} is used, compression occurs on the fly and
6624 the compressed streams are not
6625 cached. Thus, to reduce load on the machine that runs @command{guix
6626 publish}, it may be a good idea to choose a low compression level, to
6627 run @command{guix publish} behind a caching proxy, or to use
6628 @option{--cache}. Using @option{--cache} has the advantage that it
6629 allows @command{guix publish} to add @code{Content-Length} HTTP header
6632 @item --cache=@var{directory}
6633 @itemx -c @var{directory}
6634 Cache archives and meta-data (@code{.narinfo} URLs) to @var{directory}
6635 and only serve archives that are in cache.
6637 When this option is omitted, archives and meta-data are created
6638 on-the-fly. This can reduce the available bandwidth, especially when
6639 compression is enabled, since this may become CPU-bound. Another
6640 drawback of the default mode is that the length of archives is not known
6641 in advance, so @command{guix publish} does not add a
6642 @code{Content-Length} HTTP header to its responses, which in turn
6643 prevents clients from knowing the amount of data being downloaded.
6645 Conversely, when @option{--cache} is used, the first request for a store
6646 item (@i{via} a @code{.narinfo} URL) returns 404 and triggers a
6647 background process to @dfn{bake} the archive---computing its
6648 @code{.narinfo} and compressing the archive, if needed. Once the
6649 archive is cached in @var{directory}, subsequent requests succeed and
6650 are served directly from the cache, which guarantees that clients get
6651 the best possible bandwidth.
6653 The ``baking'' process is performed by worker threads. By default, one
6654 thread per CPU core is created, but this can be customized. See
6655 @option{--workers} below.
6657 When @option{--ttl} is used, cached entries are automatically deleted
6658 when they have expired.
6660 @item --workers=@var{N}
6661 When @option{--cache} is used, request the allocation of @var{N} worker
6662 threads to ``bake'' archives.
6664 @item --ttl=@var{ttl}
6665 Produce @code{Cache-Control} HTTP headers that advertise a time-to-live
6666 (TTL) of @var{ttl}. @var{ttl} must denote a duration: @code{5d} means 5
6667 days, @code{1m} means 1 month, and so on.
6669 This allows the user's Guix to keep substitute information in cache for
6670 @var{ttl}. However, note that @code{guix publish} does not itself
6671 guarantee that the store items it provides will indeed remain available
6672 for as long as @var{ttl}.
6674 Additionally, when @option{--cache} is used, cached entries that have
6675 not been accessed for @var{ttl} may be deleted.
6677 @item --nar-path=@var{path}
6678 Use @var{path} as the prefix for the URLs of ``nar'' files
6679 (@pxref{Invoking guix archive, normalized archives}).
6681 By default, nars are served at a URL such as
6682 @code{/nar/gzip/@dots{}-coreutils-8.25}. This option allows you to
6683 change the @code{/nar} part to @var{path}.
6685 @item --public-key=@var{file}
6686 @itemx --private-key=@var{file}
6687 Use the specific @var{file}s as the public/private key pair used to sign
6688 the store items being published.
6690 The files must correspond to the same key pair (the private key is used
6691 for signing and the public key is merely advertised in the signature
6692 metadata). They must contain keys in the canonical s-expression format
6693 as produced by @command{guix archive --generate-key} (@pxref{Invoking
6694 guix archive}). By default, @file{/etc/guix/signing-key.pub} and
6695 @file{/etc/guix/signing-key.sec} are used.
6697 @item --repl[=@var{port}]
6698 @itemx -r [@var{port}]
6699 Spawn a Guile REPL server (@pxref{REPL Servers,,, guile, GNU Guile
6700 Reference Manual}) on @var{port} (37146 by default). This is used
6701 primarily for debugging a running @command{guix publish} server.
6704 Enabling @command{guix publish} on a GuixSD system is a one-liner: just
6705 instantiate a @code{guix-publish-service-type} service in the @code{services} field
6706 of the @code{operating-system} declaration (@pxref{guix-publish-service-type,
6707 @code{guix-publish-service-type}}).
6709 If you are instead running Guix on a ``foreign distro'', follow these
6714 If your host distro uses the systemd init system:
6717 # ln -s ~root/.guix-profile/lib/systemd/system/guix-publish.service \
6718 /etc/systemd/system/
6719 # systemctl start guix-publish && systemctl enable guix-publish
6723 If your host distro uses the Upstart init system:
6726 # ln -s ~root/.guix-profile/lib/upstart/system/guix-publish.conf /etc/init/
6727 # start guix-publish
6731 Otherwise, proceed similarly with your distro's init system.
6734 @node Invoking guix challenge
6735 @section Invoking @command{guix challenge}
6737 @cindex reproducible builds
6738 @cindex verifiable builds
6739 @cindex @command{guix challenge}
6741 Do the binaries provided by this server really correspond to the source
6742 code it claims to build? Is a package build process deterministic?
6743 These are the questions the @command{guix challenge} command attempts to
6746 The former is obviously an important question: Before using a substitute
6747 server (@pxref{Substitutes}), one had better @emph{verify} that it
6748 provides the right binaries, and thus @emph{challenge} it. The latter
6749 is what enables the former: If package builds are deterministic, then
6750 independent builds of the package should yield the exact same result,
6751 bit for bit; if a server provides a binary different from the one
6752 obtained locally, it may be either corrupt or malicious.
6754 We know that the hash that shows up in @file{/gnu/store} file names is
6755 the hash of all the inputs of the process that built the file or
6756 directory---compilers, libraries, build scripts,
6757 etc. (@pxref{Introduction}). Assuming deterministic build processes,
6758 one store file name should map to exactly one build output.
6759 @command{guix challenge} checks whether there is, indeed, a single
6760 mapping by comparing the build outputs of several independent builds of
6761 any given store item.
6763 The command output looks like this:
6766 $ guix challenge --substitute-urls="https://hydra.gnu.org https://guix.example.org"
6767 updating list of substitutes from 'https://hydra.gnu.org'... 100.0%
6768 updating list of substitutes from 'https://guix.example.org'... 100.0%
6769 /gnu/store/@dots{}-openssl-1.0.2d contents differ:
6770 local hash: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6771 https://hydra.gnu.org/nar/@dots{}-openssl-1.0.2d: 0725l22r5jnzazaacncwsvp9kgf42266ayyp814v7djxs7nk963q
6772 https://guix.example.org/nar/@dots{}-openssl-1.0.2d: 1zy4fmaaqcnjrzzajkdn3f5gmjk754b43qkq47llbyak9z0qjyim
6773 /gnu/store/@dots{}-git-2.5.0 contents differ:
6774 local hash: 00p3bmryhjxrhpn2gxs2fy0a15lnip05l97205pgbk5ra395hyha
6775 https://hydra.gnu.org/nar/@dots{}-git-2.5.0: 069nb85bv4d4a6slrwjdy8v1cn4cwspm3kdbmyb81d6zckj3nq9f
6776 https://guix.example.org/nar/@dots{}-git-2.5.0: 0mdqa9w1p6cmli6976v4wi0sw9r4p5prkj7lzfd1877wk11c9c73
6777 /gnu/store/@dots{}-pius-2.1.1 contents differ:
6778 local hash: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6779 https://hydra.gnu.org/nar/@dots{}-pius-2.1.1: 0k4v3m9z1zp8xzzizb7d8kjj72f9172xv078sq4wl73vnq9ig3ax
6780 https://guix.example.org/nar/@dots{}-pius-2.1.1: 1cy25x1a4fzq5rk0pmvc8xhwyffnqz95h2bpvqsz2mpvlbccy0gs
6784 In this example, @command{guix challenge} first scans the store to
6785 determine the set of locally-built derivations---as opposed to store
6786 items that were downloaded from a substitute server---and then queries
6787 all the substitute servers. It then reports those store items for which
6788 the servers obtained a result different from the local build.
6790 @cindex non-determinism, in package builds
6791 As an example, @code{guix.example.org} always gets a different answer.
6792 Conversely, @code{hydra.gnu.org} agrees with local builds, except in the
6793 case of Git. This might indicate that the build process of Git is
6794 non-deterministic, meaning that its output varies as a function of
6795 various things that Guix does not fully control, in spite of building
6796 packages in isolated environments (@pxref{Features}). Most common
6797 sources of non-determinism include the addition of timestamps in build
6798 results, the inclusion of random numbers, and directory listings sorted
6799 by inode number. See @uref{https://reproducible-builds.org/docs/}, for
6802 To find out what is wrong with this Git binary, we can do something along
6803 these lines (@pxref{Invoking guix archive}):
6806 $ wget -q -O - https://hydra.gnu.org/nar/@dots{}-git-2.5.0 \
6807 | guix archive -x /tmp/git
6808 $ diff -ur --no-dereference /gnu/store/@dots{}-git.2.5.0 /tmp/git
6811 This command shows the difference between the files resulting from the
6812 local build, and the files resulting from the build on
6813 @code{hydra.gnu.org} (@pxref{Overview, Comparing and Merging Files,,
6814 diffutils, Comparing and Merging Files}). The @command{diff} command
6815 works great for text files. When binary files differ, a better option
6816 is @uref{https://diffoscope.org/, Diffoscope}, a tool that helps
6817 visualize differences for all kinds of files.
6819 Once you have done that work, you can tell whether the differences are due
6820 to a non-deterministic build process or to a malicious server. We try
6821 hard to remove sources of non-determinism in packages to make it easier
6822 to verify substitutes, but of course, this is a process that
6823 involves not just Guix, but a large part of the free software community.
6824 In the meantime, @command{guix challenge} is one tool to help address
6827 If you are writing packages for Guix, you are encouraged to check
6828 whether @code{hydra.gnu.org} and other substitute servers obtain the
6829 same build result as you did with:
6832 $ guix challenge @var{package}
6836 where @var{package} is a package specification such as
6837 @code{guile@@2.0} or @code{glibc:debug}.
6839 The general syntax is:
6842 guix challenge @var{options} [@var{packages}@dots{}]
6845 When a difference is found between the hash of a locally-built item and
6846 that of a server-provided substitute, or among substitutes provided by
6847 different servers, the command displays it as in the example above and
6848 its exit code is 2 (other non-zero exit codes denote other kinds of
6851 The one option that matters is:
6855 @item --substitute-urls=@var{urls}
6856 Consider @var{urls} the whitespace-separated list of substitute source
6861 Show details about matches (identical contents) in addition to
6862 information about mismatches.
6866 @node Invoking guix copy
6867 @section Invoking @command{guix copy}
6869 @cindex copy, of store items, over SSH
6870 @cindex SSH, copy of store items
6871 @cindex sharing store items across machines
6872 @cindex transferring store items across machines
6873 The @command{guix copy} command copies items from the store of one
6874 machine to that of another machine over a secure shell (SSH)
6875 connection@footnote{This command is available only when Guile-SSH was
6876 found. @xref{Requirements}, for details.}. For example, the following
6877 command copies the @code{coreutils} package, the user's profile, and all
6878 their dependencies over to @var{host}, logged in as @var{user}:
6881 guix copy --to=@var{user}@@@var{host} \
6882 coreutils `readlink -f ~/.guix-profile`
6885 If some of the items to be copied are already present on @var{host},
6886 they are not actually sent.
6888 The command below retrieves @code{libreoffice} and @code{gimp} from
6889 @var{host}, assuming they are available there:
6892 guix copy --from=@var{host} libreoffice gimp
6895 The SSH connection is established using the Guile-SSH client, which is
6896 compatible with OpenSSH: it honors @file{~/.ssh/known_hosts} and
6897 @file{~/.ssh/config}, and uses the SSH agent for authentication.
6899 The key used to sign items that are sent must be accepted by the remote
6900 machine. Likewise, the key used by the remote machine to sign items you
6901 are retrieving must be in @file{/etc/guix/acl} so it is accepted by your
6902 own daemon. @xref{Invoking guix archive}, for more information about
6903 store item authentication.
6905 The general syntax is:
6908 guix copy [--to=@var{spec}|--from=@var{spec}] @var{items}@dots{}
6911 You must always specify one of the following options:
6914 @item --to=@var{spec}
6915 @itemx --from=@var{spec}
6916 Specify the host to send to or receive from. @var{spec} must be an SSH
6917 spec such as @code{example.org}, @code{charlie@@example.org}, or
6918 @code{charlie@@example.org:2222}.
6921 The @var{items} can be either package names, such as @code{gimp}, or
6922 store items, such as @file{/gnu/store/@dots{}-idutils-4.6}.
6924 When specifying the name of a package to send, it is first built if
6925 needed, unless @option{--dry-run} was specified. Common build options
6926 are supported (@pxref{Common Build Options}).
6929 @node Invoking guix container
6930 @section Invoking @command{guix container}
6932 @cindex @command{guix container}
6934 As of version @value{VERSION}, this tool is experimental. The interface
6935 is subject to radical change in the future.
6938 The purpose of @command{guix container} is to manipulate processes
6939 running within an isolated environment, commonly known as a
6940 ``container'', typically created by the @command{guix environment}
6941 (@pxref{Invoking guix environment}) and @command{guix system container}
6942 (@pxref{Invoking guix system}) commands.
6944 The general syntax is:
6947 guix container @var{action} @var{options}@dots{}
6950 @var{action} specifies the operation to perform with a container, and
6951 @var{options} specifies the context-specific arguments for the action.
6953 The following actions are available:
6957 Execute a command within the context of a running container.
6962 guix container exec @var{pid} @var{program} @var{arguments}@dots{}
6965 @var{pid} specifies the process ID of the running container.
6966 @var{program} specifies an executable file name within the root file
6967 system of the container. @var{arguments} are the additional options that
6968 will be passed to @var{program}.
6970 The following command launches an interactive login shell inside a
6971 GuixSD container, started by @command{guix system container}, and whose
6975 guix container exec 9001 /run/current-system/profile/bin/bash --login
6978 Note that the @var{pid} cannot be the parent process of a container. It
6979 must be PID 1 of the container or one of its child processes.
6983 @c *********************************************************************
6984 @node GNU Distribution
6985 @chapter GNU Distribution
6987 @cindex Guix System Distribution
6989 Guix comes with a distribution of the GNU system consisting entirely of
6990 free software@footnote{The term ``free'' here refers to the
6991 @url{http://www.gnu.org/philosophy/free-sw.html,freedom provided to
6992 users of that software}.}. The
6993 distribution can be installed on its own (@pxref{System Installation}),
6994 but it is also possible to install Guix as a package manager on top of
6995 an installed GNU/Linux system (@pxref{Installation}). To distinguish
6996 between the two, we refer to the standalone distribution as the Guix
6997 System Distribution, or GuixSD.
6999 The distribution provides core GNU packages such as GNU libc, GCC, and
7000 Binutils, as well as many GNU and non-GNU applications. The complete
7001 list of available packages can be browsed
7002 @url{http://www.gnu.org/software/guix/packages,on-line} or by
7003 running @command{guix package} (@pxref{Invoking guix package}):
7006 guix package --list-available
7009 Our goal is to provide a practical 100% free software distribution of
7010 Linux-based and other variants of GNU, with a focus on the promotion and
7011 tight integration of GNU components, and an emphasis on programs and
7012 tools that help users exert that freedom.
7014 Packages are currently available on the following platforms:
7019 Intel/AMD @code{x86_64} architecture, Linux-Libre kernel;
7022 Intel 32-bit architecture (IA32), Linux-Libre kernel;
7025 ARMv7-A architecture with hard float, Thumb-2 and NEON,
7026 using the EABI hard-float application binary interface (ABI),
7027 and Linux-Libre kernel.
7030 little-endian 64-bit ARMv8-A processors, Linux-Libre kernel. This is
7031 currently in an experimental stage, with limited support.
7032 @xref{Contributing}, for how to help!
7034 @item mips64el-linux
7035 little-endian 64-bit MIPS processors, specifically the Loongson series,
7036 n32 ABI, and Linux-Libre kernel.
7040 GuixSD itself is currently only available on @code{i686} and @code{x86_64}.
7043 For information on porting to other architectures or kernels,
7047 * System Installation:: Installing the whole operating system.
7048 * System Configuration:: Configuring the operating system.
7049 * Documentation:: Browsing software user manuals.
7050 * Installing Debugging Files:: Feeding the debugger.
7051 * Security Updates:: Deploying security fixes quickly.
7052 * Package Modules:: Packages from the programmer's viewpoint.
7053 * Packaging Guidelines:: Growing the distribution.
7054 * Bootstrapping:: GNU/Linux built from scratch.
7055 * Porting:: Targeting another platform or kernel.
7058 Building this distribution is a cooperative effort, and you are invited
7059 to join! @xref{Contributing}, for information about how you can help.
7061 @node System Installation
7062 @section System Installation
7064 @cindex installing GuixSD
7065 @cindex Guix System Distribution
7066 This section explains how to install the Guix System Distribution (GuixSD)
7067 on a machine. The Guix package manager can
7068 also be installed on top of a running GNU/Linux system,
7069 @pxref{Installation}.
7073 @c This paragraph is for people reading this from tty2 of the
7074 @c installation image.
7075 You are reading this documentation with an Info reader. For details on
7076 how to use it, hit the @key{RET} key (``return'' or ``enter'') on the
7077 link that follows: @pxref{Top, Info reader,, info-stnd, Stand-alone GNU
7078 Info}. Hit @kbd{l} afterwards to come back here.
7080 Alternately, run @command{info info} in another tty to keep the manual
7086 * Limitations:: What you can expect.
7087 * Hardware Considerations:: Supported hardware.
7088 * USB Stick Installation:: Preparing the installation medium.
7089 * Preparing for Installation:: Networking, partitioning, etc.
7090 * Proceeding with the Installation:: The real thing.
7091 * Installing GuixSD in a VM:: GuixSD playground.
7092 * Building the Installation Image:: How this comes to be.
7096 @subsection Limitations
7098 As of version @value{VERSION}, the Guix System Distribution (GuixSD) is
7099 not production-ready. It may contain bugs and lack important
7100 features. Thus, if you are looking for a stable production system that
7101 respects your freedom as a computer user, a good solution at this point
7102 is to consider @url{http://www.gnu.org/distros/free-distros.html, one of
7103 the more established GNU/Linux distributions}. We hope you can soon switch
7104 to the GuixSD without fear, of course. In the meantime, you can
7105 also keep using your distribution and try out the package manager on top
7106 of it (@pxref{Installation}).
7108 Before you proceed with the installation, be aware of the following
7109 noteworthy limitations applicable to version @value{VERSION}:
7113 The installation process does not include a graphical user interface and
7114 requires familiarity with GNU/Linux (see the following subsections to
7115 get a feel of what that means.)
7118 Support for the Logical Volume Manager (LVM) is missing.
7121 Few system services are currently supported out-of-the-box
7125 More than 5,000 packages are available, but you may
7126 occasionally find that a useful package is missing.
7129 GNOME, Xfce, and Enlightenment are available (@pxref{Desktop Services}),
7130 as well as a number of X11 window managers. However, some graphical
7131 applications may be missing, as well as KDE.
7134 You have been warned! But more than a disclaimer, this is an invitation
7135 to report issues (and success stories!), and to join us in improving it.
7136 @xref{Contributing}, for more info.
7139 @node Hardware Considerations
7140 @subsection Hardware Considerations
7142 @cindex hardware support on GuixSD
7143 GNU@tie{}GuixSD focuses on respecting the user's computing freedom. It
7144 builds around the kernel Linux-libre, which means that only hardware for
7145 which free software drivers and firmware exist is supported. Nowadays,
7146 a wide range of off-the-shelf hardware is supported on
7147 GNU/Linux-libre---from keyboards to graphics cards to scanners and
7148 Ethernet controllers. Unfortunately, there are still areas where
7149 hardware vendors deny users control over their own computing, and such
7150 hardware is not supported on GuixSD.
7152 @cindex WiFi, hardware support
7153 One of the main areas where free drivers or firmware are lacking is WiFi
7154 devices. WiFi devices known to work include those using Atheros chips
7155 (AR9271 and AR7010), which corresponds to the @code{ath9k} Linux-libre
7156 driver, and those using Broadcom/AirForce chips (BCM43xx with
7157 Wireless-Core Revision 5), which corresponds to the @code{b43-open}
7158 Linux-libre driver. Free firmware exists for both and is available
7159 out-of-the-box on GuixSD, as part of @var{%base-firmware}
7160 (@pxref{operating-system Reference, @code{firmware}}).
7162 @cindex RYF, Respects Your Freedom
7163 The @uref{https://www.fsf.org/, Free Software Foundation} runs
7164 @uref{https://www.fsf.org/ryf, @dfn{Respects Your Freedom}} (RYF), a
7165 certification program for hardware products that respect your freedom
7166 and your privacy and ensure that you have control over your device. We
7167 encourage you to check the list of RYF-certified devices.
7169 Another useful resource is the @uref{https://www.h-node.org/, H-Node}
7170 web site. It contains a catalog of hardware devices with information
7171 about their support in GNU/Linux.
7174 @node USB Stick Installation
7175 @subsection USB Stick Installation
7177 An installation image for USB sticks can be downloaded from
7178 @indicateurl{ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz},
7179 where @var{system} is one of:
7183 for a GNU/Linux system on Intel/AMD-compatible 64-bit CPUs;
7186 for a 32-bit GNU/Linux system on Intel-compatible CPUs.
7189 @c start duplication of authentication part from ``Binary Installation''
7190 Make sure to download the associated @file{.sig} file and to verify the
7191 authenticity of the image against it, along these lines:
7194 $ wget ftp://alpha.gnu.org/gnu/guix/guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7195 $ gpg --verify guixsd-usb-install-@value{VERSION}.@var{system}.xz.sig
7198 If that command fails because you do not have the required public key,
7199 then run this command to import it:
7202 $ gpg --keyserver pgp.mit.edu --recv-keys @value{OPENPGP-SIGNING-KEY-ID}
7206 and rerun the @code{gpg --verify} command.
7209 This image contains a single partition with the tools necessary for an
7210 installation. It is meant to be copied @emph{as is} to a large-enough
7213 To copy the image to a USB stick, follow these steps:
7217 Decompress the image using the @command{xz} command:
7220 xz -d guixsd-usb-install-@value{VERSION}.@var{system}.xz
7224 Insert a USB stick of 1@tie{}GiB or more into your machine, and determine
7225 its device name. Assuming that the USB stick is known as @file{/dev/sdX},
7226 copy the image with:
7229 dd if=guixsd-usb-install-@value{VERSION}.x86_64 of=/dev/sdX
7232 Access to @file{/dev/sdX} usually requires root privileges.
7235 Once this is done, you should be able to reboot the system and boot from
7236 the USB stick. The latter usually requires you to get in the BIOS' boot
7237 menu, where you can choose to boot from the USB stick.
7239 @xref{Installing GuixSD in a VM}, if, instead, you would like to install
7240 GuixSD in a virtual machine (VM).
7242 @node Preparing for Installation
7243 @subsection Preparing for Installation
7245 Once you have successfully booted the image on the USB stick, you should
7246 end up with a root prompt. Several console TTYs are configured and can
7247 be used to run commands as root. TTY2 shows this documentation,
7248 browsable using the Info reader commands (@pxref{Top,,, info-stnd,
7249 Stand-alone GNU Info}). The installation system runs the GPM mouse
7250 daemon, which allows you to select text with the left mouse button and
7251 to paste it with the middle button.
7254 Installation requires access to the Internet so that any missing
7255 dependencies of your system configuration can be downloaded. See the
7256 ``Networking'' section below.
7259 The installation system includes many common tools needed for this task.
7260 But it is also a full-blown GuixSD system, which means that you can
7261 install additional packages, should you need it, using @command{guix
7262 package} (@pxref{Invoking guix package}).
7264 @subsubsection Keyboard Layout
7266 @cindex keyboard layout
7267 The installation image uses the US qwerty keyboard layout. If you want
7268 to change it, you can use the @command{loadkeys} command. For example,
7269 the following command selects the Dvorak keyboard layout:
7275 See the files under @file{/run/current-system/profile/share/keymaps} for
7276 a list of available keyboard layouts. Run @command{man loadkeys} for
7279 @subsubsection Networking
7281 Run the following command see what your network interfaces are called:
7288 @dots{} or, using the GNU/Linux-specific @command{ip} command:
7294 @c http://cgit.freedesktop.org/systemd/systemd/tree/src/udev/udev-builtin-net_id.c#n20
7295 Wired interfaces have a name starting with @samp{e}; for example, the
7296 interface corresponding to the first on-board Ethernet controller is
7297 called @samp{eno1}. Wireless interfaces have a name starting with
7298 @samp{w}, like @samp{w1p2s0}.
7301 @item Wired connection
7302 To configure a wired network run the following command, substituting
7303 @var{interface} with the name of the wired interface you want to use.
7306 ifconfig @var{interface} up
7309 @item Wireless connection
7312 To configure wireless networking, you can create a configuration file
7313 for the @command{wpa_supplicant} configuration tool (its location is not
7314 important) using one of the available text editors such as
7318 zile wpa_supplicant.conf
7321 As an example, the following stanza can go to this file and will work
7322 for many wireless networks, provided you give the actual SSID and
7323 passphrase for the network you are connecting to:
7327 ssid="@var{my-ssid}"
7329 psk="the network's secret passphrase"
7333 Start the wireless service and run it in the background with the
7334 following command (substitute @var{interface} with the name of the
7335 network interface you want to use):
7338 wpa_supplicant -c wpa_supplicant.conf -i @var{interface} -B
7341 Run @command{man wpa_supplicant} for more information.
7345 At this point, you need to acquire an IP address. On a network where IP
7346 addresses are automatically assigned @i{via} DHCP, you can run:
7349 dhclient -v @var{interface}
7352 Try to ping a server to see if networking is up and running:
7358 Setting up network access is almost always a requirement because the
7359 image does not contain all the software and tools that may be needed.
7361 @subsubsection Disk Partitioning
7363 Unless this has already been done, the next step is to partition, and
7364 then format the target partition(s).
7366 The installation image includes several partitioning tools, including
7367 Parted (@pxref{Overview,,, parted, GNU Parted User Manual}),
7368 @command{fdisk}, and @command{cfdisk}. Run it and set up your disk with
7369 the partition layout you want:
7375 If your disk uses the GUID Partition Table (GPT) format and you plan to
7376 install BIOS-based GRUB (which is the default), make sure a BIOS Boot
7377 Partition is available (@pxref{BIOS installation,,, grub, GNU GRUB
7380 Once you are done partitioning the target hard disk drive, you have to
7381 create a file system on the relevant partition(s)@footnote{Currently
7382 GuixSD only supports ext4 and btrfs file systems. In particular, code
7383 that reads partition UUIDs and labels only works for these file system
7386 Preferably, assign partitions a label so that you can easily and
7387 reliably refer to them in @code{file-system} declarations (@pxref{File
7388 Systems}). This is typically done using the @code{-L} option of
7389 @command{mkfs.ext4} and related commands. So, assuming the target root
7390 partition lives at @file{/dev/sda1}, a file system with the label
7391 @code{my-root} can be created with:
7394 mkfs.ext4 -L my-root /dev/sda1
7397 @cindex encrypted disk
7398 If you are instead planning to encrypt the root partition, you can use
7399 the Cryptsetup/LUKS utilities to do that (see @inlinefmtifelse{html,
7400 @uref{https://linux.die.net/man/8/cryptsetup, @code{man cryptsetup}},
7401 @code{man cryptsetup}} for more information.) Assuming you want to
7402 store the root partition on @file{/dev/sda1}, the command sequence would
7403 be along these lines:
7406 cryptsetup luksFormat /dev/sda1
7407 cryptsetup open --type luks /dev/sda1 my-partition
7408 mkfs.ext4 -L my-root /dev/mapper/my-partition
7411 Once that is done, mount the target root partition under @file{/mnt}
7412 with a command like (again, assuming @code{my-root} is the label of the
7416 mount LABEL=my-root /mnt
7419 Finally, if you plan to use one or more swap partitions (@pxref{Memory
7420 Concepts, swap space,, libc, The GNU C Library Reference Manual}), make
7421 sure to initialize them with @command{mkswap}. Assuming you have one
7422 swap partition on @file{/dev/sda2}, you would run:
7429 Alternatively, you may use a swap file. For example, assuming that in
7430 the new system you want to use the file @file{/swapfile} as a swap file,
7431 you would run@footnote{This example will work for many types of file
7432 systems (e.g., ext4). However, for copy-on-write file systems (e.g.,
7433 btrfs), the required steps may be different. For details, see the
7434 manual pages for @command{mkswap} and @command{swapon}.}:
7437 # This is 10 GiB of swap space. Adjust "count" to change the size.
7438 dd if=/dev/zero of=/mnt/swapfile bs=1MiB count=10240
7439 # For security, make the file readable and writable only by root.
7440 chmod 600 /mnt/swapfile
7441 mkswap /mnt/swapfile
7442 swapon /mnt/swapfile
7445 Note that if you have encrypted the root partition and created a swap
7446 file in its file system as described above, then the encryption also
7447 protects the swap file, just like any other file in that file system.
7449 @node Proceeding with the Installation
7450 @subsection Proceeding with the Installation
7452 With the target partitions ready and the target root mounted on
7453 @file{/mnt}, we're ready to go. First, run:
7456 herd start cow-store /mnt
7459 This makes @file{/gnu/store} copy-on-write, such that packages added to it
7460 during the installation phase are written to the target disk on @file{/mnt}
7461 rather than kept in memory. This is necessary because the first phase of
7462 the @command{guix system init} command (see below) entails downloads or
7463 builds to @file{/gnu/store} which, initially, is an in-memory file system.
7465 Next, you have to edit a file and
7466 provide the declaration of the operating system to be installed. To
7467 that end, the installation system comes with three text editors: GNU nano
7468 (@pxref{Top,,, nano, GNU nano Manual}), GNU Zile (an Emacs clone), and
7469 nvi (a clone of the original BSD @command{vi} editor).
7470 We strongly recommend storing that file on the target root file system, say,
7471 as @file{/mnt/etc/config.scm}. Failing to do that, you will have lost your
7472 configuration file once you have rebooted into the newly-installed system.
7474 @xref{Using the Configuration System}, for an overview of the
7475 configuration file. The example configurations discussed in that
7476 section are available under @file{/etc/configuration} in the
7477 installation image. Thus, to get started with a system configuration
7478 providing a graphical display server (a ``desktop'' system), you can run
7479 something along these lines:
7483 # cp /etc/configuration/desktop.scm /mnt/etc/config.scm
7484 # zile /mnt/etc/config.scm
7487 You should pay attention to what your configuration file contains, and
7492 Make sure the @code{grub-configuration} form refers to the device you
7493 want to install GRUB on.
7496 Be sure that your partition labels match the value of their respective
7497 @code{device} fields in your @code{file-system} configuration, assuming
7498 your @code{file-system} configuration sets the value of @code{title} to
7502 If there are encrypted or RAID partitions, make sure to add a
7503 @code{mapped-devices} field to describe them (@pxref{Mapped Devices}).
7506 Once you are done preparing the configuration file, the new system must
7507 be initialized (remember that the target root file system is mounted
7511 guix system init /mnt/etc/config.scm /mnt
7515 This copies all the necessary files and installs GRUB on
7516 @file{/dev/sdX}, unless you pass the @option{--no-bootloader} option. For
7517 more information, @pxref{Invoking guix system}. This command may trigger
7518 downloads or builds of missing packages, which can take some time.
7520 Once that command has completed---and hopefully succeeded!---you can run
7521 @command{reboot} and boot into the new system. The @code{root} password
7522 in the new system is initially empty; other users' passwords need to be
7523 initialized by running the @command{passwd} command as @code{root},
7524 unless your configuration specifies otherwise
7525 (@pxref{user-account-password, user account passwords}).
7527 @cindex upgrading GuixSD
7528 From then on, you can update GuixSD whenever you want by running
7529 @command{guix pull} as @code{root} (@pxref{Invoking guix pull}), and
7530 then running @command{guix system reconfigure} to build a new system
7531 generation with the latest packages and services (@pxref{Invoking guix
7532 system}). We recommend doing that regularly so that your system
7533 includes the latest security updates (@pxref{Security Updates}).
7535 Join us on @code{#guix} on the Freenode IRC network or on
7536 @file{guix-devel@@gnu.org} to share your experience---good or not so
7539 @node Installing GuixSD in a VM
7540 @subsection Installing GuixSD in a Virtual Machine
7542 @cindex virtual machine, GuixSD installation
7543 If you'd like to install GuixSD in a virtual machine (VM) rather than on
7544 your beloved machine, this section is for you.
7546 To boot a @uref{http://qemu.org/,QEMU} VM for installing GuixSD in a
7547 disk image, follow these steps:
7551 First, retrieve and decompress the GuixSD installation image as
7552 described previously (@pxref{USB Stick Installation}).
7555 Create a disk image that will hold the installed system. To make a
7556 qcow2-formatted disk image, use the @command{qemu-img} command:
7559 qemu-img create -f qcow2 guixsd.img 5G
7562 This will create a 5GB file.
7565 Boot the USB installation image in an VM:
7568 qemu-system-x86_64 -m 1024 -smp 1 \
7569 -net user -net nic,model=virtio -boot menu=on \
7570 -drive file=guixsd.img \
7571 -drive file=guixsd-usb-install-@value{VERSION}.@var{system}
7574 In the VM console, quickly press the @kbd{F12} key to enter the boot
7575 menu. Then press the @kbd{2} key and the @kbd{RET} key to validate your
7579 You're now root in the VM, proceed with the installation process.
7580 @xref{Preparing for Installation}, and follow the instructions.
7583 Once installation is complete, you can boot the system that's on your
7584 @file{guixsd.img} image. @xref{Running GuixSD in a VM}, for how to do
7587 @node Building the Installation Image
7588 @subsection Building the Installation Image
7590 @cindex installation image
7591 The installation image described above was built using the @command{guix
7592 system} command, specifically:
7594 @c FIXME: 1G is too much; see <http://bugs.gnu.org/23077>.
7596 guix system disk-image --image-size=1G gnu/system/install.scm
7599 Have a look at @file{gnu/system/install.scm} in the source tree,
7600 and see also @ref{Invoking guix system} for more information
7601 about the installation image.
7603 @node System Configuration
7604 @section System Configuration
7606 @cindex system configuration
7607 The Guix System Distribution supports a consistent whole-system configuration
7608 mechanism. By that we mean that all aspects of the global system
7609 configuration---such as the available system services, timezone and
7610 locale settings, user accounts---are declared in a single place. Such
7611 a @dfn{system configuration} can be @dfn{instantiated}---i.e., effected.
7613 One of the advantages of putting all the system configuration under the
7614 control of Guix is that it supports transactional system upgrades, and
7615 makes it possible to roll back to a previous system instantiation,
7616 should something go wrong with the new one (@pxref{Features}). Another
7617 advantage is that it makes it easy to replicate the exact same configuration
7618 across different machines, or at different points in time, without
7619 having to resort to additional administration tools layered on top of
7620 the own tools of the system.
7621 @c Yes, we're talking of Puppet, Chef, & co. here. ↑
7623 This section describes this mechanism. First we focus on the system
7624 administrator's viewpoint---explaining how the system is configured and
7625 instantiated. Then we show how this mechanism can be extended, for
7626 instance to support new system services.
7629 * Using the Configuration System:: Customizing your GNU system.
7630 * operating-system Reference:: Detail of operating-system declarations.
7631 * File Systems:: Configuring file system mounts.
7632 * Mapped Devices:: Block device extra processing.
7633 * User Accounts:: Specifying user accounts.
7634 * Locales:: Language and cultural convention settings.
7635 * Services:: Specifying system services.
7636 * Setuid Programs:: Programs running with root privileges.
7637 * X.509 Certificates:: Authenticating HTTPS servers.
7638 * Name Service Switch:: Configuring libc's name service switch.
7639 * Initial RAM Disk:: Linux-Libre bootstrapping.
7640 * GRUB Configuration:: Configuring the boot loader.
7641 * Invoking guix system:: Instantiating a system configuration.
7642 * Running GuixSD in a VM:: How to run GuixSD in a virtual machine.
7643 * Defining Services:: Adding new service definitions.
7646 @node Using the Configuration System
7647 @subsection Using the Configuration System
7649 The operating system is configured by providing an
7650 @code{operating-system} declaration in a file that can then be passed to
7651 the @command{guix system} command (@pxref{Invoking guix system}). A
7652 simple setup, with the default system services, the default Linux-Libre
7653 kernel, initial RAM disk, and boot loader looks like this:
7655 @findex operating-system
7657 @include os-config-bare-bones.texi
7660 This example should be self-describing. Some of the fields defined
7661 above, such as @code{host-name} and @code{bootloader}, are mandatory.
7662 Others, such as @code{packages} and @code{services}, can be omitted, in
7663 which case they get a default value.
7665 Below we discuss the effect of some of the most important fields
7666 (@pxref{operating-system Reference}, for details about all the available
7667 fields), and how to @dfn{instantiate} the operating system using
7668 @command{guix system}.
7670 @unnumberedsubsubsec Globally-Visible Packages
7672 @vindex %base-packages
7673 The @code{packages} field lists packages that will be globally visible
7674 on the system, for all user accounts---i.e., in every user's @code{PATH}
7675 environment variable---in addition to the per-user profiles
7676 (@pxref{Invoking guix package}). The @var{%base-packages} variable
7677 provides all the tools one would expect for basic user and administrator
7678 tasks---including the GNU Core Utilities, the GNU Networking Utilities,
7679 the GNU Zile lightweight text editor, @command{find}, @command{grep},
7680 etc. The example above adds tcpdump to those, taken from the @code{(gnu
7681 packages admin)} module (@pxref{Package Modules}).
7683 @findex specification->package
7684 Referring to packages by variable name, like @var{tcpdump} above, has
7685 the advantage of being unambiguous; it also allows typos and such to be
7686 diagnosed right away as ``unbound variables''. The downside is that one
7687 needs to know which module defines which package, and to augment the
7688 @code{use-package-modules} line accordingly. To avoid that, one can use
7689 the @code{specification->package} procedure of the @code{(gnu packages)}
7690 module, which returns the best package for a given name or name and
7694 (use-modules (gnu packages))
7698 (packages (append (map specification->package
7699 '("tcpdump" "htop" "gnupg@@2.0"))
7703 @unnumberedsubsubsec System Services
7706 @vindex %base-services
7707 The @code{services} field lists @dfn{system services} to be made
7708 available when the system starts (@pxref{Services}).
7709 The @code{operating-system} declaration above specifies that, in
7710 addition to the basic services, we want the @command{lshd} secure shell
7711 daemon listening on port 2222 (@pxref{Networking Services,
7712 @code{lsh-service}}). Under the hood,
7713 @code{lsh-service} arranges so that @code{lshd} is started with the
7714 right command-line options, possibly with supporting configuration files
7715 generated as needed (@pxref{Defining Services}).
7717 @cindex customization, of services
7718 @findex modify-services
7719 Occasionally, instead of using the base services as is, you will want to
7720 customize them. To do this, use @code{modify-services} (@pxref{Service
7721 Reference, @code{modify-services}}) to modify the list.
7723 For example, suppose you want to modify @code{guix-daemon} and Mingetty
7724 (the console log-in) in the @var{%base-services} list (@pxref{Base
7725 Services, @code{%base-services}}). To do that, you can write the
7726 following in your operating system declaration:
7729 (define %my-services
7730 ;; My very own list of services.
7731 (modify-services %base-services
7732 (guix-service-type config =>
7735 (use-substitutes? #f)
7736 (extra-options '("--gc-keep-derivations"))))
7737 (mingetty-service-type config =>
7738 (mingetty-configuration
7739 (inherit config)))))
7743 (services %my-services))
7746 This changes the configuration---i.e., the service parameters---of the
7747 @code{guix-service-type} instance, and that of all the
7748 @code{mingetty-service-type} instances in the @var{%base-services} list.
7749 Observe how this is accomplished: first, we arrange for the original
7750 configuration to be bound to the identifier @code{config} in the
7751 @var{body}, and then we write the @var{body} so that it evaluates to the
7752 desired configuration. In particular, notice how we use @code{inherit}
7753 to create a new configuration which has the same values as the old
7754 configuration, but with a few modifications.
7756 @cindex encrypted disk
7757 The configuration for a typical ``desktop'' usage, with an encrypted
7758 root partition, the X11 display
7759 server, GNOME and Xfce (users can choose which of these desktop
7760 environments to use at the log-in screen by pressing @kbd{F1}), network
7761 management, power management, and more, would look like this:
7764 @include os-config-desktop.texi
7767 A graphical environment with a choice of lightweight window managers
7768 instead of full-blown desktop environments would look like this:
7771 @include os-config-lightweight-desktop.texi
7774 @xref{Desktop Services}, for the exact list of services provided by
7775 @var{%desktop-services}. @xref{X.509 Certificates}, for background
7776 information about the @code{nss-certs} package that is used here.
7778 Again, @var{%desktop-services} is just a list of service objects. If
7779 you want to remove services from there, you can do so using the
7780 procedures for list filtering (@pxref{SRFI-1 Filtering and
7781 Partitioning,,, guile, GNU Guile Reference Manual}). For instance, the
7782 following expression returns a list that contains all the services in
7783 @var{%desktop-services} minus the Avahi service:
7786 (remove (lambda (service)
7787 (eq? (service-kind service) avahi-service-type))
7791 @unnumberedsubsubsec Instantiating the System
7793 Assuming the @code{operating-system} declaration
7794 is stored in the @file{my-system-config.scm}
7795 file, the @command{guix system reconfigure my-system-config.scm} command
7796 instantiates that configuration, and makes it the default GRUB boot
7797 entry (@pxref{Invoking guix system}).
7799 The normal way to change the system configuration is by updating this
7800 file and re-running @command{guix system reconfigure}. One should never
7801 have to touch files in @file{/etc} or to run commands that modify the
7802 system state such as @command{useradd} or @command{grub-install}. In
7803 fact, you must avoid that since that would not only void your warranty
7804 but also prevent you from rolling back to previous versions of your
7805 system, should you ever need to.
7807 @cindex roll-back, of the operating system
7808 Speaking of roll-back, each time you run @command{guix system
7809 reconfigure}, a new @dfn{generation} of the system is created---without
7810 modifying or deleting previous generations. Old system generations get
7811 an entry in the GRUB boot menu, allowing you to boot them in case
7812 something went wrong with the latest generation. Reassuring, no? The
7813 @command{guix system list-generations} command lists the system
7814 generations available on disk. It is also possible to roll back the
7815 system via the commands @command{guix system roll-back} and
7816 @command{guix system switch-generation}.
7818 Although the command @command{guix system reconfigure} will not modify
7819 previous generations, must take care when the current generation is not
7820 the latest (e.g., after invoking @command{guix system roll-back}), since
7821 the operation might overwrite a later generation (@pxref{Invoking guix
7824 @unnumberedsubsubsec The Programming Interface
7826 At the Scheme level, the bulk of an @code{operating-system} declaration
7827 is instantiated with the following monadic procedure (@pxref{The Store
7830 @deffn {Monadic Procedure} operating-system-derivation os
7831 Return a derivation that builds @var{os}, an @code{operating-system}
7832 object (@pxref{Derivations}).
7834 The output of the derivation is a single directory that refers to all
7835 the packages, configuration files, and other supporting files needed to
7836 instantiate @var{os}.
7839 This procedure is provided by the @code{(gnu system)} module. Along
7840 with @code{(gnu services)} (@pxref{Services}), this module contains the
7841 guts of GuixSD. Make sure to visit it!
7844 @node operating-system Reference
7845 @subsection @code{operating-system} Reference
7847 This section summarizes all the options available in
7848 @code{operating-system} declarations (@pxref{Using the Configuration
7851 @deftp {Data Type} operating-system
7852 This is the data type representing an operating system configuration.
7853 By that, we mean all the global system configuration, not per-user
7854 configuration (@pxref{Using the Configuration System}).
7857 @item @code{kernel} (default: @var{linux-libre})
7858 The package object of the operating system kernel to use@footnote{Currently
7859 only the Linux-libre kernel is supported. In the future, it will be
7860 possible to use the GNU@tie{}Hurd.}.
7862 @item @code{kernel-arguments} (default: @code{'()})
7863 List of strings or gexps representing additional arguments to pass on
7864 the command-line of the kernel---e.g., @code{("console=ttyS0")}.
7866 @item @code{bootloader}
7867 The system bootloader configuration object. @xref{GRUB Configuration}.
7869 @item @code{initrd} (default: @code{base-initrd})
7871 @cindex initial RAM disk
7872 A two-argument monadic procedure that returns an initial RAM disk for
7873 the Linux kernel. @xref{Initial RAM Disk}.
