0.7.10 release changes

[buildbot.git] / docs / buildbot.texinfo

\input texinfo @c -*-texinfo-*-
@c %**start of header
@setfilename buildbot.info
@settitle BuildBot Manual 0.7.10
@defcodeindex cs
@defcodeindex sl
@defcodeindex bf
@defcodeindex bs
@defcodeindex st
@defcodeindex bc
@c %**end of header

@c these indices are for classes useful in a master.cfg config file
@c @csindex : Change Sources
@c @slindex : Schedulers and Locks
@c @bfindex : Build Factories
@c @bsindex : Build Steps
@c @stindex : Status Targets

@c @bcindex : keys that make up BuildmasterConfig

@copying
This is the BuildBot manual.

Copyright (C) 2005,2006 Brian Warner

Copying and distribution of this file, with or without
modification, are permitted in any medium without royalty
provided the copyright notice and this notice are preserved.

@end copying

@titlepage
@title BuildBot
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@c Output the table of the contents at the beginning.
@contents

@ifnottex
@node Top, Introduction, (dir), (dir)
@top BuildBot

@insertcopying
@end ifnottex

@menu
* Introduction::                What the BuildBot does.
* Installation::                Creating a buildmaster and buildslaves,
                                running them.
* Concepts::                    What goes on in the buildbot's little mind.
* Configuration::               Controlling the buildbot.
* Getting Source Code Changes::  Discovering when to run a build.
* Build Process::               Controlling how each build is run.
* Status Delivery::             Telling the world about the build's results.
* Command-line tool::
* Resources::                   Getting help.
* Developer's Appendix::
* Index of Useful Classes::
* Index of master.cfg keys::
* Index::                       Complete index.

@detailmenu
 --- The Detailed Node Listing ---

Introduction

* History and Philosophy::
* System Architecture::
* Control Flow::

System Architecture

* BuildSlave Connections::
* Buildmaster Architecture::
* Status Delivery Architecture::

Installation

* Requirements::
* Installing the code::
* Creating a buildmaster::
* Upgrading an Existing Buildmaster::
* Creating a buildslave::
* Launching the daemons::
* Logfiles::
* Shutdown::
* Maintenance::
* Troubleshooting::

Creating a buildslave

* Buildslave Options::

Troubleshooting

* Starting the buildslave::
* Connecting to the buildmaster::
* Forcing Builds::

Concepts

* Version Control Systems::
* Schedulers::
* BuildSet::
* BuildRequest::
* Builder::
* Users::
* Build Properties::

Version Control Systems

* Generalizing VC Systems::
* Source Tree Specifications::
* How Different VC Systems Specify Sources::
* Attributes of Changes::

Users

* Doing Things With Users::
* Email Addresses::
* IRC Nicknames::
* Live Status Clients::

Configuration

* Config File Format::
* Loading the Config File::
* Testing the Config File::
* Defining the Project::
* Change Sources and Schedulers::
* Setting the slaveport::
* Buildslave Specifiers::
* On-Demand ("Latent") Buildslaves::
* Defining Global Properties::
* Defining Builders::
* Defining Status Targets::
* Debug options::

Change Sources and Schedulers

* Scheduler Scheduler::
* AnyBranchScheduler::
* Dependent Scheduler::
* Periodic Scheduler::
* Nightly Scheduler::
* Try Schedulers::
* Triggerable Scheduler::

Buildslave Specifiers
* When Buildslaves Go Missing::

On-Demand ("Latent") Buildslaves
* Amazon Web Services Elastic Compute Cloud ("AWS EC2")::
* Dangers with Latent Buildslaves::
* Writing New Latent Buildslaves::

Getting Source Code Changes

* Change Sources::
* Choosing ChangeSources::
* CVSToys - PBService::
* Mail-parsing ChangeSources::
* PBChangeSource::
* P4Source::
* BonsaiPoller::
* SVNPoller::
* MercurialHook::
* Bzr Hook::
* Bzr Poller::

Mail-parsing ChangeSources

* Subscribing the Buildmaster::
* Using Maildirs::
* Parsing Email Change Messages::

Parsing Email Change Messages

* FCMaildirSource::
* SyncmailMaildirSource::
* BonsaiMaildirSource::
* SVNCommitEmailMaildirSource::

Build Process

* Build Steps::
* Interlocks::
* Build Factories::

Build Steps

* Common Parameters::
* Using Build Properties::
* Source Checkout::
* ShellCommand::
* Simple ShellCommand Subclasses::
* Python BuildSteps::
* Transferring Files::
* Steps That Run on the Master::
* Triggering Schedulers::
* Writing New BuildSteps::

Source Checkout

* CVS::
* SVN::
* Darcs::
* Mercurial::
* Arch::
* Bazaar::
* Bzr::
* P4::
* Git::

Simple ShellCommand Subclasses

* Configure::
* Compile::
* Test::
* TreeSize::
* PerlModuleTest::
* SetProperty::

Python BuildSteps

* BuildEPYDoc::
* PyFlakes::
* PyLint::

Writing New BuildSteps

* BuildStep LogFiles::
* Reading Logfiles::
* Adding LogObservers::
* BuildStep URLs::

Build Factories

* BuildStep Objects::
* BuildFactory::
* Process-Specific build factories::

BuildStep Objects

* BuildFactory Attributes::
* Quick builds::

BuildFactory

* BuildFactory Attributes::
* Quick builds::

Process-Specific build factories

* GNUAutoconf::
* CPAN::
* Python distutils::
* Python/Twisted/trial projects::

Status Delivery

* WebStatus::
* MailNotifier::
* IRC Bot::
* PBListener::
* Writing New Status Plugins::

WebStatus

* WebStatus Configuration Parameters::
* Buildbot Web Resources::
* XMLRPC server::
* HTML Waterfall::

Command-line tool

* Administrator Tools::
* Developer Tools::
* Other Tools::
* .buildbot config directory::

Developer Tools

* statuslog::
* statusgui::
* try::

waiting for results

* try --diff::

Other Tools

* sendchange::
* debugclient::

@end detailmenu
@end menu

@node Introduction, Installation, Top, Top
@chapter Introduction

@cindex introduction

The BuildBot is a system to automate the compile/test cycle required by most
software projects to validate code changes. By automatically rebuilding and
testing the tree each time something has changed, build problems are
pinpointed quickly, before other developers are inconvenienced by the
failure. The guilty developer can be identified and harassed without human
intervention. By running the builds on a variety of platforms, developers
who do not have the facilities to test their changes everywhere before
checkin will at least know shortly afterwards whether they have broken the
build or not. Warning counts, lint checks, image size, compile time, and
other build parameters can be tracked over time, are more visible, and
are therefore easier to improve.