7875 @item @code{firmware} (default: @var{%base-firmware})
7877 List of firmware packages loadable by the operating system kernel.
7879 The default includes firmware needed for Atheros- and Broadcom-based
7880 WiFi devices (Linux-libre modules @code{ath9k} and @code{b43-open},
7881 respectively). @xref{Hardware Considerations}, for more info on
7884 @item @code{host-name}
7887 @item @code{hosts-file}
7889 A file-like object (@pxref{G-Expressions, file-like objects}) for use as
7890 @file{/etc/hosts} (@pxref{Host Names,,, libc, The GNU C Library
7891 Reference Manual}). The default is a file with entries for
7892 @code{localhost} and @var{host-name}.
7894 @item @code{mapped-devices} (default: @code{'()})
7895 A list of mapped devices. @xref{Mapped Devices}.
7897 @item @code{file-systems}
7898 A list of file systems. @xref{File Systems}.
7900 @item @code{swap-devices} (default: @code{'()})
7901 @cindex swap devices
7902 A list of strings identifying devices or files to be used for ``swap
7903 space'' (@pxref{Memory Concepts,,, libc, The GNU C Library Reference
7904 Manual}). For example, @code{'("/dev/sda3")} or @code{'("/swapfile")}.
7905 It is possible to specify a swap file in a file system on a mapped
7906 device, provided that the necessary device mapping and file system are
7907 also specified. @xref{Mapped Devices} and @ref{File Systems}.
7909 @item @code{users} (default: @code{%base-user-accounts})
7910 @itemx @code{groups} (default: @var{%base-groups})
7911 List of user accounts and groups. @xref{User Accounts}.
7913 @item @code{skeletons} (default: @code{(default-skeletons)})
7914 A list target file name/file-like object tuples (@pxref{G-Expressions,
7915 file-like objects}). These are the skeleton files that will be added to
7916 the home directory of newly-created user accounts.
7918 For instance, a valid value may look like this:
7921 `((".bashrc" ,(plain-file "bashrc" "echo Hello\n"))
7922 (".guile" ,(plain-file "guile"
7923 "(use-modules (ice-9 readline))
7924 (activate-readline)")))
7927 @item @code{issue} (default: @var{%default-issue})
7928 A string denoting the contents of the @file{/etc/issue} file, which is
7929 displayed when users log in on a text console.
7931 @item @code{packages} (default: @var{%base-packages})
7932 The set of packages installed in the global profile, which is accessible
7933 at @file{/run/current-system/profile}.
7935 The default set includes core utilities and it is good practice to
7936 install non-core utilities in user profiles (@pxref{Invoking guix
7939 @item @code{timezone}
7940 A timezone identifying string---e.g., @code{"Europe/Paris"}.
7942 You can run the @command{tzselect} command to find out which timezone
7943 string corresponds to your region. Choosing an invalid timezone name
7944 causes @command{guix system} to fail.
7946 @item @code{locale} (default: @code{"en_US.utf8"})
7947 The name of the default locale (@pxref{Locale Names,,, libc, The GNU C
7948 Library Reference Manual}). @xref{Locales}, for more information.
7950 @item @code{locale-definitions} (default: @var{%default-locale-definitions})
7951 The list of locale definitions to be compiled and that may be used at
7952 run time. @xref{Locales}.
7954 @item @code{locale-libcs} (default: @code{(list @var{glibc})})
7955 The list of GNU@tie{}libc packages whose locale data and tools are used
7956 to build the locale definitions. @xref{Locales}, for compatibility
7957 considerations that justify this option.
7959 @item @code{name-service-switch} (default: @var{%default-nss})
7960 Configuration of the libc name service switch (NSS)---a
7961 @code{<name-service-switch>} object. @xref{Name Service Switch}, for
7964 @item @code{services} (default: @var{%base-services})
7965 A list of service objects denoting system services. @xref{Services}.
7967 @item @code{pam-services} (default: @code{(base-pam-services)})
7969 @cindex pluggable authentication modules
7970 Linux @dfn{pluggable authentication module} (PAM) services.
7971 @c FIXME: Add xref to PAM services section.
7973 @item @code{setuid-programs} (default: @var{%setuid-programs})
7974 List of string-valued G-expressions denoting setuid programs.
7975 @xref{Setuid Programs}.
7977 @item @code{sudoers-file} (default: @var{%sudoers-specification})
7978 @cindex sudoers file
7979 The contents of the @file{/etc/sudoers} file as a file-like object
7980 (@pxref{G-Expressions, @code{local-file} and @code{plain-file}}).
7982 This file specifies which users can use the @command{sudo} command, what
7983 they are allowed to do, and what privileges they may gain. The default
7984 is that only @code{root} and members of the @code{wheel} group may use
7991 @subsection File Systems
7993 The list of file systems to be mounted is specified in the
7994 @code{file-systems} field of the operating system declaration
7995 (@pxref{Using the Configuration System}). Each file system is declared
7996 using the @code{file-system} form, like this:
8000 (mount-point "/home")
8001 (device "/dev/sda3")
8005 As usual, some of the fields are mandatory---those shown in the example
8006 above---while others can be omitted. These are described below.
8008 @deftp {Data Type} file-system
8009 Objects of this type represent file systems to be mounted. They
8010 contain the following members:
8014 This is a string specifying the type of the file system---e.g.,
8017 @item @code{mount-point}
8018 This designates the place where the file system is to be mounted.
8021 This names the ``source'' of the file system. By default it is the name
8022 of a node under @file{/dev}, but its meaning depends on the @code{title}
8023 field described below.
8025 @item @code{title} (default: @code{'device})
8026 This is a symbol that specifies how the @code{device} field is to be
8029 When it is the symbol @code{device}, then the @code{device} field is
8030 interpreted as a file name; when it is @code{label}, then @code{device}
8031 is interpreted as a partition label name; when it is @code{uuid},
8032 @code{device} is interpreted as a partition unique identifier (UUID).
8034 UUIDs may be converted from their string representation (as shown by the
8035 @command{tune2fs -l} command) using the @code{uuid} form@footnote{The
8036 @code{uuid} form expects 16-byte UUIDs as defined in
8037 @uref{https://tools.ietf.org/html/rfc4122, RFC@tie{}4122}. This is the
8038 form of UUID used by the ext2 family of file systems and others, but it
8039 is different from ``UUIDs'' found in FAT file systems, for instance.},
8044 (mount-point "/home")
8047 (device (uuid "4dab5feb-d176-45de-b287-9b0a6e4c01cb")))
8050 The @code{label} and @code{uuid} options offer a way to refer to disk
8051 partitions without having to hard-code their actual device
8052 name@footnote{Note that, while it is tempting to use
8053 @file{/dev/disk/by-uuid} and similar device names to achieve the same
8054 result, this is not recommended: These special device nodes are created
8055 by the udev daemon and may be unavailable at the time the device is
8058 However, when the source of a file system is a mapped device (@pxref{Mapped
8059 Devices}), its @code{device} field @emph{must} refer to the mapped
8060 device name---e.g., @file{/dev/mapper/root-partition}---and consequently
8061 @code{title} must be set to @code{'device}. This is required so that
8062 the system knows that mounting the file system depends on having the
8063 corresponding device mapping established.
8065 @item @code{flags} (default: @code{'()})
8066 This is a list of symbols denoting mount flags. Recognized flags
8067 include @code{read-only}, @code{bind-mount}, @code{no-dev} (disallow
8068 access to special files), @code{no-suid} (ignore setuid and setgid
8069 bits), and @code{no-exec} (disallow program execution.)
8071 @item @code{options} (default: @code{#f})
8072 This is either @code{#f}, or a string denoting mount options.
8074 @item @code{mount?} (default: @code{#t})
8075 This value indicates whether to automatically mount the file system when
8076 the system is brought up. When set to @code{#f}, the file system gets
8077 an entry in @file{/etc/fstab} (read by the @command{mount} command) but
8078 is not automatically mounted.
8080 @item @code{needed-for-boot?} (default: @code{#f})
8081 This Boolean value indicates whether the file system is needed when
8082 booting. If that is true, then the file system is mounted when the
8083 initial RAM disk (initrd) is loaded. This is always the case, for
8084 instance, for the root file system.
8086 @item @code{check?} (default: @code{#t})
8087 This Boolean indicates whether the file system needs to be checked for
8088 errors before being mounted.
8090 @item @code{create-mount-point?} (default: @code{#f})
8091 When true, the mount point is created if it does not exist yet.
8093 @item @code{dependencies} (default: @code{'()})
8094 This is a list of @code{<file-system>} or @code{<mapped-device>} objects
8095 representing file systems that must be mounted or mapped devices that
8096 must be opened before (and unmounted or closed after) this one.
8098 As an example, consider a hierarchy of mounts: @file{/sys/fs/cgroup} is
8099 a dependency of @file{/sys/fs/cgroup/cpu} and
8100 @file{/sys/fs/cgroup/memory}.
8102 Another example is a file system that depends on a mapped device, for
8103 example for an encrypted partition (@pxref{Mapped Devices}).
8107 The @code{(gnu system file-systems)} exports the following useful
8110 @defvr {Scheme Variable} %base-file-systems
8111 These are essential file systems that are required on normal systems,
8112 such as @var{%pseudo-terminal-file-system} and @var{%immutable-store} (see
8113 below.) Operating system declarations should always contain at least
8117 @defvr {Scheme Variable} %pseudo-terminal-file-system
8118 This is the file system to be mounted as @file{/dev/pts}. It supports
8119 @dfn{pseudo-terminals} created @i{via} @code{openpty} and similar
8120 functions (@pxref{Pseudo-Terminals,,, libc, The GNU C Library Reference
8121 Manual}). Pseudo-terminals are used by terminal emulators such as
8125 @defvr {Scheme Variable} %shared-memory-file-system
8126 This file system is mounted as @file{/dev/shm} and is used to support
8127 memory sharing across processes (@pxref{Memory-mapped I/O,
8128 @code{shm_open},, libc, The GNU C Library Reference Manual}).
8131 @defvr {Scheme Variable} %immutable-store
8132 This file system performs a read-only ``bind mount'' of
8133 @file{/gnu/store}, making it read-only for all the users including
8134 @code{root}. This prevents against accidental modification by software
8135 running as @code{root} or by system administrators.
8137 The daemon itself is still able to write to the store: it remounts it
8138 read-write in its own ``name space.''
8141 @defvr {Scheme Variable} %binary-format-file-system
8142 The @code{binfmt_misc} file system, which allows handling of arbitrary
8143 executable file types to be delegated to user space. This requires the
8144 @code{binfmt.ko} kernel module to be loaded.
8147 @defvr {Scheme Variable} %fuse-control-file-system
8148 The @code{fusectl} file system, which allows unprivileged users to mount
8149 and unmount user-space FUSE file systems. This requires the
8150 @code{fuse.ko} kernel module to be loaded.
8153 @node Mapped Devices
8154 @subsection Mapped Devices
8156 @cindex device mapping
8157 @cindex mapped devices
8158 The Linux kernel has a notion of @dfn{device mapping}: a block device,
8159 such as a hard disk partition, can be @dfn{mapped} into another device,
8160 usually in @code{/dev/mapper/},
8161 with additional processing over the data that flows through
8162 it@footnote{Note that the GNU@tie{}Hurd makes no difference between the
8163 concept of a ``mapped device'' and that of a file system: both boil down
8164 to @emph{translating} input/output operations made on a file to
8165 operations on its backing store. Thus, the Hurd implements mapped
8166 devices, like file systems, using the generic @dfn{translator} mechanism
8167 (@pxref{Translators,,, hurd, The GNU Hurd Reference Manual}).}. A
8168 typical example is encryption device mapping: all writes to the mapped
8169 device are encrypted, and all reads are deciphered, transparently.
8170 Guix extends this notion by considering any device or set of devices that
8171 are @dfn{transformed} in some way to create a new device; for instance,
8172 RAID devices are obtained by @dfn{assembling} several other devices, such
8173 as hard disks or partitions, into a new one that behaves as one partition.
8174 Other examples, not yet implemented, are LVM logical volumes.
8176 Mapped devices are declared using the @code{mapped-device} form,
8177 defined as follows; for examples, see below.
8179 @deftp {Data Type} mapped-device
8180 Objects of this type represent device mappings that will be made when
8181 the system boots up.
8185 This is either a string specifying the name of the block device to be mapped,
8186 such as @code{"/dev/sda3"}, or a list of such strings when several devices
8187 need to be assembled for creating a new one.
8190 This string specifies the name of the resulting mapped device. For
8191 kernel mappers such as encrypted devices of type @code{luks-device-mapping},
8192 specifying @code{"my-partition"} leads to the creation of
8193 the @code{"/dev/mapper/my-partition"} device.
8194 For RAID devices of type @code{raid-device-mapping}, the full device name
8195 such as @code{"/dev/md0"} needs to be given.
8198 This must be a @code{mapped-device-kind} object, which specifies how
8199 @var{source} is mapped to @var{target}.
8203 @defvr {Scheme Variable} luks-device-mapping
8204 This defines LUKS block device encryption using the @command{cryptsetup}
8205 command from the package with the same name. It relies on the
8206 @code{dm-crypt} Linux kernel module.
8209 @defvr {Scheme Variable} raid-device-mapping
8210 This defines a RAID device, which is assembled using the @code{mdadm}
8211 command from the package with the same name. It requires a Linux kernel
8212 module for the appropriate RAID level to be loaded, such as @code{raid456}
8213 for RAID-4, RAID-5 or RAID-6, or @code{raid10} for RAID-10.
8216 @cindex disk encryption
8218 The following example specifies a mapping from @file{/dev/sda3} to
8219 @file{/dev/mapper/home} using LUKS---the
8220 @url{https://gitlab.com/cryptsetup/cryptsetup,Linux Unified Key Setup}, a
8221 standard mechanism for disk encryption.
8222 The @file{/dev/mapper/home}
8223 device can then be used as the @code{device} of a @code{file-system}
8224 declaration (@pxref{File Systems}).
8228 (source "/dev/sda3")
8230 (type luks-device-mapping))
8233 Alternatively, to become independent of device numbering, one may obtain
8234 the LUKS UUID (@dfn{unique identifier}) of the source device by a
8238 cryptsetup luksUUID /dev/sda3
8241 and use it as follows:
8245 (source (uuid "cb67fc72-0d54-4c88-9d4b-b225f30b0f44"))
8247 (type luks-device-mapping))
8250 @cindex swap encryption
8251 It is also desirable to encrypt swap space, since swap space may contain
8252 sensitive data. One way to accomplish that is to use a swap file in a
8253 file system on a device mapped via LUKS encryption. In this way, the
8254 swap file is encrypted because the entire device is encrypted.
8255 @xref{Preparing for Installation,,Disk Partitioning}, for an example.
8257 A RAID device formed of the partitions @file{/dev/sda1} and @file{/dev/sdb1}
8258 may be declared as follows:
8262 (source (list "/dev/sda1" "/dev/sdb1"))
8264 (type raid-device-mapping))
8267 The @file{/dev/md0} device can then be used as the @code{device} of a
8268 @code{file-system} declaration (@pxref{File Systems}).
8269 Note that the RAID level need not be given; it is chosen during the
8270 initial creation and formatting of the RAID device and is determined
8271 automatically later.
8275 @subsection User Accounts
8279 @cindex user accounts
8280 User accounts and groups are entirely managed through the
8281 @code{operating-system} declaration. They are specified with the
8282 @code{user-account} and @code{user-group} forms:
8288 (supplementary-groups '("wheel" ;allow use of sudo, etc.
8290 "video" ;video devices such as webcams
8291 "cdrom")) ;the good ol' CD-ROM
8292 (comment "Bob's sister")
8293 (home-directory "/home/alice"))
8296 When booting or upon completion of @command{guix system reconfigure},
8297 the system ensures that only the user accounts and groups specified in
8298 the @code{operating-system} declaration exist, and with the specified
8299 properties. Thus, account or group creations or modifications made by
8300 directly invoking commands such as @command{useradd} are lost upon
8301 reconfiguration or reboot. This ensures that the system remains exactly
8304 @deftp {Data Type} user-account
8305 Objects of this type represent user accounts. The following members may
8310 The name of the user account.
8314 This is the name (a string) or identifier (a number) of the user group
8315 this account belongs to.
8317 @item @code{supplementary-groups} (default: @code{'()})
8318 Optionally, this can be defined as a list of group names that this
8321 @item @code{uid} (default: @code{#f})
8322 This is the user ID for this account (a number), or @code{#f}. In the
8323 latter case, a number is automatically chosen by the system when the
8326 @item @code{comment} (default: @code{""})
8327 A comment about the account, such as the account owner's full name.
8329 @item @code{home-directory}
8330 This is the name of the home directory for the account.
8332 @item @code{create-home-directory?} (default: @code{#t})
8333 Indicates whether the home directory of this account should be created
8334 if it does not exist yet.
8336 @item @code{shell} (default: Bash)
8337 This is a G-expression denoting the file name of a program to be used as
8338 the shell (@pxref{G-Expressions}).
8340 @item @code{system?} (default: @code{#f})
8341 This Boolean value indicates whether the account is a ``system''
8342 account. System accounts are sometimes treated specially; for instance,
8343 graphical login managers do not list them.
8345 @anchor{user-account-password}
8346 @item @code{password} (default: @code{#f})
8347 You would normally leave this field to @code{#f}, initialize user
8348 passwords as @code{root} with the @command{passwd} command, and then let
8349 users change it with @command{passwd}. Passwords set with
8350 @command{passwd} are of course preserved across reboot and
8353 If you @emph{do} want to have a preset password for an account, then
8354 this field must contain the encrypted password, as a string.
8355 @xref{crypt,,, libc, The GNU C Library Reference Manual}, for more information
8356 on password encryption, and @ref{Encryption,,, guile, GNU Guile Reference
8357 Manual}, for information on Guile's @code{crypt} procedure.
8363 User group declarations are even simpler:
8366 (user-group (name "students"))
8369 @deftp {Data Type} user-group
8370 This type is for, well, user groups. There are just a few fields:
8374 The name of the group.
8376 @item @code{id} (default: @code{#f})
8377 The group identifier (a number). If @code{#f}, a new number is
8378 automatically allocated when the group is created.
8380 @item @code{system?} (default: @code{#f})
8381 This Boolean value indicates whether the group is a ``system'' group.
8382 System groups have low numerical IDs.
8384 @item @code{password} (default: @code{#f})
8385 What, user groups can have a password? Well, apparently yes. Unless
8386 @code{#f}, this field specifies the password of the group.
8391 For convenience, a variable lists all the basic user groups one may
8394 @defvr {Scheme Variable} %base-groups
8395 This is the list of basic user groups that users and/or packages expect
8396 to be present on the system. This includes groups such as ``root'',
8397 ``wheel'', and ``users'', as well as groups used to control access to
8398 specific devices such as ``audio'', ``disk'', and ``cdrom''.
8401 @defvr {Scheme Variable} %base-user-accounts
8402 This is the list of basic system accounts that programs may expect to
8403 find on a GNU/Linux system, such as the ``nobody'' account.
8405 Note that the ``root'' account is not included here. It is a
8406 special-case and is automatically added whether or not it is specified.
8413 A @dfn{locale} defines cultural conventions for a particular language
8414 and region of the world (@pxref{Locales,,, libc, The GNU C Library
8415 Reference Manual}). Each locale has a name that typically has the form
8416 @code{@var{language}_@var{territory}.@var{codeset}}---e.g.,
8417 @code{fr_LU.utf8} designates the locale for the French language, with
8418 cultural conventions from Luxembourg, and using the UTF-8 encoding.
8420 @cindex locale definition
8421 Usually, you will want to specify the default locale for the machine
8422 using the @code{locale} field of the @code{operating-system} declaration
8423 (@pxref{operating-system Reference, @code{locale}}).
8425 The selected locale is automatically added to the @dfn{locale
8426 definitions} known to the system if needed, with its codeset inferred
8427 from its name---e.g., @code{bo_CN.utf8} will be assumed to use the
8428 @code{UTF-8} codeset. Additional locale definitions can be specified in
8429 the @code{locale-definitions} slot of @code{operating-system}---this is
8430 useful, for instance, if the codeset could not be inferred from the
8431 locale name. The default set of locale definitions includes some widely
8432 used locales, but not all the available locales, in order to save space.
8434 For instance, to add the North Frisian locale for Germany, the value of
8438 (cons (locale-definition
8439 (name "fy_DE.utf8") (source "fy_DE"))
8440 %default-locale-definitions)
8443 Likewise, to save space, one might want @code{locale-definitions} to
8444 list only the locales that are actually used, as in:
8447 (list (locale-definition
8448 (name "ja_JP.eucjp") (source "ja_JP")
8449 (charset "EUC-JP")))
8453 The compiled locale definitions are available at
8454 @file{/run/current-system/locale/X.Y}, where @code{X.Y} is the libc
8455 version, which is the default location where the GNU@tie{}libc provided
8456 by Guix looks for locale data. This can be overridden using the
8457 @code{LOCPATH} environment variable (@pxref{locales-and-locpath,
8458 @code{LOCPATH} and locale packages}).
8460 The @code{locale-definition} form is provided by the @code{(gnu system
8461 locale)} module. Details are given below.
8463 @deftp {Data Type} locale-definition
8464 This is the data type of a locale definition.
8469 The name of the locale. @xref{Locale Names,,, libc, The GNU C Library
8470 Reference Manual}, for more information on locale names.
8473 The name of the source for that locale. This is typically the
8474 @code{@var{language}_@var{territory}} part of the locale name.
8476 @item @code{charset} (default: @code{"UTF-8"})
8477 The ``character set'' or ``code set'' for that locale,
8478 @uref{http://www.iana.org/assignments/character-sets, as defined by
8484 @defvr {Scheme Variable} %default-locale-definitions
8485 A list of commonly used UTF-8 locales, used as the default
8486 value of the @code{locale-definitions} field of @code{operating-system}
8490 @cindex normalized codeset in locale names
8491 These locale definitions use the @dfn{normalized codeset} for the part
8492 that follows the dot in the name (@pxref{Using gettextized software,
8493 normalized codeset,, libc, The GNU C Library Reference Manual}). So for
8494 instance it has @code{uk_UA.utf8} but @emph{not}, say,
8498 @subsubsection Locale Data Compatibility Considerations
8500 @cindex incompatibility, of locale data
8501 @code{operating-system} declarations provide a @code{locale-libcs} field
8502 to specify the GNU@tie{}libc packages that are used to compile locale
8503 declarations (@pxref{operating-system Reference}). ``Why would I
8504 care?'', you may ask. Well, it turns out that the binary format of
8505 locale data is occasionally incompatible from one libc version to
8508 @c See <https://sourceware.org/ml/libc-alpha/2015-09/msg00575.html>
8509 @c and <https://lists.gnu.org/archive/html/guix-devel/2015-08/msg00737.html>.
8510 For instance, a program linked against libc version 2.21 is unable to
8511 read locale data produced with libc 2.22; worse, that program
8512 @emph{aborts} instead of simply ignoring the incompatible locale
8513 data@footnote{Versions 2.23 and later of GNU@tie{}libc will simply skip
8514 the incompatible locale data, which is already an improvement.}.
8515 Similarly, a program linked against libc 2.22 can read most, but not
8516 all, of the locale data from libc 2.21 (specifically, @code{LC_COLLATE}
8517 data is incompatible); thus calls to @code{setlocale} may fail, but
8518 programs will not abort.
8520 The ``problem'' in GuixSD is that users have a lot of freedom: They can
8521 choose whether and when to upgrade software in their profiles, and might
8522 be using a libc version different from the one the system administrator
8523 used to build the system-wide locale data.
8525 Fortunately, unprivileged users can also install their own locale data
8526 and define @var{GUIX_LOCPATH} accordingly (@pxref{locales-and-locpath,
8527 @code{GUIX_LOCPATH} and locale packages}).
8529 Still, it is best if the system-wide locale data at
8530 @file{/run/current-system/locale} is built for all the libc versions
8531 actually in use on the system, so that all the programs can access
8532 it---this is especially crucial on a multi-user system. To do that, the
8533 administrator can specify several libc packages in the
8534 @code{locale-libcs} field of @code{operating-system}:
8537 (use-package-modules base)
8541 (locale-libcs (list glibc-2.21 (canonical-package glibc))))
8544 This example would lead to a system containing locale definitions for
8545 both libc 2.21 and the current version of libc in
8546 @file{/run/current-system/locale}.
8550 @subsection Services
8552 @cindex system services
8553 An important part of preparing an @code{operating-system} declaration is
8554 listing @dfn{system services} and their configuration (@pxref{Using the
8555 Configuration System}). System services are typically daemons launched
8556 when the system boots, or other actions needed at that time---e.g.,
8557 configuring network access.
8559 GuixSD has a broad definition of ``service'' (@pxref{Service
8560 Composition}), but many services are managed by the GNU@tie{}Shepherd
8561 (@pxref{Shepherd Services}). On a running system, the @command{herd}
8562 command allows you to list the available services, show their status,
8563 start and stop them, or do other specific operations (@pxref{Jump
8564 Start,,, shepherd, The GNU Shepherd Manual}). For example:
8570 The above command, run as @code{root}, lists the currently defined
8571 services. The @command{herd doc} command shows a synopsis of the given
8576 Run libc's name service cache daemon (nscd).
8579 The @command{start}, @command{stop}, and @command{restart} sub-commands
8580 have the effect you would expect. For instance, the commands below stop
8581 the nscd service and restart the Xorg display server:
8585 Service nscd has been stopped.
8586 # herd restart xorg-server
8587 Service xorg-server has been stopped.
8588 Service xorg-server has been started.
8591 The following sections document the available services, starting with
8592 the core services, that may be used in an @code{operating-system}
8596 * Base Services:: Essential system services.
8597 * Scheduled Job Execution:: The mcron service.
8598 * Log Rotation:: The rottlog service.
8599 * Networking Services:: Network setup, SSH daemon, etc.
8600 * X Window:: Graphical display.
8601 * Printing Services:: Local and remote printer support.
8602 * Desktop Services:: D-Bus and desktop services.
8603 * Database Services:: SQL databases.
8604 * Mail Services:: IMAP, POP3, SMTP, and all that.
8605 * Messaging Services:: Messaging services.
8606 * Kerberos Services:: Kerberos services.
8607 * Web Services:: Web servers.
8608 * VPN Services:: VPN daemons.
8609 * Network File System:: NFS related services.
8610 * Continuous Integration:: The Cuirass service.
8611 * Power management Services:: The TLP tool.
8612 * Miscellaneous Services:: Other services.
8616 @subsubsection Base Services
8618 The @code{(gnu services base)} module provides definitions for the basic
8619 services that one expects from the system. The services exported by
8620 this module are listed below.
8622 @defvr {Scheme Variable} %base-services
8623 This variable contains a list of basic services (@pxref{Service Types
8624 and Services}, for more information on service objects) one would
8625 expect from the system: a login service (mingetty) on each tty, syslogd,
8626 the libc name service cache daemon (nscd), the udev device manager, and
8629 This is the default value of the @code{services} field of
8630 @code{operating-system} declarations. Usually, when customizing a
8631 system, you will want to append services to @var{%base-services}, like
8635 (cons* (avahi-service) (lsh-service) %base-services)
8639 @defvr {Scheme Variable} special-files-service-type
8640 This is the service that sets up ``special files'' such as
8641 @file{/bin/sh}; an instance of it is part of @code{%base-services}.
8643 The value associated with @code{special-files-service-type} services
8644 must be a list of tuples where the first element is the ``special file''
8645 and the second element is its target. By default it is:
8647 @cindex @file{/bin/sh}
8648 @cindex @file{sh}, in @file{/bin}
8650 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh")))
8653 @cindex @file{/usr/bin/env}
8654 @cindex @file{env}, in @file{/usr/bin}
8655 If you want to add, say, @code{/usr/bin/env} to your system, you can
8659 `(("/bin/sh" ,(file-append @var{bash} "/bin/sh"))
8660 ("/usr/bin/env" ,(file-append @var{coreutils} "/bin/env")))
8663 Since this is part of @code{%base-services}, you can use
8664 @code{modify-services} to customize the set of special files
8665 (@pxref{Service Reference, @code{modify-services}}). But the simple way
8666 to add a special file is @i{via} the @code{extra-special-file} procedure
8670 @deffn {Scheme Procedure} extra-special-file @var{file} @var{target}
8671 Use @var{target} as the ``special file'' @var{file}.
8673 For example, adding the following lines to the @code{services} field of
8674 your operating system declaration leads to a @file{/usr/bin/env}
8678 (extra-special-file "/usr/bin/env"
8679 (file-append coreutils "/bin/env"))
8683 @deffn {Scheme Procedure} host-name-service @var{name}
8684 Return a service that sets the host name to @var{name}.
8687 @deffn {Scheme Procedure} login-service @var{config}
8688 Return a service to run login according to @var{config}, a
8689 @code{<login-configuration>} object, which specifies the message of the day,
8693 @deftp {Data Type} login-configuration
8694 This is the data type representing the configuration of login.
8699 @cindex message of the day
8700 A file-like object containing the ``message of the day''.
8702 @item @code{allow-empty-passwords?} (default: @code{#t})
8703 Allow empty passwords by default so that first-time users can log in when
8704 the 'root' account has just been created.
8709 @deffn {Scheme Procedure} mingetty-service @var{config}
8710 Return a service to run mingetty according to @var{config}, a
8711 @code{<mingetty-configuration>} object, which specifies the tty to run, among
8715 @deftp {Data Type} mingetty-configuration
8716 This is the data type representing the configuration of Mingetty, which
8717 provides the default implementation of virtual console log-in.
8722 The name of the console this Mingetty runs on---e.g., @code{"tty1"}.
8724 @item @code{auto-login} (default: @code{#f})
8725 When true, this field must be a string denoting the user name under
8726 which the system automatically logs in. When it is @code{#f}, a
8727 user name and password must be entered to log in.
8729 @item @code{login-program} (default: @code{#f})
8730 This must be either @code{#f}, in which case the default log-in program
8731 is used (@command{login} from the Shadow tool suite), or a gexp denoting
8732 the name of the log-in program.
8734 @item @code{login-pause?} (default: @code{#f})
8735 When set to @code{#t} in conjunction with @var{auto-login}, the user
8736 will have to press a key before the log-in shell is launched.
8738 @item @code{mingetty} (default: @var{mingetty})
8739 The Mingetty package to use.
8744 @deffn {Scheme Procedure} agetty-service @var{config}
8745 Return a service to run agetty according to @var{config}, an
8746 @code{<agetty-configuration>} object, which specifies the tty to run,
8750 @deftp {Data Type} agetty-configuration
8751 This is the data type representing the configuration of agetty, which
8752 implements virtual and serial console log-in. See the @code{agetty(8)}
8753 man page for more information.
8758 The name of the console this agetty runs on, as a string---e.g.,
8759 @code{"ttyS0"}. This argument is mandatory.
8761 @item @code{baud-rate} (default: @code{#f})
8762 A string containing a comma-separated list of one or more baud rates, in
8765 @item @code{term} (default: @code{#f})
8766 A string containing the value used for the @code{TERM} environment
8769 @item @code{eight-bits?} (default: @code{#f})
8770 When @code{#t}, the tty is assumed to be 8-bit clean, and parity detection is
8773 @item @code{auto-login} (default: @code{#f})
8774 When passed a login name, as a string, the specified user will be logged
8775 in automatically without prompting for their login name or password.
8777 @item @code{no-reset?} (default: @code{#f})
8778 When @code{#t}, don't reset terminal cflags (control modes).
8780 @item @code{host} (default: @code{#f})
8781 This accepts a string containing the "login_host", which will be written
8782 into the @file{/var/run/utmpx} file.
8784 @item @code{remote?} (default: @code{#f})
8785 When set to @code{#t} in conjunction with @var{host}, this will add an
8786 @code{-r} fakehost option to the command line of the login program
8787 specified in @var{login-program}.
8789 @item @code{flow-control?} (default: @code{#f})
8790 When set to @code{#t}, enable hardware (RTS/CTS) flow control.
8792 @item @code{no-issue?} (default: @code{#f})
8793 When set to @code{#t}, the contents of the @file{/etc/issue} file will
8794 not be displayed before presenting the login prompt.
8796 @item @code{init-string} (default: @code{#f})
8797 This accepts a string that will be sent to the tty or modem before
8798 sending anything else. It can be used to initialize a modem.
8800 @item @code{no-clear?} (default: @code{#f})
8801 When set to @code{#t}, agetty will not clear the screen before showing
8804 @item @code{login-program} (default: (file-append shadow "/bin/login"))
8805 This must be either a gexp denoting the name of a log-in program, or
8806 unset, in which case the default value is the @command{login} from the
8809 @item @code{local-line} (default: @code{#f})
8810 Control the CLOCAL line flag. This accepts one of three symbols as
8811 arguments, @code{'auto}, @code{'always}, or @code{'never}. If @code{#f},
8812 the default value chosen by agetty is @code{'auto}.
8814 @item @code{extract-baud?} (default: @code{#f})
8815 When set to @code{#t}, instruct agetty to try to extract the baud rate
8816 from the status messages produced by certain types of modems.
8818 @item @code{skip-login?} (default: @code{#f})
8819 When set to @code{#t}, do not prompt the user for a login name. This
8820 can be used with @var{login-program} field to use non-standard login
8823 @item @code{no-newline?} (default: @code{#f})
8824 When set to @code{#t}, do not print a newline before printing the
8825 @file{/etc/issue} file.
8827 @c Is this dangerous only when used with login-program, or always?
8828 @item @code{login-options} (default: @code{#f})
8829 This option accepts a string containing options that are passed to the
8830 login program. When used with the @var{login-program}, be aware that a
8831 malicious user could try to enter a login name containing embedded
8832 options that could be parsed by the login program.
8834 @item @code{login-pause} (default: @code{#f})
8835 When set to @code{#t}, wait for any key before showing the login prompt.
8836 This can be used in conjunction with @var{auto-login} to save memory by
8837 lazily spawning shells.
8839 @item @code{chroot} (default: @code{#f})
8840 Change root to the specified directory. This option accepts a directory
8843 @item @code{hangup?} (default: @code{#f})
8844 Use the Linux system call @code{vhangup} to do a virtual hangup of the
8847 @item @code{keep-baud?} (default: @code{#f})
8848 When set to @code{#t}, try to keep the existing baud rate. The baud
8849 rates from @var{baud-rate} are used when agetty receives a @key{BREAK}
8852 @item @code{timeout} (default: @code{#f})
8853 When set to an integer value, terminate if no user name could be read
8854 within @var{timeout} seconds.
8856 @item @code{detect-case?} (default: @code{#f})
8857 When set to @code{#t}, turn on support for detecting an uppercase-only
8858 terminal. This setting will detect a login name containing only
8859 uppercase letters as indicating an uppercase-only terminal and turn on
8860 some upper-to-lower case conversions. Note that this will not support
8863 @item @code{wait-cr?} (default: @code{#f})
8864 When set to @code{#t}, wait for the user or modem to send a
8865 carriage-return or linefeed character before displaying
8866 @file{/etc/issue} or login prompt. This is typically used with the
8867 @var{init-string} option.
8869 @item @code{no-hints?} (default: @code{#f})
8870 When set to @code{#t}, do not print hints about Num, Caps, and Scroll
8873 @item @code{no-hostname?} (default: @code{#f})
8874 By default, the hostname is printed. When this option is set to
8875 @code{#t}, no hostname will be shown at all.
8877 @item @code{long-hostname?} (default: @code{#f})
8878 By default, the hostname is only printed until the first dot. When this
8879 option is set to @code{#t}, the fully qualified hostname by
8880 @code{gethostname} or @code{getaddrinfo} is shown.
8882 @item @code{erase-characters} (default: @code{#f})
8883 This option accepts a string of additional characters that should be
8884 interpreted as backspace when the user types their login name.
8886 @item @code{kill-characters} (default: @code{#f})
8887 This option accepts a string that should be interpreted to mean "ignore
8888 all previous characters" (also called a "kill" character) when the types
8891 @item @code{chdir} (default: @code{#f})
8892 This option accepts, as a string, a directory path that will be changed
8895 @item @code{delay} (default: @code{#f})
8896 This options accepts, as an integer, the number of seconds to sleep
8897 before opening the tty and displaying the login prompt.
8899 @item @code{nice} (default: @code{#f})
8900 This option accepts, as an integer, the nice value with which to run the
8901 @command{login} program.
8903 @item @code{extra-options} (default: @code{'()})
8904 This option provides an "escape hatch" for the user to provide arbitrary
8905 command-line arguments to @command{agetty} as a list of strings.
8910 @deffn {Scheme Procedure} kmscon-service-type @var{config}
8911 Return a service to run @uref{https://www.freedesktop.org/wiki/Software/kmscon,kmscon}
8912 according to @var{config}, a @code{<kmscon-configuration>} object, which
8913 specifies the tty to run, among other things.
8916 @deftp {Data Type} kmscon-configuration
8917 This is the data type representing the configuration of Kmscon, which
8918 implements virtual console log-in.
8922 @item @code{virtual-terminal}
8923 The name of the console this Kmscon runs on---e.g., @code{"tty1"}.
8925 @item @code{login-program} (default: @code{#~(string-append #$shadow "/bin/login")})
8926 A gexp denoting the name of the log-in program. The default log-in program is
8927 @command{login} from the Shadow tool suite.
8929 @item @code{login-arguments} (default: @code{'("-p")})
8930 A list of arguments to pass to @command{login}.
8932 @item @code{hardware-acceleration?} (default: #f)
8933 Whether to use hardware acceleration.
8935 @item @code{kmscon} (default: @var{kmscon})
8936 The Kmscon package to use.
8941 @cindex name service cache daemon
8943 @deffn {Scheme Procedure} nscd-service [@var{config}] [#:glibc glibc] @
8944 [#:name-services '()]
8945 Return a service that runs the libc name service cache daemon (nscd) with the
8946 given @var{config}---an @code{<nscd-configuration>} object. @xref{Name
8947 Service Switch}, for an example.
8950 @defvr {Scheme Variable} %nscd-default-configuration
8951 This is the default @code{<nscd-configuration>} value (see below) used
8952 by @code{nscd-service}. It uses the caches defined by
8953 @var{%nscd-default-caches}; see below.
8956 @deftp {Data Type} nscd-configuration
8957 This is the data type representing the name service cache daemon (nscd)
8962 @item @code{name-services} (default: @code{'()})
8963 List of packages denoting @dfn{name services} that must be visible to
8964 the nscd---e.g., @code{(list @var{nss-mdns})}.
8966 @item @code{glibc} (default: @var{glibc})
8967 Package object denoting the GNU C Library providing the @command{nscd}
8970 @item @code{log-file} (default: @code{"/var/log/nscd.log"})
8971 Name of the nscd log file. This is where debugging output goes when
8972 @code{debug-level} is strictly positive.
8974 @item @code{debug-level} (default: @code{0})
8975 Integer denoting the debugging levels. Higher numbers mean that more
8976 debugging output is logged.
8978 @item @code{caches} (default: @var{%nscd-default-caches})
8979 List of @code{<nscd-cache>} objects denoting things to be cached; see
8985 @deftp {Data Type} nscd-cache
8986 Data type representing a cache database of nscd and its parameters.
8990 @item @code{database}
8991 This is a symbol representing the name of the database to be cached.
8992 Valid values are @code{passwd}, @code{group}, @code{hosts}, and
8993 @code{services}, which designate the corresponding NSS database
8994 (@pxref{NSS Basics,,, libc, The GNU C Library Reference Manual}).
8996 @item @code{positive-time-to-live}
8997 @itemx @code{negative-time-to-live} (default: @code{20})
8998 A number representing the number of seconds during which a positive or
8999 negative lookup result remains in cache.
9001 @item @code{check-files?} (default: @code{#t})
9002 Whether to check for updates of the files corresponding to
9005 For instance, when @var{database} is @code{hosts}, setting this flag
9006 instructs nscd to check for updates in @file{/etc/hosts} and to take
9009 @item @code{persistent?} (default: @code{#t})
9010 Whether the cache should be stored persistently on disk.
9012 @item @code{shared?} (default: @code{#t})
9013 Whether the cache should be shared among users.
9015 @item @code{max-database-size} (default: 32@tie{}MiB)
9016 Maximum size in bytes of the database cache.
9018 @c XXX: 'suggested-size' and 'auto-propagate?' seem to be expert
9019 @c settings, so leave them out.
9024 @defvr {Scheme Variable} %nscd-default-caches
9025 List of @code{<nscd-cache>} objects used by default by
9026 @code{nscd-configuration} (see above).
9028 It enables persistent and aggressive caching of service and host name
9029 lookups. The latter provides better host name lookup performance,
9030 resilience in the face of unreliable name servers, and also better
9031 privacy---often the result of host name lookups is in local cache, so
9032 external name servers do not even need to be queried.
9035 @anchor{syslog-configuration-type}
9038 @deftp {Data Type} syslog-configuration
9039 This data type represents the configuration of the syslog daemon.
9042 @item @code{syslogd} (default: @code{#~(string-append #$inetutils "/libexec/syslogd")})
9043 The syslog daemon to use.
9045 @item @code{config-file} (default: @code{%default-syslog.conf})
9046 The syslog configuration file to use.
9051 @anchor{syslog-service}
9053 @deffn {Scheme Procedure} syslog-service @var{config}
9054 Return a service that runs a syslog daemon according to @var{config}.
9056 @xref{syslogd invocation,,, inetutils, GNU Inetutils}, for more
9057 information on the configuration file syntax.
9060 @anchor{guix-configuration-type}
9061 @deftp {Data Type} guix-configuration
9062 This data type represents the configuration of the Guix build daemon.
9063 @xref{Invoking guix-daemon}, for more information.
9066 @item @code{guix} (default: @var{guix})
9067 The Guix package to use.
9069 @item @code{build-group} (default: @code{"guixbuild"})
9070 Name of the group for build user accounts.
9072 @item @code{build-accounts} (default: @code{10})
9073 Number of build user accounts to create.
9075 @item @code{authorize-key?} (default: @code{#t})
9076 @cindex substitutes, authorization thereof
9077 Whether to authorize the substitute keys listed in
9078 @code{authorized-keys}---by default that of @code{hydra.gnu.org}
9079 (@pxref{Substitutes}).
9081 @vindex %default-authorized-guix-keys
9082 @item @code{authorized-keys} (default: @var{%default-authorized-guix-keys})
9083 The list of authorized key files for archive imports, as a list of
9084 string-valued gexps (@pxref{Invoking guix archive}). By default, it
9085 contains that of @code{hydra.gnu.org} (@pxref{Substitutes}).
9087 @item @code{use-substitutes?} (default: @code{#t})
9088 Whether to use substitutes.
9090 @item @code{substitute-urls} (default: @var{%default-substitute-urls})
9091 The list of URLs where to look for substitutes by default.
9093 @item @code{extra-options} (default: @code{'()})
9094 List of extra command-line options for @command{guix-daemon}.
9096 @item @code{log-file} (default: @code{"/var/log/guix-daemon.log"})
9097 File where @command{guix-daemon}'s standard output and standard error
9100 @item @code{lsof} (default: @var{lsof})
9101 The lsof package to use.
9103 @item @code{http-proxy} (default: @code{#f})
9104 The HTTP proxy used for downloading fixed-output derivations and
9107 @item @code{tmpdir} (default: @code{#f})
9108 A directory path where the @command{guix-daemon} will perform builds.
9113 @deffn {Scheme Procedure} guix-service @var{config}
9114 Return a service that runs the Guix build daemon according to
9118 @deffn {Scheme Procedure} udev-service [#:udev udev]
9119 Run @var{udev}, which populates the @file{/dev} directory dynamically.
9122 @deffn {Scheme Procedure} urandom-seed-service @var{#f}
9123 Save some entropy in @var{%random-seed-file} to seed @file{/dev/urandom}
9127 @defvr {Scheme Variable} %random-seed-file
9128 This is the name of the file where some random bytes are saved by
9129 @var{urandom-seed-service} to seed @file{/dev/urandom} when rebooting.
9130 It defaults to @file{/var/lib/random-seed}.
9135 @deffn {Scheme Procedure} console-keymap-service @var{files} ...
9136 @cindex keyboard layout
9137 Return a service to load console keymaps from @var{files} using
9138 @command{loadkeys} command. Most likely, you want to load some default
9139 keymap, which can be done like this:
9142 (console-keymap-service "dvorak")
9145 Or, for example, for a Swedish keyboard, you may need to combine
9146 the following keymaps:
9148 (console-keymap-service "se-lat6" "se-fi-lat6")
9151 Also you can specify a full file name (or file names) of your keymap(s).
9152 See @code{man loadkeys} for details.
9158 @deffn {Scheme Procedure} gpm-service [#:gpm @var{gpm}] @
9160 Run @var{gpm}, the general-purpose mouse daemon, with the given
9161 command-line @var{options}. GPM allows users to use the mouse in the console,
9162 notably to select, copy, and paste text. The default value of @var{options}
9163 uses the @code{ps2} protocol, which works for both USB and PS/2 mice.
9165 This service is not part of @var{%base-services}.
9168 @anchor{guix-publish-service-type}
9169 @deffn {Scheme Variable} guix-publish-service-type
9170 This is the service type for @command{guix publish} (@pxref{Invoking
9171 guix publish}). Its value must be a @code{guix-configuration}
9172 object, as described below.
9174 This assumes that @file{/etc/guix} already contains a signing key pair as
9175 created by @command{guix archive --generate-key} (@pxref{Invoking guix
9176 archive}). If that is not the case, the service will fail to start.
9179 @deftp {Data Type} guix-publish-configuration
9180 Data type representing the configuration of the @code{guix publish}
9184 @item @code{guix} (default: @code{guix})
9185 The Guix package to use.
9187 @item @code{port} (default: @code{80})
9188 The TCP port to listen for connections.
9190 @item @code{host} (default: @code{"localhost"})
9191 The host (and thus, network interface) to listen to. Use
9192 @code{"0.0.0.0"} to listen on all the network interfaces.
9194 @item @code{compression-level} (default: @code{3})
9195 The gzip compression level at which substitutes are compressed. Use
9196 @code{0} to disable compression altogether, and @code{9} to get the best
9197 compression ratio at the expense of increased CPU usage.
9199 @item @code{nar-path} (default: @code{"nar"})
9200 The URL path at which ``nars'' can be fetched. @xref{Invoking guix
9201 publish, @code{--nar-path}}, for details.
9203 @item @code{cache} (default: @code{#f})
9204 When it is @code{#f}, disable caching and instead generate archives on
9205 demand. Otherwise, this should be the name of a directory---e.g.,
9206 @code{"/var/cache/guix/publish"}---where @command{guix publish} caches
9207 archives and meta-data ready to be sent. @xref{Invoking guix publish,
9208 @option{--cache}}, for more information on the tradeoffs involved.
9210 @item @code{workers} (default: @code{#f})
9211 When it is an integer, this is the number of worker threads used for
9212 caching; when @code{#f}, the number of processors is used.
9213 @xref{Invoking guix publish, @option{--workers}}, for more information.
9215 @item @code{ttl} (default: @code{#f})
9216 When it is an integer, this denotes the @dfn{time-to-live} of the
9217 published archives. @xref{Invoking guix publish, @option{--ttl}}, for
9222 @anchor{rngd-service}
9223 @deffn {Scheme Procedure} rngd-service [#:rng-tools @var{rng-tools}] @
9224 [#:device "/dev/hwrng"]
9225 Return a service that runs the @command{rngd} program from @var{rng-tools}
9226 to add @var{device} to the kernel's entropy pool. The service will fail if
9227 @var{device} does not exist.
9230 @anchor{pam-limits-service}
9231 @cindex session limits
9234 @deffn {Scheme Procedure} pam-limits-service [#:limits @var{limits}]
9236 Return a service that installs a configuration file for the
9237 @uref{http://linux-pam.org/Linux-PAM-html/sag-pam_limits.html,
9238 @code{pam_limits} module}. The procedure optionally takes a list of
9239 @code{pam-limits-entry} values, which can be used to specify
9240 @code{ulimit} limits and nice priority limits to user sessions.
9242 The following limits definition sets two hard and soft limits for all
9243 login sessions of users in the @code{realtime} group:
9248 (pam-limits-entry "@@realtime" 'both 'rtprio 99)
9249 (pam-limits-entry "@@realtime" 'both 'memlock 'unlimited)))
9252 The first entry increases the maximum realtime priority for
9253 non-privileged processes; the second entry lifts any restriction of the
9254 maximum address space that can be locked in memory. These settings are
9255 commonly used for real-time audio systems.
9258 @node Scheduled Job Execution
9259 @subsubsection Scheduled Job Execution
9263 @cindex scheduling jobs
9264 The @code{(gnu services mcron)} module provides an interface to
9265 GNU@tie{}mcron, a daemon to run jobs at scheduled times (@pxref{Top,,,
9266 mcron, GNU@tie{}mcron}). GNU@tie{}mcron is similar to the traditional
9267 Unix @command{cron} daemon; the main difference is that it is
9268 implemented in Guile Scheme, which provides a lot of flexibility when
9269 specifying the scheduling of jobs and their actions.
9271 The example below defines an operating system that runs the
9272 @command{updatedb} (@pxref{Invoking updatedb,,, find, Finding Files})
9273 and the @command{guix gc} commands (@pxref{Invoking guix gc}) daily, as
9274 well as the @command{mkid} command on behalf of an unprivileged user
9275 (@pxref{mkid invocation,,, idutils, ID Database Utilities}). It uses
9276 gexps to introduce job definitions that are passed to mcron
9277 (@pxref{G-Expressions}).
9280 (use-modules (guix) (gnu) (gnu services mcron))
9281 (use-package-modules base idutils)
9283 (define updatedb-job
9284 ;; Run 'updatedb' at 3AM every day. Here we write the
9285 ;; job's action as a Scheme procedure.
9286 #~(job '(next-hour '(3))
9288 (execl (string-append #$findutils "/bin/updatedb")
9290 "--prunepaths=/tmp /var/tmp /gnu/store"))))
9292 (define garbage-collector-job
9293 ;; Collect garbage 5 minutes after midnight every day.
9294 ;; The job's action is a shell command.
9295 #~(job "5 0 * * *" ;Vixie cron syntax
9299 ;; Update the index database as user "charlie" at 12:15PM
9300 ;; and 19:15PM. This runs from the user's home directory.
9301 #~(job '(next-minute-from (next-hour '(12 19)) '(15))
9302 (string-append #$idutils "/bin/mkid src")
9307 (services (cons (mcron-service (list garbage-collector-job
9313 @xref{Guile Syntax, mcron job specifications,, mcron, GNU@tie{}mcron},
9314 for more information on mcron job specifications. Below is the
9315 reference of the mcron service.
9317 @deffn {Scheme Procedure} mcron-service @var{jobs} [#:mcron @var{mcron2}]
9318 Return an mcron service running @var{mcron} that schedules @var{jobs}, a
9319 list of gexps denoting mcron job specifications.
9321 This is a shorthand for:
9323 (service mcron-service-type
9324 (mcron-configuration (mcron mcron) (jobs jobs)))
9328 @defvr {Scheme Variable} mcron-service-type
9329 This is the type of the @code{mcron} service, whose value is an
9330 @code{mcron-configuration} object.
9332 This service type can be the target of a service extension that provides
9333 it additional job specifications (@pxref{Service Composition}). In
9334 other words, it is possible to define services that provide additional
9338 @deftp {Data Type} mcron-configuration
9339 Data type representing the configuration of mcron.
9342 @item @code{mcron} (default: @var{mcron2})
9343 The mcron package to use.
9346 This is a list of gexps (@pxref{G-Expressions}), where each gexp
9347 corresponds to an mcron job specification (@pxref{Syntax, mcron job
9348 specifications,, mcron, GNU@tie{}mcron}).
9354 @subsubsection Log Rotation
9357 @cindex log rotation
9359 Log files such as those found in @file{/var/log} tend to grow endlessly,
9360 so it's a good idea to @dfn{rotate} them once in a while---i.e., archive
9361 their contents in separate files, possibly compressed. The @code{(gnu
9362 services admin)} module provides an interface to GNU@tie{}Rot[t]log, a
9363 log rotation tool (@pxref{Top,,, rottlog, GNU Rot[t]log Manual}).
9365 The example below defines an operating system that provides log rotation
9366 with the default settings.
9369 (use-modules (guix) (gnu))
9370 (use-service-modules admin mcron)
9371 (use-package-modules base idutils)
9375 (services (cons* (mcron-service)
9376 (service rottlog-service-type)
9380 @defvr {Scheme Variable} rottlog-service-type
9381 This is the type of the Rottlog service, whose value is a
9382 @code{rottlog-configuration} object.
9384 This service type can define mcron jobs (@pxref{Scheduled Job
9385 Execution}) to run the rottlog service.
9388 @deftp {Data Type} rottlog-configuration
9389 Data type representing the configuration of rottlog.
9392 @item @code{rottlog} (default: @code{rottlog})
9393 The Rottlog package to use.
9395 @item @code{rc-file} (default: @code{(file-append rottlog "/etc/rc")})
9396 The Rottlog configuration file to use (@pxref{Mandatory RC Variables,,,
9397 rottlog, GNU Rot[t]log Manual}).
9399 @item @code{periodic-rotations} (default: @code{`(("weekly" %default-rotations))})
9400 A list of Rottlog period-name/period-config tuples.
9402 For example, taking an example from the Rottlog manual (@pxref{Period
9403 Related File Examples,,, rottlog, GNU Rot[t]log Manual}), a valid tuple
9407 ("daily" ,(plain-file "daily"
9409 /var/log/apache/* @{
9410 storedir apache-archives
9418 This is a list of gexps where each gexp corresponds to an mcron job
9419 specification (@pxref{Scheduled Job Execution}).
9423 @defvr {Scheme Variable} %default-rotations
9424 Specifies weekly rotation of @var{%rotated-files} and
9425 @code{"/var/log/shepherd.log"}.
9428 @defvr {Scheme Variable} %rotated-files
9429 The list of syslog-controlled files to be rotated. By default it is:
9430 @code{'("/var/log/messages" "/var/log/secure")}.
9433 @node Networking Services
9434 @subsubsection Networking Services
9436 The @code{(gnu services networking)} module provides services to configure
9437 the network interface.
9439 @cindex DHCP, networking service
9440 @deffn {Scheme Procedure} dhcp-client-service [#:dhcp @var{isc-dhcp}]
9441 Return a service that runs @var{dhcp}, a Dynamic Host Configuration
9442 Protocol (DHCP) client, on all the non-loopback network interfaces.
9445 @defvr {Scheme Variable} static-networking-service-type
9446 This is the type for statically-configured network interfaces.
9447 @c TODO Document <static-networking> data structures.
9450 @deffn {Scheme Procedure} static-networking-service @var{interface} @var{ip} @
9451 [#:netmask #f] [#:gateway #f] [#:name-servers @code{'()}]
9452 Return a service that starts @var{interface} with address @var{ip}. If
9453 @var{netmask} is true, use it as the network mask. If @var{gateway} is true,
9454 it must be a string specifying the default network gateway.
9456 This procedure can be called several times, one for each network
9457 interface of interest. Behind the scenes what it does is extend
9458 @code{static-networking-service-type} with additional network interfaces
9465 @cindex network management
9466 @deffn {Scheme Procedure} wicd-service [#:wicd @var{wicd}]
9467 Return a service that runs @url{https://launchpad.net/wicd,Wicd}, a network
9468 management daemon that aims to simplify wired and wireless networking.
9470 This service adds the @var{wicd} package to the global profile, providing
9471 several commands to interact with the daemon and configure networking:
9472 @command{wicd-client}, a graphical user interface, and the @command{wicd-cli}
9473 and @command{wicd-curses} user interfaces.
9476 @cindex NetworkManager
9478 @defvr {Scheme Variable} network-manager-service-type
9479 This is the service type for the
9480 @uref{https://wiki.gnome.org/Projects/NetworkManager, NetworkManager}
9481 service. The value for this service type is a
9482 @code{network-manager-configuration} record.
9485 @deftp {Data Type} network-manager-configuration
9486 Data type representing the configuration of NetworkManager.
9489 @item @code{network-manager} (default: @code{network-manager})
9490 The NetworkManager package to use.
9492 @item @code{dns} (default: @code{"default"})
9493 Processing mode for DNS, which affects how NetworkManager uses the
9494 @code{resolv.conf} configuration file.
9498 NetworkManager will update @code{resolv.conf} to reflect the nameservers
9499 provided by currently active connections.
9502 NetworkManager will run @code{dnsmasq} as a local caching nameserver,
9503 using a "split DNS" configuration if you are connected to a VPN, and
9504 then update @code{resolv.conf} to point to the local nameserver.
9507 NetworkManager will not modify @code{resolv.conf}.
9514 @deffn {Scheme Variable} connman-service-type
9515 This is the service type to run @url{https://01.org/connman,Connman},
9516 a network connection manager.
9518 Its value must be an
9519 @code{connman-configuration} record as in this example:
9522 (service connman-service-type
9523 (connman-configuration
9527 See below for details about @code{connman-configuration}.
9530 @deftp {Data Type} connman-configuration
9531 Data Type representing the configuration of connman.
9534 @item @code{connman} (default: @var{connman})
9535 The connman package to use.
9537 @item @code{disable-vpn?} (default: @code{#f})
9538 When true, enable connman's vpn plugin.
9542 @cindex WPA Supplicant
9543 @defvr {Scheme Variable} wpa-supplicant-service-type
9544 This is the service type to run @url{https://w1.fi/wpa_supplicant/,WPA
9545 supplicant}, an authentication daemon required to authenticate against
9546 encrypted WiFi or ethernet networks. It is configured to listen for
9549 The value of this service is the @code{wpa-supplicant} package to use.
9550 Thus, it can be instantiated like this:
9553 (use-modules (gnu services networking))
9555 (service wpa-supplicant-service-type)
9560 @cindex real time clock
9561 @deffn {Scheme Procedure} ntp-service [#:ntp @var{ntp}] @
9562 [#:servers @var{%ntp-servers}] @
9563 [#:allow-large-adjustment? #f]
9564 Return a service that runs the daemon from @var{ntp}, the
9565 @uref{http://www.ntp.org, Network Time Protocol package}. The daemon will
9566 keep the system clock synchronized with that of @var{servers}.
9567 @var{allow-large-adjustment?} determines whether @command{ntpd} is allowed to
9568 make an initial adjustment of more than 1,000 seconds.
9571 @defvr {Scheme Variable} %ntp-servers
9572 List of host names used as the default NTP servers.
9576 @deffn {Scheme variable} inetd-service-type
9577 This service runs the @command{inetd} (@pxref{inetd invocation,,,
9578 inetutils, GNU Inetutils}) daemon. @command{inetd} listens for
9579 connections on internet sockets, and lazily starts the specified server
9580 program when a connection is made on one of these sockets.
9582 The value of this service is an @code{inetd-configuration} object. The
9583 following example configures the @command{inetd} daemon to provide the
9584 built-in @command{echo} service, as well as an smtp service which
9585 forwards smtp traffic over ssh to a server @code{smtp-server} behind a
9586 gateway @code{hostname}:
9591 (inetd-configuration
9595 (socket-type 'stream)
9602 (socket-type 'stream)
9606 (program (file-append openssh "/bin/ssh"))
9608 '("ssh" "-qT" "-i" "/path/to/ssh_key"
9609 "-W" "smtp-server:25" "user@@hostname")))))
9612 See below for more details about @code{inetd-configuration}.
9615 @deftp {Data Type} inetd-configuration
9616 Data type representing the configuration of @command{inetd}.
9619 @item @code{program} (default: @code{(file-append inetutils "/libexec/inetd")})
9620 The @command{inetd} executable to use.
9622 @item @code{entries} (default: @code{'()})
9623 A list of @command{inetd} service entries. Each entry should be created
9624 by the @code{inetd-entry} constructor.
9628 @deftp {Data Type} inetd-entry
9629 Data type representing an entry in the @command{inetd} configuration.
9630 Each entry corresponds to a socket where @command{inetd} will listen for
9634 @item @code{node} (default: @code{#f})
9635 Optional string, a comma-separated list of local addresses
9636 @command{inetd} should use when listening for this service.
9637 @xref{Configuration file,,, inetutils, GNU Inetutils} for a complete
9638 description of all options.
9640 A string, the name must correspond to an entry in @code{/etc/services}.
9641 @item @code{socket-type}
9642 One of @code{'stream}, @code{'dgram}, @code{'raw}, @code{'rdm} or
9644 @item @code{protocol}
9645 A string, must correspond to an entry in @code{/etc/protocols}.
9646 @item @code{wait?} (default: @code{#t})
9647 Whether @command{inetd} should wait for the server to exit before
9648 listening to new service requests.
9650 A string containing the user (and, optionally, group) name of the user
9651 as whom the server should run. The group name can be specified in a
9652 suffix, separated by a colon or period, i.e. @code{"user"},
9653 @code{"user:group"} or @code{"user.group"}.
9654 @item @code{program} (default: @code{"internal"})
9655 The server program which will serve the requests, or @code{"internal"}
9656 if @command{inetd} should use a built-in service.
9657 @item @code{arguments} (default: @code{'()})
9658 A list strings or file-like objects, which are the server program's
9659 arguments, starting with the zeroth argument, i.e. the name of the
9660 program itself. For @command{inetd}'s internal services, this entry
9661 must be @code{'()} or @code{'("internal")}.
9664 @xref{Configuration file,,, inetutils, GNU Inetutils} for a more
9665 detailed discussion of each configuration field.
9669 @deffn {Scheme Procedure} tor-service [@var{config-file}] [#:tor @var{tor}]
9670 Return a service to run the @uref{https://torproject.org, Tor} anonymous
9673 The daemon runs as the @code{tor} unprivileged user. It is passed
9674 @var{config-file}, a file-like object, with an additional @code{User tor} line
9675 and lines for hidden services added via @code{tor-hidden-service}. Run
9676 @command{man tor} for information about the configuration file.
9679 @cindex hidden service
9680 @deffn {Scheme Procedure} tor-hidden-service @var{name} @var{mapping}
9681 Define a new Tor @dfn{hidden service} called @var{name} and implementing
9682 @var{mapping}. @var{mapping} is a list of port/host tuples, such as:
9685 '((22 "127.0.0.1:22")
9686 (80 "127.0.0.1:8080"))
9689 In this example, port 22 of the hidden service is mapped to local port 22, and
9690 port 80 is mapped to local port 8080.
9692 This creates a @file{/var/lib/tor/hidden-services/@var{name}} directory, where
9693 the @file{hostname} file contains the @code{.onion} host name for the hidden
9696 See @uref{https://www.torproject.org/docs/tor-hidden-service.html.en, the Tor
9697 project's documentation} for more information.
9700 @deffn {Scheme Procedure} bitlbee-service [#:bitlbee bitlbee] @
9701 [#:interface "127.0.0.1"] [#:port 6667] @
9702 [#:extra-settings ""]
9703 Return a service that runs @url{http://bitlbee.org,BitlBee}, a daemon that
9704 acts as a gateway between IRC and chat networks.
9706 The daemon will listen to the interface corresponding to the IP address
9707 specified in @var{interface}, on @var{port}. @code{127.0.0.1} means that only
9708 local clients can connect, whereas @code{0.0.0.0} means that connections can
9709 come from any networking interface.
9711 In addition, @var{extra-settings} specifies a string to append to the
9715 Furthermore, @code{(gnu services ssh)} provides the following services.
9719 @deffn {Scheme Procedure} lsh-service [#:host-key "/etc/lsh/host-key"] @
9720 [#:daemonic? #t] [#:interfaces '()] [#:port-number 22] @
9721 [#:allow-empty-passwords? #f] [#:root-login? #f] @
9722 [#:syslog-output? #t] [#:x11-forwarding? #t] @
9723 [#:tcp/ip-forwarding? #t] [#:password-authentication? #t] @
9724 [#:public-key-authentication? #t] [#:initialize? #t]
9725 Run the @command{lshd} program from @var{lsh} to listen on port @var{port-number}.
9726 @var{host-key} must designate a file containing the host key, and readable
9729 When @var{daemonic?} is true, @command{lshd} will detach from the
9730 controlling terminal and log its output to syslogd, unless one sets
9731 @var{syslog-output?} to false. Obviously, it also makes lsh-service
9732 depend on existence of syslogd service. When @var{pid-file?} is true,
9733 @command{lshd} writes its PID to the file called @var{pid-file}.
9735 When @var{initialize?} is true, automatically create the seed and host key
9736 upon service activation if they do not exist yet. This may take long and
9737 require interaction.
9739 When @var{initialize?} is false, it is up to the user to initialize the
9740 randomness generator (@pxref{lsh-make-seed,,, lsh, LSH Manual}), and to create
9741 a key pair with the private key stored in file @var{host-key} (@pxref{lshd
9742 basics,,, lsh, LSH Manual}).
9744 When @var{interfaces} is empty, lshd listens for connections on all the
9745 network interfaces; otherwise, @var{interfaces} must be a list of host names
9748 @var{allow-empty-passwords?} specifies whether to accept log-ins with empty
9749 passwords, and @var{root-login?} specifies whether to accept log-ins as
9752 The other options should be self-descriptive.
9757 @deffn {Scheme Variable} openssh-service-type
9758 This is the type for the @uref{http://www.openssh.org, OpenSSH} secure
9759 shell daemon, @command{sshd}. Its value must be an
9760 @code{openssh-configuration} record as in this example:
9763 (service openssh-service-type
9764 (openssh-configuration
9765 (x11-forwarding? #t)
9766 (permit-root-login 'without-password)))
9769 See below for details about @code{openssh-configuration}.
9772 @deftp {Data Type} openssh-configuration
9773 This is the configuration record for OpenSSH's @command{sshd}.
9776 @item @code{pid-file} (default: @code{"/var/run/sshd.pid"})
9777 Name of the file where @command{sshd} writes its PID.
9779 @item @code{port-number} (default: @code{22})
9780 TCP port on which @command{sshd} listens for incoming connections.
9782 @item @code{permit-root-login} (default: @code{#f})
9783 This field determines whether and when to allow logins as root. If
9784 @code{#f}, root logins are disallowed; if @code{#t}, they are allowed.
9785 If it's the symbol @code{'without-password}, then root logins are
9786 permitted but not with password-based authentication.
9788 @item @code{allow-empty-passwords?} (default: @code{#f})
9789 When true, users with empty passwords may log in. When false, they may
9792 @item @code{password-authentication?} (default: @code{#t})
9793 When true, users may log in with their password. When false, they have
9794 other authentication methods.
9796 @item @code{public-key-authentication?} (default: @code{#t})
9797 When true, users may log in using public key authentication. When
9798 false, users have to use other authentication method.
9800 Authorized public keys are stored in @file{~/.ssh/authorized_keys}.
9801 This is used only by protocol version 2.
9803 @item @code{x11-forwarding?} (default: @code{#f})
9804 When true, forwarding of X11 graphical client connections is
9805 enabled---in other words, @command{ssh} options @option{-X} and
9806 @option{-Y} will work.
9808 @item @code{challenge-response-authentication?} (default: @code{#f})
9809 Specifies whether challenge response authentication is allowed (e.g. via
9812 @item @code{use-pam?} (default: @code{#t})
9813 Enables the Pluggable Authentication Module interface. If set to
9814 @code{#t}, this will enable PAM authentication using
9815 @code{challenge-response-authentication?} and
9816 @code{password-authentication?}, in addition to PAM account and session
9817 module processing for all authentication types.
9819 Because PAM challenge response authentication usually serves an
9820 equivalent role to password authentication, you should disable either
9821 @code{challenge-response-authentication?} or
9822 @code{password-authentication?}.
9824 @item @code{print-last-log?} (default: @code{#t})
9825 Specifies whether @command{sshd} should print the date and time of the
9826 last user login when a user logs in interactively.
9828 @item @code{subsystems} (default: @code{'(("sftp" "internal-sftp"))})
9829 Configures external subsystems (e.g. file transfer daemon).
9831 This is a list of two-element lists, each of which containing the
9832 subsystem name and a command (with optional arguments) to execute upon
9835 The command @command{internal-sftp} implements an in-process SFTP
9836 server. Alternately, one can specify the @command{sftp-server} command:
9838 (service openssh-service-type
9839 (openssh-configuration
9841 '(("sftp" ,(file-append openssh "/libexec/sftp-server"))))))
9846 @deffn {Scheme Procedure} dropbear-service [@var{config}]
9847 Run the @uref{https://matt.ucc.asn.au/dropbear/dropbear.html,Dropbear SSH
9848 daemon} with the given @var{config}, a @code{<dropbear-configuration>}
9851 For example, to specify a Dropbear service listening on port 1234, add
9852 this call to the operating system's @code{services} field:
9855 (dropbear-service (dropbear-configuration
9856 (port-number 1234)))
9860 @deftp {Data Type} dropbear-configuration
9861 This data type represents the configuration of a Dropbear SSH daemon.
9864 @item @code{dropbear} (default: @var{dropbear})
9865 The Dropbear package to use.
9867 @item @code{port-number} (default: 22)
9868 The TCP port where the daemon waits for incoming connections.
9870 @item @code{syslog-output?} (default: @code{#t})
9871 Whether to enable syslog output.
9873 @item @code{pid-file} (default: @code{"/var/run/dropbear.pid"})
9874 File name of the daemon's PID file.
9876 @item @code{root-login?} (default: @code{#f})
9877 Whether to allow @code{root} logins.
9879 @item @code{allow-empty-passwords?} (default: @code{#f})
9880 Whether to allow empty passwords.
9882 @item @code{password-authentication?} (default: @code{#t})
9883 Whether to enable password-based authentication.
9887 @defvr {Scheme Variable} %facebook-host-aliases
9888 This variable contains a string for use in @file{/etc/hosts}
9889 (@pxref{Host Names,,, libc, The GNU C Library Reference Manual}). Each
9890 line contains a entry that maps a known server name of the Facebook
9891 on-line service---e.g., @code{www.facebook.com}---to the local
9892 host---@code{127.0.0.1} or its IPv6 equivalent, @code{::1}.
9894 This variable is typically used in the @code{hosts-file} field of an
9895 @code{operating-system} declaration (@pxref{operating-system Reference,
9896 @file{/etc/hosts}}):
9899 (use-modules (gnu) (guix))
9902 (host-name "mymachine")
9905 ;; Create a /etc/hosts file with aliases for "localhost"
9906 ;; and "mymachine", as well as for Facebook servers.
9908 (string-append (local-host-aliases host-name)
9909 %facebook-host-aliases))))
9912 This mechanism can prevent programs running locally, such as Web
9913 browsers, from accessing Facebook.
9916 The @code{(gnu services avahi)} provides the following definition.
9918 @deffn {Scheme Procedure} avahi-service [#:avahi @var{avahi}] @
9919 [#:host-name #f] [#:publish? #t] [#:ipv4? #t] @
9920 [#:ipv6? #t] [#:wide-area? #f] @
9921 [#:domains-to-browse '()] [#:debug? #f]
9922 Return a service that runs @command{avahi-daemon}, a system-wide
9923 mDNS/DNS-SD responder that allows for service discovery and
9924 "zero-configuration" host name lookups (see @uref{http://avahi.org/}), and
9925 extends the name service cache daemon (nscd) so that it can resolve
9926 @code{.local} host names using
9927 @uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
9928 add the @var{avahi} package to the system profile so that commands such as
9929 @command{avahi-browse} are directly usable.
9931 If @var{host-name} is different from @code{#f}, use that as the host name to
9932 publish for this machine; otherwise, use the machine's actual host name.
9934 When @var{publish?} is true, publishing of host names and services is allowed;
9935 in particular, avahi-daemon will publish the machine's host name and IP
9936 address via mDNS on the local network.
9938 When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
9940 Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
9944 @deffn {Scheme Variable} openvswitch-service-type
9945 This is the type of the @uref{http://www.openvswitch.org, Open vSwitch}
9946 service, whose value should be an @code{openvswitch-configuration}
9950 @deftp {Data Type} openvswitch-configuration
9951 Data type representing the configuration of Open vSwitch, a multilayer
9952 virtual switch which is designed to enable massive network automation
9953 through programmatic extension.
9956 @item @code{package} (default: @var{openvswitch})
9957 Package object of the Open vSwitch.
9963 @subsubsection X Window
9966 @cindex X Window System
9967 Support for the X Window graphical display system---specifically
9968 Xorg---is provided by the @code{(gnu services xorg)} module. Note that
9969 there is no @code{xorg-service} procedure. Instead, the X server is
9970 started by the @dfn{login manager}, currently SLiM.
9972 @deftp {Data Type} sddm-configuration
9973 This is the data type representing the sddm service configuration.
9976 @item @code{display-server} (default: "x11")
9977 Select display server to use for the greeter. Valid values are "x11"
9980 @item @code{numlock} (default: "on")
9981 Valid values are "on", "off" or "none".
9983 @item @code{halt-command} (default @code{#~(string-apppend #$shepherd "/sbin/halt")})
9984 Command to run when halting.
9986 @item @code{reboot-command} (default @code{#~(string-append #$shepherd "/sbin/reboot")})
9987 Command to run when rebooting.
9989 @item @code{theme} (default "maldives")
9990 Theme to use. Default themes provided by SDDM are "elarun" or "maldives".
9992 @item @code{themes-directory} (default "/run/current-system/profile/share/sddm/themes")
9993 Directory to look for themes.
9995 @item @code{faces-directory} (default "/run/current-system/profile/share/sddm/faces")
9996 Directory to look for faces.
9998 @item @code{default-path} (default "/run/current-system/profile/bin")
9999 Default PATH to use.
10001 @item @code{minimum-uid} (default 1000)
10002 Minimum UID to display in SDDM.
10004 @item @code{maximum-uid} (default 2000)
10005 Maximum UID to display in SDDM
10007 @item @code{remember-last-user?} (default #t)
10008 Remember last user.
10010 @item @code{remember-last-session?} (default #t)
10011 Remember last session.
10013 @item @code{hide-users} (default "")
10014 Usernames to hide from SDDM greeter.
10016 @item @code{hide-shells} (default @code{#~(string-append #$shadow "/sbin/nologin")})
10017 Users with shells listed will be hidden from the SDDM greeter.
10019 @item @code{session-command} (default @code{#~(string-append #$sddm "/share/sddm/scripts/wayland-session")})
10020 Script to run before starting a wayland session.
10022 @item @code{sessions-directory} (default "/run/current-system/profile/share/wayland-sessions")
10023 Directory to look for desktop files starting wayland sessions.
10025 @item @code{xorg-server-path} (default @code{xorg-start-command})
10026 Path to xorg-server.
10028 @item @code{xauth-path} (default @code{#~(string-append #$xauth "/bin/xauth")})
10031 @item @code{xephyr-path} (default @code{#~(string-append #$xorg-server "/bin/Xephyr")})
10034 @item @code{xdisplay-start} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xsetup")})
10035 Script to run after starting xorg-server.
10037 @item @code{xdisplay-stop} (default @code{#~(string-append #$sddm "/share/sddm/scripts/Xstop")})
10038 Script to run before stopping xorg-server.
10040 @item @code{xsession-command} (default: @code{xinitr })
10041 Script to run before starting a X session.
10043 @item @code{xsessions-directory} (default: "/run/current-system/profile/share/xsessions")
10044 Directory to look for desktop files starting X sessions.
10046 @item @code{minimum-vt} (default: 7)
10049 @item @code{xserver-arguments} (default "-nolisten tcp")
10050 Arguments to pass to xorg-server.
10052 @item @code{auto-login-user} (default "")
10053 User to use for auto-login.
10055 @item @code{auto-login-session} (default "")
10056 Desktop file to use for auto-login.
10058 @item @code{relogin?} (default #f)
10059 Relogin after logout.
10064 @cindex login manager
10065 @deffn {Scheme Procedure} sddm-service config
10066 Return a service that spawns the SDDM graphical login manager for config of
10067 type @code{<sddm-configuration>}.
10070 (sddm-service (sddm-configuration
10071 (auto-login-user "Alice")
10072 (auto-login-session "xfce.desktop")))
10076 @deffn {Scheme Procedure} slim-service [#:allow-empty-passwords? #f] @
10077 [#:auto-login? #f] [#:default-user ""] [#:startx] @
10078 [#:theme @var{%default-slim-theme}] @
10079 [#:theme-name @var{%default-slim-theme-name}]
10080 Return a service that spawns the SLiM graphical login manager, which in
10081 turn starts the X display server with @var{startx}, a command as returned by
10082 @code{xorg-start-command}.
10086 SLiM automatically looks for session types described by the @file{.desktop}
10087 files in @file{/run/current-system/profile/share/xsessions} and allows users
10088 to choose a session from the log-in screen using @kbd{F1}. Packages such as
10089 @var{xfce}, @var{sawfish}, and @var{ratpoison} provide @file{.desktop} files;
10090 adding them to the system-wide set of packages automatically makes them
10091 available at the log-in screen.
10093 In addition, @file{~/.xsession} files are honored. When available,
10094 @file{~/.xsession} must be an executable that starts a window manager
10095 and/or other X clients.
10097 When @var{allow-empty-passwords?} is true, allow logins with an empty
10098 password. When @var{auto-login?} is true, log in automatically as
10099 @var{default-user}.
10101 If @var{theme} is @code{#f}, use the default log-in theme; otherwise
10102 @var{theme} must be a gexp denoting the name of a directory containing the
10103 theme to use. In that case, @var{theme-name} specifies the name of the
10107 @defvr {Scheme Variable} %default-theme
10108 @defvrx {Scheme Variable} %default-theme-name
10109 The G-Expression denoting the default SLiM theme and its name.
10112 @deffn {Scheme Procedure} xorg-start-command [#:guile] @
10113 [#:configuration-file #f] [#:xorg-server @var{xorg-server}]
10114 Return a derivation that builds a @var{guile} script to start the X server
10115 from @var{xorg-server}. @var{configuration-file} is the server configuration
10116 file or a derivation that builds it; when omitted, the result of
10117 @code{xorg-configuration-file} is used.
10119 Usually the X server is started by a login manager.
10122 @deffn {Scheme Procedure} xorg-configuration-file @
10123 [#:drivers '()] [#:resolutions '()] [#:extra-config '()]
10124 Return a configuration file for the Xorg server containing search paths for
10125 all the common drivers.
10127 @var{drivers} must be either the empty list, in which case Xorg chooses a
10128 graphics driver automatically, or a list of driver names that will be tried in
10129 this order---e.g., @code{(\"modesetting\" \"vesa\")}.
10131 Likewise, when @var{resolutions} is the empty list, Xorg chooses an
10132 appropriate screen resolution; otherwise, it must be a list of
10133 resolutions---e.g., @code{((1024 768) (640 480))}.
10135 Last, @var{extra-config} is a list of strings or objects appended to the
10136 @code{text-file*} argument list. It is used to pass extra text to be added
10137 verbatim to the configuration file.
10140 @deffn {Scheme Procedure} screen-locker-service @var{package} [@var{name}]
10141 Add @var{package}, a package for a screen-locker or screen-saver whose
10142 command is @var{program}, to the set of setuid programs and add a PAM entry
10143 for it. For example:
10146 (screen-locker-service xlockmore "xlock")
10149 makes the good ol' XlockMore usable.
10153 @node Printing Services
10154 @subsubsection Printing Services
10156 @cindex printer support with CUPS
10157 The @code{(gnu services cups)} module provides a Guix service definition
10158 for the CUPS printing service. To add printer support to a GuixSD
10159 system, add a @code{cups-service} to the operating system definition:
10161 @deffn {Scheme Variable} cups-service-type
10162 The service type for the CUPS print server. Its value should be a valid
10163 CUPS configuration (see below). To use the default settings, simply
10166 (service cups-service-type)
10170 The CUPS configuration controls the basic things about your CUPS
10171 installation: what interfaces it listens on, what to do if a print job
10172 fails, how much logging to do, and so on. To actually add a printer,
10173 you have to visit the @url{http://localhost:631} URL, or use a tool such
10174 as GNOME's printer configuration services. By default, configuring a
10175 CUPS service will generate a self-signed certificate if needed, for
10176 secure connections to the print server.
10178 Suppose you want to enable the Web interface of CUPS and also add
10179 support for HP printers @i{via} the @code{hplip} package. You can do
10180 that directly, like this (you need to use the @code{(gnu packages cups)}
10184 (service cups-service-type
10185 (cups-configuration
10186 (web-interface? #t)
10188 (list cups-filters hplip))))
10191 The available configuration parameters follow. Each parameter
10192 definition is preceded by its type; for example, @samp{string-list foo}
10193 indicates that the @code{foo} parameter should be specified as a list of
10194 strings. There is also a way to specify the configuration as a string,
10195 if you have an old @code{cupsd.conf} file that you want to port over
10196 from some other system; see the end for more details.
10198 @c The following documentation was initially generated by
10199 @c (generate-documentation) in (gnu services cups). Manually maintained
10200 @c documentation is better, so we shouldn't hesitate to edit below as
10201 @c needed. However if the change you want to make to this documentation
10202 @c can be done in an automated way, it's probably easier to change
10203 @c (generate-documentation) than to make it below and have to deal with
10204 @c the churn as CUPS updates.
10207 Available @code{cups-configuration} fields are:
10209 @deftypevr {@code{cups-configuration} parameter} package cups
10213 @deftypevr {@code{cups-configuration} parameter} package-list extensions
10214 Drivers and other extensions to the CUPS package.
10217 @deftypevr {@code{cups-configuration} parameter} files-configuration files-configuration
10218 Configuration of where to write logs, what directories to use for print
10219 spools, and related privileged configuration parameters.
10221 Available @code{files-configuration} fields are:
10223 @deftypevr {@code{files-configuration} parameter} log-location access-log
10224 Defines the access log filename. Specifying a blank filename disables
10225 access log generation. The value @code{stderr} causes log entries to be
10226 sent to the standard error file when the scheduler is running in the
10227 foreground, or to the system log daemon when run in the background. The
10228 value @code{syslog} causes log entries to be sent to the system log
10229 daemon. The server name may be included in filenames using the string
10230 @code{%s}, as in @code{/var/log/cups/%s-access_log}.
10232 Defaults to @samp{"/var/log/cups/access_log"}.
10235 @deftypevr {@code{files-configuration} parameter} file-name cache-dir
10236 Where CUPS should cache data.
10238 Defaults to @samp{"/var/cache/cups"}.
10241 @deftypevr {@code{files-configuration} parameter} string config-file-perm
10242 Specifies the permissions for all configuration files that the scheduler
10245 Note that the permissions for the printers.conf file are currently
10246 masked to only allow access from the scheduler user (typically root).
10247 This is done because printer device URIs sometimes contain sensitive
10248 authentication information that should not be generally known on the
10249 system. There is no way to disable this security feature.
10251 Defaults to @samp{"0640"}.
10254 @deftypevr {@code{files-configuration} parameter} log-location error-log
10255 Defines the error log filename. Specifying a blank filename disables
10256 access log generation. The value @code{stderr} causes log entries to be
10257 sent to the standard error file when the scheduler is running in the
10258 foreground, or to the system log daemon when run in the background. The
10259 value @code{syslog} causes log entries to be sent to the system log
10260 daemon. The server name may be included in filenames using the string
10261 @code{%s}, as in @code{/var/log/cups/%s-error_log}.
10263 Defaults to @samp{"/var/log/cups/error_log"}.
10266 @deftypevr {@code{files-configuration} parameter} string fatal-errors
10267 Specifies which errors are fatal, causing the scheduler to exit. The
10272 No errors are fatal.
10275 All of the errors below are fatal.
10278 Browsing initialization errors are fatal, for example failed connections
10279 to the DNS-SD daemon.
10282 Configuration file syntax errors are fatal.
10285 Listen or Port errors are fatal, except for IPv6 failures on the
10286 loopback or @code{any} addresses.
10289 Log file creation or write errors are fatal.
10292 Bad startup file permissions are fatal, for example shared TLS
10293 certificate and key files with world-read permissions.
10296 Defaults to @samp{"all -browse"}.
10299 @deftypevr {@code{files-configuration} parameter} boolean file-device?
10300 Specifies whether the file pseudo-device can be used for new printer
10301 queues. The URI @uref{file:///dev/null} is always allowed.
10303 Defaults to @samp{#f}.
10306 @deftypevr {@code{files-configuration} parameter} string group
10307 Specifies the group name or ID that will be used when executing external
10310 Defaults to @samp{"lp"}.
10313 @deftypevr {@code{files-configuration} parameter} string log-file-perm
10314 Specifies the permissions for all log files that the scheduler writes.
10316 Defaults to @samp{"0644"}.
10319 @deftypevr {@code{files-configuration} parameter} log-location page-log
10320 Defines the page log filename. Specifying a blank filename disables
10321 access log generation. The value @code{stderr} causes log entries to be
10322 sent to the standard error file when the scheduler is running in the
10323 foreground, or to the system log daemon when run in the background. The
10324 value @code{syslog} causes log entries to be sent to the system log
10325 daemon. The server name may be included in filenames using the string
10326 @code{%s}, as in @code{/var/log/cups/%s-page_log}.
10328 Defaults to @samp{"/var/log/cups/page_log"}.
10331 @deftypevr {@code{files-configuration} parameter} string remote-root
10332 Specifies the username that is associated with unauthenticated accesses
10333 by clients claiming to be the root user. The default is @code{remroot}.
10335 Defaults to @samp{"remroot"}.
10338 @deftypevr {@code{files-configuration} parameter} file-name request-root
10339 Specifies the directory that contains print jobs and other HTTP request
10342 Defaults to @samp{"/var/spool/cups"}.
10345 @deftypevr {@code{files-configuration} parameter} sandboxing sandboxing
10346 Specifies the level of security sandboxing that is applied to print
10347 filters, backends, and other child processes of the scheduler; either
10348 @code{relaxed} or @code{strict}. This directive is currently only
10349 used/supported on macOS.
10351 Defaults to @samp{strict}.
10354 @deftypevr {@code{files-configuration} parameter} file-name server-keychain
10355 Specifies the location of TLS certificates and private keys. CUPS will
10356 look for public and private keys in this directory: a @code{.crt} files
10357 for PEM-encoded certificates and corresponding @code{.key} files for
10358 PEM-encoded private keys.
10360 Defaults to @samp{"/etc/cups/ssl"}.
10363 @deftypevr {@code{files-configuration} parameter} file-name server-root
10364 Specifies the directory containing the server configuration files.
10366 Defaults to @samp{"/etc/cups"}.
10369 @deftypevr {@code{files-configuration} parameter} boolean sync-on-close?
10370 Specifies whether the scheduler calls fsync(2) after writing
10371 configuration or state files.
10373 Defaults to @samp{#f}.
10376 @deftypevr {@code{files-configuration} parameter} space-separated-string-list system-group
10377 Specifies the group(s) to use for @code{@@SYSTEM} group authentication.
10380 @deftypevr {@code{files-configuration} parameter} file-name temp-dir
10381 Specifies the directory where temporary files are stored.
10383 Defaults to @samp{"/var/spool/cups/tmp"}.
10386 @deftypevr {@code{files-configuration} parameter} string user
10387 Specifies the user name or ID that is used when running external
10390 Defaults to @samp{"lp"}.
10394 @deftypevr {@code{cups-configuration} parameter} access-log-level access-log-level
10395 Specifies the logging level for the AccessLog file. The @code{config}
10396 level logs when printers and classes are added, deleted, or modified and
10397 when configuration files are accessed or updated. The @code{actions}
10398 level logs when print jobs are submitted, held, released, modified, or
10399 canceled, and any of the conditions for @code{config}. The @code{all}
10400 level logs all requests.
10402 Defaults to @samp{actions}.
10405 @deftypevr {@code{cups-configuration} parameter} boolean auto-purge-jobs?
10406 Specifies whether to purge job history data automatically when it is no
10407 longer required for quotas.
10409 Defaults to @samp{#f}.
10412 @deftypevr {@code{cups-configuration} parameter} browse-local-protocols browse-local-protocols
10413 Specifies which protocols to use for local printer sharing.
10415 Defaults to @samp{dnssd}.
10418 @deftypevr {@code{cups-configuration} parameter} boolean browse-web-if?
10419 Specifies whether the CUPS web interface is advertised.
10421 Defaults to @samp{#f}.
10424 @deftypevr {@code{cups-configuration} parameter} boolean browsing?
10425 Specifies whether shared printers are advertised.
10427 Defaults to @samp{#f}.
10430 @deftypevr {@code{cups-configuration} parameter} string classification
10431 Specifies the security classification of the server. Any valid banner
10432 name can be used, including "classified", "confidential", "secret",
10433 "topsecret", and "unclassified", or the banner can be omitted to disable
10434 secure printing functions.
10436 Defaults to @samp{""}.
10439 @deftypevr {@code{cups-configuration} parameter} boolean classify-override?
10440 Specifies whether users may override the classification (cover page) of
10441 individual print jobs using the @code{job-sheets} option.
10443 Defaults to @samp{#f}.
10446 @deftypevr {@code{cups-configuration} parameter} default-auth-type default-auth-type
10447 Specifies the default type of authentication to use.
10449 Defaults to @samp{Basic}.
10452 @deftypevr {@code{cups-configuration} parameter} default-encryption default-encryption
10453 Specifies whether encryption will be used for authenticated requests.
10455 Defaults to @samp{Required}.
10458 @deftypevr {@code{cups-configuration} parameter} string default-language
10459 Specifies the default language to use for text and web content.
10461 Defaults to @samp{"en"}.
10464 @deftypevr {@code{cups-configuration} parameter} string default-paper-size
10465 Specifies the default paper size for new print queues. @samp{"Auto"}
10466 uses a locale-specific default, while @samp{"None"} specifies there is
10467 no default paper size. Specific size names are typically
10468 @samp{"Letter"} or @samp{"A4"}.