The overall goal is to reduce tree breakage and provide a platform to
run tests or code-quality checks that are too annoying or pedantic for
any human to waste their time with. Developers get immediate (and
potentially public) feedback about their changes, encouraging them to
be more careful about testing before checkin.

Features:

@itemize @bullet
@item
run builds on a variety of slave platforms
@item
arbitrary build process: handles projects using C, Python, whatever
@item
minimal host requirements: python and Twisted
@item
slaves can be behind a firewall if they can still do checkout
@item
status delivery through web page, email, IRC, other protocols
@item
track builds in progress, provide estimated completion time
@item
flexible configuration by subclassing generic build process classes
@item
debug tools to force a new build, submit fake Changes, query slave status
@item
released under the GPL
@end itemize

@menu
* History and Philosophy::
* System Architecture::
* Control Flow::
@end menu


@node History and Philosophy, System Architecture, Introduction, Introduction
@section History and Philosophy

@cindex Philosophy of operation

The Buildbot was inspired by a similar project built for a development
team writing a cross-platform embedded system. The various components
of the project were supposed to compile and run on several flavors of
unix (linux, solaris, BSD), but individual developers had their own
preferences and tended to stick to a single platform. From time to
time, incompatibilities would sneak in (some unix platforms want to
use @code{string.h}, some prefer @code{strings.h}), and then the tree
would compile for some developers but not others. The buildbot was
written to automate the human process of walking into the office,
updating a tree, compiling (and discovering the breakage), finding the
developer at fault, and complaining to them about the problem they had
introduced. With multiple platforms it was difficult for developers to
do the right thing (compile their potential change on all platforms);
the buildbot offered a way to help.

Another problem was when programmers would change the behavior of a
library without warning its users, or change internal aspects that
other code was (unfortunately) depending upon. Adding unit tests to
the codebase helps here: if an application's unit tests pass despite
changes in the libraries it uses, you can have more confidence that
the library changes haven't broken anything. Many developers
complained that the unit tests were inconvenient or took too long to
run: having the buildbot run them reduces the developer's workload to
a minimum.

In general, having more visibility into the project is always good,
and automation makes it easier for developers to do the right thing.
When everyone can see the status of the project, developers are
encouraged to keep the tree in good working order. Unit tests that
aren't run on a regular basis tend to suffer from bitrot just like
code does: exercising them on a regular basis helps to keep them
functioning and useful.

The current version of the Buildbot is additionally targeted at
distributed free-software projects, where resources and platforms are
only available when provided by interested volunteers. The buildslaves
are designed to require an absolute minimum of configuration, reducing
the effort a potential volunteer needs to expend to be able to
contribute a new test environment to the project. The goal is for
anyone who wishes that a given project would run on their favorite
platform should be able to offer that project a buildslave, running on
that platform, where they can verify that their portability code
works, and keeps working.

@node System Architecture, Control Flow, History and Philosophy, Introduction
@comment  node-name,  next,  previous,  up
@section System Architecture

The Buildbot consists of a single @code{buildmaster} and one or more
@code{buildslaves}, connected in a star topology. The buildmaster
makes all decisions about what, when, and how to build. It sends
commands to be run on the build slaves, which simply execute the
commands and return the results. (certain steps involve more local
decision making, where the overhead of sending a lot of commands back
and forth would be inappropriate, but in general the buildmaster is
responsible for everything).

The buildmaster is usually fed @code{Changes} by some sort of version
control system (@pxref{Change Sources}), which may cause builds to be
run. As the builds are performed, various status messages are
produced, which are then sent to any registered Status Targets
(@pxref{Status Delivery}).

@c @image{FILENAME, WIDTH, HEIGHT, ALTTEXT, EXTENSION}
@image{images/overview,,,Overview Diagram,}

The buildmaster is configured and maintained by the ``buildmaster
admin'', who is generally the project team member responsible for
build process issues. Each buildslave is maintained by a ``buildslave
admin'', who do not need to be quite as involved. Generally slaves are
run by anyone who has an interest in seeing the project work well on
their favorite platform.

@menu
* BuildSlave Connections::
* Buildmaster Architecture::
* Status Delivery Architecture::
@end menu

@node BuildSlave Connections, Buildmaster Architecture, System Architecture, System Architecture
@subsection BuildSlave Connections

The buildslaves are typically run on a variety of separate machines,
at least one per platform of interest. These machines connect to the
buildmaster over a TCP connection to a publically-visible port. As a
result, the buildslaves can live behind a NAT box or similar
firewalls, as long as they can get to buildmaster. The TCP connections
are initiated by the buildslave and accepted by the buildmaster, but
commands and results travel both ways within this connection. The
buildmaster is always in charge, so all commands travel exclusively
from the buildmaster to the buildslave.

To perform builds, the buildslaves must typically obtain source code
from a CVS/SVN/etc repository. Therefore they must also be able to
reach the repository. The buildmaster provides instructions for
performing builds, but does not provide the source code itself.

@image{images/slaves,,,BuildSlave Connections,}

@node Buildmaster Architecture, Status Delivery Architecture, BuildSlave Connections, System Architecture
@subsection Buildmaster Architecture

The Buildmaster consists of several pieces:

@image{images/master,,,BuildMaster Architecture,}

@itemize @bullet

@item
Change Sources, which create a Change object each time something is
modified in the VC repository. Most ChangeSources listen for messages
from a hook script of some sort. Some sources actively poll the
repository on a regular basis. All Changes are fed to the Schedulers.

@item
Schedulers, which decide when builds should be performed. They collect
Changes into BuildRequests, which are then queued for delivery to
Builders until a buildslave is available.

@item
Builders, which control exactly @emph{how} each build is performed
(with a series of BuildSteps, configured in a BuildFactory). Each
Build is run on a single buildslave.

@item
Status plugins, which deliver information about the build results
through protocols like HTTP, mail, and IRC.