10470 Defaults to @samp{"Auto"}.
10473 @deftypevr {@code{cups-configuration} parameter} string default-policy
10474 Specifies the default access policy to use.
10476 Defaults to @samp{"default"}.
10479 @deftypevr {@code{cups-configuration} parameter} boolean default-shared?
10480 Specifies whether local printers are shared by default.
10482 Defaults to @samp{#t}.
10485 @deftypevr {@code{cups-configuration} parameter} non-negative-integer dirty-clean-interval
10486 Specifies the delay for updating of configuration and state files, in
10487 seconds. A value of 0 causes the update to happen as soon as possible,
10488 typically within a few milliseconds.
10490 Defaults to @samp{30}.
10493 @deftypevr {@code{cups-configuration} parameter} error-policy error-policy
10494 Specifies what to do when an error occurs. Possible values are
10495 @code{abort-job}, which will discard the failed print job;
10496 @code{retry-job}, which will retry the job at a later time;
10497 @code{retry-this-job}, which retries the failed job immediately; and
10498 @code{stop-printer}, which stops the printer.
10500 Defaults to @samp{stop-printer}.
10503 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-limit
10504 Specifies the maximum cost of filters that are run concurrently, which
10505 can be used to minimize disk, memory, and CPU resource problems. A
10506 limit of 0 disables filter limiting. An average print to a
10507 non-PostScript printer needs a filter limit of about 200. A PostScript
10508 printer needs about half that (100). Setting the limit below these
10509 thresholds will effectively limit the scheduler to printing a single job
10512 Defaults to @samp{0}.
10515 @deftypevr {@code{cups-configuration} parameter} non-negative-integer filter-nice
10516 Specifies the scheduling priority of filters that are run to print a
10517 job. The nice value ranges from 0, the highest priority, to 19, the
10520 Defaults to @samp{0}.
10523 @deftypevr {@code{cups-configuration} parameter} host-name-lookups host-name-lookups
10524 Specifies whether to do reverse lookups on connecting clients. The
10525 @code{double} setting causes @code{cupsd} to verify that the hostname
10526 resolved from the address matches one of the addresses returned for that
10527 hostname. Double lookups also prevent clients with unregistered
10528 addresses from connecting to your server. Only set this option to
10529 @code{#t} or @code{double} if absolutely required.
10531 Defaults to @samp{#f}.
10534 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-kill-delay
10535 Specifies the number of seconds to wait before killing the filters and
10536 backend associated with a canceled or held job.
10538 Defaults to @samp{30}.
10541 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-interval
10542 Specifies the interval between retries of jobs in seconds. This is
10543 typically used for fax queues but can also be used with normal print
10544 queues whose error policy is @code{retry-job} or
10545 @code{retry-current-job}.
10547 Defaults to @samp{30}.
10550 @deftypevr {@code{cups-configuration} parameter} non-negative-integer job-retry-limit
10551 Specifies the number of retries that are done for jobs. This is
10552 typically used for fax queues but can also be used with normal print
10553 queues whose error policy is @code{retry-job} or
10554 @code{retry-current-job}.
10556 Defaults to @samp{5}.
10559 @deftypevr {@code{cups-configuration} parameter} boolean keep-alive?
10560 Specifies whether to support HTTP keep-alive connections.
10562 Defaults to @samp{#t}.
10565 @deftypevr {@code{cups-configuration} parameter} non-negative-integer keep-alive-timeout
10566 Specifies how long an idle client connection remains open, in seconds.
10568 Defaults to @samp{30}.
10571 @deftypevr {@code{cups-configuration} parameter} non-negative-integer limit-request-body
10572 Specifies the maximum size of print files, IPP requests, and HTML form
10573 data. A limit of 0 disables the limit check.
10575 Defaults to @samp{0}.
10578 @deftypevr {@code{cups-configuration} parameter} multiline-string-list listen
10579 Listens on the specified interfaces for connections. Valid values are
10580 of the form @var{address}:@var{port}, where @var{address} is either an
10581 IPv6 address enclosed in brackets, an IPv4 address, or @code{*} to
10582 indicate all addresses. Values can also be file names of local UNIX
10583 domain sockets. The Listen directive is similar to the Port directive
10584 but allows you to restrict access to specific interfaces or networks.
10587 @deftypevr {@code{cups-configuration} parameter} non-negative-integer listen-back-log
10588 Specifies the number of pending connections that will be allowed. This
10589 normally only affects very busy servers that have reached the MaxClients
10590 limit, but can also be triggered by large numbers of simultaneous
10591 connections. When the limit is reached, the operating system will
10592 refuse additional connections until the scheduler can accept the pending
10595 Defaults to @samp{128}.
10598 @deftypevr {@code{cups-configuration} parameter} location-access-control-list location-access-controls
10599 Specifies a set of additional access controls.
10601 Available @code{location-access-controls} fields are:
10603 @deftypevr {@code{location-access-controls} parameter} file-name path
10604 Specifies the URI path to which the access control applies.
10607 @deftypevr {@code{location-access-controls} parameter} access-control-list access-controls
10608 Access controls for all access to this path, in the same format as the
10609 @code{access-controls} of @code{operation-access-control}.
10611 Defaults to @samp{()}.
10614 @deftypevr {@code{location-access-controls} parameter} method-access-control-list method-access-controls
10615 Access controls for method-specific access to this path.
10617 Defaults to @samp{()}.
10619 Available @code{method-access-controls} fields are:
10621 @deftypevr {@code{method-access-controls} parameter} boolean reverse?
10622 If @code{#t}, apply access controls to all methods except the listed
10623 methods. Otherwise apply to only the listed methods.
10625 Defaults to @samp{#f}.
10628 @deftypevr {@code{method-access-controls} parameter} method-list methods
10629 Methods to which this access control applies.
10631 Defaults to @samp{()}.
10634 @deftypevr {@code{method-access-controls} parameter} access-control-list access-controls
10635 Access control directives, as a list of strings. Each string should be
10636 one directive, such as "Order allow,deny".
10638 Defaults to @samp{()}.
10643 @deftypevr {@code{cups-configuration} parameter} non-negative-integer log-debug-history
10644 Specifies the number of debugging messages that are retained for logging
10645 if an error occurs in a print job. Debug messages are logged regardless
10646 of the LogLevel setting.
10648 Defaults to @samp{100}.
10651 @deftypevr {@code{cups-configuration} parameter} log-level log-level
10652 Specifies the level of logging for the ErrorLog file. The value
10653 @code{none} stops all logging while @code{debug2} logs everything.
10655 Defaults to @samp{info}.
10658 @deftypevr {@code{cups-configuration} parameter} log-time-format log-time-format
10659 Specifies the format of the date and time in the log files. The value
10660 @code{standard} logs whole seconds while @code{usecs} logs microseconds.
10662 Defaults to @samp{standard}.
10665 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients
10666 Specifies the maximum number of simultaneous clients that are allowed by
10669 Defaults to @samp{100}.
10672 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-clients-per-host
10673 Specifies the maximum number of simultaneous clients that are allowed
10674 from a single address.
10676 Defaults to @samp{100}.
10679 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-copies
10680 Specifies the maximum number of copies that a user can print of each
10683 Defaults to @samp{9999}.
10686 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-hold-time
10687 Specifies the maximum time a job may remain in the @code{indefinite}
10688 hold state before it is canceled. A value of 0 disables cancellation of
10691 Defaults to @samp{0}.
10694 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs
10695 Specifies the maximum number of simultaneous jobs that are allowed. Set
10696 to 0 to allow an unlimited number of jobs.
10698 Defaults to @samp{500}.
10701 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-printer
10702 Specifies the maximum number of simultaneous jobs that are allowed per
10703 printer. A value of 0 allows up to MaxJobs jobs per printer.
10705 Defaults to @samp{0}.
10708 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-jobs-per-user
10709 Specifies the maximum number of simultaneous jobs that are allowed per
10710 user. A value of 0 allows up to MaxJobs jobs per user.
10712 Defaults to @samp{0}.
10715 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-job-time
10716 Specifies the maximum time a job may take to print before it is
10717 canceled, in seconds. Set to 0 to disable cancellation of "stuck" jobs.
10719 Defaults to @samp{10800}.
10722 @deftypevr {@code{cups-configuration} parameter} non-negative-integer max-log-size
10723 Specifies the maximum size of the log files before they are rotated, in
10724 bytes. The value 0 disables log rotation.
10726 Defaults to @samp{1048576}.
10729 @deftypevr {@code{cups-configuration} parameter} non-negative-integer multiple-operation-timeout
10730 Specifies the maximum amount of time to allow between files in a
10731 multiple file print job, in seconds.
10733 Defaults to @samp{300}.
10736 @deftypevr {@code{cups-configuration} parameter} string page-log-format
10737 Specifies the format of PageLog lines. Sequences beginning with percent
10738 (@samp{%}) characters are replaced with the corresponding information,
10739 while all other characters are copied literally. The following percent
10740 sequences are recognized:
10744 insert a single percent character
10747 insert the value of the specified IPP attribute
10750 insert the number of copies for the current page
10753 insert the current page number
10756 insert the current date and time in common log format
10762 insert the printer name
10765 insert the username
10768 A value of the empty string disables page logging. The string @code{%p
10769 %u %j %T %P %C %@{job-billing@} %@{job-originating-host-name@}
10770 %@{job-name@} %@{media@} %@{sides@}} creates a page log with the
10773 Defaults to @samp{""}.
10776 @deftypevr {@code{cups-configuration} parameter} environment-variables environment-variables
10777 Passes the specified environment variable(s) to child processes; a list
10780 Defaults to @samp{()}.
10783 @deftypevr {@code{cups-configuration} parameter} policy-configuration-list policies
10784 Specifies named access control policies.
10786 Available @code{policy-configuration} fields are:
10788 @deftypevr {@code{policy-configuration} parameter} string name
10789 Name of the policy.
10792 @deftypevr {@code{policy-configuration} parameter} string job-private-access
10793 Specifies an access list for a job's private values. @code{@@ACL} maps
10794 to the printer's requesting-user-name-allowed or
10795 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10796 owner. @code{@@SYSTEM} maps to the groups listed for the
10797 @code{system-group} field of the @code{files-config} configuration,
10798 which is reified into the @code{cups-files.conf(5)} file. Other
10799 possible elements of the access list include specific user names, and
10800 @code{@@@var{group}} to indicate members of a specific group. The
10801 access list may also be simply @code{all} or @code{default}.
10803 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10806 @deftypevr {@code{policy-configuration} parameter} string job-private-values
10807 Specifies the list of job values to make private, or @code{all},
10808 @code{default}, or @code{none}.
10810 Defaults to @samp{"job-name job-originating-host-name
10811 job-originating-user-name phone"}.
10814 @deftypevr {@code{policy-configuration} parameter} string subscription-private-access
10815 Specifies an access list for a subscription's private values.
10816 @code{@@ACL} maps to the printer's requesting-user-name-allowed or
10817 requesting-user-name-denied values. @code{@@OWNER} maps to the job's
10818 owner. @code{@@SYSTEM} maps to the groups listed for the
10819 @code{system-group} field of the @code{files-config} configuration,
10820 which is reified into the @code{cups-files.conf(5)} file. Other
10821 possible elements of the access list include specific user names, and
10822 @code{@@@var{group}} to indicate members of a specific group. The
10823 access list may also be simply @code{all} or @code{default}.
10825 Defaults to @samp{"@@OWNER @@SYSTEM"}.
10828 @deftypevr {@code{policy-configuration} parameter} string subscription-private-values
10829 Specifies the list of job values to make private, or @code{all},
10830 @code{default}, or @code{none}.
10832 Defaults to @samp{"notify-events notify-pull-method notify-recipient-uri
10833 notify-subscriber-user-name notify-user-data"}.
10836 @deftypevr {@code{policy-configuration} parameter} operation-access-control-list access-controls
10837 Access control by IPP operation.
10839 Defaults to @samp{()}.
10843 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-files
10844 Specifies whether job files (documents) are preserved after a job is
10845 printed. If a numeric value is specified, job files are preserved for
10846 the indicated number of seconds after printing. Otherwise a boolean
10847 value applies indefinitely.
10849 Defaults to @samp{86400}.
10852 @deftypevr {@code{cups-configuration} parameter} boolean-or-non-negative-integer preserve-job-history
10853 Specifies whether the job history is preserved after a job is printed.
10854 If a numeric value is specified, the job history is preserved for the
10855 indicated number of seconds after printing. If @code{#t}, the job
10856 history is preserved until the MaxJobs limit is reached.
10858 Defaults to @samp{#t}.
10861 @deftypevr {@code{cups-configuration} parameter} non-negative-integer reload-timeout
10862 Specifies the amount of time to wait for job completion before
10863 restarting the scheduler.
10865 Defaults to @samp{30}.
10868 @deftypevr {@code{cups-configuration} parameter} string rip-cache
10869 Specifies the maximum amount of memory to use when converting documents
10870 into bitmaps for a printer.
10872 Defaults to @samp{"128m"}.
10875 @deftypevr {@code{cups-configuration} parameter} string server-admin
10876 Specifies the email address of the server administrator.
10878 Defaults to @samp{"root@@localhost.localdomain"}.
10881 @deftypevr {@code{cups-configuration} parameter} host-name-list-or-* server-alias
10882 The ServerAlias directive is used for HTTP Host header validation when
10883 clients connect to the scheduler from external interfaces. Using the
10884 special name @code{*} can expose your system to known browser-based DNS
10885 rebinding attacks, even when accessing sites through a firewall. If the
10886 auto-discovery of alternate names does not work, we recommend listing
10887 each alternate name with a ServerAlias directive instead of using
10890 Defaults to @samp{*}.
10893 @deftypevr {@code{cups-configuration} parameter} string server-name
10894 Specifies the fully-qualified host name of the server.
10896 Defaults to @samp{"localhost"}.
10899 @deftypevr {@code{cups-configuration} parameter} server-tokens server-tokens
10900 Specifies what information is included in the Server header of HTTP
10901 responses. @code{None} disables the Server header. @code{ProductOnly}
10902 reports @code{CUPS}. @code{Major} reports @code{CUPS 2}. @code{Minor}
10903 reports @code{CUPS 2.0}. @code{Minimal} reports @code{CUPS 2.0.0}.
10904 @code{OS} reports @code{CUPS 2.0.0 (@var{uname})} where @var{uname} is
10905 the output of the @code{uname} command. @code{Full} reports @code{CUPS
10906 2.0.0 (@var{uname}) IPP/2.0}.
10908 Defaults to @samp{Minimal}.
10911 @deftypevr {@code{cups-configuration} parameter} string set-env
10912 Set the specified environment variable to be passed to child processes.
10914 Defaults to @samp{"variable value"}.
10917 @deftypevr {@code{cups-configuration} parameter} multiline-string-list ssl-listen
10918 Listens on the specified interfaces for encrypted connections. Valid
10919 values are of the form @var{address}:@var{port}, where @var{address} is
10920 either an IPv6 address enclosed in brackets, an IPv4 address, or
10921 @code{*} to indicate all addresses.
10923 Defaults to @samp{()}.
10926 @deftypevr {@code{cups-configuration} parameter} ssl-options ssl-options
10927 Sets encryption options. By default, CUPS only supports encryption
10928 using TLS v1.0 or higher using known secure cipher suites. The
10929 @code{AllowRC4} option enables the 128-bit RC4 cipher suites, which are
10930 required for some older clients that do not implement newer ones. The
10931 @code{AllowSSL3} option enables SSL v3.0, which is required for some
10932 older clients that do not support TLS v1.0.
10934 Defaults to @samp{()}.
10937 @deftypevr {@code{cups-configuration} parameter} boolean strict-conformance?
10938 Specifies whether the scheduler requires clients to strictly adhere to
10939 the IPP specifications.
10941 Defaults to @samp{#f}.
10944 @deftypevr {@code{cups-configuration} parameter} non-negative-integer timeout
10945 Specifies the HTTP request timeout, in seconds.
10947 Defaults to @samp{300}.
10951 @deftypevr {@code{cups-configuration} parameter} boolean web-interface?
10952 Specifies whether the web interface is enabled.
10954 Defaults to @samp{#f}.
10957 At this point you're probably thinking ``oh dear, Guix manual, I like
10958 you but you can stop already with the configuration options''. Indeed.
10959 However, one more point: it could be that you have an existing
10960 @code{cupsd.conf} that you want to use. In that case, you can pass an
10961 @code{opaque-cups-configuration} as the configuration of a
10962 @code{cups-service-type}.
10964 Available @code{opaque-cups-configuration} fields are:
10966 @deftypevr {@code{opaque-cups-configuration} parameter} package cups
10970 @deftypevr {@code{opaque-cups-configuration} parameter} string cupsd.conf
10971 The contents of the @code{cupsd.conf}, as a string.
10974 @deftypevr {@code{opaque-cups-configuration} parameter} string cups-files.conf
10975 The contents of the @code{cups-files.conf} file, as a string.
10978 For example, if your @code{cupsd.conf} and @code{cups-files.conf} are in
10979 strings of the same name, you could instantiate a CUPS service like
10983 (service cups-service-type
10984 (opaque-cups-configuration
10985 (cupsd.conf cupsd.conf)
10986 (cups-files.conf cups-files.conf)))
10990 @node Desktop Services
10991 @subsubsection Desktop Services
10993 The @code{(gnu services desktop)} module provides services that are
10994 usually useful in the context of a ``desktop'' setup---that is, on a
10995 machine running a graphical display server, possibly with graphical user
10996 interfaces, etc. It also defines services that provide specific desktop
10997 environments like GNOME and XFCE.
10999 To simplify things, the module defines a variable containing the set of
11000 services that users typically expect on a machine with a graphical
11001 environment and networking:
11003 @defvr {Scheme Variable} %desktop-services
11004 This is a list of services that builds upon @var{%base-services} and
11005 adds or adjusts services for a typical ``desktop'' setup.
11007 In particular, it adds a graphical login manager (@pxref{X Window,
11008 @code{slim-service}}), screen lockers,
11009 a network management tool (@pxref{Networking
11010 Services, @code{wicd-service}}), energy and color management services,
11011 the @code{elogind} login and seat manager, the Polkit privilege service,
11012 the GeoClue location service, an NTP client (@pxref{Networking
11013 Services}), the Avahi daemon, and has the name service switch service
11014 configured to be able to use @code{nss-mdns} (@pxref{Name Service
11018 The @var{%desktop-services} variable can be used as the @code{services}
11019 field of an @code{operating-system} declaration (@pxref{operating-system
11020 Reference, @code{services}}).
11022 Additionally, the @code{gnome-desktop-service} and
11023 @code{xfce-desktop-service} procedures can add GNOME and/or XFCE to a
11024 system. To ``add GNOME'' means that system-level services like the
11025 backlight adjustment helpers and the power management utilities are
11026 added to the system, extending @code{polkit} and @code{dbus}
11027 appropriately, allowing GNOME to operate with elevated privileges on a
11028 limited number of special-purpose system interfaces. Additionally,
11029 adding a service made by @code{gnome-desktop-service} adds the GNOME
11030 metapackage to the system profile. Likewise, adding the XFCE service
11031 not only adds the @code{xfce} metapackage to the system profile, but it
11032 also gives the Thunar file manager the ability to open a ``root-mode''
11033 file management window, if the user authenticates using the
11034 administrator's password via the standard polkit graphical interface.
11036 @deffn {Scheme Procedure} gnome-desktop-service
11037 Return a service that adds the @code{gnome} package to the system
11038 profile, and extends polkit with the actions from
11039 @code{gnome-settings-daemon}.
11042 @deffn {Scheme Procedure} xfce-desktop-service
11043 Return a service that adds the @code{xfce} package to the system profile,
11044 and extends polkit with the ability for @code{thunar} to manipulate the
11045 file system as root from within a user session, after the user has
11046 authenticated with the administrator's password.
11049 Because the GNOME and XFCE desktop services pull in so many packages,
11050 the default @code{%desktop-services} variable doesn't include either of
11051 them by default. To add GNOME or XFCE, just @code{cons} them onto
11052 @code{%desktop-services} in the @code{services} field of your
11053 @code{operating-system}:
11056 (use-modules (gnu))
11057 (use-service-modules desktop)
11060 ;; cons* adds items to the list given as its last argument.
11061 (services (cons* (gnome-desktop-service)
11062 (xfce-desktop-service)
11063 %desktop-services))
11067 These desktop environments will then be available as options in the
11068 graphical login window.
11070 The actual service definitions included in @code{%desktop-services} and
11071 provided by @code{(gnu services dbus)} and @code{(gnu services desktop)}
11072 are described below.
11074 @deffn {Scheme Procedure} dbus-service [#:dbus @var{dbus}] [#:services '()]
11075 Return a service that runs the ``system bus'', using @var{dbus}, with
11076 support for @var{services}.
11078 @uref{http://dbus.freedesktop.org/, D-Bus} is an inter-process communication
11079 facility. Its system bus is used to allow system services to communicate
11080 and to be notified of system-wide events.
11082 @var{services} must be a list of packages that provide an
11083 @file{etc/dbus-1/system.d} directory containing additional D-Bus configuration
11084 and policy files. For example, to allow avahi-daemon to use the system bus,
11085 @var{services} must be equal to @code{(list avahi)}.
11088 @deffn {Scheme Procedure} elogind-service [#:config @var{config}]
11089 Return a service that runs the @code{elogind} login and
11090 seat management daemon. @uref{https://github.com/andywingo/elogind,
11091 Elogind} exposes a D-Bus interface that can be used to know which users
11092 are logged in, know what kind of sessions they have open, suspend the
11093 system, inhibit system suspend, reboot the system, and other tasks.
11095 Elogind handles most system-level power events for a computer, for
11096 example suspending the system when a lid is closed, or shutting it down
11097 when the power button is pressed.
11099 The @var{config} keyword argument specifies the configuration for
11100 elogind, and should be the result of an @code{(elogind-configuration
11101 (@var{parameter} @var{value})...)} invocation. Available parameters and
11102 their default values are:
11105 @item kill-user-processes?
11107 @item kill-only-users
11109 @item kill-exclude-users
11111 @item inhibit-delay-max-seconds
11113 @item handle-power-key
11115 @item handle-suspend-key
11117 @item handle-hibernate-key
11119 @item handle-lid-switch
11121 @item handle-lid-switch-docked
11123 @item power-key-ignore-inhibited?
11125 @item suspend-key-ignore-inhibited?
11127 @item hibernate-key-ignore-inhibited?
11129 @item lid-switch-ignore-inhibited?
11131 @item holdoff-timeout-seconds
11135 @item idle-action-seconds
11137 @item runtime-directory-size-percent
11139 @item runtime-directory-size
11143 @item suspend-state
11144 @code{("mem" "standby" "freeze")}
11147 @item hibernate-state
11149 @item hibernate-mode
11150 @code{("platform" "shutdown")}
11151 @item hybrid-sleep-state
11153 @item hybrid-sleep-mode
11154 @code{("suspend" "platform" "shutdown")}
11158 @deffn {Scheme Procedure} polkit-service @
11159 [#:polkit @var{polkit}]
11160 Return a service that runs the
11161 @uref{http://www.freedesktop.org/wiki/Software/polkit/, Polkit privilege
11162 management service}, which allows system administrators to grant access to
11163 privileged operations in a structured way. By querying the Polkit service, a
11164 privileged system component can know when it should grant additional
11165 capabilities to ordinary users. For example, an ordinary user can be granted
11166 the capability to suspend the system if the user is logged in locally.
11169 @deffn {Scheme Procedure} upower-service [#:upower @var{upower}] @
11170 [#:watts-up-pro? #f] @
11171 [#:poll-batteries? #t] @
11172 [#:ignore-lid? #f] @
11173 [#:use-percentage-for-policy? #f] @
11174 [#:percentage-low 10] @
11175 [#:percentage-critical 3] @
11176 [#:percentage-action 2] @
11177 [#:time-low 1200] @
11178 [#:time-critical 300] @
11179 [#:time-action 120] @
11180 [#:critical-power-action 'hybrid-sleep]
11181 Return a service that runs @uref{http://upower.freedesktop.org/,
11182 @command{upowerd}}, a system-wide monitor for power consumption and battery
11183 levels, with the given configuration settings. It implements the
11184 @code{org.freedesktop.UPower} D-Bus interface, and is notably used by
11188 @deffn {Scheme Procedure} udisks-service [#:udisks @var{udisks}]
11189 Return a service for @uref{http://udisks.freedesktop.org/docs/latest/,
11190 UDisks}, a @dfn{disk management} daemon that provides user interfaces with
11191 notifications and ways to mount/unmount disks. Programs that talk to UDisks
11192 include the @command{udisksctl} command, part of UDisks, and GNOME Disks.
11195 @deffn {Scheme Procedure} colord-service [#:colord @var{colord}]
11196 Return a service that runs @command{colord}, a system service with a D-Bus
11197 interface to manage the color profiles of input and output devices such as
11198 screens and scanners. It is notably used by the GNOME Color Manager graphical
11199 tool. See @uref{http://www.freedesktop.org/software/colord/, the colord web
11200 site} for more information.
11203 @deffn {Scheme Procedure} geoclue-application name [#:allowed? #t] [#:system? #f] [#:users '()]
11204 Return a configuration allowing an application to access GeoClue
11205 location data. @var{name} is the Desktop ID of the application, without
11206 the @code{.desktop} part. If @var{allowed?} is true, the application
11207 will have access to location information by default. The boolean
11208 @var{system?} value indicates whether an application is a system component
11209 or not. Finally @var{users} is a list of UIDs of all users for which
11210 this application is allowed location info access. An empty users list
11211 means that all users are allowed.
11214 @defvr {Scheme Variable} %standard-geoclue-applications
11215 The standard list of well-known GeoClue application configurations,
11216 granting authority to the GNOME date-and-time utility to ask for the
11217 current location in order to set the time zone, and allowing the
11218 IceCat and Epiphany web browsers to request location information.
11219 IceCat and Epiphany both query the user before allowing a web page to
11220 know the user's location.
11223 @deffn {Scheme Procedure} geoclue-service [#:colord @var{colord}] @
11224 [#:whitelist '()] @
11225 [#:wifi-geolocation-url "https://location.services.mozilla.com/v1/geolocate?key=geoclue"] @
11226 [#:submit-data? #f]
11227 [#:wifi-submission-url "https://location.services.mozilla.com/v1/submit?key=geoclue"] @
11228 [#:submission-nick "geoclue"] @
11229 [#:applications %standard-geoclue-applications]
11230 Return a service that runs the GeoClue location service. This service
11231 provides a D-Bus interface to allow applications to request access to a
11232 user's physical location, and optionally to add information to online
11233 location databases. See
11234 @uref{https://wiki.freedesktop.org/www/Software/GeoClue/, the GeoClue
11235 web site} for more information.
11238 @deffn {Scheme Procedure} bluetooth-service [#:bluez @var{bluez}]
11239 Return a service that runs the @command{bluetoothd} daemon, which manages
11240 all the Bluetooth devices and provides a number of D-Bus interfaces.
11242 Users need to be in the @code{lp} group to access the D-Bus service.
11245 @node Database Services
11246 @subsubsection Database Services
11250 The @code{(gnu services databases)} module provides the following services.
11252 @deffn {Scheme Procedure} postgresql-service [#:postgresql postgresql] @
11253 [#:config-file] [#:data-directory ``/var/lib/postgresql/data''] @
11254 [#:port 5432] [#:locale ``en_US.utf8'']
11255 Return a service that runs @var{postgresql}, the PostgreSQL database
11258 The PostgreSQL daemon loads its runtime configuration from @var{config-file},
11259 creates a database cluster with @var{locale} as the default
11260 locale, stored in @var{data-directory}. It then listens on @var{port}.
11263 @deffn {Scheme Procedure} mysql-service [#:config (mysql-configuration)]
11264 Return a service that runs @command{mysqld}, the MySQL or MariaDB
11267 The optional @var{config} argument specifies the configuration for
11268 @command{mysqld}, which should be a @code{<mysql-configuration>} object.
11271 @deftp {Data Type} mysql-configuration
11272 Data type representing the configuration of @var{mysql-service}.
11275 @item @code{mysql} (default: @var{mariadb})
11276 Package object of the MySQL database server, can be either @var{mariadb}
11279 For MySQL, a temporary root password will be displayed at activation time.
11280 For MariaDB, the root password is empty.
11282 @item @code{port} (default: @code{3306})
11283 TCP port on which the database server listens for incoming connections.
11287 @defvr {Scheme Variable} redis-service-type
11288 This is the service type for the @uref{https://redis.io/, Redis}
11289 key/value store, whose value is a @code{redis-configuration} object.
11292 @deftp {Data Type} redis-configuration
11293 Data type representing the configuration of redis.
11296 @item @code{redis} (default: @code{redis})
11297 The Redis package to use.
11299 @item @code{bind} (default: @code{"127.0.0.1"})
11300 Network interface on which to listen.
11302 @item @code{port} (default: @code{6379})
11303 Port on which to accept connections on, a value of 0 will disable
11304 listening on a TCP socket.
11306 @item @code{working-directory} (default: @code{"/var/lib/redis"})
11307 Directory in which to store the database and related files.
11311 @node Mail Services
11312 @subsubsection Mail Services
11316 The @code{(gnu services mail)} module provides Guix service definitions
11317 for email services: IMAP, POP3, and LMTP servers, as well as mail
11318 transport agents (MTAs). Lots of acronyms! These services are detailed
11319 in the subsections below.
11321 @subsubheading Dovecot Service
11323 @deffn {Scheme Procedure} dovecot-service [#:config (dovecot-configuration)]
11324 Return a service that runs the Dovecot IMAP/POP3/LMTP mail server.
11327 By default, Dovecot does not need much configuration; the default
11328 configuration object created by @code{(dovecot-configuration)} will
11329 suffice if your mail is delivered to @code{~/Maildir}. A self-signed
11330 certificate will be generated for TLS-protected connections, though
11331 Dovecot will also listen on cleartext ports by default. There are a
11332 number of options, though, which mail administrators might need to change,
11333 and as is the case with other services, Guix allows the system
11334 administrator to specify these parameters via a uniform Scheme interface.
11336 For example, to specify that mail is located at @code{maildir~/.mail},
11337 one would instantiate the Dovecot service like this:
11340 (dovecot-service #:config
11341 (dovecot-configuration
11342 (mail-location "maildir:~/.mail")))
11345 The available configuration parameters follow. Each parameter
11346 definition is preceded by its type; for example, @samp{string-list foo}
11347 indicates that the @code{foo} parameter should be specified as a list of
11348 strings. There is also a way to specify the configuration as a string,
11349 if you have an old @code{dovecot.conf} file that you want to port over
11350 from some other system; see the end for more details.
11352 @c The following documentation was initially generated by
11353 @c (generate-documentation) in (gnu services mail). Manually maintained
11354 @c documentation is better, so we shouldn't hesitate to edit below as
11355 @c needed. However if the change you want to make to this documentation
11356 @c can be done in an automated way, it's probably easier to change
11357 @c (generate-documentation) than to make it below and have to deal with
11358 @c the churn as dovecot updates.
11360 Available @code{dovecot-configuration} fields are:
11362 @deftypevr {@code{dovecot-configuration} parameter} package dovecot
11363 The dovecot package.
11366 @deftypevr {@code{dovecot-configuration} parameter} comma-separated-string-list listen
11367 A list of IPs or hosts where to listen for connections. @samp{*}
11368 listens on all IPv4 interfaces, @samp{::} listens on all IPv6
11369 interfaces. If you want to specify non-default ports or anything more
11370 complex, customize the address and port fields of the
11371 @samp{inet-listener} of the specific services you are interested in.
11374 @deftypevr {@code{dovecot-configuration} parameter} protocol-configuration-list protocols
11375 List of protocols we want to serve. Available protocols include
11376 @samp{imap}, @samp{pop3}, and @samp{lmtp}.
11378 Available @code{protocol-configuration} fields are:
11380 @deftypevr {@code{protocol-configuration} parameter} string name
11381 The name of the protocol.
11384 @deftypevr {@code{protocol-configuration} parameter} string auth-socket-path
11385 UNIX socket path to the master authentication server to find users.
11386 This is used by imap (for shared users) and lda.
11387 It defaults to @samp{"/var/run/dovecot/auth-userdb"}.
11390 @deftypevr {@code{protocol-configuration} parameter} space-separated-string-list mail-plugins
11391 Space separated list of plugins to load.
11394 @deftypevr {@code{protocol-configuration} parameter} non-negative-integer mail-max-userip-connections
11395 Maximum number of IMAP connections allowed for a user from each IP
11396 address. NOTE: The username is compared case-sensitively.
11397 Defaults to @samp{10}.
11402 @deftypevr {@code{dovecot-configuration} parameter} service-configuration-list services
11403 List of services to enable. Available services include @samp{imap},
11404 @samp{imap-login}, @samp{pop3}, @samp{pop3-login}, @samp{auth}, and
11407 Available @code{service-configuration} fields are:
11409 @deftypevr {@code{service-configuration} parameter} string kind
11410 The service kind. Valid values include @code{director},
11411 @code{imap-login}, @code{pop3-login}, @code{lmtp}, @code{imap},
11412 @code{pop3}, @code{auth}, @code{auth-worker}, @code{dict},
11413 @code{tcpwrap}, @code{quota-warning}, or anything else.
11416 @deftypevr {@code{service-configuration} parameter} listener-configuration-list listeners
11417 Listeners for the service. A listener is either a
11418 @code{unix-listener-configuration}, a @code{fifo-listener-configuration}, or
11419 an @code{inet-listener-configuration}.
11420 Defaults to @samp{()}.
11422 Available @code{unix-listener-configuration} fields are:
11424 @deftypevr {@code{unix-listener-configuration} parameter} string path
11425 Path to the file, relative to @code{base-dir} field. This is also used as
11429 @deftypevr {@code{unix-listener-configuration} parameter} string mode
11430 The access mode for the socket.
11431 Defaults to @samp{"0600"}.
11434 @deftypevr {@code{unix-listener-configuration} parameter} string user
11435 The user to own the socket.
11436 Defaults to @samp{""}.
11439 @deftypevr {@code{unix-listener-configuration} parameter} string group
11440 The group to own the socket.
11441 Defaults to @samp{""}.
11445 Available @code{fifo-listener-configuration} fields are:
11447 @deftypevr {@code{fifo-listener-configuration} parameter} string path
11448 Path to the file, relative to @code{base-dir} field. This is also used as
11452 @deftypevr {@code{fifo-listener-configuration} parameter} string mode
11453 The access mode for the socket.
11454 Defaults to @samp{"0600"}.
11457 @deftypevr {@code{fifo-listener-configuration} parameter} string user
11458 The user to own the socket.
11459 Defaults to @samp{""}.
11462 @deftypevr {@code{fifo-listener-configuration} parameter} string group
11463 The group to own the socket.
11464 Defaults to @samp{""}.
11468 Available @code{inet-listener-configuration} fields are:
11470 @deftypevr {@code{inet-listener-configuration} parameter} string protocol
11471 The protocol to listen for.
11474 @deftypevr {@code{inet-listener-configuration} parameter} string address
11475 The address on which to listen, or empty for all addresses.
11476 Defaults to @samp{""}.
11479 @deftypevr {@code{inet-listener-configuration} parameter} non-negative-integer port
11480 The port on which to listen.
11483 @deftypevr {@code{inet-listener-configuration} parameter} boolean ssl?
11484 Whether to use SSL for this service; @samp{yes}, @samp{no}, or
11486 Defaults to @samp{#t}.
11491 @deftypevr {@code{service-configuration} parameter} non-negative-integer service-count
11492 Number of connections to handle before starting a new process.
11493 Typically the only useful values are 0 (unlimited) or 1. 1 is more
11494 secure, but 0 is faster. <doc/wiki/LoginProcess.txt>.
11495 Defaults to @samp{1}.
11498 @deftypevr {@code{service-configuration} parameter} non-negative-integer process-min-avail
11499 Number of processes to always keep waiting for more connections.
11500 Defaults to @samp{0}.
11503 @deftypevr {@code{service-configuration} parameter} non-negative-integer vsz-limit
11504 If you set @samp{service-count 0}, you probably need to grow
11506 Defaults to @samp{256000000}.
11511 @deftypevr {@code{dovecot-configuration} parameter} dict-configuration dict
11512 Dict configuration, as created by the @code{dict-configuration}
11515 Available @code{dict-configuration} fields are:
11517 @deftypevr {@code{dict-configuration} parameter} free-form-fields entries
11518 A list of key-value pairs that this dict should hold.
11519 Defaults to @samp{()}.
11524 @deftypevr {@code{dovecot-configuration} parameter} passdb-configuration-list passdbs
11525 A list of passdb configurations, each one created by the
11526 @code{passdb-configuration} constructor.
11528 Available @code{passdb-configuration} fields are:
11530 @deftypevr {@code{passdb-configuration} parameter} string driver
11531 The driver that the passdb should use. Valid values include
11532 @samp{pam}, @samp{passwd}, @samp{shadow}, @samp{bsdauth}, and
11534 Defaults to @samp{"pam"}.
11537 @deftypevr {@code{passdb-configuration} parameter} space-separated-string-list args
11538 Space separated list of arguments to the passdb driver.
11539 Defaults to @samp{""}.
11544 @deftypevr {@code{dovecot-configuration} parameter} userdb-configuration-list userdbs
11545 List of userdb configurations, each one created by the
11546 @code{userdb-configuration} constructor.
11548 Available @code{userdb-configuration} fields are:
11550 @deftypevr {@code{userdb-configuration} parameter} string driver
11551 The driver that the userdb should use. Valid values include
11552 @samp{passwd} and @samp{static}.
11553 Defaults to @samp{"passwd"}.
11556 @deftypevr {@code{userdb-configuration} parameter} space-separated-string-list args
11557 Space separated list of arguments to the userdb driver.
11558 Defaults to @samp{""}.
11561 @deftypevr {@code{userdb-configuration} parameter} free-form-args override-fields
11562 Override fields from passwd.
11563 Defaults to @samp{()}.
11568 @deftypevr {@code{dovecot-configuration} parameter} plugin-configuration plugin-configuration
11569 Plug-in configuration, created by the @code{plugin-configuration}
11573 @deftypevr {@code{dovecot-configuration} parameter} list-of-namespace-configuration namespaces
11574 List of namespaces. Each item in the list is created by the
11575 @code{namespace-configuration} constructor.
11577 Available @code{namespace-configuration} fields are:
11579 @deftypevr {@code{namespace-configuration} parameter} string name
11580 Name for this namespace.
11583 @deftypevr {@code{namespace-configuration} parameter} string type
11584 Namespace type: @samp{private}, @samp{shared} or @samp{public}.
11585 Defaults to @samp{"private"}.
11588 @deftypevr {@code{namespace-configuration} parameter} string separator
11589 Hierarchy separator to use. You should use the same separator for
11590 all namespaces or some clients get confused. @samp{/} is usually a good
11591 one. The default however depends on the underlying mail storage
11593 Defaults to @samp{""}.
11596 @deftypevr {@code{namespace-configuration} parameter} string prefix
11597 Prefix required to access this namespace. This needs to be
11598 different for all namespaces. For example @samp{Public/}.
11599 Defaults to @samp{""}.
11602 @deftypevr {@code{namespace-configuration} parameter} string location
11603 Physical location of the mailbox. This is in the same format as
11604 mail_location, which is also the default for it.
11605 Defaults to @samp{""}.
11608 @deftypevr {@code{namespace-configuration} parameter} boolean inbox?
11609 There can be only one INBOX, and this setting defines which
11611 Defaults to @samp{#f}.
11614 @deftypevr {@code{namespace-configuration} parameter} boolean hidden?
11615 If namespace is hidden, it's not advertised to clients via NAMESPACE
11616 extension. You'll most likely also want to set @samp{list? #f}. This is mostly
11617 useful when converting from another server with different namespaces
11618 which you want to deprecate but still keep working. For example you can
11619 create hidden namespaces with prefixes @samp{~/mail/}, @samp{~%u/mail/}
11621 Defaults to @samp{#f}.
11624 @deftypevr {@code{namespace-configuration} parameter} boolean list?
11625 Show the mailboxes under this namespace with the LIST command. This
11626 makes the namespace visible for clients that do not support the NAMESPACE
11627 extension. The special @code{children} value lists child mailboxes, but
11628 hides the namespace prefix.
11629 Defaults to @samp{#t}.
11632 @deftypevr {@code{namespace-configuration} parameter} boolean subscriptions?
11633 Namespace handles its own subscriptions. If set to @code{#f}, the
11634 parent namespace handles them. The empty prefix should always have this
11636 Defaults to @samp{#t}.
11639 @deftypevr {@code{namespace-configuration} parameter} mailbox-configuration-list mailboxes
11640 List of predefined mailboxes in this namespace.
11641 Defaults to @samp{()}.
11643 Available @code{mailbox-configuration} fields are:
11645 @deftypevr {@code{mailbox-configuration} parameter} string name
11646 Name for this mailbox.
11649 @deftypevr {@code{mailbox-configuration} parameter} string auto
11650 @samp{create} will automatically create this mailbox.
11651 @samp{subscribe} will both create and subscribe to the mailbox.
11652 Defaults to @samp{"no"}.
11655 @deftypevr {@code{mailbox-configuration} parameter} space-separated-string-list special-use
11656 List of IMAP @code{SPECIAL-USE} attributes as specified by RFC 6154.
11657 Valid values are @code{\All}, @code{\Archive}, @code{\Drafts},
11658 @code{\Flagged}, @code{\Junk}, @code{\Sent}, and @code{\Trash}.
11659 Defaults to @samp{()}.
11666 @deftypevr {@code{dovecot-configuration} parameter} file-name base-dir
11667 Base directory where to store runtime data.
11668 Defaults to @samp{"/var/run/dovecot/"}.
11671 @deftypevr {@code{dovecot-configuration} parameter} string login-greeting
11672 Greeting message for clients.
11673 Defaults to @samp{"Dovecot ready."}.
11676 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-trusted-networks
11677 List of trusted network ranges. Connections from these IPs are
11678 allowed to override their IP addresses and ports (for logging and for
11679 authentication checks). @samp{disable-plaintext-auth} is also ignored
11680 for these networks. Typically you would specify your IMAP proxy servers
11682 Defaults to @samp{()}.
11685 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-access-sockets
11686 List of login access check sockets (e.g. tcpwrap).
11687 Defaults to @samp{()}.
11690 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-proctitle?
11691 Show more verbose process titles (in ps). Currently shows user name
11692 and IP address. Useful for seeing who is actually using the IMAP
11693 processes (e.g. shared mailboxes or if the same uid is used for multiple
11695 Defaults to @samp{#f}.
11698 @deftypevr {@code{dovecot-configuration} parameter} boolean shutdown-clients?
11699 Should all processes be killed when Dovecot master process shuts down.
11700 Setting this to @code{#f} means that Dovecot can be upgraded without
11701 forcing existing client connections to close (although that could also
11702 be a problem if the upgrade is e.g. due to a security fix).
11703 Defaults to @samp{#t}.
11706 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer doveadm-worker-count
11707 If non-zero, run mail commands via this many connections to doveadm
11708 server, instead of running them directly in the same process.
11709 Defaults to @samp{0}.
11712 @deftypevr {@code{dovecot-configuration} parameter} string doveadm-socket-path
11713 UNIX socket or host:port used for connecting to doveadm server.
11714 Defaults to @samp{"doveadm-server"}.
11717 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list import-environment
11718 List of environment variables that are preserved on Dovecot startup
11719 and passed down to all of its child processes. You can also give
11720 key=value pairs to always set specific settings.
11723 @deftypevr {@code{dovecot-configuration} parameter} boolean disable-plaintext-auth?
11724 Disable LOGIN command and all other plaintext authentications unless
11725 SSL/TLS is used (LOGINDISABLED capability). Note that if the remote IP
11726 matches the local IP (i.e. you're connecting from the same computer),
11727 the connection is considered secure and plaintext authentication is
11728 allowed. See also ssl=required setting.
11729 Defaults to @samp{#t}.
11732 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-cache-size
11733 Authentication cache size (e.g. @samp{#e10e6}). 0 means it's disabled.
11734 Note that bsdauth, PAM and vpopmail require @samp{cache-key} to be set
11735 for caching to be used.
11736 Defaults to @samp{0}.
11739 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-ttl
11740 Time to live for cached data. After TTL expires the cached record
11741 is no longer used, *except* if the main database lookup returns internal
11742 failure. We also try to handle password changes automatically: If
11743 user's previous authentication was successful, but this one wasn't, the
11744 cache isn't used. For now this works only with plaintext
11746 Defaults to @samp{"1 hour"}.
11749 @deftypevr {@code{dovecot-configuration} parameter} string auth-cache-negative-ttl
11750 TTL for negative hits (user not found, password mismatch).
11751 0 disables caching them completely.
11752 Defaults to @samp{"1 hour"}.
11755 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-realms
11756 List of realms for SASL authentication mechanisms that need them.
11757 You can leave it empty if you don't want to support multiple realms.
11758 Many clients simply use the first one listed here, so keep the default
11760 Defaults to @samp{()}.
11763 @deftypevr {@code{dovecot-configuration} parameter} string auth-default-realm
11764 Default realm/domain to use if none was specified. This is used for
11765 both SASL realms and appending @@domain to username in plaintext
11767 Defaults to @samp{""}.
11770 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-chars
11771 List of allowed characters in username. If the user-given username
11772 contains a character not listed in here, the login automatically fails.
11773 This is just an extra check to make sure user can't exploit any
11774 potential quote escaping vulnerabilities with SQL/LDAP databases. If
11775 you want to allow all characters, set this value to empty.
11776 Defaults to @samp{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@@"}.
11779 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-translation
11780 Username character translations before it's looked up from
11781 databases. The value contains series of from -> to characters. For
11782 example @samp{#@@/@@} means that @samp{#} and @samp{/} characters are
11783 translated to @samp{@@}.
11784 Defaults to @samp{""}.
11787 @deftypevr {@code{dovecot-configuration} parameter} string auth-username-format
11788 Username formatting before it's looked up from databases. You can
11789 use the standard variables here, e.g. %Lu would lowercase the username,
11790 %n would drop away the domain if it was given, or @samp{%n-AT-%d} would
11791 change the @samp{@@} into @samp{-AT-}. This translation is done after
11792 @samp{auth-username-translation} changes.
11793 Defaults to @samp{"%Lu"}.
11796 @deftypevr {@code{dovecot-configuration} parameter} string auth-master-user-separator
11797 If you want to allow master users to log in by specifying the master
11798 username within the normal username string (i.e. not using SASL
11799 mechanism's support for it), you can specify the separator character
11800 here. The format is then <username><separator><master username>.
11801 UW-IMAP uses @samp{*} as the separator, so that could be a good
11803 Defaults to @samp{""}.
11806 @deftypevr {@code{dovecot-configuration} parameter} string auth-anonymous-username
11807 Username to use for users logging in with ANONYMOUS SASL
11809 Defaults to @samp{"anonymous"}.
11812 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer auth-worker-max-count
11813 Maximum number of dovecot-auth worker processes. They're used to
11814 execute blocking passdb and userdb queries (e.g. MySQL and PAM).
11815 They're automatically created and destroyed as needed.
11816 Defaults to @samp{30}.
11819 @deftypevr {@code{dovecot-configuration} parameter} string auth-gssapi-hostname
11820 Host name to use in GSSAPI principal names. The default is to use
11821 the name returned by gethostname(). Use @samp{$ALL} (with quotes) to
11822 allow all keytab entries.
11823 Defaults to @samp{""}.
11826 @deftypevr {@code{dovecot-configuration} parameter} string auth-krb5-keytab
11827 Kerberos keytab to use for the GSSAPI mechanism. Will use the
11828 system default (usually @file{/etc/krb5.keytab}) if not specified. You may
11829 need to change the auth service to run as root to be able to read this
11831 Defaults to @samp{""}.
11834 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-use-winbind?
11835 Do NTLM and GSS-SPNEGO authentication using Samba's winbind daemon
11836 and @samp{ntlm-auth} helper.
11837 <doc/wiki/Authentication/Mechanisms/Winbind.txt>.
11838 Defaults to @samp{#f}.
11841 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-winbind-helper-path
11842 Path for Samba's @samp{ntlm-auth} helper binary.
11843 Defaults to @samp{"/usr/bin/ntlm_auth"}.
11846 @deftypevr {@code{dovecot-configuration} parameter} string auth-failure-delay
11847 Time to delay before replying to failed authentications.
11848 Defaults to @samp{"2 secs"}.
11851 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-require-client-cert?
11852 Require a valid SSL client certificate or the authentication
11854 Defaults to @samp{#f}.
11857 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-ssl-username-from-cert?
11858 Take the username from client's SSL certificate, using
11859 @code{X509_NAME_get_text_by_NID()} which returns the subject's DN's
11861 Defaults to @samp{#f}.
11864 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list auth-mechanisms
11865 List of wanted authentication mechanisms. Supported mechanisms are:
11866 @samp{plain}, @samp{login}, @samp{digest-md5}, @samp{cram-md5},
11867 @samp{ntlm}, @samp{rpa}, @samp{apop}, @samp{anonymous}, @samp{gssapi},
11868 @samp{otp}, @samp{skey}, and @samp{gss-spnego}. NOTE: See also
11869 @samp{disable-plaintext-auth} setting.
11872 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-servers
11873 List of IPs or hostnames to all director servers, including ourself.
11874 Ports can be specified as ip:port. The default port is the same as what
11875 director service's @samp{inet-listener} is using.
11876 Defaults to @samp{()}.
11879 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list director-mail-servers
11880 List of IPs or hostnames to all backend mail servers. Ranges are
11881 allowed too, like 10.0.0.10-10.0.0.30.
11882 Defaults to @samp{()}.
11885 @deftypevr {@code{dovecot-configuration} parameter} string director-user-expire
11886 How long to redirect users to a specific server after it no longer
11887 has any connections.
11888 Defaults to @samp{"15 min"}.
11891 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer director-doveadm-port
11892 TCP/IP port that accepts doveadm connections (instead of director
11893 connections) If you enable this, you'll also need to add
11894 @samp{inet-listener} for the port.
11895 Defaults to @samp{0}.
11898 @deftypevr {@code{dovecot-configuration} parameter} string director-username-hash
11899 How the username is translated before being hashed. Useful values
11900 include %Ln if user can log in with or without @@domain, %Ld if mailboxes
11901 are shared within domain.
11902 Defaults to @samp{"%Lu"}.
11905 @deftypevr {@code{dovecot-configuration} parameter} string log-path
11906 Log file to use for error messages. @samp{syslog} logs to syslog,
11907 @samp{/dev/stderr} logs to stderr.
11908 Defaults to @samp{"syslog"}.
11911 @deftypevr {@code{dovecot-configuration} parameter} string info-log-path
11912 Log file to use for informational messages. Defaults to
11914 Defaults to @samp{""}.
11917 @deftypevr {@code{dovecot-configuration} parameter} string debug-log-path
11918 Log file to use for debug messages. Defaults to
11919 @samp{info-log-path}.
11920 Defaults to @samp{""}.
11923 @deftypevr {@code{dovecot-configuration} parameter} string syslog-facility
11924 Syslog facility to use if you're logging to syslog. Usually if you
11925 don't want to use @samp{mail}, you'll use local0..local7. Also other
11926 standard facilities are supported.
11927 Defaults to @samp{"mail"}.
11930 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose?
11931 Log unsuccessful authentication attempts and the reasons why they
11933 Defaults to @samp{#f}.
11936 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-verbose-passwords?
11937 In case of password mismatches, log the attempted password. Valid
11938 values are no, plain and sha1. sha1 can be useful for detecting brute
11939 force password attempts vs. user simply trying the same password over
11940 and over again. You can also truncate the value to n chars by appending
11941 ":n" (e.g. sha1:6).
11942 Defaults to @samp{#f}.
11945 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug?
11946 Even more verbose logging for debugging purposes. Shows for example
11948 Defaults to @samp{#f}.
11951 @deftypevr {@code{dovecot-configuration} parameter} boolean auth-debug-passwords?
11952 In case of password mismatches, log the passwords and used scheme so
11953 the problem can be debugged. Enabling this also enables
11955 Defaults to @samp{#f}.
11958 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-debug?
11959 Enable mail process debugging. This can help you figure out why
11960 Dovecot isn't finding your mails.
11961 Defaults to @samp{#f}.
11964 @deftypevr {@code{dovecot-configuration} parameter} boolean verbose-ssl?
11965 Show protocol level SSL errors.
11966 Defaults to @samp{#f}.
11969 @deftypevr {@code{dovecot-configuration} parameter} string log-timestamp
11970 Prefix for each line written to log file. % codes are in
11971 strftime(3) format.
11972 Defaults to @samp{"\"%b %d %H:%M:%S \""}.
11975 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list login-log-format-elements
11976 List of elements we want to log. The elements which have a
11977 non-empty variable value are joined together to form a comma-separated
11981 @deftypevr {@code{dovecot-configuration} parameter} string login-log-format
11982 Login log format. %s contains @samp{login-log-format-elements}
11983 string, %$ contains the data we want to log.
11984 Defaults to @samp{"%$: %s"}.
11987 @deftypevr {@code{dovecot-configuration} parameter} string mail-log-prefix
11988 Log prefix for mail processes. See doc/wiki/Variables.txt for list
11989 of possible variables you can use.
11990 Defaults to @samp{"\"%s(%u): \""}.
11993 @deftypevr {@code{dovecot-configuration} parameter} string deliver-log-format
11994 Format to use for logging mail deliveries. You can use variables:
11997 Delivery status message (e.g. @samp{saved to INBOX})
12009 Defaults to @samp{"msgid=%m: %$"}.
12012 @deftypevr {@code{dovecot-configuration} parameter} string mail-location
12013 Location for users' mailboxes. The default is empty, which means
12014 that Dovecot tries to find the mailboxes automatically. This won't work
12015 if the user doesn't yet have any mail, so you should explicitly tell
12016 Dovecot the full location.
12018 If you're using mbox, giving a path to the INBOX
12019 file (e.g. /var/mail/%u) isn't enough. You'll also need to tell Dovecot
12020 where the other mailboxes are kept. This is called the "root mail
12021 directory", and it must be the first path given in the
12022 @samp{mail-location} setting.
12024 There are a few special variables you can use, eg.:
12030 user part in user@@domain, same as %u if there's no domain
12032 domain part in user@@domain, empty if there's no domain
12037 See doc/wiki/Variables.txt for full list. Some examples:
12039 @item maildir:~/Maildir
12040 @item mbox:~/mail:INBOX=/var/mail/%u
12041 @item mbox:/var/mail/%d/%1n/%n:INDEX=/var/indexes/%d/%1n/%
12043 Defaults to @samp{""}.
12046 @deftypevr {@code{dovecot-configuration} parameter} string mail-uid
12047 System user and group used to access mails. If you use multiple,
12048 userdb can override these by returning uid or gid fields. You can use
12049 either numbers or names. <doc/wiki/UserIds.txt>.
12050 Defaults to @samp{""}.
12053 @deftypevr {@code{dovecot-configuration} parameter} string mail-gid
12055 Defaults to @samp{""}.
12058 @deftypevr {@code{dovecot-configuration} parameter} string mail-privileged-group
12059 Group to enable temporarily for privileged operations. Currently
12060 this is used only with INBOX when either its initial creation or
12061 dotlocking fails. Typically this is set to "mail" to give access to
12063 Defaults to @samp{""}.
12066 @deftypevr {@code{dovecot-configuration} parameter} string mail-access-groups
12067 Grant access to these supplementary groups for mail processes.
12068 Typically these are used to set up access to shared mailboxes. Note
12069 that it may be dangerous to set these if users can create
12070 symlinks (e.g. if "mail" group is set here, ln -s /var/mail ~/mail/var
12071 could allow a user to delete others' mailboxes, or ln -s
12072 /secret/shared/box ~/mail/mybox would allow reading it).
12073 Defaults to @samp{""}.
12076 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-full-filesystem-access?
12077 Allow full file system access to clients. There's no access checks
12078 other than what the operating system does for the active UID/GID. It
12079 works with both maildir and mboxes, allowing you to prefix mailboxes
12080 names with e.g. /path/ or ~user/.
12081 Defaults to @samp{#f}.
12084 @deftypevr {@code{dovecot-configuration} parameter} boolean mmap-disable?
12085 Don't use mmap() at all. This is required if you store indexes to
12086 shared file systems (NFS or clustered file system).
12087 Defaults to @samp{#f}.
12090 @deftypevr {@code{dovecot-configuration} parameter} boolean dotlock-use-excl?
12091 Rely on @samp{O_EXCL} to work when creating dotlock files. NFS
12092 supports @samp{O_EXCL} since version 3, so this should be safe to use
12093 nowadays by default.
12094 Defaults to @samp{#t}.
12097 @deftypevr {@code{dovecot-configuration} parameter} string mail-fsync
12098 When to use fsync() or fdatasync() calls:
12101 Whenever necessary to avoid losing important data
12103 Useful with e.g. NFS when write()s are delayed
12105 Never use it (best performance, but crashes can lose data).
12107 Defaults to @samp{"optimized"}.
12110 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-storage?
12111 Mail storage exists in NFS. Set this to yes to make Dovecot flush
12112 NFS caches whenever needed. If you're using only a single mail server
12114 Defaults to @samp{#f}.
12117 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-nfs-index?
12118 Mail index files also exist in NFS. Setting this to yes requires
12119 @samp{mmap-disable? #t} and @samp{fsync-disable? #f}.
12120 Defaults to @samp{#f}.
12123 @deftypevr {@code{dovecot-configuration} parameter} string lock-method
12124 Locking method for index files. Alternatives are fcntl, flock and
12125 dotlock. Dotlocking uses some tricks which may create more disk I/O
12126 than other locking methods. NFS users: flock doesn't work, remember to
12127 change @samp{mmap-disable}.
12128 Defaults to @samp{"fcntl"}.
12131 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-temp-dir
12132 Directory in which LDA/LMTP temporarily stores incoming mails >128
12134 Defaults to @samp{"/tmp"}.
12137 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-uid
12138 Valid UID range for users. This is mostly to make sure that users can't
12139 log in as daemons or other system users. Note that denying root logins is
12140 hardcoded to dovecot binary and can't be done even if @samp{first-valid-uid}
12142 Defaults to @samp{500}.
12145 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-uid
12147 Defaults to @samp{0}.
12150 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer first-valid-gid
12151 Valid GID range for users. Users having non-valid GID as primary group ID
12152 aren't allowed to log in. If user belongs to supplementary groups with
12153 non-valid GIDs, those groups are not set.
12154 Defaults to @samp{1}.
12157 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer last-valid-gid
12159 Defaults to @samp{0}.
12162 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-max-keyword-length
12163 Maximum allowed length for mail keyword name. It's only forced when
12164 trying to create new keywords.
12165 Defaults to @samp{50}.
12168 @deftypevr {@code{dovecot-configuration} parameter} colon-separated-file-name-list valid-chroot-dirs
12169 List of directories under which chrooting is allowed for mail
12170 processes (i.e. /var/mail will allow chrooting to /var/mail/foo/bar
12171 too). This setting doesn't affect @samp{login-chroot}
12172 @samp{mail-chroot} or auth chroot settings. If this setting is empty,
12173 "/./" in home dirs are ignored. WARNING: Never add directories here
12174 which local users can modify, that may lead to root exploit. Usually
12175 this should be done only if you don't allow shell access for users.
12176 <doc/wiki/Chrooting.txt>.
12177 Defaults to @samp{()}.
12180 @deftypevr {@code{dovecot-configuration} parameter} string mail-chroot
12181 Default chroot directory for mail processes. This can be overridden
12182 for specific users in user database by giving /./ in user's home
12183 directory (e.g. /home/./user chroots into /home). Note that usually
12184 there is no real need to do chrooting, Dovecot doesn't allow users to
12185 access files outside their mail directory anyway. If your home
12186 directories are prefixed with the chroot directory, append "/." to
12187 @samp{mail-chroot}. <doc/wiki/Chrooting.txt>.
12188 Defaults to @samp{""}.
12191 @deftypevr {@code{dovecot-configuration} parameter} file-name auth-socket-path
12192 UNIX socket path to master authentication server to find users.
12193 This is used by imap (for shared users) and lda.
12194 Defaults to @samp{"/var/run/dovecot/auth-userdb"}.
12197 @deftypevr {@code{dovecot-configuration} parameter} file-name mail-plugin-dir
12198 Directory where to look up mail plugins.
12199 Defaults to @samp{"/usr/lib/dovecot"}.
12202 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mail-plugins
12203 List of plugins to load for all services. Plugins specific to IMAP,
12204 LDA, etc. are added to this list in their own .conf files.
12205 Defaults to @samp{()}.
12208 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-cache-min-mail-count
12209 The minimum number of mails in a mailbox before updates are done to
12210 cache file. This allows optimizing Dovecot's behavior to do less disk
12211 writes at the cost of more disk reads.
12212 Defaults to @samp{0}.
12215 @deftypevr {@code{dovecot-configuration} parameter} string mailbox-idle-check-interval
12216 When IDLE command is running, mailbox is checked once in a while to
12217 see if there are any new mails or other changes. This setting defines
12218 the minimum time to wait between those checks. Dovecot can also use
12219 dnotify, inotify and kqueue to find out immediately when changes
12221 Defaults to @samp{"30 secs"}.
12224 @deftypevr {@code{dovecot-configuration} parameter} boolean mail-save-crlf?
12225 Save mails with CR+LF instead of plain LF. This makes sending those
12226 mails take less CPU, especially with sendfile() syscall with Linux and
12227 FreeBSD. But it also creates a bit more disk I/O which may just make it
12228 slower. Also note that if other software reads the mboxes/maildirs,
12229 they may handle the extra CRs wrong and cause problems.
12230 Defaults to @samp{#f}.
12233 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-stat-dirs?
12234 By default LIST command returns all entries in maildir beginning
12235 with a dot. Enabling this option makes Dovecot return only entries
12236 which are directories. This is done by stat()ing each entry, so it
12237 causes more disk I/O.
12238 (For systems setting struct @samp{dirent->d_type} this check is free
12239 and it's done always regardless of this setting).
12240 Defaults to @samp{#f}.
12243 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-copy-with-hardlinks?
12244 When copying a message, do it with hard links whenever possible.
12245 This makes the performance much better, and it's unlikely to have any
12247 Defaults to @samp{#t}.
12250 @deftypevr {@code{dovecot-configuration} parameter} boolean maildir-very-dirty-syncs?
12251 Assume Dovecot is the only MUA accessing Maildir: Scan cur/
12252 directory only when its mtime changes unexpectedly or when we can't find
12253 the mail otherwise.
12254 Defaults to @samp{#f}.
12257 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-read-locks
12258 Which locking methods to use for locking mbox. There are four
12263 Create <mailbox>.lock file. This is the oldest and most NFS-safe
12264 solution. If you want to use /var/mail/ like directory, the users will
12265 need write access to that directory.
12267 Same as dotlock, but if it fails because of permissions or because there
12268 isn't enough disk space, just skip it.
12270 Use this if possible. Works with NFS too if lockd is used.
12272 May not exist in all systems. Doesn't work with NFS.
12274 May not exist in all systems. Doesn't work with NFS.
12277 You can use multiple locking methods; if you do the order they're declared
12278 in is important to avoid deadlocks if other MTAs/MUAs are using multiple
12279 locking methods as well. Some operating systems don't allow using some of
12280 them simultaneously.
12283 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list mbox-write-locks
12287 @deftypevr {@code{dovecot-configuration} parameter} string mbox-lock-timeout
12288 Maximum time to wait for lock (all of them) before aborting.
12289 Defaults to @samp{"5 mins"}.
12292 @deftypevr {@code{dovecot-configuration} parameter} string mbox-dotlock-change-timeout
12293 If dotlock exists but the mailbox isn't modified in any way,
12294 override the lock file after this much time.
12295 Defaults to @samp{"2 mins"}.
12298 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-dirty-syncs?
12299 When mbox changes unexpectedly we have to fully read it to find out
12300 what changed. If the mbox is large this can take a long time. Since
12301 the change is usually just a newly appended mail, it'd be faster to
12302 simply read the new mails. If this setting is enabled, Dovecot does
12303 this but still safely fallbacks to re-reading the whole mbox file
12304 whenever something in mbox isn't how it's expected to be. The only real
12305 downside to this setting is that if some other MUA changes message
12306 flags, Dovecot doesn't notice it immediately. Note that a full sync is
12307 done with SELECT, EXAMINE, EXPUNGE and CHECK commands.
12308 Defaults to @samp{#t}.
12311 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-very-dirty-syncs?
12312 Like @samp{mbox-dirty-syncs}, but don't do full syncs even with SELECT,
12313 EXAMINE, EXPUNGE or CHECK commands. If this is set,
12314 @samp{mbox-dirty-syncs} is ignored.
12315 Defaults to @samp{#f}.
12318 @deftypevr {@code{dovecot-configuration} parameter} boolean mbox-lazy-writes?
12319 Delay writing mbox headers until doing a full write sync (EXPUNGE
12320 and CHECK commands and when closing the mailbox). This is especially
12321 useful for POP3 where clients often delete all mails. The downside is
12322 that our changes aren't immediately visible to other MUAs.
12323 Defaults to @samp{#t}.
12326 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mbox-min-index-size
12327 If mbox size is smaller than this (e.g. 100k), don't write index
12328 files. If an index file already exists it's still read, just not
12330 Defaults to @samp{0}.
12333 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mdbox-rotate-size
12334 Maximum dbox file size until it's rotated.
12335 Defaults to @samp{2000000}.
12338 @deftypevr {@code{dovecot-configuration} parameter} string mdbox-rotate-interval
12339 Maximum dbox file age until it's rotated. Typically in days. Day
12340 begins from midnight, so 1d = today, 2d = yesterday, etc. 0 = check
12342 Defaults to @samp{"1d"}.
12345 @deftypevr {@code{dovecot-configuration} parameter} boolean mdbox-preallocate-space?
12346 When creating new mdbox files, immediately preallocate their size to
12347 @samp{mdbox-rotate-size}. This setting currently works only in Linux
12348 with some file systems (ext4, xfs).
12349 Defaults to @samp{#f}.
12352 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-dir
12353 sdbox and mdbox support saving mail attachments to external files,
12354 which also allows single instance storage for them. Other backends
12355 don't support this for now.
12357 WARNING: This feature hasn't been tested much yet. Use at your own risk.
12359 Directory root where to store mail attachments. Disabled, if empty.
12360 Defaults to @samp{""}.
12363 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer mail-attachment-min-size
12364 Attachments smaller than this aren't saved externally. It's also
12365 possible to write a plugin to disable saving specific attachments
12367 Defaults to @samp{128000}.
12370 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-fs
12371 File system backend to use for saving attachments:
12374 No SiS done by Dovecot (but this might help FS's own deduplication)
12376 SiS with immediate byte-by-byte comparison during saving
12377 @item sis-queue posix
12378 SiS with delayed comparison and deduplication.
12380 Defaults to @samp{"sis posix"}.
12383 @deftypevr {@code{dovecot-configuration} parameter} string mail-attachment-hash
12384 Hash format to use in attachment filenames. You can add any text and
12385 variables: @code{%@{md4@}}, @code{%@{md5@}}, @code{%@{sha1@}},
12386 @code{%@{sha256@}}, @code{%@{sha512@}}, @code{%@{size@}}. Variables can be
12387 truncated, e.g. @code{%@{sha256:80@}} returns only first 80 bits.
12388 Defaults to @samp{"%@{sha1@}"}.
12391 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-process-limit
12393 Defaults to @samp{100}.
12396 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-client-limit
12398 Defaults to @samp{1000}.
12401 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer default-vsz-limit
12402 Default VSZ (virtual memory size) limit for service processes.
12403 This is mainly intended to catch and kill processes that leak memory
12404 before they eat up everything.
12405 Defaults to @samp{256000000}.
12408 @deftypevr {@code{dovecot-configuration} parameter} string default-login-user
12409 Login user is internally used by login processes. This is the most
12410 untrusted user in Dovecot system. It shouldn't have access to anything
12412 Defaults to @samp{"dovenull"}.
12415 @deftypevr {@code{dovecot-configuration} parameter} string default-internal-user
12416 Internal user is used by unprivileged processes. It should be
12417 separate from login user, so that login processes can't disturb other
12419 Defaults to @samp{"dovecot"}.
12422 @deftypevr {@code{dovecot-configuration} parameter} string ssl?
12423 SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>.
12424 Defaults to @samp{"required"}.
12427 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert
12428 PEM encoded X.509 SSL/TLS certificate (public key).
12429 Defaults to @samp{"</etc/dovecot/default.pem"}.
12432 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key
12433 PEM encoded SSL/TLS private key. The key is opened before
12434 dropping root privileges, so keep the key file unreadable by anyone but
12436 Defaults to @samp{"</etc/dovecot/private/default.pem"}.
12439 @deftypevr {@code{dovecot-configuration} parameter} string ssl-key-password
12440 If key file is password protected, give the password here.
12441 Alternatively give it when starting dovecot with -p parameter. Since
12442 this file is often world-readable, you may want to place this setting
12443 instead to a different.
12444 Defaults to @samp{""}.
12447 @deftypevr {@code{dovecot-configuration} parameter} string ssl-ca
12448 PEM encoded trusted certificate authority. Set this only if you
12449 intend to use @samp{ssl-verify-client-cert? #t}. The file should
12450 contain the CA certificate(s) followed by the matching
12451 CRL(s). (e.g. @samp{ssl-ca </etc/ssl/certs/ca.pem}).
12452 Defaults to @samp{""}.
12455 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-require-crl?
12456 Require that CRL check succeeds for client certificates.
12457 Defaults to @samp{#t}.
12460 @deftypevr {@code{dovecot-configuration} parameter} boolean ssl-verify-client-cert?
12461 Request client to send a certificate. If you also want to require
12462 it, set @samp{auth-ssl-require-client-cert? #t} in auth section.
12463 Defaults to @samp{#f}.
12466 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cert-username-field
12467 Which field from certificate to use for username. commonName and
12468 x500UniqueIdentifier are the usual choices. You'll also need to set
12469 @samp{auth-ssl-username-from-cert? #t}.
12470 Defaults to @samp{"commonName"}.
12473 @deftypevr {@code{dovecot-configuration} parameter} hours ssl-parameters-regenerate
12474 How often to regenerate the SSL parameters file. Generation is
12475 quite CPU intensive operation. The value is in hours, 0 disables
12476 regeneration entirely.
12477 Defaults to @samp{168}.
12480 @deftypevr {@code{dovecot-configuration} parameter} string ssl-protocols
12481 SSL protocols to use.
12482 Defaults to @samp{"!SSLv2"}.
12485 @deftypevr {@code{dovecot-configuration} parameter} string ssl-cipher-list
12486 SSL ciphers to use.
12487 Defaults to @samp{"ALL:!LOW:!SSLv2:!EXP:!aNULL"}.
12490 @deftypevr {@code{dovecot-configuration} parameter} string ssl-crypto-device
12491 SSL crypto device to use, for valid values run "openssl engine".
12492 Defaults to @samp{""}.
12495 @deftypevr {@code{dovecot-configuration} parameter} string postmaster-address
12496 Address to use when sending rejection mails.
12497 %d expands to recipient domain.
12498 Defaults to @samp{"postmaster@@%d"}.
12501 @deftypevr {@code{dovecot-configuration} parameter} string hostname
12502 Hostname to use in various parts of sent mails (e.g. in Message-Id)
12503 and in LMTP replies. Default is the system's real hostname@@domain.
12504 Defaults to @samp{""}.
12507 @deftypevr {@code{dovecot-configuration} parameter} boolean quota-full-tempfail?
12508 If user is over quota, return with temporary failure instead of
12510 Defaults to @samp{#f}.
12513 @deftypevr {@code{dovecot-configuration} parameter} file-name sendmail-path
12514 Binary to use for sending mails.
12515 Defaults to @samp{"/usr/sbin/sendmail"}.
12518 @deftypevr {@code{dovecot-configuration} parameter} string submission-host
12519 If non-empty, send mails via this SMTP host[:port] instead of
12521 Defaults to @samp{""}.
12524 @deftypevr {@code{dovecot-configuration} parameter} string rejection-subject
12525 Subject: header to use for rejection mails. You can use the same
12526 variables as for @samp{rejection-reason} below.
12527 Defaults to @samp{"Rejected: %s"}.
12530 @deftypevr {@code{dovecot-configuration} parameter} string rejection-reason
12531 Human readable error message for rejection mails. You can use
12544 Defaults to @samp{"Your message to <%t> was automatically rejected:%n%r"}.
12547 @deftypevr {@code{dovecot-configuration} parameter} string recipient-delimiter
12548 Delimiter character between local-part and detail in email
12550 Defaults to @samp{"+"}.
12553 @deftypevr {@code{dovecot-configuration} parameter} string lda-original-recipient-header
12554 Header where the original recipient address (SMTP's RCPT TO:
12555 address) is taken from if not available elsewhere. With dovecot-lda -a
12556 parameter overrides this. A commonly used header for this is
12558 Defaults to @samp{""}.
12561 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autocreate?
12562 Should saving a mail to a nonexistent mailbox automatically create
12564 Defaults to @samp{#f}.
12567 @deftypevr {@code{dovecot-configuration} parameter} boolean lda-mailbox-autosubscribe?
12568 Should automatically created mailboxes be also automatically
12570 Defaults to @samp{#f}.
12573 @deftypevr {@code{dovecot-configuration} parameter} non-negative-integer imap-max-line-length
12574 Maximum IMAP command line length. Some clients generate very long
12575 command lines with huge mailboxes, so you may need to raise this if you
12576 get "Too long argument" or "IMAP command line too large" errors
12578 Defaults to @samp{64000}.
12581 @deftypevr {@code{dovecot-configuration} parameter} string imap-logout-format
12582 IMAP logout format string:
12585 total number of bytes read from client
12587 total number of bytes sent to client.
12589 Defaults to @samp{"in=%i out=%o"}.
12592 @deftypevr {@code{dovecot-configuration} parameter} string imap-capability
12593 Override the IMAP CAPABILITY response. If the value begins with '+',
12594 add the given capabilities on top of the defaults (e.g. +XFOO XBAR).
12595 Defaults to @samp{""}.
12598 @deftypevr {@code{dovecot-configuration} parameter} string imap-idle-notify-interval
12599 How long to wait between "OK Still here" notifications when client
12601 Defaults to @samp{"2 mins"}.
12604 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-send
12605 ID field names and values to send to clients. Using * as the value
12606 makes Dovecot use the default value. The following fields have default
12607 values currently: name, version, os, os-version, support-url,
12609 Defaults to @samp{""}.
12612 @deftypevr {@code{dovecot-configuration} parameter} string imap-id-log
12613 ID fields sent by client to log. * means everything.
12614 Defaults to @samp{""}.
12617 @deftypevr {@code{dovecot-configuration} parameter} space-separated-string-list imap-client-workarounds
12618 Workarounds for various client bugs:
12621 @item delay-newmail
12622 Send EXISTS/RECENT new mail notifications only when replying to NOOP and
12623 CHECK commands. Some clients ignore them otherwise, for example OSX
12624 Mail (<v2.1). Outlook Express breaks more badly though, without this it
12625 may show user "Message no longer in server" errors. Note that OE6
12626 still breaks even with this workaround if synchronization is set to
12629 @item tb-extra-mailbox-sep
12630 Thunderbird gets somehow confused with LAYOUT=fs (mbox and dbox) and
12631 adds extra @samp{/} suffixes to mailbox names. This option causes Dovecot to
12632 ignore the extra @samp{/} instead of treating it as invalid mailbox name.
12634 @item tb-lsub-flags
12635 Show \Noselect flags for LSUB replies with LAYOUT=fs (e.g. mbox).
12636 This makes Thunderbird realize they aren't selectable and show them
12637 greyed out, instead of only later giving "not selectable" popup error.
12639 Defaults to @samp{()}.
12642 @deftypevr {@code{dovecot-configuration} parameter} string imap-urlauth-host
12643 Host allowed in URLAUTH URLs sent by client. "*" allows all.
12644 Defaults to @samp{""}.
12648 Whew! Lots of configuration options. The nice thing about it though is
12649 that GuixSD has a complete interface to Dovecot's configuration
12650 language. This allows not only a nice way to declare configurations,
12651 but also offers reflective capabilities as well: users can write code to
12652 inspect and transform configurations from within Scheme.
12654 However, it could be that you just want to get a @code{dovecot.conf} up
12655 and running. In that case, you can pass an
12656 @code{opaque-dovecot-configuration} as the @code{#:config} parameter to
12657 @code{dovecot-service}. As its name indicates, an opaque configuration
12658 does not have easy reflective capabilities.
12660 Available @code{opaque-dovecot-configuration} fields are:
12662 @deftypevr {@code{opaque-dovecot-configuration} parameter} package dovecot
12663 The dovecot package.
12666 @deftypevr {@code{opaque-dovecot-configuration} parameter} string string
12667 The contents of the @code{dovecot.conf}, as a string.
12670 For example, if your @code{dovecot.conf} is just the empty string, you
12671 could instantiate a dovecot service like this:
12674 (dovecot-service #:config
12675 (opaque-dovecot-configuration
12679 @subsubheading OpenSMTPD Service
12681 @deffn {Scheme Variable} opensmtpd-service-type
12682 This is the type of the @uref{https://www.opensmtpd.org, OpenSMTPD}
12683 service, whose value should be an @code{opensmtpd-configuration} object
12684 as in this example:
12687 (service opensmtpd-service-type
12688 (opensmtpd-configuration
12689 (config-file (local-file "./my-smtpd.conf"))))
12693 @deftp {Data Type} opensmtpd-configuration
12694 Data type representing the configuration of opensmtpd.
12697 @item @code{package} (default: @var{opensmtpd})
12698 Package object of the OpenSMTPD SMTP server.
12700 @item @code{config-file} (default: @var{%default-opensmtpd-file})
12701 File-like object of the OpenSMTPD configuration file to use. By default
12702 it listens on the loopback network interface, and allows for mail from
12703 users and daemons on the local machine, as well as permitting email to
12704 remote servers. Run @command{man smtpd.conf} for more information.
12709 @subsubheading Exim Service
12711 @cindex mail transfer agent (MTA)
12712 @cindex MTA (mail transfer agent)
12715 @deffn {Scheme Variable} exim-service-type
12716 This is the type of the @uref{https://exim.org, Exim} mail transfer
12717 agent (MTA), whose value should be an @code{exim-configuration} object
12718 as in this example:
12721 (service exim-service-type
12722 (exim-configuration
12723 (config-file (local-file "./my-exim.conf"))))
12727 In order to use an @code{exim-service-type} service you must also have a
12728 @code{mail-aliases-service-type} service present in your
12729 @code{operating-system} (even if it has no aliases).
12731 @deftp {Data Type} exim-configuration
12732 Data type representing the configuration of exim.
12735 @item @code{package} (default: @var{exim})
12736 Package object of the Exim server.
12738 @item @code{config-file} (default: @code{#f})
12739 File-like object of the Exim configuration file to use. If its value is
12740 @code{#f} then use the default configuration file from the package
12741 provided in @code{package}. The resulting configuration file is loaded
12742 after setting the @code{exim_user} and @code{exim_group} configuration
12748 @subsubheading Mail Aliases Service
12750 @cindex email aliases
12751 @cindex aliases, for email addresses
12753 @deffn {Scheme Variable} mail-aliases-service-type
12754 This is the type of the service which provides @code{/etc/aliases},
12755 specifying how to deliver mail to users on this system.
12758 (service mail-aliases-service-type
12759 '(("postmaster" "bob")
12760 ("bob" "bob@@example.com" "bob@@example2.com")))
12764 The configuration for a @code{mail-aliases-service-type} service is an
12765 association list denoting how to deliver mail that comes to this
12766 system. Each entry is of the form @code{(alias addresses ...)}, with
12767 @code{alias} specifying the local alias and @code{addresses} specifying
12768 where to deliver this user's mail.
12770 The aliases aren't required to exist as users on the local system. In
12771 the above example, there doesn't need to be a @code{postmaster} entry in
12772 the @code{operating-system}'s @code{user-accounts} in order to deliver
12773 the @code{postmaster} mail to @code{bob} (which subsequently would
12774 deliver mail to @code{bob@@example.com} and @code{bob@@example2.com}).
12776 @node Messaging Services
12777 @subsubsection Messaging Services
12782 The @code{(gnu services messaging)} module provides Guix service
12783 definitions for messaging services: currently only Prosody is supported.
12785 @subsubheading Prosody Service
12787 @deffn {Scheme Variable} prosody-service-type
12788 This is the type for the @uref{http://prosody.im, Prosody XMPP
12789 communication server}. Its value must be a @code{prosody-configuration}
12790 record as in this example:
12793 (service prosody-service-type
12794 (prosody-configuration
12795 (modules-enabled (cons "groups" %default-modules-enabled))
12798 (int-component-configuration
12799 (hostname "conference.example.net")
12801 (mod-muc (mod-muc-configuration)))))
12804 (virtualhost-configuration
12805 (domain "example.net"))))))
12808 See below for details about @code{prosody-configuration}.
12812 By default, Prosody does not need much configuration. Only one
12813 @code{virtualhosts} field is needed: it specifies the domain you wish
12816 Prosodyctl will help you generate X.509 certificates and keys:
12819 prosodyctl cert request example.net
12822 The available configuration parameters follow. Each parameter
12823 definition is preceded by its type; for example, @samp{string-list foo}
12824 indicates that the @code{foo} parameter should be specified as a list of
12825 strings. Types starting with @code{maybe-} denote parameters that won't
12826 show up in @code{prosody.cfg.lua} when their value is @code{'disabled}.
12828 There is also a way to specify the configuration as a string, if you
12829 have an old @code{prosody.cfg.lua} file that you want to port over from
12830 some other system; see the end for more details.
12832 @c The following documentation was initially generated by
12833 @c (generate-documentation) in (gnu services messaging). Manually maintained
12834 @c documentation is better, so we shouldn't hesitate to edit below as
12835 @c needed. However if the change you want to make to this documentation
12836 @c can be done in an automated way, it's probably easier to change
12837 @c (generate-documentation) than to make it below and have to deal with
12838 @c the churn as Prosody updates.
12840 Available @code{prosody-configuration} fields are:
12842 @deftypevr {@code{prosody-configuration} parameter} package prosody
12843 The Prosody package.
12846 @deftypevr {@code{prosody-configuration} parameter} file-name data-path
12847 Location of the Prosody data storage directory. See
12848 @url{http://prosody.im/doc/configure}.
12849 Defaults to @samp{"/var/lib/prosody"}.
12852 @deftypevr {@code{prosody-configuration} parameter} file-name-list plugin-paths
12853 Additional plugin directories. They are searched in all the specified
12854 paths in order. See @url{http://prosody.im/doc/plugins_directory}.
12855 Defaults to @samp{()}.
12858 @deftypevr {@code{prosody-configuration} parameter} string-list admins
12859 This is a list of accounts that are admins for the server. Note that you
12860 must create the accounts separately. See @url{http://prosody.im/doc/admins} and
12861 @url{http://prosody.im/doc/creating_accounts}.
12862 Example: @code{(admins '("user1@@example.com" "user2@@example.net"))}
12863 Defaults to @samp{()}.
12866 @deftypevr {@code{prosody-configuration} parameter} boolean use-libevent?
12867 Enable use of libevent for better performance under high load. See
12868 @url{http://prosody.im/doc/libevent}.
12869 Defaults to @samp{#f}.
12872 @deftypevr {@code{prosody-configuration} parameter} module-list modules-enabled
12873 This is the list of modules Prosody will load on startup. It looks for
12874 @code{mod_modulename.lua} in the plugins folder, so make sure that exists too.
12875 Documentation on modules can be found at: @url{http://prosody.im/doc/modules}.
12876 Defaults to @samp{%default-modules-enabled}.
12879 @deftypevr {@code{prosody-configuration} parameter} string-list modules-disabled
12880 @samp{"offline"}, @samp{"c2s"} and @samp{"s2s"} are auto-loaded, but
12881 should you want to disable them then add them to this list.
12882 Defaults to @samp{()}.
12885 @deftypevr {@code{prosody-configuration} parameter} file-name groups-file
12886 Path to a text file where the shared groups are defined. If this path is
12887 empty then @samp{mod_groups} does nothing. See
12888 @url{http://prosody.im/doc/modules/mod_groups}.
12889 Defaults to @samp{"/var/lib/prosody/sharedgroups.txt"}.
12892 @deftypevr {@code{prosody-configuration} parameter} boolean allow-registration?
12893 Disable account creation by default, for security. See
12894 @url{http://prosody.im/doc/creating_accounts}.
12895 Defaults to @samp{#f}.
12898 @deftypevr {@code{prosody-configuration} parameter} maybe-ssl-configuration ssl
12899 These are the SSL/TLS-related settings. Most of them are disabled so to
12900 use Prosody's defaults. If you do not completely understand these options, do
12901 not add them to your config, it is easy to lower the security of your server
12902 using them. See @url{http://prosody.im/doc/advanced_ssl_config}.
12904 Available @code{ssl-configuration} fields are:
12906 @deftypevr {@code{ssl-configuration} parameter} maybe-string protocol
12907 This determines what handshake to use.
12910 @deftypevr {@code{ssl-configuration} parameter} file-name key
12911 Path to your private key file, relative to @code{/etc/prosody}.
12912 Defaults to @samp{"/etc/prosody/certs/key.pem"}.
12915 @deftypevr {@code{ssl-configuration} parameter} file-name certificate
12916 Path to your certificate file, relative to @code{/etc/prosody}.
12917 Defaults to @samp{"/etc/prosody/certs/cert.pem"}.
12920 @deftypevr {@code{ssl-configuration} parameter} file-name capath
12921 Path to directory containing root certificates that you wish Prosody to
12922 trust when verifying the certificates of remote servers.
12923 Defaults to @samp{"/etc/ssl/certs"}.
12926 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name cafile
12927 Path to a file containing root certificates that you wish Prosody to trust.
12928 Similar to @code{capath} but with all certificates concatenated together.
12931 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verify
12932 A list of verification options (these mostly map to OpenSSL's
12933 @code{set_verify()} flags).
12936 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list options
12937 A list of general options relating to SSL/TLS. These map to OpenSSL's
12938 @code{set_options()}. For a full list of options available in LuaSec, see the
12942 @deftypevr {@code{ssl-configuration} parameter} maybe-non-negative-integer depth
12943 How long a chain of certificate authorities to check when looking for a
12944 trusted root certificate.
12947 @deftypevr {@code{ssl-configuration} parameter} maybe-string ciphers
12948 An OpenSSL cipher string. This selects what ciphers Prosody will offer to
12949 clients, and in what order.
12952 @deftypevr {@code{ssl-configuration} parameter} maybe-file-name dhparam
12953 A path to a file containing parameters for Diffie-Hellman key exchange. You
12954 can create such a file with:
12955 @code{openssl dhparam -out /etc/prosody/certs/dh-2048.pem 2048}
12958 @deftypevr {@code{ssl-configuration} parameter} maybe-string curve
12959 Curve for Elliptic curve Diffie-Hellman. Prosody's default is
12960 @samp{"secp384r1"}.
12963 @deftypevr {@code{ssl-configuration} parameter} maybe-string-list verifyext
12964 A list of "extra" verification options.
12967 @deftypevr {@code{ssl-configuration} parameter} maybe-string password
12968 Password for encrypted private keys.
12973 @deftypevr {@code{prosody-configuration} parameter} boolean c2s-require-encryption?
12974 Whether to force all client-to-server connections to be encrypted or not.
12975 See @url{http://prosody.im/doc/modules/mod_tls}.
12976 Defaults to @samp{#f}.
12979 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-require-encryption?
12980 Whether to force all server-to-server connections to be encrypted or not.
12981 See @url{http://prosody.im/doc/modules/mod_tls}.
12982 Defaults to @samp{#f}.
12985 @deftypevr {@code{prosody-configuration} parameter} boolean s2s-secure-auth?
12986 Whether to require encryption and certificate authentication. This
12987 provides ideal security, but requires servers you communicate with to support
12988 encryption AND present valid, trusted certificates. See
12989 @url{http://prosody.im/doc/s2s#security}.
12990 Defaults to @samp{#f}.
12993 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-insecure-domains
12994 Many servers don't support encryption or have invalid or self-signed
12995 certificates. You can list domains here that will not be required to
12996 authenticate using certificates. They will be authenticated using DNS. See
12997 @url{http://prosody.im/doc/s2s#security}.
12998 Defaults to @samp{()}.
13001 @deftypevr {@code{prosody-configuration} parameter} string-list s2s-secure-domains
13002 Even if you leave @code{s2s-secure-auth?} disabled, you can still require
13003 valid certificates for some domains by specifying a list here. See
13004 @url{http://prosody.im/doc/s2s#security}.