@end itemize

@image{images/slavebuilder,,,SlaveBuilders,}

Each Builder is configured with a list of BuildSlaves that it will use
for its builds. These buildslaves are expected to behave identically:
the only reason to use multiple BuildSlaves for a single Builder is to
provide a measure of load-balancing.

Within a single BuildSlave, each Builder creates its own SlaveBuilder
instance. These SlaveBuilders operate independently from each other.
Each gets its own base directory to work in. It is quite common to
have many Builders sharing the same buildslave. For example, there
might be two buildslaves: one for i386, and a second for PowerPC.
There may then be a pair of Builders that do a full compile/test run,
one for each architecture, and a lone Builder that creates snapshot
source tarballs if the full builders complete successfully. The full
builders would each run on a single buildslave, whereas the tarball
creation step might run on either buildslave (since the platform
doesn't matter when creating source tarballs). In this case, the
mapping would look like:

@example
Builder(full-i386)  ->  BuildSlaves(slave-i386)
Builder(full-ppc)   ->  BuildSlaves(slave-ppc)
Builder(source-tarball) -> BuildSlaves(slave-i386, slave-ppc)
@end example

and each BuildSlave would have two SlaveBuilders inside it, one for a
full builder, and a second for the source-tarball builder.

Once a SlaveBuilder is available, the Builder pulls one or more
BuildRequests off its incoming queue. (It may pull more than one if it
determines that it can merge the requests together; for example, there
may be multiple requests to build the current HEAD revision). These
requests are merged into a single Build instance, which includes the
SourceStamp that describes what exact version of the source code
should be used for the build. The Build is then randomly assigned to a
free SlaveBuilder and the build begins.

The behaviour when BuildRequests are merged can be customized, @pxref{Merging
BuildRequests}.

@node Status Delivery Architecture,  , Buildmaster Architecture, System Architecture
@subsection Status Delivery Architecture

The buildmaster maintains a central Status object, to which various
status plugins are connected. Through this Status object, a full
hierarchy of build status objects can be obtained.

@image{images/status,,,Status Delivery,}

The configuration file controls which status plugins are active. Each
status plugin gets a reference to the top-level Status object. From
there they can request information on each Builder, Build, Step, and
LogFile. This query-on-demand interface is used by the html.Waterfall
plugin to create the main status page each time a web browser hits the
main URL.

The status plugins can also subscribe to hear about new Builds as they
occur: this is used by the MailNotifier to create new email messages
for each recently-completed Build.

The Status object records the status of old builds on disk in the
buildmaster's base directory. This allows it to return information
about historical builds.

There are also status objects that correspond to Schedulers and
BuildSlaves. These allow status plugins to report information about
upcoming builds, and the online/offline status of each buildslave.


@node Control Flow,  , System Architecture, Introduction
@comment  node-name,  next,  previous,  up
@section Control Flow

A day in the life of the buildbot:

@itemize @bullet

@item
A developer commits some source code changes to the repository. A hook
script or commit trigger of some sort sends information about this
change to the buildmaster through one of its configured Change
Sources. This notification might arrive via email, or over a network
connection (either initiated by the buildmaster as it ``subscribes''
to changes, or by the commit trigger as it pushes Changes towards the
buildmaster). The Change contains information about who made the
change, what files were modified, which revision contains the change,
and any checkin comments.

@item
The buildmaster distributes this change to all of its configured
Schedulers. Any ``important'' changes cause the ``tree-stable-timer''
to be started, and the Change is added to a list of those that will go
into a new Build. When the timer expires, a Build is started on each
of a set of configured Builders, all compiling/testing the same source
code. Unless configured otherwise, all Builds run in parallel on the
various buildslaves.

@item
The Build consists of a series of Steps. Each Step causes some number
of commands to be invoked on the remote buildslave associated with
that Builder. The first step is almost always to perform a checkout of
the appropriate revision from the same VC system that produced the
Change. The rest generally perform a compile and run unit tests. As
each Step runs, the buildslave reports back command output and return
status to the buildmaster.

@item
As the Build runs, status messages like ``Build Started'', ``Step
Started'', ``Build Finished'', etc, are published to a collection of
Status Targets. One of these targets is usually the HTML ``Waterfall''
display, which shows a chronological list of events, and summarizes
the results of the most recent build at the top of each column.
Developers can periodically check this page to see how their changes
have fared. If they see red, they know that they've made a mistake and
need to fix it. If they see green, they know that they've done their
duty and don't need to worry about their change breaking anything.

@item
If a MailNotifier status target is active, the completion of a build
will cause email to be sent to any developers whose Changes were
incorporated into this Build. The MailNotifier can be configured to
only send mail upon failing builds, or for builds which have just
transitioned from passing to failing. Other status targets can provide
similar real-time notification via different communication channels,
like IRC.

@end itemize


@node Installation, Concepts, Introduction, Top
@chapter Installation

@menu
* Requirements::
* Installing the code::
* Creating a buildmaster::
* Upgrading an Existing Buildmaster::
* Creating a buildslave::
* Launching the daemons::
* Logfiles::
* Shutdown::
* Maintenance::
* Troubleshooting::
@end menu

@node Requirements, Installing the code, Installation, Installation
@section Requirements

At a bare minimum, you'll need the following (for both the buildmaster
and a buildslave):

@itemize @bullet
@item
Python: http://www.python.org

Buildbot requires python-2.3 or later, and is primarily developed
against python-2.4. It is also tested against python-2.5 .

@item
Twisted: http://twistedmatrix.com

Both the buildmaster and the buildslaves require Twisted-2.0.x or
later. It has been tested against all releases of Twisted up to
Twisted-2.5.0 (the most recent as of this writing). As always, the
most recent version is recommended.

Twisted is delivered as a collection of subpackages. You'll need at
least "Twisted" (the core package), and you'll also want TwistedMail,
TwistedWeb, and TwistedWords (for sending email, serving a web status
page, and delivering build status via IRC, respectively). You might
also want TwistedConch (for the encrypted Manhole debug port). Note
that Twisted requires ZopeInterface to be installed as well.

@end itemize

Certain other packages may be useful on the system running the
buildmaster:

@itemize @bullet
@item
CVSToys: http://purl.net/net/CVSToys

If your buildmaster uses FreshCVSSource to receive change notification
from a cvstoys daemon, it will require CVSToys be installed (tested
with CVSToys-1.0.10). If the it doesn't use that source (i.e. if you
only use a mail-parsing change source, or the SVN notification
script), you will not need CVSToys.