13005 Defaults to @samp{()}.
13008 @deftypevr {@code{prosody-configuration} parameter} string authentication
13009 Select the authentication backend to use. The default provider stores
13010 passwords in plaintext and uses Prosody's configured data storage to store the
13011 authentication data. If you do not trust your server please see
13012 @url{http://prosody.im/doc/modules/mod_auth_internal_hashed} for information
13013 about using the hashed backend. See also
13014 @url{http://prosody.im/doc/authentication}
13015 Defaults to @samp{"internal_plain"}.
13018 @deftypevr {@code{prosody-configuration} parameter} maybe-string log
13019 Set logging options. Advanced logging configuration is not yet supported
13020 by the GuixSD Prosody Service. See @url{http://prosody.im/doc/logging}.
13021 Defaults to @samp{"*syslog"}.
13024 @deftypevr {@code{prosody-configuration} parameter} file-name pidfile
13025 File to write pid in. See @url{http://prosody.im/doc/modules/mod_posix}.
13026 Defaults to @samp{"/var/run/prosody/prosody.pid"}.
13029 @deftypevr {@code{prosody-configuration} parameter} virtualhost-configuration-list virtualhosts
13030 A host in Prosody is a domain on which user accounts can be created. For
13031 example if you want your users to have addresses like
13032 @samp{"john.smith@@example.com"} then you need to add a host
13033 @samp{"example.com"}. All options in this list will apply only to this host.
13035 Note: the name "virtual" host is used in configuration to avoid confusion with
13036 the actual physical host that Prosody is installed on. A single Prosody
13037 instance can serve many domains, each one defined as a VirtualHost entry in
13038 Prosody's configuration. Conversely a server that hosts a single domain would
13039 have just one VirtualHost entry.
13041 See @url{http://prosody.im/doc/configure#virtual_host_settings}.
13043 Available @code{virtualhost-configuration} fields are:
13045 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13046 @deftypevr {@code{virtualhost-configuration} parameter} string domain
13047 Domain you wish Prosody to serve.
13052 @deftypevr {@code{prosody-configuration} parameter} int-component-configuration-list int-components
13053 Components are extra services on a server which are available to clients,
13054 usually on a subdomain of the main server (such as
13055 @samp{"mycomponent.example.com"}). Example components might be chatroom
13056 servers, user directories, or gateways to other protocols.
13058 Internal components are implemented with Prosody-specific plugins. To add an
13059 internal component, you simply fill the hostname field, and the plugin you wish
13060 to use for the component.
13062 See @url{http://prosody.im/doc/components}.
13063 Defaults to @samp{()}.
13065 Available @code{int-component-configuration} fields are:
13067 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13068 @deftypevr {@code{int-component-configuration} parameter} string hostname
13069 Hostname of the component.
13072 @deftypevr {@code{int-component-configuration} parameter} string plugin
13073 Plugin you wish to use for the component.
13076 @deftypevr {@code{int-component-configuration} parameter} maybe-mod-muc-configuration mod-muc
13077 Multi-user chat (MUC) is Prosody's module for allowing you to create
13078 hosted chatrooms/conferences for XMPP users.
13080 General information on setting up and using multi-user chatrooms can be found
13081 in the "Chatrooms" documentation (@url{http://prosody.im/doc/chatrooms}),
13082 which you should read if you are new to XMPP chatrooms.
13084 See also @url{http://prosody.im/doc/modules/mod_muc}.
13086 Available @code{mod-muc-configuration} fields are:
13088 @deftypevr {@code{mod-muc-configuration} parameter} string name
13089 The name to return in service discovery responses.
13090 Defaults to @samp{"Prosody Chatrooms"}.
13093 @deftypevr {@code{mod-muc-configuration} parameter} string-or-boolean restrict-room-creation
13094 If @samp{#t}, this will only allow admins to create new chatrooms.
13095 Otherwise anyone can create a room. The value @samp{"local"} restricts room
13096 creation to users on the service's parent domain. E.g. @samp{user@@example.com}
13097 can create rooms on @samp{rooms.example.com}. The value @samp{"admin"}
13098 restricts to service administrators only.
13099 Defaults to @samp{#f}.
13102 @deftypevr {@code{mod-muc-configuration} parameter} non-negative-integer max-history-messages
13103 Maximum number of history messages that will be sent to the member that has
13104 just joined the room.
13105 Defaults to @samp{20}.
13112 @deftypevr {@code{prosody-configuration} parameter} ext-component-configuration-list ext-components
13113 External components use XEP-0114, which most standalone components
13114 support. To add an external component, you simply fill the hostname field. See
13115 @url{http://prosody.im/doc/components}.
13116 Defaults to @samp{()}.
13118 Available @code{ext-component-configuration} fields are:
13120 all these @code{prosody-configuration} fields: @code{admins}, @code{use-libevent?}, @code{modules-enabled}, @code{modules-disabled}, @code{groups-file}, @code{allow-registration?}, @code{ssl}, @code{c2s-require-encryption?}, @code{s2s-require-encryption?}, @code{s2s-secure-auth?}, @code{s2s-insecure-domains}, @code{s2s-secure-domains}, @code{authentication}, @code{log}, plus:
13121 @deftypevr {@code{ext-component-configuration} parameter} string component-secret
13122 Password which the component will use to log in.
13125 @deftypevr {@code{ext-component-configuration} parameter} string hostname
13126 Hostname of the component.
13131 @deftypevr {@code{prosody-configuration} parameter} non-negative-integer-list component-ports
13132 Port(s) Prosody listens on for component connections.
13135 @deftypevr {@code{prosody-configuration} parameter} string component-interface
13136 Interface Prosody listens on for component connections.
13137 Defaults to @samp{"127.0.0.1"}.
13140 It could be that you just want to get a @code{prosody.cfg.lua}
13141 up and running. In that case, you can pass an
13142 @code{opaque-prosody-configuration} record as the value of
13143 @code{prosody-service-type}. As its name indicates, an opaque configuration
13144 does not have easy reflective capabilities.
13145 Available @code{opaque-prosody-configuration} fields are:
13147 @deftypevr {@code{opaque-prosody-configuration} parameter} package prosody
13148 The prosody package.
13151 @deftypevr {@code{opaque-prosody-configuration} parameter} string prosody.cfg.lua
13152 The contents of the @code{prosody.cfg.lua} to use.
13155 For example, if your @code{prosody.cfg.lua} is just the empty
13156 string, you could instantiate a prosody service like this:
13159 (service prosody-service-type
13160 (opaque-prosody-configuration
13161 (prosody.cfg.lua "")))
13164 @node Kerberos Services
13165 @subsubsection Kerberos Services
13168 The @code{(gnu services kerberos)} module provides services relating to
13169 the authentication protocol @dfn{Kerberos}.
13171 @subsubheading Krb5 Service
13173 Programs using a Kerberos client library normally
13174 expect a configuration file in @file{/etc/krb5.conf}.
13175 This service generates such a file from a definition provided in the
13176 operating system declaration.
13177 It does not cause any daemon to be started.
13179 No ``keytab'' files are provided by this service---you must explicitly create them.
13180 This service is known to work with the MIT client library, @code{mit-krb5}.
13181 Other implementations have not been tested.
13183 @defvr {Scheme Variable} krb5-service-type
13184 A service type for Kerberos 5 clients.
13188 Here is an example of its use:
13190 (service krb5-service-type
13191 (krb5-configuration
13192 (default-realm "EXAMPLE.COM")
13193 (allow-weak-crypto? #t)
13196 (name "EXAMPLE.COM")
13197 (admin-server "groucho.example.com")
13198 (kdc "karl.example.com"))
13201 (admin-server "kerb-admin.argrx.edu")
13202 (kdc "keys.argrx.edu"))))))
13206 This example provides a Kerberos@tie{}5 client configuration which:
13208 @item Recognizes two realms, @i{viz:} ``EXAMPLE.COM'' and ``ARGRX.EDU'', both
13209 of which have distinct administration servers and key distribution centers;
13210 @item Will default to the realm ``EXAMPLE.COM'' if the realm is not explicitly
13211 specified by clients;
13212 @item Accepts services which only support encryption types known to be weak.
13215 The @code{krb5-realm} and @code{krb5-configuration} types have many fields.
13216 Only the most commonly used ones are described here.
13217 For a full list, and more detailed explanation of each, see the MIT
13218 @uref{http://web.mit.edu/kerberos/krb5-devel/doc/admin/conf_files/krb5_conf.html,,krb5.conf}
13222 @deftp {Data Type} krb5-realm
13223 @cindex realm, kerberos
13226 This field is a string identifying the name of the realm.
13227 A common convention is to use the fully qualified DNS name of your organization,
13228 converted to upper case.
13230 @item @code{admin-server}
13231 This field is a string identifying the host where the administration server is
13235 This field is a string identifying the key distribution center
13240 @deftp {Data Type} krb5-configuration
13243 @item @code{allow-weak-crypto?} (default: @code{#f})
13244 If this flag is @code{#t} then services which only offer encryption algorithms
13245 known to be weak will be accepted.
13247 @item @code{default-realm} (default: @code{#f})
13248 This field should be a string identifying the default Kerberos
13249 realm for the client.
13250 You should set this field to the name of your Kerberos realm.
13251 If this value is @code{#f}
13252 then a realm must be specified with every Kerberos principal when invoking programs
13253 such as @command{kinit}.
13255 @item @code{realms}
13256 This should be a non-empty list of @code{krb5-realm} objects, which clients may
13258 Normally, one of them will have a @code{name} field matching the @code{default-realm}
13264 @subsubheading PAM krb5 Service
13267 The @code{pam-krb5} service allows for login authentication and password
13268 management via Kerberos.
13269 You will need this service if you want PAM enabled applications to authenticate
13270 users using Kerberos.
13272 @defvr {Scheme Variable} pam-krb5-service-type
13273 A service type for the Kerberos 5 PAM module.
13276 @deftp {Data Type} pam-krb5-configuration
13277 Data type representing the configuration of the Kerberos 5 PAM module
13278 This type has the following parameters:
13280 @item @code{pam-krb5} (default: @code{pam-krb5})
13281 The pam-krb5 package to use.
13283 @item @code{minimum-uid} (default: @code{1000})
13284 The smallest user ID for which Kerberos authentications should be attempted.
13285 Local accounts with lower values will silently fail to authenticate.
13291 @subsubsection Web Services
13296 The @code{(gnu services web)} module provides the following service:
13298 @deffn {Scheme Procedure} nginx-service [#:nginx nginx] @
13299 [#:log-directory ``/var/log/nginx''] @
13300 [#:run-directory ``/var/run/nginx''] @
13301 [#:server-list '()] @
13302 [#:upstream-list '()] @
13303 [#:config-file @code{#f}]
13305 Return a service that runs @var{nginx}, the nginx web server.
13307 The nginx daemon loads its runtime configuration from @var{config-file}.
13308 Log files are written to @var{log-directory} and temporary runtime data
13309 files are written to @var{run-directory}. For proper operation, these
13310 arguments should match what is in @var{config-file} to ensure that the
13311 directories are created when the service is activated.
13313 As an alternative to using a @var{config-file}, @var{server-list} can be
13314 used to specify the list of @dfn{server blocks} required on the host and
13315 @var{upstream-list} can be used to specify a list of @dfn{upstream
13316 blocks} to configure. For this to work, use the default value for
13319 At startup, @command{nginx} has not yet read its configuration file, so it
13320 uses a default file to log error messages. If it fails to load its
13321 configuration file, that is where error messages are logged. After the
13322 configuration file is loaded, the default error log file changes as per
13323 configuration. In our case, startup error messages can be found in
13324 @file{/var/run/nginx/logs/error.log}, and after configuration in
13325 @file{/var/log/nginx/error.log}. The second location can be changed with the
13326 @var{log-directory} configuration option.
13330 @deffn {Scheme Variable} nginx-service-type
13331 This is type for the nginx web server.
13333 This service can be extended to add server blocks in addition to the
13334 default one, as in this example:
13337 (simple-service 'my-extra-server nginx-service-type
13338 (list (nginx-server-configuration
13340 (root "/srv/http/extra-website"))))
13344 @deftp {Data Type} nginx-server-configuration
13345 Data type representing the configuration of an nginx server block.
13346 This type has the following parameters:
13349 @item @code{http-port} (default: @code{80})
13350 Nginx will listen for HTTP connection on this port. Set it at @code{#f} if
13351 nginx should not listen for HTTP (non secure) connection for this
13352 @dfn{server block}.
13354 @item @code{https-port} (default: @code{443})
13355 Nginx will listen for HTTPS connection on this port. Set it at @code{#f} if
13356 nginx should not listen for HTTPS (secure) connection for this @dfn{server block}.
13358 Note that nginx can listen for HTTP and HTTPS connections in the same
13359 @dfn{server block}.
13361 @item @code{server-name} (default: @code{(list 'default)})
13362 A list of server names this server represents. @code{'default} represents the
13363 default server for connections matching no other server.
13365 @item @code{root} (default: @code{"/srv/http"})
13366 Root of the website nginx will serve.
13368 @item @code{locations} (default: @code{'()})
13369 A list of @dfn{nginx-location-configuration} or
13370 @dfn{nginx-named-location-configuration} records to use within this
13373 @item @code{index} (default: @code{(list "index.html")})
13374 Index files to look for when clients ask for a directory. If it cannot be found,
13375 Nginx will send the list of files in the directory.
13377 @item @code{ssl-certificate} (default: @code{"/etc/nginx/cert.pem"})
13378 Where to find the certificate for secure connections. Set it to @code{#f} if
13379 you don't have a certificate or you don't want to use HTTPS.
13381 @item @code{ssl-certificate-key} (default: @code{"/etc/nginx/key.pem"})
13382 Where to find the private key for secure connections. Set it to @code{#f} if
13383 you don't have a key or you don't want to use HTTPS.
13385 @item @code{server-tokens?} (default: @code{#f})
13386 Whether the server should add its configuration to response.
13392 @subsubsection VPN Services
13393 @cindex VPN (virtual private network)
13394 @cindex virtual private network (VPN)
13396 The @code{(gnu services vpn)} module provides services related to
13397 @dfn{virtual private networks} (VPNs). It provides a @emph{client} service for
13398 your machine to connect to a VPN, and a @emph{servire} service for your machine
13399 to host a VPN. Both services use @uref{https://openvpn.net/, OpenVPN}.
13401 @deffn {Scheme Procedure} openvpn-client-service @
13402 [#:config (openvpn-client-configuration)]
13404 Return a service that runs @command{openvpn}, a VPN daemon, as a client.
13407 @deffn {Scheme Procedure} openvpn-server-service @
13408 [#:config (openvpn-server-configuration)]
13410 Return a service that runs @command{openvpn}, a VPN daemon, as a server.
13412 Both can be run simultaneously.
13415 @c %automatically generated documentation
13417 Available @code{openvpn-client-configuration} fields are:
13419 @deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
13420 The OpenVPN package.
13424 @deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
13425 The OpenVPN pid file.
13427 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13431 @deftypevr {@code{openvpn-client-configuration} parameter} proto proto
13432 The protocol (UDP or TCP) used to open a channel between clients and
13435 Defaults to @samp{udp}.
13439 @deftypevr {@code{openvpn-client-configuration} parameter} dev dev
13440 The device type used to represent the VPN connection.
13442 Defaults to @samp{tun}.
13446 @deftypevr {@code{openvpn-client-configuration} parameter} string ca
13447 The certificate authority to check connections against.
13449 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13453 @deftypevr {@code{openvpn-client-configuration} parameter} string cert
13454 The certificate of the machine the daemon is running on. It should be
13455 signed by the authority given in @code{ca}.
13457 Defaults to @samp{"/etc/openvpn/client.crt"}.
13461 @deftypevr {@code{openvpn-client-configuration} parameter} string key
13462 The key of the machine the daemon is running on. It must be the key whose
13463 certificate is @code{cert}.
13465 Defaults to @samp{"/etc/openvpn/client.key"}.
13469 @deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
13470 Whether to use the lzo compression algorithm.
13472 Defaults to @samp{#t}.
13476 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
13477 Don't re-read key files across SIGUSR1 or --ping-restart.
13479 Defaults to @samp{#t}.
13483 @deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
13484 Don't close and reopen TUN/TAP device or run up/down scripts across
13485 SIGUSR1 or --ping-restart restarts.
13487 Defaults to @samp{#t}.
13491 @deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
13494 Defaults to @samp{3}.
13498 @deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client tls-auth
13499 Add an additional layer of HMAC authentication on top of the TLS control
13500 channel to protect against DoS attacks.
13502 Defaults to @samp{#f}.
13506 @deftypevr {@code{openvpn-client-configuration} parameter} key-usage verify-key-usage?
13507 Whether to check the server certificate has server usage extension.
13509 Defaults to @samp{#t}.
13513 @deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
13514 Bind to a specific local port number.
13516 Defaults to @samp{#f}.
13520 @deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry resolv-retry?
13521 Retry resolving server address.
13523 Defaults to @samp{#t}.
13527 @deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list remote
13528 A list of remote servers to connect to.
13530 Defaults to @samp{()}.
13532 Available @code{openvpn-remote-configuration} fields are:
13534 @deftypevr {@code{openvpn-remote-configuration} parameter} string name
13537 Defaults to @samp{"my-server"}.
13541 @deftypevr {@code{openvpn-remote-configuration} parameter} number port
13542 Port number the server listens to.
13544 Defaults to @samp{1194}.
13549 @c %end of automatic openvpn-client documentation
13551 @c %automatically generated documentation
13553 Available @code{openvpn-server-configuration} fields are:
13555 @deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
13556 The OpenVPN package.
13560 @deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
13561 The OpenVPN pid file.
13563 Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
13567 @deftypevr {@code{openvpn-server-configuration} parameter} proto proto
13568 The protocol (UDP or TCP) used to open a channel between clients and
13571 Defaults to @samp{udp}.
13575 @deftypevr {@code{openvpn-server-configuration} parameter} dev dev
13576 The device type used to represent the VPN connection.
13578 Defaults to @samp{tun}.
13582 @deftypevr {@code{openvpn-server-configuration} parameter} string ca
13583 The certificate authority to check connections against.
13585 Defaults to @samp{"/etc/openvpn/ca.crt"}.
13589 @deftypevr {@code{openvpn-server-configuration} parameter} string cert
13590 The certificate of the machine the daemon is running on. It should be
13591 signed by the authority given in @code{ca}.
13593 Defaults to @samp{"/etc/openvpn/client.crt"}.
13597 @deftypevr {@code{openvpn-server-configuration} parameter} string key
13598 The key of the machine the daemon is running on. It must be the key whose
13599 certificate is @code{cert}.
13601 Defaults to @samp{"/etc/openvpn/client.key"}.
13605 @deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
13606 Whether to use the lzo compression algorithm.
13608 Defaults to @samp{#t}.
13612 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
13613 Don't re-read key files across SIGUSR1 or --ping-restart.
13615 Defaults to @samp{#t}.
13619 @deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
13620 Don't close and reopen TUN/TAP device or run up/down scripts across
13621 SIGUSR1 or --ping-restart restarts.
13623 Defaults to @samp{#t}.
13627 @deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
13630 Defaults to @samp{3}.
13634 @deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server tls-auth
13635 Add an additional layer of HMAC authentication on top of the TLS control
13636 channel to protect against DoS attacks.
13638 Defaults to @samp{#f}.
13642 @deftypevr {@code{openvpn-server-configuration} parameter} number port
13643 Specifies the port number on which the server listens.
13645 Defaults to @samp{1194}.
13649 @deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
13650 An ip and mask specifying the subnet inside the virtual network.
13652 Defaults to @samp{"10.8.0.0 255.255.255.0"}.
13656 @deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
13657 A CIDR notation specifying the IPv6 subnet inside the virtual network.
13659 Defaults to @samp{#f}.
13663 @deftypevr {@code{openvpn-server-configuration} parameter} string dh
13664 The Diffie-Hellman parameters file.
13666 Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
13670 @deftypevr {@code{openvpn-server-configuration} parameter} string ifconfig-pool-persist
13671 The file that records client IPs.
13673 Defaults to @samp{"/etc/openvpn/ipp.txt"}.
13677 @deftypevr {@code{openvpn-server-configuration} parameter} gateway redirect-gateway?
13678 When true, the server will act as a gateway for its clients.
13680 Defaults to @samp{#f}.
13684 @deftypevr {@code{openvpn-server-configuration} parameter} boolean client-to-client?
13685 When true, clients are allowed to talk to each other inside the VPN.
13687 Defaults to @samp{#f}.
13691 @deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
13692 Causes ping-like messages to be sent back and forth over the link so
13693 that each side knows when the other side has gone down. @code{keepalive}
13694 requires a pair. The first element is the period of the ping sending,
13695 and the second element is the timeout before considering the other side
13700 @deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
13701 The maximum number of clients.
13703 Defaults to @samp{100}.
13707 @deftypevr {@code{openvpn-server-configuration} parameter} string status
13708 The status file. This file shows a small report on current connection.
13709 It is truncated and rewritten every minute.
13711 Defaults to @samp{"/var/run/openvpn/status"}.
13715 @deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list client-config-dir
13716 The list of configuration for some clients.
13718 Defaults to @samp{()}.
13720 Available @code{openvpn-ccd-configuration} fields are:
13722 @deftypevr {@code{openvpn-ccd-configuration} parameter} string name
13725 Defaults to @samp{"client"}.
13729 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
13732 Defaults to @samp{#f}.
13736 @deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
13739 Defaults to @samp{#f}.
13746 @c %end of automatic openvpn-server documentation
13749 @deftp {Data Type} nginx-upstream-configuration
13750 Data type representing the configuration of an nginx @code{upstream}
13751 block. This type has the following parameters:
13755 Name for this group of servers.
13757 @item @code{servers}
13758 Specify the addresses of the servers in the group. The address can be
13759 specified as a IP address (e.g. @samp{127.0.0.1}), domain name
13760 (e.g. @samp{backend1.example.com}) or a path to a UNIX socket using the
13761 prefix @samp{unix:}. For addresses using an IP address or domain name,
13762 the default port is 80, and a different port can be specified
13768 @deftp {Data Type} nginx-location-configuration
13769 Data type representing the configuration of an nginx @code{location}
13770 block. This type has the following parameters:
13774 URI which this location block matches.
13776 @anchor{nginx-location-configuration body}
13778 Body of the location block, specified as a string. This can contain many
13779 configuration directives. For example, to pass requests to a upstream
13780 server group defined using an @code{nginx-upstream-configuration} block,
13781 the following directive would be specified in the body @samp{proxy_pass
13782 http://upstream-name;}.
13787 @deftp {Data Type} nginx-named-location-configuration
13788 Data type representing the configuration of an nginx named location
13789 block. Named location blocks are used for request redirection, and not
13790 used for regular request processing. This type has the following
13795 Name to identify this location block.
13798 @xref{nginx-location-configuration body}, as the body for named location
13799 blocks can be used in a similar way to the
13800 @code{nginx-location-configuration body}. One restriction is that the
13801 body of a named location block cannot contain location blocks.
13806 @node Network File System
13807 @subsubsection Network File System
13810 The @code{(gnu services nfs)} module provides the following services,
13811 which are most commonly used in relation to mounting or exporting
13812 directory trees as @dfn{network file systems} (NFS).
13814 @subsubheading RPC Bind Service
13817 The RPC Bind service provides a facility to map program numbers into
13818 universal addresses.
13819 Many NFS related services use this facility. Hence it is automatically
13820 started when a dependent service starts.
13822 @defvr {Scheme Variable} rpcbind-service-type
13823 A service type for the RPC portmapper daemon.
13827 @deftp {Data Type} rpcbind-configuration
13828 Data type representing the configuration of the RPC Bind Service.
13829 This type has the following parameters:
13831 @item @code{rpcbind} (default: @code{rpcbind})
13832 The rpcbind package to use.
13834 @item @code{warm-start?} (default: @code{#t})
13835 If this parameter is @code{#t}, then the daemon will read a
13836 state file on startup thus reloading state information saved by a previous
13842 @subsubheading Pipefs Pseudo File System
13846 The pipefs file system is used to transfer NFS related data
13847 between the kernel and user space programs.
13849 @defvr {Scheme Variable} pipefs-service-type
13850 A service type for the pipefs pseudo file system.
13853 @deftp {Data Type} pipefs-configuration
13854 Data type representing the configuration of the pipefs pseudo file system service.
13855 This type has the following parameters:
13857 @item @code{mount-point} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13858 The directory to which the file system is to be attached.
13863 @subsubheading GSS Daemon Service
13866 @cindex global security system
13868 The @dfn{global security system} (GSS) daemon provides strong security for RPC
13870 Before exchanging RPC requests an RPC client must establish a security
13871 context. Typically this is done using the Kerberos command @command{kinit}
13872 or automatically at login time using PAM services (@pxref{Kerberos Services}).
13874 @defvr {Scheme Variable} gss-service-type
13875 A service type for the Global Security System (GSS) daemon.
13878 @deftp {Data Type} gss-configuration
13879 Data type representing the configuration of the GSS daemon service.
13880 This type has the following parameters:
13882 @item @code{nfs-utils} (default: @code{nfs-utils})
13883 The package in which the @command{rpc.gssd} command is to be found.
13885 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13886 The directory where the pipefs file system is mounted.
13892 @subsubheading IDMAP Daemon Service
13894 @cindex name mapper
13896 The idmap daemon service provides mapping between user IDs and user names.
13897 Typically it is required in order to access file systems mounted via NFSv4.
13899 @defvr {Scheme Variable} idmap-service-type
13900 A service type for the Identity Mapper (IDMAP) daemon.
13903 @deftp {Data Type} idmap-configuration
13904 Data type representing the configuration of the IDMAP daemon service.
13905 This type has the following parameters:
13907 @item @code{nfs-utils} (default: @code{nfs-utils})
13908 The package in which the @command{rpc.idmapd} command is to be found.
13910 @item @code{pipefs-directory} (default: @code{"/var/lib/nfs/rpc_pipefs"})
13911 The directory where the pipefs file system is mounted.
13913 @item @code{domain} (default: @code{#f})
13914 The local NFSv4 domain name.
13915 This must be a string or @code{#f}.
13916 If it is @code{#f} then the daemon will use the host's fully qualified domain name.
13921 @node Continuous Integration
13922 @subsubsection Continuous Integration
13924 @cindex continuous integration
13925 @uref{https://notabug.org/mthl/cuirass, Cuirass} is a continuous
13926 integration tool for Guix. It can be used both for development and for
13927 providing substitutes to others (@pxref{Substitutes}).
13929 The @code{(gnu services cuirass)} module provides the following service.
13931 @defvr {Scheme Procedure} cuirass-service-type
13932 The type of the Cuirass service. Its value must be a
13933 @code{cuirass-configuration} object, as described below.
13936 To add build jobs, you have to set the @code{specifications} field of
13937 the configuration. Here is an example of a service defining a build job
13938 based on a specification that can be found in Cuirass source tree. This
13939 service polls the Guix repository and builds a subset of the Guix
13940 packages, as prescribed in the @file{gnu-system.scm} example spec:
13943 (let ((spec #~((#:name . "guix")
13944 (#:url . "git://git.savannah.gnu.org/guix.git")
13945 (#:load-path . ".")
13947 ;; Here we must provide an absolute file name.
13948 ;; We take jobs from one of the examples provided
13950 (#:file . #$(file-append
13952 "/tests/gnu-system.scm"))
13954 (#:proc . hydra-jobs)
13955 (#:arguments (subset . "hello"))
13956 (#:branch . "master"))))
13957 (service cuirass-service-type
13958 (cuirass-configuration
13959 (specifications #~(list #$spec)))))
13962 While information related to build jobs is located directly in the
13963 specifications, global settings for the @command{cuirass} process are
13964 accessible in other @code{cuirass-configuration} fields.
13966 @deftp {Data Type} cuirass-configuration
13967 Data type representing the configuration of Cuirass.
13970 @item @code{log-file} (default: @code{"/var/log/cuirass.log"})
13971 Location of the log file.
13973 @item @code{cache-directory} (default: @code{"/var/cache/cuirass"})
13974 Location of the repository cache.
13976 @item @code{user} (default: @code{"cuirass"})
13977 Owner of the @code{cuirass} process.
13979 @item @code{group} (default: @code{"cuirass"})
13980 Owner's group of the @code{cuirass} process.
13982 @item @code{interval} (default: @code{60})
13983 Number of seconds between the poll of the repositories followed by the
13986 @item @code{database} (default: @code{"/var/run/cuirass/cuirass.db"})
13987 Location of sqlite database which contains the build results and previously
13988 added specifications.
13990 @item @code{port} (default: @code{8080})
13991 Port number used by the HTTP server.
13993 @item @code{specifications} (default: @code{#~'()})
13994 A gexp (@pxref{G-Expressions}) that evaluates to a list of specifications,
13995 where a specification is an association list
13996 (@pxref{Associations Lists,,, guile, GNU Guile Reference Manual}) whose
13997 keys are keywords (@code{#:keyword-example}) as shown in the example
14000 @item @code{use-substitutes?} (default: @code{#f})
14001 This allows using substitutes to avoid building every dependencies of a job
14004 @item @code{one-shot?} (default: @code{#f})
14005 Only evaluate specifications and build derivations once.
14007 @item @code{load-path} (default: @code{'()})
14008 This allows users to define their own packages and make them visible to
14009 cuirass as in @command{guix build} command.
14011 @item @code{cuirass} (default: @code{cuirass})
14012 The Cuirass package to use.
14016 @node Power management Services
14017 @subsubsection Power management Services
14019 @cindex power management with TLP
14020 The @code{(gnu services pm)} module provides a Guix service definition
14021 for the Linux power management tool TLP.
14023 TLP enables various powersaving modes in userspace and kernel.
14024 Contrary to @code{upower-service}, it is not a passive,
14025 monitoring tool, as it will apply custom settings each time a new power
14026 source is detected. More information can be found at
14027 @uref{http://linrunner.de/en/tlp/tlp.html, TLP home page}.
14029 @deffn {Scheme Variable} tlp-service-type
14030 The service type for the TLP tool. Its value should be a valid
14031 TLP configuration (see below). To use the default settings, simply
14034 (service tlp-service-type)
14038 By default TLP does not need much configuration but most TLP parameters
14039 can be tweaked using @code{tlp-configuration}.
14041 Each parameter definition is preceded by its type; for example,
14042 @samp{boolean foo} indicates that the @code{foo} parameter
14043 should be specified as a boolean. Types starting with
14044 @code{maybe-} denote parameters that won't show up in TLP config file
14045 when their value is @code{'disabled}.
14047 @c The following documentation was initially generated by
14048 @c (generate-tlp-documentation) in (gnu services pm). Manually maintained
14049 @c documentation is better, so we shouldn't hesitate to edit below as
14050 @c needed. However if the change you want to make to this documentation
14051 @c can be done in an automated way, it's probably easier to change
14052 @c (generate-documentation) than to make it below and have to deal with
14053 @c the churn as TLP updates.
14055 Available @code{tlp-configuration} fields are:
14057 @deftypevr {@code{tlp-configuration} parameter} package tlp
14062 @deftypevr {@code{tlp-configuration} parameter} boolean tlp-enable?
14063 Set to true if you wish to enable TLP.
14065 Defaults to @samp{#t}.
14069 @deftypevr {@code{tlp-configuration} parameter} string tlp-default-mode
14070 Default mode when no power supply can be detected. Alternatives are AC
14073 Defaults to @samp{"AC"}.
14077 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-ac
14078 Number of seconds Linux kernel has to wait after the disk goes idle,
14079 before syncing on AC.
14081 Defaults to @samp{0}.
14085 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer disk-idle-secs-on-bat
14086 Same as @code{disk-idle-ac} but on BAT mode.
14088 Defaults to @samp{2}.
14092 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-ac
14093 Dirty pages flushing periodicity, expressed in seconds.
14095 Defaults to @samp{15}.
14099 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer max-lost-work-secs-on-bat
14100 Same as @code{max-lost-work-secs-on-ac} but on BAT mode.
14102 Defaults to @samp{60}.
14106 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-ac
14107 CPU frequency scaling governor on AC mode. With intel_pstate driver,
14108 alternatives are powersave and performance. With acpi-cpufreq driver,
14109 alternatives are ondemand, powersave, performance and conservative.
14111 Defaults to @samp{disabled}.
14115 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list cpu-scaling-governor-on-bat
14116 Same as @code{cpu-scaling-governor-on-ac} but on BAT mode.
14118 Defaults to @samp{disabled}.
14122 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-ac
14123 Set the min available frequency for the scaling governor on AC.
14125 Defaults to @samp{disabled}.
14129 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-ac
14130 Set the max available frequency for the scaling governor on AC.
14132 Defaults to @samp{disabled}.
14136 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-min-freq-on-bat
14137 Set the min available frequency for the scaling governor on BAT.
14139 Defaults to @samp{disabled}.
14143 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-scaling-max-freq-on-bat
14144 Set the max available frequency for the scaling governor on BAT.
14146 Defaults to @samp{disabled}.
14150 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-ac
14151 Limit the min P-state to control the power dissipation of the CPU, in AC
14152 mode. Values are stated as a percentage of the available performance.
14154 Defaults to @samp{disabled}.
14158 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-ac
14159 Limit the max P-state to control the power dissipation of the CPU, in AC
14160 mode. Values are stated as a percentage of the available performance.
14162 Defaults to @samp{disabled}.
14166 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-min-perf-on-bat
14167 Same as @code{cpu-min-perf-on-ac} on BAT mode.
14169 Defaults to @samp{disabled}.
14173 @deftypevr {@code{tlp-configuration} parameter} maybe-non-negative-integer cpu-max-perf-on-bat
14174 Same as @code{cpu-max-perf-on-ac} on BAT mode.
14176 Defaults to @samp{disabled}.
14180 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-ac?
14181 Enable CPU turbo boost feature on AC mode.
14183 Defaults to @samp{disabled}.
14187 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean cpu-boost-on-bat?
14188 Same as @code{cpu-boost-on-ac?} on BAT mode.
14190 Defaults to @samp{disabled}.
14194 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-ac?
14195 Allow Linux kernel to minimize the number of CPU cores/hyper-threads
14196 used under light load conditions.
14198 Defaults to @samp{#f}.
14202 @deftypevr {@code{tlp-configuration} parameter} boolean sched-powersave-on-bat?
14203 Same as @code{sched-powersave-on-ac?} but on BAT mode.
14205 Defaults to @samp{#t}.
14209 @deftypevr {@code{tlp-configuration} parameter} boolean nmi-watchdog?
14210 Enable Linux kernel NMI watchdog.
14212 Defaults to @samp{#f}.
14216 @deftypevr {@code{tlp-configuration} parameter} maybe-string phc-controls
14217 For Linux kernels with PHC patch applied, change CPU voltages. An
14218 example value would be @samp{"F:V F:V F:V F:V"}.
14220 Defaults to @samp{disabled}.
14224 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-ac
14225 Set CPU performance versus energy saving policy on AC. Alternatives are
14226 performance, normal, powersave.
14228 Defaults to @samp{"performance"}.
14232 @deftypevr {@code{tlp-configuration} parameter} string energy-perf-policy-on-bat
14233 Same as @code{energy-perf-policy-ac} but on BAT mode.
14235 Defaults to @samp{"powersave"}.
14239 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disks-devices
14244 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-ac
14245 Hard disk advanced power management level.
14249 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list disk-apm-level-on-bat
14250 Same as @code{disk-apm-bat} but on BAT mode.
14254 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-ac
14255 Hard disk spin down timeout. One value has to be specified for each
14256 declared hard disk.
14258 Defaults to @samp{disabled}.
14262 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-spindown-timeout-on-bat
14263 Same as @code{disk-spindown-timeout-on-ac} but on BAT mode.
14265 Defaults to @samp{disabled}.
14269 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list disk-iosched
14270 Select IO scheduler for disk devices. One value has to be specified for
14271 each declared hard disk. Example alternatives are cfq, deadline and
14274 Defaults to @samp{disabled}.
14278 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-ac
14279 SATA aggressive link power management (ALPM) level. Alternatives are
14280 min_power, medium_power, max_performance.
14282 Defaults to @samp{"max_performance"}.
14286 @deftypevr {@code{tlp-configuration} parameter} string sata-linkpwr-on-bat
14287 Same as @code{sata-linkpwr-ac} but on BAT mode.
14289 Defaults to @samp{"min_power"}.
14293 @deftypevr {@code{tlp-configuration} parameter} maybe-string sata-linkpwr-blacklist
14294 Exclude specified SATA host devices for link power management.
14296 Defaults to @samp{disabled}.
14300 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-ac?
14301 Enable Runtime Power Management for AHCI controller and disks on AC
14304 Defaults to @samp{disabled}.
14308 @deftypevr {@code{tlp-configuration} parameter} maybe-on-off-boolean ahci-runtime-pm-on-bat?
14309 Same as @code{ahci-runtime-pm-on-ac} on BAT mode.
14311 Defaults to @samp{disabled}.
14315 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer ahci-runtime-pm-timeout
14316 Seconds of inactivity before disk is suspended.
14318 Defaults to @samp{15}.
14322 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-ac
14323 PCI Express Active State Power Management level. Alternatives are
14324 default, performance, powersave.
14326 Defaults to @samp{"performance"}.
14330 @deftypevr {@code{tlp-configuration} parameter} string pcie-aspm-on-bat
14331 Same as @code{pcie-aspm-ac} but on BAT mode.
14333 Defaults to @samp{"powersave"}.
14337 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-ac
14338 Radeon graphics clock speed level. Alternatives are low, mid, high,
14341 Defaults to @samp{"high"}.
14345 @deftypevr {@code{tlp-configuration} parameter} string radeon-power-profile-on-bat
14346 Same as @code{radeon-power-ac} but on BAT mode.
14348 Defaults to @samp{"low"}.
14352 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-ac
14353 Radeon dynamic power management method (DPM). Alternatives are battery,
14356 Defaults to @samp{"performance"}.
14360 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-state-on-bat
14361 Same as @code{radeon-dpm-state-ac} but on BAT mode.
14363 Defaults to @samp{"battery"}.
14367 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-ac
14368 Radeon DPM performance level. Alternatives are auto, low, high.
14370 Defaults to @samp{"auto"}.
14374 @deftypevr {@code{tlp-configuration} parameter} string radeon-dpm-perf-level-on-bat
14375 Same as @code{radeon-dpm-perf-ac} but on BAT mode.
14377 Defaults to @samp{"auto"}.
14381 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-ac?
14382 Wifi power saving mode.
14384 Defaults to @samp{#f}.
14388 @deftypevr {@code{tlp-configuration} parameter} on-off-boolean wifi-pwr-on-bat?
14389 Same as @code{wifi-power-ac?} but on BAT mode.
14391 Defaults to @samp{#t}.
14395 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean wol-disable?
14396 Disable wake on LAN.
14398 Defaults to @samp{#t}.
14402 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-ac
14403 Timeout duration in seconds before activating audio power saving on
14404 Intel HDA and AC97 devices. A value of 0 disables power saving.
14406 Defaults to @samp{0}.
14410 @deftypevr {@code{tlp-configuration} parameter} non-negative-integer sound-power-save-on-bat
14411 Same as @code{sound-powersave-ac} but on BAT mode.
14413 Defaults to @samp{1}.
14417 @deftypevr {@code{tlp-configuration} parameter} y-n-boolean sound-power-save-controller?
14418 Disable controller in powersaving mode on Intel HDA devices.
14420 Defaults to @samp{#t}.
14424 @deftypevr {@code{tlp-configuration} parameter} boolean bay-poweroff-on-bat?
14425 Enable optical drive in UltraBay/MediaBay on BAT mode. Drive can be
14426 powered on again by releasing (and reinserting) the eject lever or by
14427 pressing the disc eject button on newer models.
14429 Defaults to @samp{#f}.
14433 @deftypevr {@code{tlp-configuration} parameter} string bay-device
14434 Name of the optical drive device to power off.
14436 Defaults to @samp{"sr0"}.
14440 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-ac
14441 Runtime Power Management for PCI(e) bus devices. Alternatives are on
14444 Defaults to @samp{"on"}.
14448 @deftypevr {@code{tlp-configuration} parameter} string runtime-pm-on-bat
14449 Same as @code{runtime-pm-ac} but on BAT mode.
14451 Defaults to @samp{"auto"}.
14455 @deftypevr {@code{tlp-configuration} parameter} boolean runtime-pm-all?
14456 Runtime Power Management for all PCI(e) bus devices, except blacklisted
14459 Defaults to @samp{#t}.
14463 @deftypevr {@code{tlp-configuration} parameter} maybe-space-separated-string-list runtime-pm-blacklist
14464 Exclude specified PCI(e) device addresses from Runtime Power Management.
14466 Defaults to @samp{disabled}.
14470 @deftypevr {@code{tlp-configuration} parameter} space-separated-string-list runtime-pm-driver-blacklist
14471 Exclude PCI(e) devices assigned to the specified drivers from Runtime
14476 @deftypevr {@code{tlp-configuration} parameter} boolean usb-autosuspend?
14477 Enable USB autosuspend feature.
14479 Defaults to @samp{#t}.
14483 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-blacklist
14484 Exclude specified devices from USB autosuspend.
14486 Defaults to @samp{disabled}.
14490 @deftypevr {@code{tlp-configuration} parameter} boolean usb-blacklist-wwan?
14491 Exclude WWAN devices from USB autosuspend.
14493 Defaults to @samp{#t}.
14497 @deftypevr {@code{tlp-configuration} parameter} maybe-string usb-whitelist
14498 Include specified devices into USB autosuspend, even if they are already
14499 excluded by the driver or via @code{usb-blacklist-wwan?}.
14501 Defaults to @samp{disabled}.
14505 @deftypevr {@code{tlp-configuration} parameter} maybe-boolean usb-autosuspend-disable-on-shutdown?
14506 Enable USB autosuspend before shutdown.
14508 Defaults to @samp{disabled}.
14512 @deftypevr {@code{tlp-configuration} parameter} boolean restore-device-state-on-startup?
14513 Restore radio device state (bluetooth, wifi, wwan) from previous
14514 shutdown on system startup.
14516 Defaults to @samp{#f}.
14520 @node Miscellaneous Services
14521 @subsubsection Miscellaneous Services
14525 @subsubheading Lirc Service
14527 The @code{(gnu services lirc)} module provides the following service.
14529 @deffn {Scheme Procedure} lirc-service [#:lirc lirc] @
14530 [#:device #f] [#:driver #f] [#:config-file #f] @
14531 [#:extra-options '()]
14532 Return a service that runs @url{http://www.lirc.org,LIRC}, a daemon that
14533 decodes infrared signals from remote controls.
14535 Optionally, @var{device}, @var{driver} and @var{config-file}
14536 (configuration file name) may be specified. See @command{lircd} manual
14539 Finally, @var{extra-options} is a list of additional command-line options
14540 passed to @command{lircd}.
14544 @subsubheading Spice Service
14546 The @code{(gnu services spice)} module provides the following service.
14548 @deffn {Scheme Procedure} spice-vdagent-service [#:spice-vdagent]
14549 Returns a service that runs @url{http://www.spice-space.org,VDAGENT}, a daemon
14550 that enables sharing the clipboard with a vm and setting the guest display
14551 resolution when the graphical console window resizes.
14554 @subsubsection Dictionary Services
14556 The @code{(gnu services dict)} module provides the following service:
14558 @deffn {Scheme Procedure} dicod-service [#:config (dicod-configuration)]
14559 Return a service that runs the @command{dicod} daemon, an implementation
14560 of DICT server (@pxref{Dicod,,, dico, GNU Dico Manual}).
14562 The optional @var{config} argument specifies the configuration for
14563 @command{dicod}, which should be a @code{<dicod-configuration>} object, by
14564 default it serves the GNU Collaborative International Dictonary of English.
14566 You can add @command{open localhost} to your @file{~/.dico} file to make
14567 @code{localhost} the default server for @command{dico} client
14568 (@pxref{Initialization File,,, dico, GNU Dico Manual}).
14571 @deftp {Data Type} dicod-configuration
14572 Data type representing the configuration of dicod.
14575 @item @code{dico} (default: @var{dico})
14576 Package object of the GNU Dico dictionary server.
14578 @item @code{interfaces} (default: @var{'("localhost")})
14579 This is the list of IP addresses and ports and possibly socket file
14580 names to listen to (@pxref{Server Settings, @code{listen} directive,,
14581 dico, GNU Dico Manual}).
14583 @item @code{handlers} (default: @var{'()})
14584 List of @code{<dicod-handler>} objects denoting handlers (module instances).
14586 @item @code{databases} (default: @var{(list %dicod-database:gcide)})
14587 List of @code{<dicod-database>} objects denoting dictionaries to be served.
14591 @deftp {Data Type} dicod-handler
14592 Data type representing a dictionary handler (module instance).
14596 Name of the handler (module instance).
14598 @item @code{module} (default: @var{#f})
14599 Name of the dicod module of the handler (instance). If it is @code{#f},
14600 the module has the same name as the handler.