@end itemize

And of course, your project's build process will impose additional
requirements on the buildslaves. These hosts must have all the tools
necessary to compile and test your project's source code.


@node Installing the code, Creating a buildmaster, Requirements, Installation
@section Installing the code

@cindex installation

The Buildbot is installed using the standard python @code{distutils}
module. After unpacking the tarball, the process is:

@example
python setup.py build
python setup.py install
@end example

where the install step may need to be done as root. This will put the
bulk of the code in somewhere like
/usr/lib/python2.3/site-packages/buildbot . It will also install the
@code{buildbot} command-line tool in /usr/bin/buildbot.

To test this, shift to a different directory (like /tmp), and run:

@example
buildbot --version
@end example

If it shows you the versions of Buildbot and Twisted, the install went
ok. If it says @code{no such command} or it gets an @code{ImportError}
when it tries to load the libaries, then something went wrong.
@code{pydoc buildbot} is another useful diagnostic tool.

Windows users will find these files in other places. You will need to
make sure that python can find the libraries, and will probably find
it convenient to have @code{buildbot} on your PATH.

If you wish, you can run the buildbot unit test suite like this:

@example
PYTHONPATH=. trial buildbot.test
@end example

This should run up to 192 tests, depending upon what VC tools you have
installed. On my desktop machine it takes about five minutes to
complete. Nothing should fail, a few might be skipped. If any of the
tests fail, you should stop and investigate the cause before
continuing the installation process, as it will probably be easier to
track down the bug early.

If you cannot or do not wish to install the buildbot into a site-wide
location like @file{/usr} or @file{/usr/local}, you can also install
it into the account's home directory. Do the install command like
this:

@example
python setup.py install --home=~
@end example

That will populate @file{~/lib/python} and create
@file{~/bin/buildbot}. Make sure this lib directory is on your
@code{PYTHONPATH}.


@node Creating a buildmaster, Upgrading an Existing Buildmaster, Installing the code, Installation
@section Creating a buildmaster

As you learned earlier (@pxref{System Architecture}), the buildmaster
runs on a central host (usually one that is publically visible, so
everybody can check on the status of the project), and controls all
aspects of the buildbot system. Let us call this host
@code{buildbot.example.org}.

You may wish to create a separate user account for the buildmaster,
perhaps named @code{buildmaster}. This can help keep your personal
configuration distinct from that of the buildmaster and is useful if
you have to use a mail-based notification system (@pxref{Change
Sources}). However, the Buildbot will work just fine with your regular
user account.

You need to choose a directory for the buildmaster, called the
@code{basedir}. This directory will be owned by the buildmaster, which
will use configuration files therein, and create status files as it
runs. @file{~/Buildbot} is a likely value. If you run multiple
buildmasters in the same account, or if you run both masters and
slaves, you may want a more distinctive name like
@file{~/Buildbot/master/gnomovision} or
@file{~/Buildmasters/fooproject}. If you are using a separate user
account, this might just be @file{~buildmaster/masters/fooproject}.

Once you've picked a directory, use the @command{buildbot
create-master} command to create the directory and populate it with
startup files:

@example
buildbot create-master @var{basedir}
@end example

You will need to create a configuration file (@pxref{Configuration})
before starting the buildmaster. Most of the rest of this manual is
dedicated to explaining how to do this. A sample configuration file is
placed in the working directory, named @file{master.cfg.sample}, which
can be copied to @file{master.cfg} and edited to suit your purposes.

(Internal details: This command creates a file named
@file{buildbot.tac} that contains all the state necessary to create
the buildmaster. Twisted has a tool called @code{twistd} which can use
this .tac file to create and launch a buildmaster instance. twistd
takes care of logging and daemonization (running the program in the
background). @file{/usr/bin/buildbot} is a front end which runs twistd
for you.)

In addition to @file{buildbot.tac}, a small @file{Makefile.sample} is
installed. This can be used as the basis for customized daemon startup,
@xref{Launching the daemons}.

@node Upgrading an Existing Buildmaster, Creating a buildslave, Creating a buildmaster, Installation
@section Upgrading an Existing Buildmaster

If you have just installed a new version of the Buildbot code, and you
have buildmasters that were created using an older version, you'll
need to upgrade these buildmasters before you can use them. The
upgrade process adds and modifies files in the buildmaster's base
directory to make it compatible with the new code.

@example
buildbot upgrade-master @var{basedir}
@end example

This command will also scan your @file{master.cfg} file for
incompatbilities (by loading it and printing any errors or deprecation
warnings that occur). Each buildbot release tries to be compatible
with configurations that worked cleanly (i.e. without deprecation
warnings) on the previous release: any functions or classes that are
to be removed will first be deprecated in a release, to give users a
chance to start using their replacement.

The 0.7.6 release introduced the @file{public_html/} directory, which
contains @file{index.html} and other files served by the
@code{WebStatus} and @code{Waterfall} status displays. The
@code{upgrade-master} command will create these files if they do not
already exist. It will not modify existing copies, but it will write a
new copy in e.g. @file{index.html.new} if the new version differs from
the version that already exists.

The @code{upgrade-master} command is idempotent. It is safe to run it
multiple times. After each upgrade of the buildbot code, you should
use @code{upgrade-master} on all your buildmasters.


@node Creating a buildslave, Launching the daemons, Upgrading an Existing Buildmaster, Installation
@section Creating a buildslave

Typically, you will be adding a buildslave to an existing buildmaster,
to provide additional architecture coverage. The buildbot
administrator will give you several pieces of information necessary to
connect to the buildmaster. You should also be somewhat familiar with
the project being tested, so you can troubleshoot build problems
locally.

The buildbot exists to make sure that the project's stated ``how to
build it'' process actually works. To this end, the buildslave should
run in an environment just like that of your regular developers.
Typically the project build process is documented somewhere
(@file{README}, @file{INSTALL}, etc), in a document that should
mention all library dependencies and contain a basic set of build
instructions. This document will be useful as you configure the host
and account in which the buildslave runs.

Here's a good checklist for setting up a buildslave:

@enumerate
@item
Set up the account

It is recommended (although not mandatory) to set up a separate user
account for the buildslave. This account is frequently named
@code{buildbot} or @code{buildslave}. This serves to isolate your
personal working environment from that of the slave's, and helps to
minimize the security threat posed by letting possibly-unknown
contributors run arbitrary code on your system. The account should
have a minimum of fancy init scripts.