14601 (@pxref{Modules,,, dico, GNU Dico Manual}).
14603 @item @code{options}
14604 List of strings or gexps representing the arguments for the module handler
14608 @deftp {Data Type} dicod-database
14609 Data type representing a dictionary database.
14613 Name of the database, will be used in DICT commands.
14615 @item @code{handler}
14616 Name of the dicod handler (module instance) used by this database
14617 (@pxref{Handlers,,, dico, GNU Dico Manual}).
14619 @item @code{complex?} (default: @var{#f})
14620 Whether the database configuration complex. The complex configuration
14621 will need a corresponding @code{<dicod-handler>} object, otherwise not.
14623 @item @code{options}
14624 List of strings or gexps representing the arguments for the database
14625 (@pxref{Databases,,, dico, GNU Dico Manual}).
14629 @defvr {Scheme Variable} %dicod-database:gcide
14630 A @code{<dicod-database>} object serving the GNU Collaborative International
14631 Dictionary of English using the @code{gcide} package.
14634 The following is an example @code{dicod-service} configuration.
14637 (dicod-service #:config
14638 (dicod-configuration
14639 (handlers (list (dicod-handler
14643 (list #~(string-append "dbdir=" #$wordnet))))))
14644 (databases (list (dicod-database
14647 (handler "wordnet")
14648 (options '("database=wn")))
14649 %dicod-database:gcide))))
14652 @subsubsection Version Control
14654 The @code{(gnu services version-control)} module provides the following services:
14656 @subsubheading Git daemon service
14658 @deffn {Scheme Procedure} git-daemon-service [#:config (git-daemon-configuration)]
14660 Return a service that runs @command{git daemon}, a simple TCP server to
14661 expose repositories over the Git protocol for anonymous access.
14663 The optional @var{config} argument should be a
14664 @code{<git-daemon-configuration>} object, by default it allows read-only
14665 access to exported@footnote{By creating the magic file
14666 "git-daemon-export-ok" in the repository directory.} repositories under
14671 @deftp {Data Type} git-daemon-configuration
14672 Data type representing the configuration for @code{git-daemon-service}.
14675 @item @code{package} (default: @var{git})
14676 Package object of the Git distributed version control system.
14678 @item @code{export-all?} (default: @var{#f})
14679 Whether to allow access for all Git repositories, even if they do not
14680 have the @file{git-daemon-export-ok} file.
14682 @item @code{base-path} (default: @file{/srv/git})
14683 Whether to remap all the path requests as relative to the given path.
14684 If you run git daemon with @var{(base-path "/srv/git")} on example.com,
14685 then if you later try to pull @code{git://example.com/hello.git}, git
14686 daemon will interpret the path as @code{/srv/git/hello.git}.
14688 @item @code{user-path} (default: @var{#f})
14689 Whether to allow @code{~user} notation to be used in requests. When
14690 specified with empty string, requests to @code{git://host/~alice/foo} is
14691 taken as a request to access @code{foo} repository in the home directory
14692 of user @code{alice}. If @var{(user-path "path")} is specified, the
14693 same request is taken as a request to access @code{path/foo} repository
14694 in the home directory of user @code{alice}.
14696 @item @code{listen} (default: @var{'()})
14697 Whether to listen on specific IP addresses or hostnames, defaults to
14700 @item @code{port} (default: @var{#f})
14701 Whether to listen on an alternative port, which defaults to 9418.
14703 @item @code{whitelist} (default: @var{'()})
14704 If not empty, only allow access to this list of directories.
14706 @item @code{extra-options} (default: @var{'()})
14707 Extra options will be passed to @code{git daemon}, please run
14708 @command{man git-daemon} for more information.
14713 @node Setuid Programs
14714 @subsection Setuid Programs
14716 @cindex setuid programs
14717 Some programs need to run with ``root'' privileges, even when they are
14718 launched by unprivileged users. A notorious example is the
14719 @command{passwd} program, which users can run to change their
14720 password, and which needs to access the @file{/etc/passwd} and
14721 @file{/etc/shadow} files---something normally restricted to root, for
14722 obvious security reasons. To address that, these executables are
14723 @dfn{setuid-root}, meaning that they always run with root privileges
14724 (@pxref{How Change Persona,,, libc, The GNU C Library Reference Manual},
14725 for more info about the setuid mechanism.)
14727 The store itself @emph{cannot} contain setuid programs: that would be a
14728 security issue since any user on the system can write derivations that
14729 populate the store (@pxref{The Store}). Thus, a different mechanism is
14730 used: instead of changing the setuid bit directly on files that are in
14731 the store, we let the system administrator @emph{declare} which programs
14732 should be setuid root.
14734 The @code{setuid-programs} field of an @code{operating-system}
14735 declaration contains a list of G-expressions denoting the names of
14736 programs to be setuid-root (@pxref{Using the Configuration System}).
14737 For instance, the @command{passwd} program, which is part of the Shadow
14738 package, can be designated by this G-expression (@pxref{G-Expressions}):
14741 #~(string-append #$shadow "/bin/passwd")
14744 A default set of setuid programs is defined by the
14745 @code{%setuid-programs} variable of the @code{(gnu system)} module.
14747 @defvr {Scheme Variable} %setuid-programs
14748 A list of G-expressions denoting common programs that are setuid-root.
14750 The list includes commands such as @command{passwd}, @command{ping},
14751 @command{su}, and @command{sudo}.
14754 Under the hood, the actual setuid programs are created in the
14755 @file{/run/setuid-programs} directory at system activation time. The
14756 files in this directory refer to the ``real'' binaries, which are in the
14759 @node X.509 Certificates
14760 @subsection X.509 Certificates
14762 @cindex HTTPS, certificates
14763 @cindex X.509 certificates
14765 Web servers available over HTTPS (that is, HTTP over the transport-layer
14766 security mechanism, TLS) send client programs an @dfn{X.509 certificate}
14767 that the client can then use to @emph{authenticate} the server. To do
14768 that, clients verify that the server's certificate is signed by a
14769 so-called @dfn{certificate authority} (CA). But to verify the CA's
14770 signature, clients must have first acquired the CA's certificate.
14772 Web browsers such as GNU@tie{}IceCat include their own set of CA
14773 certificates, such that they are able to verify CA signatures
14776 However, most other programs that can talk HTTPS---@command{wget},
14777 @command{git}, @command{w3m}, etc.---need to be told where CA
14778 certificates can be found.
14780 @cindex @code{nss-certs}
14781 In GuixSD, this is done by adding a package that provides certificates
14782 to the @code{packages} field of the @code{operating-system} declaration
14783 (@pxref{operating-system Reference}). GuixSD includes one such package,
14784 @code{nss-certs}, which is a set of CA certificates provided as part of
14785 Mozilla's Network Security Services.
14787 Note that it is @emph{not} part of @var{%base-packages}, so you need to
14788 explicitly add it. The @file{/etc/ssl/certs} directory, which is where
14789 most applications and libraries look for certificates by default, points
14790 to the certificates installed globally.
14792 Unprivileged users, including users of Guix on a foreign distro,
14793 can also install their own certificate package in
14794 their profile. A number of environment variables need to be defined so
14795 that applications and libraries know where to find them. Namely, the
14796 OpenSSL library honors the @code{SSL_CERT_DIR} and @code{SSL_CERT_FILE}
14797 variables. Some applications add their own environment variables; for
14798 instance, the Git version control system honors the certificate bundle
14799 pointed to by the @code{GIT_SSL_CAINFO} environment variable. Thus, you
14800 would typically run something like:
14803 $ guix package -i nss-certs
14804 $ export SSL_CERT_DIR="$HOME/.guix-profile/etc/ssl/certs"
14805 $ export SSL_CERT_FILE="$HOME/.guix-profile/etc/ssl/certs/ca-certificates.crt"
14806 $ export GIT_SSL_CAINFO="$SSL_CERT_FILE"
14809 @node Name Service Switch
14810 @subsection Name Service Switch
14812 @cindex name service switch
14814 The @code{(gnu system nss)} module provides bindings to the
14815 configuration file of the libc @dfn{name service switch} or @dfn{NSS}
14816 (@pxref{NSS Configuration File,,, libc, The GNU C Library Reference
14817 Manual}). In a nutshell, the NSS is a mechanism that allows libc to be
14818 extended with new ``name'' lookup methods for system databases, which
14819 includes host names, service names, user accounts, and more (@pxref{Name
14820 Service Switch, System Databases and Name Service Switch,, libc, The GNU
14821 C Library Reference Manual}).
14823 The NSS configuration specifies, for each system database, which lookup
14824 method is to be used, and how the various methods are chained
14825 together---for instance, under which circumstances NSS should try the
14826 next method in the list. The NSS configuration is given in the
14827 @code{name-service-switch} field of @code{operating-system} declarations
14828 (@pxref{operating-system Reference, @code{name-service-switch}}).
14831 @cindex .local, host name lookup
14832 As an example, the declaration below configures the NSS to use the
14833 @uref{http://0pointer.de/lennart/projects/nss-mdns/, @code{nss-mdns}
14834 back-end}, which supports host name lookups over multicast DNS (mDNS)
14835 for host names ending in @code{.local}:
14838 (name-service-switch
14839 (hosts (list %files ;first, check /etc/hosts
14841 ;; If the above did not succeed, try
14842 ;; with 'mdns_minimal'.
14844 (name "mdns_minimal")
14846 ;; 'mdns_minimal' is authoritative for
14847 ;; '.local'. When it returns "not found",
14848 ;; no need to try the next methods.
14849 (reaction (lookup-specification
14850 (not-found => return))))
14852 ;; Then fall back to DNS.
14856 ;; Finally, try with the "full" 'mdns'.
14861 Do not worry: the @code{%mdns-host-lookup-nss} variable (see below)
14862 contains this configuration, so you will not have to type it if all you
14863 want is to have @code{.local} host lookup working.
14865 Note that, in this case, in addition to setting the
14866 @code{name-service-switch} of the @code{operating-system} declaration,
14867 you also need to use @code{avahi-service} (@pxref{Networking Services,
14868 @code{avahi-service}}), or @var{%desktop-services}, which includes it
14869 (@pxref{Desktop Services}). Doing this makes @code{nss-mdns} accessible
14870 to the name service cache daemon (@pxref{Base Services,
14871 @code{nscd-service}}).
14873 For convenience, the following variables provide typical NSS
14876 @defvr {Scheme Variable} %default-nss
14877 This is the default name service switch configuration, a
14878 @code{name-service-switch} object.
14881 @defvr {Scheme Variable} %mdns-host-lookup-nss
14882 This is the name service switch configuration with support for host name
14883 lookup over multicast DNS (mDNS) for host names ending in @code{.local}.
14886 The reference for name service switch configuration is given below. It
14887 is a direct mapping of the configuration file format of the C library , so
14888 please refer to the C library manual for more information (@pxref{NSS
14889 Configuration File,,, libc, The GNU C Library Reference Manual}).
14890 Compared to the configuration file format of libc NSS, it has the advantage
14891 not only of adding this warm parenthetic feel that we like, but also
14892 static checks: you will know about syntax errors and typos as soon as you
14893 run @command{guix system}.
14895 @deftp {Data Type} name-service-switch
14897 This is the data type representation the configuration of libc's name
14898 service switch (NSS). Each field below represents one of the supported
14915 The system databases handled by the NSS. Each of these fields must be a
14916 list of @code{<name-service>} objects (see below).
14920 @deftp {Data Type} name-service
14922 This is the data type representing an actual name service and the
14923 associated lookup action.
14927 A string denoting the name service (@pxref{Services in the NSS
14928 configuration,,, libc, The GNU C Library Reference Manual}).
14930 Note that name services listed here must be visible to nscd. This is
14931 achieved by passing the @code{#:name-services} argument to
14932 @code{nscd-service} the list of packages providing the needed name
14933 services (@pxref{Base Services, @code{nscd-service}}).
14936 An action specified using the @code{lookup-specification} macro
14937 (@pxref{Actions in the NSS configuration,,, libc, The GNU C Library
14938 Reference Manual}). For example:
14941 (lookup-specification (unavailable => continue)
14942 (success => return))
14947 @node Initial RAM Disk
14948 @subsection Initial RAM Disk
14951 @cindex initial RAM disk
14952 For bootstrapping purposes, the Linux-Libre kernel is passed an
14953 @dfn{initial RAM disk}, or @dfn{initrd}. An initrd contains a temporary
14954 root file system as well as an initialization script. The latter is
14955 responsible for mounting the real root file system, and for loading any
14956 kernel modules that may be needed to achieve that.
14958 The @code{initrd} field of an @code{operating-system} declaration allows
14959 you to specify which initrd you would like to use. The @code{(gnu
14960 system linux-initrd)} module provides three ways to build an initrd: the
14961 high-level @code{base-initrd} procedure and the low-level
14962 @code{raw-initrd} and @code{expression->initrd} procedures.
14964 The @code{base-initrd} procedure is intended to cover most common uses.
14965 For example, if you want to add a bunch of kernel modules to be loaded
14966 at boot time, you can define the @code{initrd} field of the operating
14967 system declaration like this:
14970 (initrd (lambda (file-systems . rest)
14971 ;; Create a standard initrd that has modules "foo.ko"
14972 ;; and "bar.ko", as well as their dependencies, in
14973 ;; addition to the modules available by default.
14974 (apply base-initrd file-systems
14975 #:extra-modules '("foo" "bar")
14979 The @code{base-initrd} procedure also handles common use cases that
14980 involves using the system as a QEMU guest, or as a ``live'' system with
14981 volatile root file system.
14983 The @code{base-initrd} procedure is built from @code{raw-initrd} procedure.
14984 Unlike @code{base-initrd}, @code{raw-initrd} doesn't do anything high-level,
14985 such as trying to guess which kernel modules and packages should be included
14986 to the initrd. An example use of @code{raw-initrd} is when a user has
14987 a custom Linux kernel configuration and default kernel modules included by
14988 @code{base-initrd} are not available.
14990 The initial RAM disk produced by @code{base-initrd} or @code{raw-initrd}
14991 honors several options passed on the Linux kernel command line
14992 (that is, arguments passed @i{via} the @code{linux} command of GRUB, or the
14993 @code{-append} option of QEMU), notably:
14996 @item --load=@var{boot}
14997 Tell the initial RAM disk to load @var{boot}, a file containing a Scheme
14998 program, once it has mounted the root file system.
15000 GuixSD uses this option to yield control to a boot program that runs the
15001 service activation programs and then spawns the GNU@tie{}Shepherd, the
15002 initialization system.
15004 @item --root=@var{root}
15005 Mount @var{root} as the root file system. @var{root} can be a
15006 device name like @code{/dev/sda1}, a partition label, or a partition
15009 @item --system=@var{system}
15010 Have @file{/run/booted-system} and @file{/run/current-system} point to
15013 @item modprobe.blacklist=@var{modules}@dots{}
15014 @cindex module, black-listing
15015 @cindex black list, of kernel modules
15016 Instruct the initial RAM disk as well as the @command{modprobe} command
15017 (from the kmod package) to refuse to load @var{modules}. @var{modules}
15018 must be a comma-separated list of module names---e.g.,
15019 @code{usbkbd,9pnet}.
15022 Start a read-eval-print loop (REPL) from the initial RAM disk before it
15023 tries to load kernel modules and to mount the root file system. Our
15024 marketing team calls it @dfn{boot-to-Guile}. The Schemer in you will
15025 love it. @xref{Using Guile Interactively,,, guile, GNU Guile Reference
15026 Manual}, for more information on Guile's REPL.
15030 Now that you know all the features that initial RAM disks produced by
15031 @code{base-initrd} and @code{raw-initrd} provide,
15032 here is how to use it and customize it further.
15035 @cindex initial RAM disk
15036 @deffn {Monadic Procedure} raw-initrd @var{file-systems} @
15037 [#:linux-modules '()] [#:mapped-devices '()] @
15038 [#:helper-packages '()] [#:qemu-networking? #f] [#:volatile-root? #f]
15039 Return a monadic derivation that builds a raw initrd. @var{file-systems} is
15040 a list of file systems to be mounted by the initrd, possibly in addition to
15041 the root file system specified on the kernel command line via @code{--root}.
15042 @var{linux-modules} is a list of kernel modules to be loaded at boot time.
15043 @var{mapped-devices} is a list of device mappings to realize before
15044 @var{file-systems} are mounted (@pxref{Mapped Devices}).
15045 @var{helper-packages} is a list of packages to be copied in the initrd. It may
15046 include @code{e2fsck/static} or other packages needed by the initrd to check
15049 When @var{qemu-networking?} is true, set up networking with the standard QEMU
15050 parameters. When @var{virtio?} is true, load additional modules so that the
15051 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15053 When @var{volatile-root?} is true, the root file system is writable but any changes
15057 @deffn {Monadic Procedure} base-initrd @var{file-systems} @
15058 [#:mapped-devices '()] [#:qemu-networking? #f] [#:volatile-root? #f]@
15059 [#:virtio? #t] [#:extra-modules '()]
15060 Return a monadic derivation that builds a generic initrd. @var{file-systems} is
15061 a list of file systems to be mounted by the initrd like for @code{raw-initrd}.
15062 @var{mapped-devices}, @var{qemu-networking?} and @var{volatile-root?}
15063 also behaves as in @code{raw-initrd}.
15065 When @var{virtio?} is true, load additional modules so that the
15066 initrd can be used as a QEMU guest with para-virtualized I/O drivers.
15068 The initrd is automatically populated with all the kernel modules necessary
15069 for @var{file-systems} and for the given options. However, additional kernel
15070 modules can be listed in @var{extra-modules}. They will be added to the initrd, and
15071 loaded at boot time in the order in which they appear.
15074 Needless to say, the initrds we produce and use embed a
15075 statically-linked Guile, and the initialization program is a Guile
15076 program. That gives a lot of flexibility. The
15077 @code{expression->initrd} procedure builds such an initrd, given the
15078 program to run in that initrd.
15080 @deffn {Monadic Procedure} expression->initrd @var{exp} @
15081 [#:guile %guile-static-stripped] [#:name "guile-initrd"]
15082 Return a derivation that builds a Linux initrd (a gzipped cpio archive)
15083 containing @var{guile} and that evaluates @var{exp}, a G-expression,
15084 upon booting. All the derivations referenced by @var{exp} are
15085 automatically copied to the initrd.
15088 @node GRUB Configuration
15089 @subsection GRUB Configuration
15092 @cindex boot loader
15094 The operating system uses GNU@tie{}GRUB as its boot loader
15095 (@pxref{Overview, overview of GRUB,, grub, GNU GRUB Manual}). It is
15096 configured using a @code{grub-configuration} declaration. This data type
15097 is exported by the @code{(gnu system grub)} module and described below.
15099 @deftp {Data Type} grub-configuration
15100 The type of a GRUB configuration declaration.
15104 @item @code{device}
15105 This is a string denoting the boot device. It must be a device name
15106 understood by the @command{grub-install} command, such as
15107 @code{/dev/sda} or @code{(hd0)} (@pxref{Invoking grub-install,,, grub,
15110 @item @code{menu-entries} (default: @code{()})
15111 A possibly empty list of @code{menu-entry} objects (see below), denoting
15112 entries to appear in the GRUB boot menu, in addition to the current
15113 system entry and the entry pointing to previous system generations.
15115 @item @code{default-entry} (default: @code{0})
15116 The index of the default boot menu entry. Index 0 is for the entry of the
15119 @item @code{timeout} (default: @code{5})
15120 The number of seconds to wait for keyboard input before booting. Set to
15121 0 to boot immediately, and to -1 to wait indefinitely.
15123 @item @code{theme} (default: @var{%default-theme})
15124 The @code{grub-theme} object describing the theme to use.
15126 @item @code{grub} (default: @code{grub})
15127 The GRUB package to use.
15134 Should you want to list additional boot menu entries @i{via} the
15135 @code{menu-entries} field above, you will need to create them with the
15136 @code{menu-entry} form. For example, imagine you want to be able to
15137 boot another distro (hard to imagine!), you can define a menu entry
15142 (label "The Other Distro")
15143 (linux "/boot/old/vmlinux-2.6.32")
15144 (linux-arguments '("root=/dev/sda2"))
15145 (initrd "/boot/old/initrd"))
15150 @deftp {Data Type} menu-entry
15151 The type of an entry in the GRUB boot menu.
15156 The label to show in the menu---e.g., @code{"GNU"}.
15159 The Linux kernel image to boot, for example:
15162 (file-append linux-libre "/bzImage")
15165 It is also possible to specify a device explicitly in the file path
15166 using GRUB's device naming convention (@pxref{Naming convention,,, grub,
15167 GNU GRUB manual}), for example:
15170 "(hd0,msdos1)/boot/vmlinuz"
15173 If the device is specified explicitly as above, then the @code{device}
15174 field is ignored entirely.
15176 @item @code{linux-arguments} (default: @code{()})
15177 The list of extra Linux kernel command-line arguments---e.g.,
15178 @code{("console=ttyS0")}.
15180 @item @code{initrd}
15181 A G-Expression or string denoting the file name of the initial RAM disk
15182 to use (@pxref{G-Expressions}).
15184 @item @code{device} (default: @code{#f})
15185 The device where the kernel and initrd are to be found---i.e., the GRUB
15186 @dfn{root} for this menu entry (@pxref{root,,, grub, GNU GRUB manual}).
15188 This may be a file system label (a string), a file system UUID (a
15189 bytevector, @pxref{File Systems}), or @code{#f}, in which case GRUB will
15190 search the device containing the file specified by the @code{linux}
15191 field (@pxref{search,,, grub, GNU GRUB manual}). It must @emph{not} be
15192 an OS device name such as @file{/dev/sda1}.
15194 @item @code{device-mount-point} (default: @code{"/"})
15195 The mount point of the above device on the system. You probably do not
15196 need to change the default value. GuixSD uses it to strip the prefix of
15197 store file names for systems where @file{/gnu} or @file{/gnu/store} is
15198 on a separate partition.
15203 @c FIXME: Write documentation once it's stable.
15204 Themes are created using the @code{grub-theme} form, which is not
15207 @defvr {Scheme Variable} %default-theme
15208 This is the default GRUB theme used by the operating system, with a
15209 fancy background image displaying the GNU and Guix logos.
15213 @node Invoking guix system
15214 @subsection Invoking @code{guix system}
15216 Once you have written an operating system declaration as seen in the
15217 previous section, it can be @dfn{instantiated} using the @command{guix
15218 system} command. The synopsis is:
15221 guix system @var{options}@dots{} @var{action} @var{file}
15224 @var{file} must be the name of a file containing an
15225 @code{operating-system} declaration. @var{action} specifies how the
15226 operating system is instantiated. Currently the following values are
15231 Build the operating system described in @var{file}, activate it, and
15232 switch to it@footnote{This action (and the related actions
15233 @code{switch-generation} and @code{roll-back}) are usable only on
15234 systems already running GuixSD.}.
15236 This effects all the configuration specified in @var{file}: user
15237 accounts, system services, global package list, setuid programs, etc.
15238 The command starts system services specified in @var{file} that are not
15239 currently running; if a service is currently running, it does not
15240 attempt to upgrade it since this would not be possible without stopping it
15243 This command creates a new generation whose number is one greater than
15244 the current generation (as reported by @command{guix system
15245 list-generations}). If that generation already exists, it will be
15246 overwritten. This behavior mirrors that of @command{guix package}
15247 (@pxref{Invoking guix package}).
15249 It also adds a GRUB menu entry for the new OS configuration, and moves
15250 entries for older configurations to a submenu---unless
15251 @option{--no-bootloader} is passed.
15254 @c The paragraph below refers to the problem discussed at
15255 @c <http://lists.gnu.org/archive/html/guix-devel/2014-08/msg00057.html>.
15256 It is highly recommended to run @command{guix pull} once before you run
15257 @command{guix system reconfigure} for the first time (@pxref{Invoking
15258 guix pull}). Failing to do that you would see an older version of Guix
15259 once @command{reconfigure} has completed.
15262 @item switch-generation
15263 @cindex generations
15264 Switch to an existing system generation. This action atomically
15265 switches the system profile to the specified system generation. It also
15266 rearranges the system's existing GRUB menu entries. It makes the menu
15267 entry for the specified system generation the default, and it moves the
15268 entries for the other generations to a submenu. The next time the
15269 system boots, it will use the specified system generation.
15271 The target generation can be specified explicitly by its generation
15272 number. For example, the following invocation would switch to system
15276 guix system switch-generation 7
15279 The target generation can also be specified relative to the current
15280 generation with the form @code{+N} or @code{-N}, where @code{+3} means
15281 ``3 generations ahead of the current generation,'' and @code{-1} means
15282 ``1 generation prior to the current generation.'' When specifying a
15283 negative value such as @code{-1}, you must precede it with @code{--} to
15284 prevent it from being parsed as an option. For example:
15287 guix system switch-generation -- -1
15290 Currently, the effect of invoking this action is @emph{only} to switch
15291 the system profile to an existing generation and rearrange the GRUB menu
15292 entries. To actually start using the target system generation, you must
15293 reboot after running this action. In the future, it will be updated to
15294 do the same things as @command{reconfigure}, like activating and
15295 deactivating services.
15297 This action will fail if the specified generation does not exist.
15300 @cindex rolling back
15301 Switch to the preceding system generation. The next time the system
15302 boots, it will use the preceding system generation. This is the inverse
15303 of @command{reconfigure}, and it is exactly the same as invoking
15304 @command{switch-generation} with an argument of @code{-1}.
15306 Currently, as with @command{switch-generation}, you must reboot after
15307 running this action to actually start using the preceding system
15311 Build the derivation of the operating system, which includes all the
15312 configuration files and programs needed to boot and run the system.
15313 This action does not actually install anything.
15316 Populate the given directory with all the files necessary to run the
15317 operating system specified in @var{file}. This is useful for first-time
15318 installations of GuixSD. For instance:
15321 guix system init my-os-config.scm /mnt
15324 copies to @file{/mnt} all the store items required by the configuration
15325 specified in @file{my-os-config.scm}. This includes configuration
15326 files, packages, and so on. It also creates other essential files
15327 needed for the system to operate correctly---e.g., the @file{/etc},
15328 @file{/var}, and @file{/run} directories, and the @file{/bin/sh} file.
15330 This command also installs GRUB on the device specified in
15331 @file{my-os-config}, unless the @option{--no-bootloader} option was passed.
15334 @cindex virtual machine
15336 @anchor{guix system vm}
15337 Build a virtual machine that contains the operating system declared in
15338 @var{file}, and return a script to run that virtual machine (VM).
15339 Arguments given to the script are passed to QEMU.
15341 The VM shares its store with the host system.
15343 Additional file systems can be shared between the host and the VM using
15344 the @code{--share} and @code{--expose} command-line options: the former
15345 specifies a directory to be shared with write access, while the latter
15346 provides read-only access to the shared directory.
15348 The example below creates a VM in which the user's home directory is
15349 accessible read-only, and where the @file{/exchange} directory is a
15350 read-write mapping of @file{$HOME/tmp} on the host:
15353 guix system vm my-config.scm \
15354 --expose=$HOME --share=$HOME/tmp=/exchange
15357 On GNU/Linux, the default is to boot directly to the kernel; this has
15358 the advantage of requiring only a very tiny root disk image since the
15359 store of the host can then be mounted.
15361 The @code{--full-boot} option forces a complete boot sequence, starting
15362 with the bootloader. This requires more disk space since a root image
15363 containing at least the kernel, initrd, and bootloader data files must
15364 be created. The @code{--image-size} option can be used to specify the
15369 Return a virtual machine or disk image of the operating system declared
15370 in @var{file} that stands alone. Use the @option{--image-size} option
15371 to specify the size of the image.
15373 When using @code{vm-image}, the returned image is in qcow2 format, which
15374 the QEMU emulator can efficiently use. @xref{Running GuixSD in a VM},
15375 for more information on how to run the image in a virtual machine.
15377 When using @code{disk-image}, a raw disk image is produced; it can be
15378 copied as is to a USB stick, for instance. Assuming @code{/dev/sdc} is
15379 the device corresponding to a USB stick, one can copy the image to it
15380 using the following command:
15383 # dd if=$(guix system disk-image my-os.scm) of=/dev/sdc
15387 Return a script to run the operating system declared in @var{file}
15388 within a container. Containers are a set of lightweight isolation
15389 mechanisms provided by the kernel Linux-libre. Containers are
15390 substantially less resource-demanding than full virtual machines since
15391 the kernel, shared objects, and other resources can be shared with the
15392 host system; this also means they provide thinner isolation.
15394 Currently, the script must be run as root in order to support more than
15395 a single user and group. The container shares its store with the host
15398 As with the @code{vm} action (@pxref{guix system vm}), additional file
15399 systems to be shared between the host and container can be specified
15400 using the @option{--share} and @option{--expose} options:
15403 guix system container my-config.scm \
15404 --expose=$HOME --share=$HOME/tmp=/exchange
15408 This option requires Linux-libre 3.19 or newer.
15413 @var{options} can contain any of the common build options (@pxref{Common
15414 Build Options}). In addition, @var{options} can contain one of the
15418 @item --system=@var{system}
15419 @itemx -s @var{system}
15420 Attempt to build for @var{system} instead of the host system type.
15421 This works as per @command{guix build} (@pxref{Invoking guix build}).
15425 Return the derivation file name of the given operating system without
15428 @item --image-size=@var{size}
15429 For the @code{vm-image} and @code{disk-image} actions, create an image
15430 of the given @var{size}. @var{size} may be a number of bytes, or it may
15431 include a unit as a suffix (@pxref{Block size, size specifications,,
15432 coreutils, GNU Coreutils}).
15434 @item --root=@var{file}
15435 @itemx -r @var{file}
15436 Make @var{file} a symlink to the result, and register it as a garbage
15439 @item --on-error=@var{strategy}
15440 Apply @var{strategy} when an error occurs when reading @var{file}.
15441 @var{strategy} may be one of the following:
15444 @item nothing-special
15445 Report the error concisely and exit. This is the default strategy.
15448 Likewise, but also display a backtrace.
15451 Report the error and enter Guile's debugger. From there, you can run
15452 commands such as @code{,bt} to get a backtrace, @code{,locals} to
15453 display local variable values, and more generally inspect the state of the
15454 program. @xref{Debug Commands,,, guile, GNU Guile Reference Manual}, for
15455 a list of available debugging commands.
15460 All the actions above, except @code{build} and @code{init},
15461 can use KVM support in the Linux-libre kernel. Specifically, if the
15462 machine has hardware virtualization support, the corresponding
15463 KVM kernel module should be loaded, and the @file{/dev/kvm} device node
15464 must exist and be readable and writable by the user and by the
15465 build users of the daemon (@pxref{Build Environment Setup}).
15468 Once you have built, configured, re-configured, and re-re-configured
15469 your GuixSD installation, you may find it useful to list the operating
15470 system generations available on disk---and that you can choose from the
15475 @item list-generations
15476 List a summary of each generation of the operating system available on
15477 disk, in a human-readable way. This is similar to the
15478 @option{--list-generations} option of @command{guix package}
15479 (@pxref{Invoking guix package}).
15481 Optionally, one can specify a pattern, with the same syntax that is used
15482 in @command{guix package --list-generations}, to restrict the list of
15483 generations displayed. For instance, the following command displays
15484 generations that are up to 10 days old:
15487 $ guix system list-generations 10d
15492 The @command{guix system} command has even more to offer! The following
15493 sub-commands allow you to visualize how your system services relate to
15496 @anchor{system-extension-graph}
15499 @item extension-graph
15500 Emit in Dot/Graphviz format to standard output the @dfn{service
15501 extension graph} of the operating system defined in @var{file}
15502 (@pxref{Service Composition}, for more information on service
15508 $ guix system extension-graph @var{file} | dot -Tpdf > services.pdf
15511 produces a PDF file showing the extension relations among services.
15513 @anchor{system-shepherd-graph}
15514 @item shepherd-graph
15515 Emit in Dot/Graphviz format to standard output the @dfn{dependency
15516 graph} of shepherd services of the operating system defined in
15517 @var{file}. @xref{Shepherd Services}, for more information and for an
15522 @node Running GuixSD in a VM
15523 @subsection Running GuixSD in a Virtual Machine
15525 @cindex virtual machine
15526 One way to run GuixSD in a virtual machine (VM) is to build a GuixSD
15527 virtual machine image using @command{guix system vm-image}
15528 (@pxref{Invoking guix system}). The returned image is in qcow2 format,
15529 which the @uref{http://qemu.org/, QEMU emulator} can efficiently use.
15532 To run the image in QEMU, copy it out of the store (@pxref{The Store})
15533 and give yourself permission to write to the copy. When invoking QEMU,
15534 you must choose a system emulator that is suitable for your hardware
15535 platform. Here is a minimal QEMU invocation that will boot the result
15536 of @command{guix system vm-image} on x86_64 hardware:
15539 $ qemu-system-x86_64 \
15540 -net user -net nic,model=virtio \
15541 -enable-kvm -m 256 /tmp/qemu-image
15544 Here is what each of these options means:
15547 @item qemu-system-x86_64
15548 This specifies the hardware platform to emulate. This should match the
15552 Enable the unprivileged user-mode network stack. The guest OS can
15553 access the host but not vice versa. This is the simplest way to get the
15556 @item -net nic,model=virtio
15557 You must create a network interface of a given model. If you do not
15558 create a NIC, the boot will fail. Assuming your hardware platform is
15559 x86_64, you can get a list of available NIC models by running
15560 @command{qemu-system-x86_64 -net nic,model=help}.
15563 If your system has hardware virtualization extensions, enabling the
15564 virtual machine support (KVM) of the Linux kernel will make things run
15568 RAM available to the guest OS, in mebibytes. Defaults to 128@tie{}MiB,
15569 which may be insufficient for some operations.
15571 @item /tmp/qemu-image
15572 The file name of the qcow2 image.
15575 The default @command{run-vm.sh} script that is returned by an invocation of
15576 @command{guix system vm} does not add a @command{-net user} flag by default.
15577 To get network access from within the vm add the @code{(dhcp-client-service)}
15578 to your system definition and start the VM using
15579 @command{`guix system vm config.scm` -net user}. An important caveat of using
15580 @command{-net user} for networking is that @command{ping} will not work, because
15581 it uses the ICMP protocol. You'll have to use a different command to check for
15582 network connectivity, like for example @command{curl}.
15584 @subsubsection Connecting Through SSH
15588 To enable SSH inside a VM you need to add a SSH server like @code{(dropbear-service)}
15589 or @code{(lsh-service)} to your VM. The @code{(lsh-service}) doesn't currently
15590 boot unsupervised. It requires you to type some characters to initialize the
15591 randomness generator. In addition you need to forward the SSH port, 22 by
15592 default, to the host. You can do this with
15595 `guix system vm config.scm` -net user,hostfwd=tcp::10022-:22
15598 To connect to the VM you can run
15601 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p 10022
15604 The @command{-p} tells @command{ssh} the port you want to connect to.
15605 @command{-o UserKnownHostsFile=/dev/null} prevents @command{ssh} from complaining
15606 every time you modify your @command{config.scm} file and the
15607 @command{-o StrictHostKeyChecking=no} prevents you from having to allow a
15608 connection to an unknown host every time you connect.
15610 @subsubsection Using @command{virt-viewer} with Spice
15612 As an alternative to the default @command{qemu} graphical client you can
15613 use the @command{remote-viewer} from the @command{virt-viewer} package. To
15614 connect pass the @command{-spice port=5930,disable-ticketing} flag to
15615 @command{qemu}. See previous section for further information on how to do this.
15617 Spice also allows you to do some nice stuff like share your clipboard with your
15618 VM. To enable that you'll also have to pass the following flags to @command{qemu}:
15621 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5
15622 -chardev spicevmc,name=vdagent,id=vdagent
15623 -device virtserialport,nr=1,bus=virtio-serial0.0,chardev=vdagent,
15624 name=com.redhat.spice.0
15627 You'll also need to add the @pxref{Miscellaneous Services, Spice service}.
15629 @node Defining Services
15630 @subsection Defining Services
15632 The previous sections show the available services and how one can combine
15633 them in an @code{operating-system} declaration. But how do we define
15634 them in the first place? And what is a service anyway?
15637 * Service Composition:: The model for composing services.
15638 * Service Types and Services:: Types and services.
15639 * Service Reference:: API reference.
15640 * Shepherd Services:: A particular type of service.
15643 @node Service Composition
15644 @subsubsection Service Composition
15648 Here we define a @dfn{service} as, broadly, something that extends the
15649 functionality of the operating system. Often a service is a process---a
15650 @dfn{daemon}---started when the system boots: a secure shell server, a
15651 Web server, the Guix build daemon, etc. Sometimes a service is a daemon
15652 whose execution can be triggered by another daemon---e.g., an FTP server
15653 started by @command{inetd} or a D-Bus service activated by
15654 @command{dbus-daemon}. Occasionally, a service does not map to a
15655 daemon. For instance, the ``account'' service collects user accounts
15656 and makes sure they exist when the system runs; the ``udev'' service
15657 collects device management rules and makes them available to the eudev
15658 daemon; the @file{/etc} service populates the @file{/etc} directory
15661 @cindex service extensions
15662 GuixSD services are connected by @dfn{extensions}. For instance, the
15663 secure shell service @emph{extends} the Shepherd---the GuixSD
15664 initialization system, running as PID@tie{}1---by giving it the command
15665 lines to start and stop the secure shell daemon (@pxref{Networking
15666 Services, @code{lsh-service}}); the UPower service extends the D-Bus
15667 service by passing it its @file{.service} specification, and extends the
15668 udev service by passing it device management rules (@pxref{Desktop
15669 Services, @code{upower-service}}); the Guix daemon service extends the
15670 Shepherd by passing it the command lines to start and stop the daemon,
15671 and extends the account service by passing it a list of required build
15672 user accounts (@pxref{Base Services}).
15674 All in all, services and their ``extends'' relations form a directed
15675 acyclic graph (DAG). If we represent services as boxes and extensions
15676 as arrows, a typical system might provide something like this:
15678 @image{images/service-graph,,5in,Typical service extension graph.}
15680 @cindex system service
15681 At the bottom, we see the @dfn{system service}, which produces the
15682 directory containing everything to run and boot the system, as returned
15683 by the @command{guix system build} command. @xref{Service Reference},
15684 to learn about the other service types shown here.
15685 @xref{system-extension-graph, the @command{guix system extension-graph}
15686 command}, for information on how to generate this representation for a
15687 particular operating system definition.
15689 @cindex service types
15690 Technically, developers can define @dfn{service types} to express these
15691 relations. There can be any number of services of a given type on the
15692 system---for instance, a system running two instances of the GNU secure
15693 shell server (lsh) has two instances of @var{lsh-service-type}, with
15694 different parameters.
15696 The following section describes the programming interface for service
15697 types and services.
15699 @node Service Types and Services
15700 @subsubsection Service Types and Services
15702 A @dfn{service type} is a node in the DAG described above. Let us start
15703 with a simple example, the service type for the Guix build daemon
15704 (@pxref{Invoking guix-daemon}):
15707 (define guix-service-type
15711 (list (service-extension shepherd-root-service-type guix-shepherd-service)
15712 (service-extension account-service-type guix-accounts)
15713 (service-extension activation-service-type guix-activation)))
15714 (default-value (guix-configuration))))
15718 It defines three things:
15722 A name, whose sole purpose is to make inspection and debugging easier.
15725 A list of @dfn{service extensions}, where each extension designates the
15726 target service type and a procedure that, given the parameters of the
15727 service, returns a list of objects to extend the service of that type.
15729 Every service type has at least one service extension. The only
15730 exception is the @dfn{boot service type}, which is the ultimate service.
15733 Optionally, a default value for instances of this type.
15736 In this example, @var{guix-service-type} extends three services:
15739 @item shepherd-root-service-type
15740 The @var{guix-shepherd-service} procedure defines how the Shepherd
15741 service is extended. Namely, it returns a @code{<shepherd-service>}
15742 object that defines how @command{guix-daemon} is started and stopped
15743 (@pxref{Shepherd Services}).
15745 @item account-service-type
15746 This extension for this service is computed by @var{guix-accounts},
15747 which returns a list of @code{user-group} and @code{user-account}
15748 objects representing the build user accounts (@pxref{Invoking
15751 @item activation-service-type
15752 Here @var{guix-activation} is a procedure that returns a gexp, which is
15753 a code snippet to run at ``activation time''---e.g., when the service is
15757 A service of this type is instantiated like this:
15760 (service guix-service-type
15761 (guix-configuration
15763 (use-substitutes? #f)))
15766 The second argument to the @code{service} form is a value representing
15767 the parameters of this specific service instance.
15768 @xref{guix-configuration-type, @code{guix-configuration}}, for
15769 information about the @code{guix-configuration} data type. When the
15770 value is omitted, the default value specified by
15771 @code{guix-service-type} is used:
15774 (service guix-service-type)
15777 @var{guix-service-type} is quite simple because it extends other
15778 services but is not extensible itself.
15780 @c @subsubsubsection Extensible Service Types
15782 The service type for an @emph{extensible} service looks like this:
15785 (define udev-service-type
15786 (service-type (name 'udev)
15788 (list (service-extension shepherd-root-service-type
15789 udev-shepherd-service)))
15791 (compose concatenate) ;concatenate the list of rules
15792 (extend (lambda (config rules)
15794 (($ <udev-configuration> udev initial-rules)
15795 (udev-configuration
15796 (udev udev) ;the udev package to use
15797 (rules (append initial-rules rules)))))))))
15800 This is the service type for the
15801 @uref{https://wiki.gentoo.org/wiki/Project:Eudev, eudev device
15802 management daemon}. Compared to the previous example, in addition to an
15803 extension of @var{shepherd-root-service-type}, we see two new fields:
15807 This is the procedure to @dfn{compose} the list of extensions to
15808 services of this type.
15810 Services can extend the udev service by passing it lists of rules; we
15811 compose those extensions simply by concatenating them.
15814 This procedure defines how the value of the service is @dfn{extended} with
15815 the composition of the extensions.
15817 Udev extensions are composed into a list of rules, but the udev service
15818 value is itself a @code{<udev-configuration>} record. So here, we
15819 extend that record by appending the list of rules it contains to the
15820 list of contributed rules.
15823 There can be only one instance of an extensible service type such as
15824 @var{udev-service-type}. If there were more, the
15825 @code{service-extension} specifications would be ambiguous.
15827 Still here? The next section provides a reference of the programming
15828 interface for services.
15830 @node Service Reference
15831 @subsubsection Service Reference
15833 We have seen an overview of service types (@pxref{Service Types and
15834 Services}). This section provides a reference on how to manipulate
15835 services and service types. This interface is provided by the
15836 @code{(gnu services)} module.
15838 @deffn {Scheme Procedure} service @var{type} [@var{value}]
15839 Return a new service of @var{type}, a @code{<service-type>} object (see
15840 below.) @var{value} can be any object; it represents the parameters of
15841 this particular service instance.
15843 When @var{value} is omitted, the default value specified by @var{type}
15844 is used; if @var{type} does not specify a default value, an error is
15847 For instance, this:
15850 (service openssh-service-type)
15854 is equivalent to this:
15857 (service openssh-service-type
15858 (openssh-configuration))
15861 In both cases the result is an instance of @code{openssh-service-type}
15862 with the default configuration.
15865 @deffn {Scheme Procedure} service? @var{obj}
15866 Return true if @var{obj} is a service.
15869 @deffn {Scheme Procedure} service-kind @var{service}
15870 Return the type of @var{service}---i.e., a @code{<service-type>} object.
15873 @deffn {Scheme Procedure} service-value @var{service}
15874 Return the value associated with @var{service}. It represents its
15878 Here is an example of how a service is created and manipulated:
15882 (service nginx-service-type
15883 (nginx-configuration
15885 (log-directory log-directory)
15886 (run-directory run-directory)
15887 (file config-file))))
15892 (eq? (service-kind s) nginx-service-type)
15896 The @code{modify-services} form provides a handy way to change the
15897 parameters of some of the services of a list such as
15898 @var{%base-services} (@pxref{Base Services, @code{%base-services}}). It
15899 evaluates to a list of services. Of course, you could always use
15900 standard list combinators such as @code{map} and @code{fold} to do that
15901 (@pxref{SRFI-1, List Library,, guile, GNU Guile Reference Manual});
15902 @code{modify-services} simply provides a more concise form for this
15905 @deffn {Scheme Syntax} modify-services @var{services} @
15906 (@var{type} @var{variable} => @var{body}) @dots{}
15908 Modify the services listed in @var{services} according to the given
15909 clauses. Each clause has the form:
15912 (@var{type} @var{variable} => @var{body})
15915 where @var{type} is a service type---e.g.,
15916 @code{guix-service-type}---and @var{variable} is an identifier that is
15917 bound within the @var{body} to the service parameters---e.g., a
15918 @code{guix-configuration} instance---of the original service of that
15921 The @var{body} should evaluate to the new service parameters, which will
15922 be used to configure the new service. This new service will replace the
15923 original in the resulting list. Because a service's service parameters
15924 are created using @code{define-record-type*}, you can write a succinct
15925 @var{body} that evaluates to the new service parameters by using the
15926 @code{inherit} feature that @code{define-record-type*} provides.