@item
Install the buildbot code

Follow the instructions given earlier (@pxref{Installing the code}).
If you use a separate buildslave account, and you didn't install the
buildbot code to a shared location, then you will need to install it
with @code{--home=~} for each account that needs it.

@item
Set up the host

Make sure the host can actually reach the buildmaster. Usually the
buildmaster is running a status webserver on the same machine, so
simply point your web browser at it and see if you can get there.
Install whatever additional packages or libraries the project's
INSTALL document advises. (or not: if your buildslave is supposed to
make sure that building without optional libraries still works, then
don't install those libraries).

Again, these libraries don't necessarily have to be installed to a
site-wide shared location, but they must be available to your build
process. Accomplishing this is usually very specific to the build
process, so installing them to @file{/usr} or @file{/usr/local} is
usually the best approach.

@item
Test the build process

Follow the instructions in the INSTALL document, in the buildslave's
account. Perform a full CVS (or whatever) checkout, configure, make,
run tests, etc. Confirm that the build works without manual fussing.
If it doesn't work when you do it by hand, it will be unlikely to work
when the buildbot attempts to do it in an automated fashion.

@item
Choose a base directory

This should be somewhere in the buildslave's account, typically named
after the project which is being tested. The buildslave will not touch
any file outside of this directory. Something like @file{~/Buildbot}
or @file{~/Buildslaves/fooproject} is appropriate.

@item
Get the buildmaster host/port, botname, and password

When the buildbot admin configures the buildmaster to accept and use
your buildslave, they will provide you with the following pieces of
information:

@itemize @bullet
@item
your buildslave's name
@item
the password assigned to your buildslave
@item
the hostname and port number of the buildmaster, i.e. buildbot.example.org:8007
@end itemize

@item
Create the buildslave

Now run the 'buildbot' command as follows:

@example
buildbot create-slave @var{BASEDIR} @var{MASTERHOST}:@var{PORT} @var{SLAVENAME} @var{PASSWORD}
@end example

This will create the base directory and a collection of files inside,
including the @file{buildbot.tac} file that contains all the
information you passed to the @code{buildbot} command.

@item
Fill in the hostinfo files

When it first connects, the buildslave will send a few files up to the
buildmaster which describe the host that it is running on. These files
are presented on the web status display so that developers have more
information to reproduce any test failures that are witnessed by the
buildbot. There are sample files in the @file{info} subdirectory of
the buildbot's base directory. You should edit these to correctly
describe you and your host.

@file{BASEDIR/info/admin} should contain your name and email address.
This is the ``buildslave admin address'', and will be visible from the
build status page (so you may wish to munge it a bit if
address-harvesting spambots are a concern).

@file{BASEDIR/info/host} should be filled with a brief description of
the host: OS, version, memory size, CPU speed, versions of relevant
libraries installed, and finally the version of the buildbot code
which is running the buildslave.

If you run many buildslaves, you may want to create a single
@file{~buildslave/info} file and share it among all the buildslaves
with symlinks.

@end enumerate

@menu
* Buildslave Options::
@end menu

@node Buildslave Options,  , Creating a buildslave, Creating a buildslave
@subsection Buildslave Options

There are a handful of options you might want to use when creating the
buildslave with the @command{buildbot create-slave <options> DIR <params>}
command. You can type @command{buildbot create-slave --help} for a summary.
To use these, just include them on the @command{buildbot create-slave}
command line, like this:

@example
buildbot create-slave --umask=022 ~/buildslave buildmaster.example.org:42012 myslavename mypasswd
@end example

@table @code
@item --usepty
This is a boolean flag that tells the buildslave whether to launch child
processes in a PTY or with regular pipes (the default) when the master does not
specify.  This option is deprecated, as this particular parameter is better
specified on the master.

@item --umask
This is a string (generally an octal representation of an integer)
which will cause the buildslave process' ``umask'' value to be set
shortly after initialization. The ``twistd'' daemonization utility
forces the umask to 077 at startup (which means that all files created
by the buildslave or its child processes will be unreadable by any
user other than the buildslave account). If you want build products to
be readable by other accounts, you can add @code{--umask=022} to tell
the buildslave to fix the umask after twistd clobbers it. If you want
build products to be @emph{writable} by other accounts too, use
@code{--umask=000}, but this is likely to be a security problem.

@item --keepalive
This is a number that indicates how frequently ``keepalive'' messages
should be sent from the buildslave to the buildmaster, expressed in
seconds. The default (600) causes a message to be sent to the
buildmaster at least once every 10 minutes. To set this to a lower
value, use e.g. @code{--keepalive=120}.

If the buildslave is behind a NAT box or stateful firewall, these
messages may help to keep the connection alive: some NAT boxes tend to
forget about a connection if it has not been used in a while. When
this happens, the buildmaster will think that the buildslave has
disappeared, and builds will time out. Meanwhile the buildslave will
not realize than anything is wrong.

@item --maxdelay
This is a number that indicates the maximum amount of time the
buildslave will wait between connection attempts, expressed in
seconds. The default (300) causes the buildslave to wait at most 5
minutes before trying to connect to the buildmaster again.

@item --log-size
This is the size in bytes when to rotate the Twisted log files.

@item --log-count
This is the number of log rotations to keep around. You can either
specify a number or @code{None} (the default) to keep all
@file{twistd.log} files around.

@end table


@node Launching the daemons, Logfiles, Creating a buildslave, Installation
@section Launching the daemons

Both the buildmaster and the buildslave run as daemon programs. To
launch them, pass the working directory to the @code{buildbot}
command:

@example
buildbot start @var{BASEDIR}
@end example

This command will start the daemon and then return, so normally it
will not produce any output. To verify that the programs are indeed
running, look for a pair of files named @file{twistd.log} and
@file{twistd.pid} that should be created in the working directory.
@file{twistd.pid} contains the process ID of the newly-spawned daemon.

When the buildslave connects to the buildmaster, new directories will
start appearing in its base directory. The buildmaster tells the slave
to create a directory for each Builder which will be using that slave.
All build operations are performed within these directories: CVS
checkouts, compiles, and tests.

Once you get everything running, you will want to arrange for the
buildbot daemons to be started at boot time. One way is to use
@code{cron}, by putting them in a @@reboot crontab entry@footnote{this
@@reboot syntax is understood by Vixie cron, which is the flavor
usually provided with linux systems. Other unices may have a cron that
doesn't understand @@reboot}:

@example
@@reboot buildbot start @var{BASEDIR}
@end example

When you run @command{crontab} to set this up, remember to do it as
the buildmaster or buildslave account! If you add this to your crontab
when running as your regular account (or worse yet, root), then the
daemon will run as the wrong user, quite possibly as one with more
authority than you intended to provide.

It is important to remember that the environment provided to cron jobs
and init scripts can be quite different that your normal runtime.
There may be fewer environment variables specified, and the PATH may
be shorter than usual. It is a good idea to test out this method of
launching the buildslave by using a cron job with a time in the near
future, with the same command, and then check @file{twistd.log} to
make sure the slave actually started correctly. Common problems here
are for @file{/usr/local} or @file{~/bin} to not be on your
@code{PATH}, or for @code{PYTHONPATH} to not be set correctly.
Sometimes @code{HOME} is messed up too.

To modify the way the daemons are started (perhaps you want to set
some environment variables first, or perform some cleanup each time),
you can create a file named @file{Makefile.buildbot} in the base
directory. When the @file{buildbot} front-end tool is told to
@command{start} the daemon, and it sees this file (and
@file{/usr/bin/make} exists), it will do @command{make -f
Makefile.buildbot start} instead of its usual action (which involves
running @command{twistd}). When the buildmaster or buildslave is
installed, a @file{Makefile.sample} is created which implements the
same behavior as the the @file{buildbot} tool uses, so if you want to
customize the process, just copy @file{Makefile.sample} to
@file{Makefile.buildbot} and edit it as necessary.

Some distributions may include conveniences to make starting buildbot
at boot time easy.  For instance, with the default buildbot package in
Debian-based distributions, you may only need to modify
@code{/etc/default/buildbot} (see also @code{/etc/init.d/buildbot}, which
reads the configuration in @code{/etc/default/buildbot}).

@node Logfiles, Shutdown, Launching the daemons, Installation
@section Logfiles

@cindex logfiles

While a buildbot daemon runs, it emits text to a logfile, named
@file{twistd.log}. A command like @code{tail -f twistd.log} is useful
to watch the command output as it runs.

The buildmaster will announce any errors with its configuration file
in the logfile, so it is a good idea to look at the log at startup
time to check for any problems. Most buildmaster activities will cause
lines to be added to the log.

@node Shutdown, Maintenance, Logfiles, Installation
@section Shutdown

To stop a buildmaster or buildslave manually, use:

@example
buildbot stop @var{BASEDIR}
@end example

This simply looks for the @file{twistd.pid} file and kills whatever
process is identified within.

At system shutdown, all processes are sent a @code{SIGKILL}. The
buildmaster and buildslave will respond to this by shutting down
normally.

The buildmaster will respond to a @code{SIGHUP} by re-reading its
config file. Of course, this only works on unix-like systems with
signal support, and won't work on Windows. The following shortcut is
available:

@example
buildbot reconfig @var{BASEDIR}
@end example

When you update the Buildbot code to a new release, you will need to
restart the buildmaster and/or buildslave before it can take advantage
of the new code. You can do a @code{buildbot stop @var{BASEDIR}} and
@code{buildbot start @var{BASEDIR}} in quick succession, or you can
use the @code{restart} shortcut, which does both steps for you:

@example
buildbot restart @var{BASEDIR}
@end example

There are certain configuration changes that are not handled cleanly
by @code{buildbot reconfig}. If this occurs, @code{buildbot restart}
is a more robust tool to fully switch over to the new configuration.

@code{buildbot restart} may also be used to start a stopped Buildbot
instance. This behaviour is useful when writing scripts that stop, start
and restart Buildbot.

A buildslave may also be gracefully shutdown from the
@pxref{WebStatus} status plugin. This is useful to shutdown a
buildslave without interrupting any current builds. The buildmaster
will wait until the buildslave is finished all its current builds, and
will then tell the buildslave to shutdown.

@node Maintenance, Troubleshooting, Shutdown, Installation
@section Maintenance

It is a good idea to check the buildmaster's status page every once in
a while, to see if your buildslave is still online. Eventually the
buildbot will probably be enhanced to send you email (via the
@file{info/admin} email address) when the slave has been offline for
more than a few hours.

If you find you can no longer provide a buildslave to the project, please
let the project admins know, so they can put out a call for a
replacement.

The Buildbot records status and logs output continually, each time a
build is performed. The status tends to be small, but the build logs
can become quite large. Each build and log are recorded in a separate
file, arranged hierarchically under the buildmaster's base directory.
To prevent these files from growing without bound, you should
periodically delete old build logs. A simple cron job to delete
anything older than, say, two weeks should do the job. The only trick
is to leave the @file{buildbot.tac} and other support files alone, for
which find's @code{-mindepth} argument helps skip everything in the
top directory. You can use something like the following:

@example
@@weekly cd BASEDIR && find . -mindepth 2 i-path './public_html/*' -prune -o -type f -mtime +14 -exec rm @{@} \;
@@weekly cd BASEDIR && find twistd.log* -mtime +14 -exec rm @{@} \;
@end example

@node Troubleshooting,  , Maintenance, Installation
@section Troubleshooting

Here are a few hints on diagnosing common problems.

@menu
* Starting the buildslave::
* Connecting to the buildmaster::
* Forcing Builds::
@end menu

@node Starting the buildslave, Connecting to the buildmaster, Troubleshooting, Troubleshooting
@subsection Starting the buildslave

Cron jobs are typically run with a minimal shell (@file{/bin/sh}, not
@file{/bin/bash}), and tilde expansion is not always performed in such
commands. You may want to use explicit paths, because the @code{PATH}
is usually quite short and doesn't include anything set by your
shell's startup scripts (@file{.profile}, @file{.bashrc}, etc). If
you've installed buildbot (or other python libraries) to an unusual
location, you may need to add a @code{PYTHONPATH} specification (note
that python will do tilde-expansion on @code{PYTHONPATH} elements by
itself). Sometimes it is safer to fully-specify everything:

@example
@@reboot PYTHONPATH=~/lib/python /usr/local/bin/buildbot start /usr/home/buildbot/basedir
@end example

Take the time to get the @@reboot job set up. Otherwise, things will work
fine for a while, but the first power outage or system reboot you have will
stop the buildslave with nothing but the cries of sorrowful developers to
remind you that it has gone away.