15928 @xref{Using the Configuration System}, for example usage.
15932 Next comes the programming interface for service types. This is
15933 something you want to know when writing new service definitions, but not
15934 necessarily when simply looking for ways to customize your
15935 @code{operating-system} declaration.
15937 @deftp {Data Type} service-type
15938 @cindex service type
15939 This is the representation of a @dfn{service type} (@pxref{Service Types
15944 This is a symbol, used only to simplify inspection and debugging.
15946 @item @code{extensions}
15947 A non-empty list of @code{<service-extension>} objects (see below).
15949 @item @code{compose} (default: @code{#f})
15950 If this is @code{#f}, then the service type denotes services that cannot
15951 be extended---i.e., services that do not receive ``values'' from other
15954 Otherwise, it must be a one-argument procedure. The procedure is called
15955 by @code{fold-services} and is passed a list of values collected from
15956 extensions. It must return a value that is a valid parameter value for
15957 the service instance.
15959 @item @code{extend} (default: @code{#f})
15960 If this is @code{#f}, services of this type cannot be extended.
15962 Otherwise, it must be a two-argument procedure: @code{fold-services}
15963 calls it, passing it the initial value of the service as the first argument
15964 and the result of applying @code{compose} to the extension values as the
15968 @xref{Service Types and Services}, for examples.
15971 @deffn {Scheme Procedure} service-extension @var{target-type} @
15973 Return a new extension for services of type @var{target-type}.
15974 @var{compute} must be a one-argument procedure: @code{fold-services}
15975 calls it, passing it the value associated with the service that provides
15976 the extension; it must return a valid value for the target service.
15979 @deffn {Scheme Procedure} service-extension? @var{obj}
15980 Return true if @var{obj} is a service extension.
15983 Occasionally, you might want to simply extend an existing service. This
15984 involves creating a new service type and specifying the extension of
15985 interest, which can be verbose; the @code{simple-service} procedure
15986 provides a shorthand for this.
15988 @deffn {Scheme Procedure} simple-service @var{name} @var{target} @var{value}
15989 Return a service that extends @var{target} with @var{value}. This works
15990 by creating a singleton service type @var{name}, of which the returned
15991 service is an instance.
15993 For example, this extends mcron (@pxref{Scheduled Job Execution}) with
15997 (simple-service 'my-mcron-job mcron-service-type
15998 #~(job '(next-hour (3)) "guix gc -F 2G"))
16002 At the core of the service abstraction lies the @code{fold-services}
16003 procedure, which is responsible for ``compiling'' a list of services
16004 down to a single directory that contains everything needed to boot and
16005 run the system---the directory shown by the @command{guix system build}
16006 command (@pxref{Invoking guix system}). In essence, it propagates
16007 service extensions down the service graph, updating each node parameters
16008 on the way, until it reaches the root node.
16010 @deffn {Scheme Procedure} fold-services @var{services} @
16011 [#:target-type @var{system-service-type}]
16012 Fold @var{services} by propagating their extensions down to the root of
16013 type @var{target-type}; return the root service adjusted accordingly.
16016 Lastly, the @code{(gnu services)} module also defines several essential
16017 service types, some of which are listed below.
16019 @defvr {Scheme Variable} system-service-type
16020 This is the root of the service graph. It produces the system directory
16021 as returned by the @command{guix system build} command.
16024 @defvr {Scheme Variable} boot-service-type
16025 The type of the ``boot service'', which produces the @dfn{boot script}.
16026 The boot script is what the initial RAM disk runs when booting.
16029 @defvr {Scheme Variable} etc-service-type
16030 The type of the @file{/etc} service. This service can be extended by
16031 passing it name/file tuples such as:
16034 (list `("issue" ,(plain-file "issue" "Welcome!\n")))
16037 In this example, the effect would be to add an @file{/etc/issue} file
16038 pointing to the given file.
16041 @defvr {Scheme Variable} setuid-program-service-type
16042 Type for the ``setuid-program service''. This service collects lists of
16043 executable file names, passed as gexps, and adds them to the set of
16044 setuid-root programs on the system (@pxref{Setuid Programs}).
16047 @defvr {Scheme Variable} profile-service-type
16048 Type of the service that populates the @dfn{system profile}---i.e., the
16049 programs under @file{/run/current-system/profile}. Other services can
16050 extend it by passing it lists of packages to add to the system profile.
16054 @node Shepherd Services
16055 @subsubsection Shepherd Services
16057 @cindex shepherd services
16059 @cindex init system
16060 The @code{(gnu services shepherd)} module provides a way to define
16061 services managed by the GNU@tie{}Shepherd, which is the GuixSD
16062 initialization system---the first process that is started when the
16063 system boots, also known as PID@tie{}1
16064 (@pxref{Introduction,,, shepherd, The GNU Shepherd Manual}).
16066 Services in the Shepherd can depend on each other. For instance, the
16067 SSH daemon may need to be started after the syslog daemon has been
16068 started, which in turn can only happen once all the file systems have
16069 been mounted. The simple operating system defined earlier (@pxref{Using
16070 the Configuration System}) results in a service graph like this:
16072 @image{images/shepherd-graph,,5in,Typical shepherd service graph.}
16074 You can actually generate such a graph for any operating system
16075 definition using the @command{guix system shepherd-graph} command
16076 (@pxref{system-shepherd-graph, @command{guix system shepherd-graph}}).
16078 The @var{%shepherd-root-service} is a service object representing
16079 PID@tie{}1, of type @var{shepherd-root-service-type}; it can be extended
16080 by passing it lists of @code{<shepherd-service>} objects.
16082 @deftp {Data Type} shepherd-service
16083 The data type representing a service managed by the Shepherd.
16086 @item @code{provision}
16087 This is a list of symbols denoting what the service provides.
16089 These are the names that may be passed to @command{herd start},
16090 @command{herd status}, and similar commands (@pxref{Invoking herd,,,
16091 shepherd, The GNU Shepherd Manual}). @xref{Slots of services, the
16092 @code{provides} slot,, shepherd, The GNU Shepherd Manual}, for details.
16094 @item @code{requirements} (default: @code{'()})
16095 List of symbols denoting the Shepherd services this one depends on.
16097 @item @code{respawn?} (default: @code{#t})
16098 Whether to restart the service when it stops, for instance when the
16099 underlying process dies.
16102 @itemx @code{stop} (default: @code{#~(const #f)})
16103 The @code{start} and @code{stop} fields refer to the Shepherd's
16104 facilities to start and stop processes (@pxref{Service De- and
16105 Constructors,,, shepherd, The GNU Shepherd Manual}). They are given as
16106 G-expressions that get expanded in the Shepherd configuration file
16107 (@pxref{G-Expressions}).
16109 @item @code{documentation}
16110 A documentation string, as shown when running:
16113 herd doc @var{service-name}
16116 where @var{service-name} is one of the symbols in @var{provision}
16117 (@pxref{Invoking herd,,, shepherd, The GNU Shepherd Manual}).
16119 @item @code{modules} (default: @var{%default-modules})
16120 This is the list of modules that must be in scope when @code{start} and
16121 @code{stop} are evaluated.
16126 @defvr {Scheme Variable} shepherd-root-service-type
16127 The service type for the Shepherd ``root service''---i.e., PID@tie{}1.
16129 This is the service type that extensions target when they want to create
16130 shepherd services (@pxref{Service Types and Services}, for an example).
16131 Each extension must pass a list of @code{<shepherd-service>}.
16134 @defvr {Scheme Variable} %shepherd-root-service
16135 This service represents PID@tie{}1.
16139 @node Documentation
16140 @section Documentation
16142 @cindex documentation, searching for
16143 @cindex searching for documentation
16144 @cindex Info, documentation format
16146 @cindex manual pages
16147 In most cases packages installed with Guix come with documentation.
16148 There are two main documentation formats: ``Info'', a browseable
16149 hypertext format used for GNU software, and ``manual pages'' (or ``man
16150 pages''), the linear documentation format traditionally found on Unix.
16151 Info manuals are accessed with the @command{info} command or with Emacs,
16152 and man pages are accessed using @command{man}.
16154 You can look for documentation of software installed on your system by
16155 keyword. For example, the following command searches for information
16156 about ``TLS'' in Info manuals:
16160 "(emacs)Network Security" -- STARTTLS
16161 "(emacs)Network Security" -- TLS
16162 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_flags
16163 "(gnutls)Core TLS API" -- gnutls_certificate_set_verify_function
16168 The command below searches for the same keyword in man pages:
16172 SSL (7) - OpenSSL SSL/TLS library
16173 certtool (1) - GnuTLS certificate tool
16177 These searches are purely local to your computer so you have the
16178 guarantee that documentation you find corresponds to what you have
16179 actually installed, you can access it off-line, and your privacy is
16182 Once you have these results, you can view the relevant documentation by
16186 $ info "(gnutls)Core TLS API"
16196 Info manuals contain sections and indices as well as hyperlinks like
16197 those found in Web pages. The @command{info} reader (@pxref{Top, Info
16198 reader,, info-stnd, Stand-alone GNU Info}) and its Emacs counterpart
16199 (@pxref{Misc Help,,, emacs, The GNU Emacs Manual}) provide intuitive key
16200 bindings to navigate manuals. @xref{Getting Started,,, info, Info: An
16201 Introduction}, for an introduction to Info navigation.
16203 @node Installing Debugging Files
16204 @section Installing Debugging Files
16206 @cindex debugging files
16207 Program binaries, as produced by the GCC compilers for instance, are
16208 typically written in the ELF format, with a section containing
16209 @dfn{debugging information}. Debugging information is what allows the
16210 debugger, GDB, to map binary code to source code; it is required to
16211 debug a compiled program in good conditions.
16213 The problem with debugging information is that is takes up a fair amount
16214 of disk space. For example, debugging information for the GNU C Library
16215 weighs in at more than 60 MiB. Thus, as a user, keeping all the
16216 debugging info of all the installed programs is usually not an option.
16217 Yet, space savings should not come at the cost of an impediment to
16218 debugging---especially in the GNU system, which should make it easier
16219 for users to exert their computing freedom (@pxref{GNU Distribution}).
16221 Thankfully, the GNU Binary Utilities (Binutils) and GDB provide a
16222 mechanism that allows users to get the best of both worlds: debugging
16223 information can be stripped from the binaries and stored in separate
16224 files. GDB is then able to load debugging information from those files,
16225 when they are available (@pxref{Separate Debug Files,,, gdb, Debugging
16228 The GNU distribution takes advantage of this by storing debugging
16229 information in the @code{lib/debug} sub-directory of a separate package
16230 output unimaginatively called @code{debug} (@pxref{Packages with
16231 Multiple Outputs}). Users can choose to install the @code{debug} output
16232 of a package when they need it. For instance, the following command
16233 installs the debugging information for the GNU C Library and for GNU
16237 guix package -i glibc:debug guile:debug
16240 GDB must then be told to look for debug files in the user's profile, by
16241 setting the @code{debug-file-directory} variable (consider setting it
16242 from the @file{~/.gdbinit} file, @pxref{Startup,,, gdb, Debugging with
16246 (gdb) set debug-file-directory ~/.guix-profile/lib/debug
16249 From there on, GDB will pick up debugging information from the
16250 @code{.debug} files under @file{~/.guix-profile/lib/debug}.
16252 In addition, you will most likely want GDB to be able to show the source
16253 code being debugged. To do that, you will have to unpack the source
16254 code of the package of interest (obtained with @code{guix build
16255 --source}, @pxref{Invoking guix build}), and to point GDB to that source
16256 directory using the @code{directory} command (@pxref{Source Path,
16257 @code{directory},, gdb, Debugging with GDB}).
16259 @c XXX: keep me up-to-date
16260 The @code{debug} output mechanism in Guix is implemented by the
16261 @code{gnu-build-system} (@pxref{Build Systems}). Currently, it is
16262 opt-in---debugging information is available only for the packages
16263 with definitions explicitly declaring a @code{debug} output. This may be
16264 changed to opt-out in the future if our build farm servers can handle
16265 the load. To check whether a package has a @code{debug} output, use
16266 @command{guix package --list-available} (@pxref{Invoking guix package}).
16269 @node Security Updates
16270 @section Security Updates
16272 @cindex security updates
16273 @cindex security vulnerabilities
16274 Occasionally, important security vulnerabilities are discovered in software
16275 packages and must be patched. Guix developers try hard to keep track of
16276 known vulnerabilities and to apply fixes as soon as possible in the
16277 @code{master} branch of Guix (we do not yet provide a ``stable'' branch
16278 containing only security updates.) The @command{guix lint} tool helps
16279 developers find out about vulnerable versions of software packages in the
16284 gnu/packages/base.scm:652:2: glibc@@2.21: probably vulnerable to CVE-2015-1781, CVE-2015-7547
16285 gnu/packages/gcc.scm:334:2: gcc@@4.9.3: probably vulnerable to CVE-2015-5276
16286 gnu/packages/image.scm:312:2: openjpeg@@2.1.0: probably vulnerable to CVE-2016-1923, CVE-2016-1924
16290 @xref{Invoking guix lint}, for more information.
16293 As of version @value{VERSION}, the feature described below is considered
16297 Guix follows a functional
16298 package management discipline (@pxref{Introduction}), which implies
16299 that, when a package is changed, @emph{every package that depends on it}
16300 must be rebuilt. This can significantly slow down the deployment of
16301 fixes in core packages such as libc or Bash, since basically the whole
16302 distribution would need to be rebuilt. Using pre-built binaries helps
16303 (@pxref{Substitutes}), but deployment may still take more time than
16307 To address this, Guix implements @dfn{grafts}, a mechanism that allows
16308 for fast deployment of critical updates without the costs associated
16309 with a whole-distribution rebuild. The idea is to rebuild only the
16310 package that needs to be patched, and then to ``graft'' it onto packages
16311 explicitly installed by the user and that were previously referring to
16312 the original package. The cost of grafting is typically very low, and
16313 order of magnitudes lower than a full rebuild of the dependency chain.
16315 @cindex replacements of packages, for grafts
16316 For instance, suppose a security update needs to be applied to Bash.
16317 Guix developers will provide a package definition for the ``fixed''
16318 Bash, say @var{bash-fixed}, in the usual way (@pxref{Defining
16319 Packages}). Then, the original package definition is augmented with a
16320 @code{replacement} field pointing to the package containing the bug fix:
16327 (replacement bash-fixed)))
16330 From there on, any package depending directly or indirectly on Bash---as
16331 reported by @command{guix gc --requisites} (@pxref{Invoking guix
16332 gc})---that is installed is automatically ``rewritten'' to refer to
16333 @var{bash-fixed} instead of @var{bash}. This grafting process takes
16334 time proportional to the size of the package, usually less than a
16335 minute for an ``average'' package on a recent machine. Grafting is
16336 recursive: when an indirect dependency requires grafting, then grafting
16337 ``propagates'' up to the package that the user is installing.
16339 Currently, the length of the name and version of the graft and that of
16340 the package it replaces (@var{bash-fixed} and @var{bash} in the example
16341 above) must be equal. This restriction mostly comes from the fact that
16342 grafting works by patching files, including binary files, directly.
16343 Other restrictions may apply: for instance, when adding a graft to a
16344 package providing a shared library, the original shared library and its
16345 replacement must have the same @code{SONAME} and be binary-compatible.
16347 The @option{--no-grafts} command-line option allows you to forcefully
16348 avoid grafting (@pxref{Common Build Options, @option{--no-grafts}}).
16352 guix build bash --no-grafts
16356 returns the store file name of the original Bash, whereas:
16363 returns the store file name of the ``fixed'', replacement Bash. This
16364 allows you to distinguish between the two variants of Bash.
16366 To verify which Bash your whole profile refers to, you can run
16367 (@pxref{Invoking guix gc}):
16370 guix gc -R `readlink -f ~/.guix-profile` | grep bash
16374 @dots{} and compare the store file names that you get with those above.
16375 Likewise for a complete GuixSD system generation:
16378 guix gc -R `guix system build my-config.scm` | grep bash
16381 Lastly, to check which Bash running processes are using, you can use the
16382 @command{lsof} command:
16385 lsof | grep /gnu/store/.*bash
16389 @node Package Modules
16390 @section Package Modules
16392 From a programming viewpoint, the package definitions of the
16393 GNU distribution are provided by Guile modules in the @code{(gnu packages
16394 @dots{})} name space@footnote{Note that packages under the @code{(gnu
16395 packages @dots{})} module name space are not necessarily ``GNU
16396 packages''. This module naming scheme follows the usual Guile module
16397 naming convention: @code{gnu} means that these modules are distributed
16398 as part of the GNU system, and @code{packages} identifies modules that
16399 define packages.} (@pxref{Modules, Guile modules,, guile, GNU Guile
16400 Reference Manual}). For instance, the @code{(gnu packages emacs)}
16401 module exports a variable named @code{emacs}, which is bound to a
16402 @code{<package>} object (@pxref{Defining Packages}).
16404 The @code{(gnu packages @dots{})} module name space is
16405 automatically scanned for packages by the command-line tools. For
16406 instance, when running @code{guix package -i emacs}, all the @code{(gnu
16407 packages @dots{})} modules are scanned until one that exports a package
16408 object whose name is @code{emacs} is found. This package search
16409 facility is implemented in the @code{(gnu packages)} module.
16411 @cindex customization, of packages
16412 @cindex package module search path
16413 Users can store package definitions in modules with different
16414 names---e.g., @code{(my-packages emacs)}@footnote{Note that the file
16415 name and module name must match. For instance, the @code{(my-packages
16416 emacs)} module must be stored in a @file{my-packages/emacs.scm} file
16417 relative to the load path specified with @option{--load-path} or
16418 @code{GUIX_PACKAGE_PATH}. @xref{Modules and the File System,,,
16419 guile, GNU Guile Reference Manual}, for details.}. These package definitions
16420 will not be visible by default. Users can invoke commands such as
16421 @command{guix package} and @command{guix build} with the
16422 @code{-e} option so that they know where to find the package. Better
16423 yet, they can use the
16424 @code{-L} option of these commands to make those modules visible
16425 (@pxref{Invoking guix build, @code{--load-path}}), or define the
16426 @code{GUIX_PACKAGE_PATH} environment variable. This environment
16427 variable makes it easy to extend or customize the distribution and is
16428 honored by all the user interfaces.
16430 @defvr {Environment Variable} GUIX_PACKAGE_PATH
16431 This is a colon-separated list of directories to search for additional
16432 package modules. Directories listed in this variable take precedence
16433 over the own modules of the distribution.
16436 The distribution is fully @dfn{bootstrapped} and @dfn{self-contained}:
16437 each package is built based solely on other packages in the
16438 distribution. The root of this dependency graph is a small set of
16439 @dfn{bootstrap binaries}, provided by the @code{(gnu packages
16440 bootstrap)} module. For more information on bootstrapping,
16441 @pxref{Bootstrapping}.
16443 @node Packaging Guidelines
16444 @section Packaging Guidelines
16446 @cindex packages, creating
16447 The GNU distribution is nascent and may well lack some of your favorite
16448 packages. This section describes how you can help make the distribution
16449 grow. @xref{Contributing}, for additional information on how you can
16452 Free software packages are usually distributed in the form of
16453 @dfn{source code tarballs}---typically @file{tar.gz} files that contain
16454 all the source files. Adding a package to the distribution means
16455 essentially two things: adding a @dfn{recipe} that describes how to
16456 build the package, including a list of other packages required to build
16457 it, and adding @dfn{package metadata} along with that recipe, such as a
16458 description and licensing information.
16460 In Guix all this information is embodied in @dfn{package definitions}.
16461 Package definitions provide a high-level view of the package. They are
16462 written using the syntax of the Scheme programming language; in fact,
16463 for each package we define a variable bound to the package definition,
16464 and export that variable from a module (@pxref{Package Modules}).
16465 However, in-depth Scheme knowledge is @emph{not} a prerequisite for
16466 creating packages. For more information on package definitions,
16467 @pxref{Defining Packages}.
16469 Once a package definition is in place, stored in a file in the Guix
16470 source tree, it can be tested using the @command{guix build} command
16471 (@pxref{Invoking guix build}). For example, assuming the new package is
16472 called @code{gnew}, you may run this command from the Guix build tree
16473 (@pxref{Running Guix Before It Is Installed}):
16476 ./pre-inst-env guix build gnew --keep-failed
16479 Using @code{--keep-failed} makes it easier to debug build failures since
16480 it provides access to the failed build tree. Another useful
16481 command-line option when debugging is @code{--log-file}, to access the
16484 If the package is unknown to the @command{guix} command, it may be that
16485 the source file contains a syntax error, or lacks a @code{define-public}
16486 clause to export the package variable. To figure it out, you may load
16487 the module from Guile to get more information about the actual error:
16490 ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
16493 Once your package builds correctly, please send us a patch
16494 (@pxref{Contributing}). Well, if you need help, we will be happy to
16495 help you too. Once the patch is committed in the Guix repository, the
16496 new package automatically gets built on the supported platforms by
16497 @url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
16500 @cindex substituter
16501 Users can obtain the new package definition simply by running
16502 @command{guix pull} (@pxref{Invoking guix pull}). When
16503 @code{hydra.gnu.org} is done building the package, installing the
16504 package automatically downloads binaries from there
16505 (@pxref{Substitutes}). The only place where human intervention is
16506 needed is to review and apply the patch.
16510 * Software Freedom:: What may go into the distribution.
16511 * Package Naming:: What's in a name?
16512 * Version Numbers:: When the name is not enough.
16513 * Synopses and Descriptions:: Helping users find the right package.
16514 * Python Modules:: A touch of British comedy.
16515 * Perl Modules:: Little pearls.
16516 * Java Packages:: Coffee break.
16517 * Fonts:: Fond of fonts.
16520 @node Software Freedom
16521 @subsection Software Freedom
16523 @c Adapted from http://www.gnu.org/philosophy/philosophy.html.
16524 @cindex free software
16525 The GNU operating system has been developed so that users can have
16526 freedom in their computing. GNU is @dfn{free software}, meaning that
16527 users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
16528 essential freedoms}: to run the program, to study and change the program
16529 in source code form, to redistribute exact copies, and to distribute
16530 modified versions. Packages found in the GNU distribution provide only
16531 software that conveys these four freedoms.
16533 In addition, the GNU distribution follow the
16534 @url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
16535 software distribution guidelines}. Among other things, these guidelines
16536 reject non-free firmware, recommendations of non-free software, and
16537 discuss ways to deal with trademarks and patents.
16539 Some otherwise free upstream package sources contain a small and optional
16540 subset that violates the above guidelines, for instance because this subset
16541 is itself non-free code. When that happens, the offending items are removed
16542 with appropriate patches or code snippets in the @code{origin} form of the
16543 package (@pxref{Defining Packages}). This way, @code{guix
16544 build --source} returns the ``freed'' source rather than the unmodified
16548 @node Package Naming
16549 @subsection Package Naming
16551 @cindex package name
16552 A package has actually two names associated with it:
16553 First, there is the name of the @emph{Scheme variable}, the one following
16554 @code{define-public}. By this name, the package can be made known in the
16555 Scheme code, for instance as input to another package. Second, there is
16556 the string in the @code{name} field of a package definition. This name
16557 is used by package management commands such as
16558 @command{guix package} and @command{guix build}.
16560 Both are usually the same and correspond to the lowercase conversion of
16561 the project name chosen upstream, with underscores replaced with
16562 hyphens. For instance, GNUnet is available as @code{gnunet}, and
16563 SDL_net as @code{sdl-net}.
16565 We do not add @code{lib} prefixes for library packages, unless these are
16566 already part of the official project name. But @pxref{Python
16567 Modules} and @ref{Perl Modules} for special rules concerning modules for
16568 the Python and Perl languages.
16570 Font package names are handled differently, @pxref{Fonts}.
16573 @node Version Numbers
16574 @subsection Version Numbers
16576 @cindex package version
16577 We usually package only the latest version of a given free software
16578 project. But sometimes, for instance for incompatible library versions,
16579 two (or more) versions of the same package are needed. These require
16580 different Scheme variable names. We use the name as defined
16581 in @ref{Package Naming}
16582 for the most recent version; previous versions use the same name, suffixed
16583 by @code{-} and the smallest prefix of the version number that may
16584 distinguish the two versions.
16586 The name inside the package definition is the same for all versions of a
16587 package and does not contain any version number.
16589 For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
16592 (define-public gtk+
16597 (define-public gtk+-2
16600 (version "2.24.20")
16603 If we also wanted GTK+ 3.8.2, this would be packaged as
16605 (define-public gtk+-3.8
16612 @c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
16613 @c for a discussion of what follows.
16614 @cindex version number, for VCS snapshots
16615 Occasionally, we package snapshots of upstream's version control system
16616 (VCS) instead of formal releases. This should remain exceptional,
16617 because it is up to upstream developers to clarify what the stable
16618 release is. Yet, it is sometimes necessary. So, what should we put in
16619 the @code{version} field?
16621 Clearly, we need to make the commit identifier of the VCS snapshot
16622 visible in the version string, but we also need to make sure that the
16623 version string is monotonically increasing so that @command{guix package
16624 --upgrade} can determine which version is newer. Since commit
16625 identifiers, notably with Git, are not monotonically increasing, we add
16626 a revision number that we increase each time we upgrade to a newer
16627 snapshot. The resulting version string looks like this:
16632 | | `-- upstream commit ID
16634 | `--- Guix package revision
16636 latest upstream version
16639 It is a good idea to strip commit identifiers in the @code{version}
16640 field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
16641 aesthetics have a role to play here) as well as problems related to OS
16642 limits such as the maximum shebang length (127 bytes for the Linux
16643 kernel.) It is best to use the full commit identifiers in
16644 @code{origin}s, though, to avoid ambiguities. A typical package
16645 definition may look like this:
16649 (let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
16650 (revision "1")) ;Guix package revision
16652 (version (string-append "0.9-" revision "."
16653 (string-take commit 7)))
16656 (uri (git-reference
16657 (url "git://example.org/my-package.git")
16659 (sha256 (base32 "1mbikn@dots{}"))
16660 (file-name (string-append "my-package-" version
16666 @node Synopses and Descriptions
16667 @subsection Synopses and Descriptions
16669 @cindex package description
16670 @cindex package synopsis
16671 As we have seen before, each package in GNU@tie{}Guix includes a
16672 synopsis and a description (@pxref{Defining Packages}). Synopses and
16673 descriptions are important: They are what @command{guix package
16674 --search} searches, and a crucial piece of information to help users
16675 determine whether a given package suits their needs. Consequently,
16676 packagers should pay attention to what goes into them.
16678 Synopses must start with a capital letter and must not end with a
16679 period. They must not start with ``a'' or ``the'', which usually does
16680 not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
16681 tool that frobs files''. The synopsis should say what the package
16682 is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
16683 used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
16684 matching a pattern''.
16686 Keep in mind that the synopsis must be meaningful for a very wide
16687 audience. For example, ``Manipulate alignments in the SAM format''
16688 might make sense for a seasoned bioinformatics researcher, but might be
16689 fairly unhelpful or even misleading to a non-specialized audience. It
16690 is a good idea to come up with a synopsis that gives an idea of the
16691 application domain of the package. In this example, this might give
16692 something like ``Manipulate nucleotide sequence alignments'', which
16693 hopefully gives the user a better idea of whether this is what they are
16696 Descriptions should take between five and ten lines. Use full
16697 sentences, and avoid using acronyms without first introducing them.
16698 Please avoid marketing phrases such as ``world-leading'',
16699 ``industrial-strength'', and ``next-generation'', and avoid superlatives
16700 like ``the most advanced''---they are not helpful to users looking for a
16701 package and may even sound suspicious. Instead, try to be factual,
16702 mentioning use cases and features.
16704 @cindex Texinfo markup, in package descriptions
16705 Descriptions can include Texinfo markup, which is useful to introduce
16706 ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
16707 hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
16708 should be careful when using some characters for example @samp{@@} and
16709 curly braces which are the basic special characters in Texinfo
16710 (@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
16711 such as @command{guix package --show} take care of rendering it
16714 Synopses and descriptions are translated by volunteers
16715 @uref{http://translationproject.org/domain/guix-packages.html, at the
16716 Translation Project} so that as many users as possible can read them in
16717 their native language. User interfaces search them and display them in
16718 the language specified by the current locale.
16720 Translation is a lot of work so, as a packager, please pay even more
16721 attention to your synopses and descriptions as every change may entail
16722 additional work for translators. In order to help them, it is possible
16723 to make recommendations or instructions visible to them by inserting
16724 special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
16728 ;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
16729 (description "ARandR is designed to provide a simple visual front end
16730 for the X11 resize-and-rotate (RandR) extension. @dots{}")
16734 @node Python Modules
16735 @subsection Python Modules
16738 We currently package Python 2 and Python 3, under the Scheme variable names
16739 @code{python-2} and @code{python} as explained in @ref{Version Numbers}.
16740 To avoid confusion and naming clashes with other programming languages, it
16741 seems desirable that the name of a package for a Python module contains
16742 the word @code{python}.
16744 Some modules are compatible with only one version of Python, others with both.
16745 If the package Foo compiles only with Python 3, we name it
16746 @code{python-foo}; if it compiles only with Python 2, we name it
16747 @code{python2-foo}. If it is compatible with both versions, we create two
16748 packages with the corresponding names.
16750 If a project already contains the word @code{python}, we drop this;
16751 for instance, the module python-dateutil is packaged under the names
16752 @code{python-dateutil} and @code{python2-dateutil}. If the project name
16753 starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as
16756 @subsubsection Specifying Dependencies
16757 @cindex inputs, for Python packages
16759 Dependency information for Python packages is usually available in the
16760 package source tree, with varying degrees of accuracy: in the
16761 @file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}.
16763 Your mission, when writing a recipe for a Python package, is to map
16764 these dependencies to the appropriate type of ``input'' (@pxref{package
16765 Reference, inputs}). Although the @code{pypi} importer normally does a
16766 good job (@pxref{Invoking guix import}), you may want to check the
16767 following check list to determine which dependency goes where.
16772 We currently package Python 2 with @code{setuptools} and @code{pip}
16773 installed like Python 3.4 has per default. Thus you don't need to
16774 specify either of these as an input. @command{guix lint} will warn you
16778 Python dependencies required at run time go into
16779 @code{propagated-inputs}. They are typically defined with the
16780 @code{install_requires} keyword in @file{setup.py}, or in the
16781 @file{requirements.txt} file.
16784 Python packages required only at build time---e.g., those listed with
16785 the @code{setup_requires} keyword in @file{setup.py}---or only for
16786 testing---e.g., those in @code{tests_require}---go into
16787 @code{native-inputs}. The rationale is that (1) they do not need to be
16788 propagated because they are not needed at run time, and (2) in a
16789 cross-compilation context, it's the ``native'' input that we'd want.
16791 Examples are the @code{pytest}, @code{mock}, and @code{nose} test
16792 frameworks. Of course if any of these packages is also required at
16793 run-time, it needs to go to @code{propagated-inputs}.
16796 Anything that does not fall in the previous categories goes to
16797 @code{inputs}, for example programs or C libraries required for building
16798 Python packages containing C extensions.
16801 If a Python package has optional dependencies (@code{extras_require}),
16802 it is up to you to decide whether to add them or not, based on their
16803 usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix
16810 @subsection Perl Modules
16813 Perl programs standing for themselves are named as any other package,
16814 using the lowercase upstream name.
16815 For Perl packages containing a single class, we use the lowercase class name,
16816 replace all occurrences of @code{::} by dashes and prepend the prefix
16818 So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
16819 Modules containing several classes keep their lowercase upstream name and
16820 are also prepended by @code{perl-}. Such modules tend to have the word
16821 @code{perl} somewhere in their name, which gets dropped in favor of the
16822 prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
16825 @node Java Packages
16826 @subsection Java Packages
16829 Java programs standing for themselves are named as any other package,
16830 using the lowercase upstream name.
16832 To avoid confusion and naming clashes with other programming languages,
16833 it is desirable that the name of a package for a Java package is
16834 prefixed with @code{java-}. If a project already contains the word
16835 @code{java}, we drop this; for instance, the package @code{ngsjava} is
16836 packaged under the name @code{java-ngs}.
16838 For Java packages containing a single class or a small class hierarchy,
16839 we use the lowercase class name, replace all occurrences of @code{.} by
16840 dashes and prepend the prefix @code{java-}. So the class
16841 @code{apache.commons.cli} becomes package
16842 @code{java-apache-commons-cli}.
16849 For fonts that are in general not installed by a user for typesetting
16850 purposes, or that are distributed as part of a larger software package,
16851 we rely on the general packaging rules for software; for instance, this
16852 applies to the fonts delivered as part of the X.Org system or fonts that
16853 are part of TeX Live.
16855 To make it easier for a user to search for fonts, names for other packages
16856 containing only fonts are constructed as follows, independently of the
16857 upstream package name.
16859 The name of a package containing only one font family starts with
16860 @code{font-}; it is followed by the foundry name and a dash @code{-}
16861 if the foundry is known, and the font family name, in which spaces are
16862 replaced by dashes (and as usual, all upper case letters are transformed
16864 For example, the Gentium font family by SIL is packaged under the name
16865 @code{font-sil-gentium}.
16867 For a package containing several font families, the name of the collection
16868 is used in the place of the font family name.
16869 For instance, the Liberation fonts consist of three families,
16870 Liberation Sans, Liberation Serif and Liberation Mono.
16871 These could be packaged separately under the names
16872 @code{font-liberation-sans} and so on; but as they are distributed together
16873 under a common name, we prefer to package them together as
16874 @code{font-liberation}.
16876 In the case where several formats of the same font family or font collection
16877 are packaged separately, a short form of the format, prepended by a dash,
16878 is added to the package name. We use @code{-ttf} for TrueType fonts,
16879 @code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
16884 @node Bootstrapping
16885 @section Bootstrapping
16887 @c Adapted from the ELS 2013 paper.
16889 @cindex bootstrapping
16891 Bootstrapping in our context refers to how the distribution gets built
16892 ``from nothing''. Remember that the build environment of a derivation
16893 contains nothing but its declared inputs (@pxref{Introduction}). So
16894 there's an obvious chicken-and-egg problem: how does the first package
16895 get built? How does the first compiler get compiled? Note that this is
16896 a question of interest only to the curious hacker, not to the regular
16897 user, so you can shamelessly skip this section if you consider yourself
16898 a ``regular user''.
16900 @cindex bootstrap binaries
16901 The GNU system is primarily made of C code, with libc at its core. The
16902 GNU build system itself assumes the availability of a Bourne shell and
16903 command-line tools provided by GNU Coreutils, Awk, Findutils, `sed', and
16904 `grep'. Furthermore, build programs---programs that run
16905 @code{./configure}, @code{make}, etc.---are written in Guile Scheme
16906 (@pxref{Derivations}). Consequently, to be able to build anything at
16907 all, from scratch, Guix relies on pre-built binaries of Guile, GCC,
16908 Binutils, libc, and the other packages mentioned above---the
16909 @dfn{bootstrap binaries}.
16911 These bootstrap binaries are ``taken for granted'', though we can also
16912 re-create them if needed (more on that later).
16914 @unnumberedsubsec Preparing to Use the Bootstrap Binaries
16916 @c As of Emacs 24.3, Info-mode displays the image, but since it's a
16917 @c large image, it's hard to scroll. Oh well.
16918 @image{images/bootstrap-graph,6in,,Dependency graph of the early bootstrap derivations}
16920 The figure above shows the very beginning of the dependency graph of the
16921 distribution, corresponding to the package definitions of the @code{(gnu
16922 packages bootstrap)} module. A similar figure can be generated with
16923 @command{guix graph} (@pxref{Invoking guix graph}), along the lines of:
16926 guix graph -t derivation \
16927 -e '(@@@@ (gnu packages bootstrap) %bootstrap-gcc)' \
16931 At this level of detail, things are
16932 slightly complex. First, Guile itself consists of an ELF executable,
16933 along with many source and compiled Scheme files that are dynamically
16934 loaded when it runs. This gets stored in the @file{guile-2.0.7.tar.xz}
16935 tarball shown in this graph. This tarball is part of Guix's ``source''
16936 distribution, and gets inserted into the store with @code{add-to-store}
16937 (@pxref{The Store}).
16939 But how do we write a derivation that unpacks this tarball and adds it
16940 to the store? To solve this problem, the @code{guile-bootstrap-2.0.drv}
16941 derivation---the first one that gets built---uses @code{bash} as its
16942 builder, which runs @code{build-bootstrap-guile.sh}, which in turn calls
16943 @code{tar} to unpack the tarball. Thus, @file{bash}, @file{tar},
16944 @file{xz}, and @file{mkdir} are statically-linked binaries, also part of
16945 the Guix source distribution, whose sole purpose is to allow the Guile
16946 tarball to be unpacked.
16948 Once @code{guile-bootstrap-2.0.drv} is built, we have a functioning
16949 Guile that can be used to run subsequent build programs. Its first task
16950 is to download tarballs containing the other pre-built binaries---this
16951 is what the @code{.tar.xz.drv} derivations do. Guix modules such as
16952 @code{ftp-client.scm} are used for this purpose. The
16953 @code{module-import.drv} derivations import those modules in a directory
16954 in the store, using the original layout. The
16955 @code{module-import-compiled.drv} derivations compile those modules, and
16956 write them in an output directory with the right layout. This
16957 corresponds to the @code{#:modules} argument of
16958 @code{build-expression->derivation} (@pxref{Derivations}).
16960 Finally, the various tarballs are unpacked by the
16961 derivations @code{gcc-bootstrap-0.drv}, @code{glibc-bootstrap-0.drv},
16962 etc., at which point we have a working C tool chain.
16965 @unnumberedsubsec Building the Build Tools
16967 Bootstrapping is complete when we have a full tool chain that does not
16968 depend on the pre-built bootstrap tools discussed above. This
16969 no-dependency requirement is verified by checking whether the files of
16970 the final tool chain contain references to the @file{/gnu/store}
16971 directories of the bootstrap inputs. The process that leads to this
16972 ``final'' tool chain is described by the package definitions found in
16973 the @code{(gnu packages commencement)} module.
16975 The @command{guix graph} command allows us to ``zoom out'' compared to
16976 the graph above, by looking at the level of package objects instead of
16977 individual derivations---remember that a package may translate to
16978 several derivations, typically one derivation to download its source,
16979 one to build the Guile modules it needs, and one to actually build the
16980 package from source. The command:
16983 guix graph -t bag \
16984 -e '(@@@@ (gnu packages commencement)
16985 glibc-final-with-bootstrap-bash)' | dot -Tps > t.ps
16989 produces the dependency graph leading to the ``final'' C
16990 library@footnote{You may notice the @code{glibc-intermediate} label,
16991 suggesting that it is not @emph{quite} final, but as a good
16992 approximation, we will consider it final.}, depicted below.
16994 @image{images/bootstrap-packages,6in,,Dependency graph of the early packages}
16996 @c See <http://lists.gnu.org/archive/html/gnu-system-discuss/2012-10/msg00000.html>.
16997 The first tool that gets built with the bootstrap binaries is
16998 GNU@tie{}Make---noted @code{make-boot0} above---which is a prerequisite
16999 for all the following packages. From there Findutils and Diffutils get
17002 Then come the first-stage Binutils and GCC, built as pseudo cross
17003 tools---i.e., with @code{--target} equal to @code{--host}. They are
17004 used to build libc. Thanks to this cross-build trick, this libc is
17005 guaranteed not to hold any reference to the initial tool chain.
17007 From there the final Binutils and GCC (not shown above) are built.
17009 from the final Binutils, and links programs against the just-built libc.
17010 This tool chain is used to build the other packages used by Guix and by
17011 the GNU Build System: Guile, Bash, Coreutils, etc.
17013 And voilà! At this point we have the complete set of build tools that
17014 the GNU Build System expects. These are in the @code{%final-inputs}
17015 variable of the @code{(gnu packages commencement)} module, and are
17016 implicitly used by any package that uses @code{gnu-build-system}
17017 (@pxref{Build Systems, @code{gnu-build-system}}).
17020 @unnumberedsubsec Building the Bootstrap Binaries
17022 @cindex bootstrap binaries
17023 Because the final tool chain does not depend on the bootstrap binaries,
17024 those rarely need to be updated. Nevertheless, it is useful to have an
17025 automated way to produce them, should an update occur, and this is what
17026 the @code{(gnu packages make-bootstrap)} module provides.
17028 The following command builds the tarballs containing the bootstrap
17029 binaries (Guile, Binutils, GCC, libc, and a tarball containing a mixture
17030 of Coreutils and other basic command-line tools):
17033 guix build bootstrap-tarballs
17036 The generated tarballs are those that should be referred to in the
17037 @code{(gnu packages bootstrap)} module mentioned at the beginning of
17040 Still here? Then perhaps by now you've started to wonder: when do we
17041 reach a fixed point? That is an interesting question! The answer is
17042 unknown, but if you would like to investigate further (and have
17043 significant computational and storage resources to do so), then let us
17047 @section Porting to a New Platform
17049 As discussed above, the GNU distribution is self-contained, and
17050 self-containment is achieved by relying on pre-built ``bootstrap
17051 binaries'' (@pxref{Bootstrapping}). These binaries are specific to an
17052 operating system kernel, CPU architecture, and application binary
17053 interface (ABI). Thus, to port the distribution to a platform that is
17054 not yet supported, one must build those bootstrap binaries, and update
17055 the @code{(gnu packages bootstrap)} module to use them on that platform.
17057 Fortunately, Guix can @emph{cross compile} those bootstrap binaries.
17058 When everything goes well, and assuming the GNU tool chain supports the
17059 target platform, this can be as simple as running a command like this
17063 guix build --target=armv5tel-linux-gnueabi bootstrap-tarballs
17066 For this to work, the @code{glibc-dynamic-linker} procedure in
17067 @code{(gnu packages bootstrap)} must be augmented to return the right
17068 file name for libc's dynamic linker on that platform; likewise,
17069 @code{system->linux-architecture} in @code{(gnu packages linux)} must be
17070 taught about the new platform.
17072 Once these are built, the @code{(gnu packages bootstrap)} module needs
17073 to be updated to refer to these binaries on the target platform. That
17074 is, the hashes and URLs of the bootstrap tarballs for the new platform
17075 must be added alongside those of the currently supported platforms. The
17076 bootstrap Guile tarball is treated specially: it is expected to be
17077 available locally, and @file{gnu/local.mk} has rules do download it for
17078 the supported architectures; a rule for the new platform must be added
17081 In practice, there may be some complications. First, it may be that the
17082 extended GNU triplet that specifies an ABI (like the @code{eabi} suffix
17083 above) is not recognized by all the GNU tools. Typically, glibc
17084 recognizes some of these, whereas GCC uses an extra @code{--with-abi}
17085 configure flag (see @code{gcc.scm} for examples of how to handle this).
17086 Second, some of the required packages could fail to build for that
17087 platform. Lastly, the generated binaries could be broken for some
17090 @c *********************************************************************
17091 @include contributing.texi
17093 @c *********************************************************************
17094 @node Acknowledgments
17095 @chapter Acknowledgments
17097 Guix is based on the @uref{http://nixos.org/nix/, Nix package manager},
17098 which was designed and
17099 implemented by Eelco Dolstra, with contributions from other people (see
17100 the @file{nix/AUTHORS} file in Guix.) Nix pioneered functional package
17101 management, and promoted unprecedented features, such as transactional
17102 package upgrades and rollbacks, per-user profiles, and referentially
17103 transparent build processes. Without this work, Guix would not exist.
17105 The Nix-based software distributions, Nixpkgs and NixOS, have also been
17106 an inspiration for Guix.
17108 GNU@tie{}Guix itself is a collective work with contributions from a
17109 number of people. See the @file{AUTHORS} file in Guix for more
17110 information on these fine people. The @file{THANKS} file lists people
17111 who have helped by reporting bugs, taking care of the infrastructure,
17112 providing artwork and themes, making suggestions, and more---thank you!
17115 @c *********************************************************************
17116 @node GNU Free Documentation License
17117 @appendix GNU Free Documentation License
17118 @cindex license, GNU Free Documentation License
17119 @include fdl-1.3.texi
17121 @c *********************************************************************
17122 @node Concept Index
17123 @unnumbered Concept Index
17126 @node Programming Index
17127 @unnumbered Programming Index
17128 @syncodeindex tp fn
17129 @syncodeindex vr fn
17134 @c Local Variables:
17135 @c ispell-local-dictionary: "american";