@node Connecting to the buildmaster, Forcing Builds, Starting the buildslave, Troubleshooting
@subsection Connecting to the buildmaster

If the buildslave cannot connect to the buildmaster, the reason should
be described in the @file{twistd.log} logfile. Some common problems
are an incorrect master hostname or port number, or a mistyped bot
name or password. If the buildslave loses the connection to the
master, it is supposed to attempt to reconnect with an
exponentially-increasing backoff. Each attempt (and the time of the
next attempt) will be logged. If you get impatient, just manually stop
and re-start the buildslave.

When the buildmaster is restarted, all slaves will be disconnected,
and will attempt to reconnect as usual. The reconnect time will depend
upon how long the buildmaster is offline (i.e. how far up the
exponential backoff curve the slaves have travelled). Again,
@code{buildbot stop @var{BASEDIR}; buildbot start @var{BASEDIR}} will
speed up the process.

@node Forcing Builds,  , Connecting to the buildmaster, Troubleshooting
@subsection Forcing Builds

From the buildmaster's main status web page, you can force a build to
be run on your build slave. Figure out which column is for a builder
that runs on your slave, click on that builder's name, and the page
that comes up will have a ``Force Build'' button. Fill in the form,
hit the button, and a moment later you should see your slave's
@file{twistd.log} filling with commands being run. Using @code{pstree}
or @code{top} should also reveal the cvs/make/gcc/etc processes being
run by the buildslave. Note that the same web page should also show
the @file{admin} and @file{host} information files that you configured
earlier.

@node Concepts, Configuration, Installation, Top
@chapter Concepts

This chapter defines some of the basic concepts that the Buildbot
uses. You'll need to understand how the Buildbot sees the world to
configure it properly.

@menu
* Version Control Systems::
* Schedulers::
* BuildSet::
* BuildRequest::
* Builder::
* Users::
* Build Properties::
@end menu

@node Version Control Systems, Schedulers, Concepts, Concepts
@section Version Control Systems

@cindex Version Control

These source trees come from a Version Control System of some kind.
CVS and Subversion are two popular ones, but the Buildbot supports
others. All VC systems have some notion of an upstream
@code{repository} which acts as a server@footnote{except Darcs, but
since the Buildbot never modifies its local source tree we can ignore
the fact that Darcs uses a less centralized model}, from which clients
can obtain source trees according to various parameters. The VC
repository provides source trees of various projects, for different
branches, and from various points in time. The first thing we have to
do is to specify which source tree we want to get.

@menu
* Generalizing VC Systems::
* Source Tree Specifications::
* How Different VC Systems Specify Sources::
* Attributes of Changes::
@end menu

@node Generalizing VC Systems, Source Tree Specifications, Version Control Systems, Version Control Systems
@subsection Generalizing VC Systems

For the purposes of the Buildbot, we will try to generalize all VC
systems as having repositories that each provide sources for a variety
of projects. Each project is defined as a directory tree with source
files. The individual files may each have revisions, but we ignore
that and treat the project as a whole as having a set of revisions
(CVS is really the only VC system still in widespread use that has
per-file revisions.. everything modern has moved to atomic tree-wide
changesets). Each time someone commits a change to the project, a new
revision becomes available. These revisions can be described by a
tuple with two items: the first is a branch tag, and the second is
some kind of revision stamp or timestamp. Complex projects may have
multiple branch tags, but there is always a default branch. The
timestamp may be an actual timestamp (such as the -D option to CVS),
or it may be a monotonically-increasing transaction number (such as
the change number used by SVN and P4, or the revision number used by
Arch/Baz/Bazaar, or a labeled tag used in CVS)@footnote{many VC
systems provide more complexity than this: in particular the local
views that P4 and ClearCase can assemble out of various source
directories are more complex than we're prepared to take advantage of
here}. The SHA1 revision ID used by Monotone, Mercurial, and Git is
also a kind of revision stamp, in that it specifies a unique copy of
the source tree, as does a Darcs ``context'' file.

When we aren't intending to make any changes to the sources we check out
(at least not any that need to be committed back upstream), there are two
basic ways to use a VC system:

@itemize @bullet
@item
Retrieve a specific set of source revisions: some tag or key is used
to index this set, which is fixed and cannot be changed by subsequent
developers committing new changes to the tree. Releases are built from
tagged revisions like this, so that they can be rebuilt again later
(probably with controlled modifications).
@item
Retrieve the latest sources along a specific branch: some tag is used
to indicate which branch is to be used, but within that constraint we want
to get the latest revisions.
@end itemize

Build personnel or CM staff typically use the first approach: the
build that results is (ideally) completely specified by the two
parameters given to the VC system: repository and revision tag. This
gives QA and end-users something concrete to point at when reporting
bugs. Release engineers are also reportedly fond of shipping code that
can be traced back to a concise revision tag of some sort.

Developers are more likely to use the second approach: each morning
the developer does an update to pull in the changes committed by the
team over the last day. These builds are not easy to fully specify: it
depends upon exactly when you did a checkout, and upon what local
changes the developer has in their tree. Developers do not normally
tag each build they produce, because there is usually significant
overhead involved in creating these tags. Recreating the trees used by
one of these builds can be a challenge. Some VC systems may provide
implicit tags (like a revision number), while others may allow the use
of timestamps to mean ``the state of the tree at time X'' as opposed
to a tree-state that has been explicitly marked.

The Buildbot is designed to help developers, so it usually works in
terms of @emph{the latest} sources as opposed to specific tagged
revisions. However, it would really prefer to build from reproducible
source trees, so implicit revisions are used whenever possible.

@node Source Tree Specifications, How Different VC Systems Specify Sources, Generalizing VC Systems, Version Control Systems
@subsection Source Tree Specifications

So for the Buildbot's purposes we treat each VC system as a server
which can take a list of specifications as input and produce a source
tree as output. Some of these specifications are static: they are
attributes of the builder and do not change over time. Others are more
variable: each build will have a different value. The repository is
changed over time by a sequence of Changes, each of which represents a
single developer making changes to some set of files. These Changes
are cumulative@footnote{Monotone's @emph{multiple heads} feature
violates this assumption of cumulative Changes, but in most situations
the changes don't occur frequently enough for this to be a significant
problem}.

For normal builds, the Buildbot wants to get well-defined source trees
that contain specific Changes, and exclude other Changes that may have
occurred after the desired ones. We assume that the Changes arrive at
the buildbot (through one of the mechanisms described in @pxref{Change
Sources}) in the same order in which they are committed to the
repository. The Buildbot waits for the tree to become ``stable''
before initiating a build, for two reasons. The first is that
developers frequently make multiple related commits in quick
succession, even when the VC system provides ways to make atomic
transactions involving multiple files at the same time. Running a
build in the middle of these sets of changes would use an inconsistent
set of source files, and is likely to fail (and is certain to be less
useful than a build which uses the full set of changes). The
tree-stable-timer is intended to avoid these useless builds that
include some of the developer's changes but not all. The second reason
is that some VC systems (i.e. CVS) do not provide repository-wide
transaction numbers, so that timestamps are the only way to refer to
a specific repository state. These timestamps may be somewhat
ambiguous, due to processing and notification delays. By waiting until
the tree has been stable for, say, 10 minutes, we can choose a
timestamp from the middle of that period to use for our source
checkout, and then be reasonably sure that any clock-skew errors will
not cause the build to be performed on an inconsistent set of source
files.

The Schedulers always use the tree-stable-timer, with a timeout that
is configured to reflect a reasonable tradeoff between build latency
and change frequency. When the VC system provides coherent
repository-wide revision markers (such as Subversion's revision
numbers, or in fact anything other than CVS's timestamps), the
resulting Build is simply performed against a source tree defined by
that revision marker. When the VC system does not provide this, a
timestamp from the middle of the tree-stable period is used to
generate the source tree@footnote{this @code{checkoutDelay} defaults
to half the tree-stable timer, but it can be overridden with an
argument to the Source Step}.

@node How Different VC Systems Specify Sources, Attributes of Changes, Source Tree Specifications, Version Control Systems
@subsection How Different VC Systems Specify Sources

For CVS, the static specifications are @code{repository} and
@code{module}. In addition to those, each build uses a timestamp (or
omits the timestamp to mean @code{the latest}) and @code{branch tag}
(which defaults to HEAD). These parameters collectively specify a set
of sources from which a build may be performed.

@uref{http://subversion.tigris.org, Subversion} combines the
repository, module, and branch into a single @code{Subversion URL}
parameter. Within that scope, source checkouts can be specified by a
numeric @code{revision number} (a repository-wide
monotonically-increasing marker, such that each transaction that
changes the repository is indexed by a different revision number), or
a revision timestamp. When branches are used, the repository and
module form a static @code{baseURL}, while each build has a
@code{revision number} and a @code{branch} (which defaults to a
statically-specified @code{defaultBranch}). The @code{baseURL} and
@code{branch} are simply concatenated together to derive the
@code{svnurl} to use for the checkout.

@uref{http://www.perforce.com/, Perforce} is similar. The server
is specified through a @code{P4PORT} parameter. Module and branch
are specified in a single depot path, and revisions are
depot-wide. When branches are used, the @code{p4base} and
@code{defaultBranch} are concatenated together to produce the depot
path.

@uref{http://wiki.gnuarch.org/, Arch} and
@uref{http://bazaar.canonical.com/, Bazaar} specify a repository by
URL, as well as a @code{version} which is kind of like a branch name.
Arch uses the word @code{archive} to represent the repository. Arch
lets you push changes from one archive to another, removing the strict
centralization required by CVS and SVN. It retains the distinction
between repository and working directory that most other VC systems
use. For complex multi-module directory structures, Arch has a
built-in @code{build config} layer with which the checkout process has
two steps. First, an initial bootstrap checkout is performed to
retrieve a set of build-config files. Second, one of these files is
used to figure out which archives/modules should be used to populate
subdirectories of the initial checkout.

Builders which use Arch and Bazaar therefore have a static archive
@code{url}, and a default ``branch'' (which is a string that specifies
a complete category--branch--version triple). Each build can have its
own branch (the category--branch--version string) to override the
default, as well as a revision number (which is turned into a
--patch-NN suffix when performing the checkout).


@uref{http://bazaar-vcs.org, Bzr} (which is a descendant of
Arch/Bazaar, and is frequently referred to as ``Bazaar'') has the same
sort of repository-vs-workspace model as Arch, but the repository data
can either be stored inside the working directory or kept elsewhere
(either on the same machine or on an entirely different machine). For
the purposes of Buildbot (which never commits changes), the repository
is specified with a URL and a revision number.

The most common way to obtain read-only access to a bzr tree is via
HTTP, simply by making the repository visible through a web server
like Apache. Bzr can also use FTP and SFTP servers, if the buildslave
process has sufficient privileges to access them. Higher performance
can be obtained by running a special Bazaar-specific server. None of
these matter to the buildbot: the repository URL just has to match the
kind of server being used. The @code{repoURL} argument provides the
location of the repository.

Branches are expressed as subdirectories of the main central
repository, which means that if branches are being used, the BZR step
is given a @code{baseURL} and @code{defaultBranch} instead of getting
the @code{repoURL} argument.


@uref{http://darcs.net/, Darcs} doesn't really have the
notion of a single master repository. Nor does it really have
branches. In Darcs, each working directory is also a repository, and
there are operations to push and pull patches from one of these
@code{repositories} to another. For the Buildbot's purposes, all you
need to do is specify the URL of a repository that you want to build
from. The build slave will then pull the latest patches from that
repository and build them. Multiple branches are implemented by using
multiple repositories (possibly living on the same server).

Builders which use Darcs therefore have a static @code{repourl} which
specifies the location of the repository. If branches are being used,
the source Step is instead configured with a @code{baseURL} and a
@code{defaultBranch}, and the two strings are simply concatenated
together to obtain the repository's URL. Each build then has a
specific branch which replaces @code{defaultBranch}, or just uses the
default one. Instead of a revision number, each build can have a
``context'', which is a string that records all the patches that are
present in a given tree (this is the output of @command{darcs changes
--context}, and is considerably less concise than, e.g. Subversion's
revision number, but the patch-reordering flexibility of Darcs makes
it impossible to provide a shorter useful specification).

@uref{http://selenic.com/mercurial, Mercurial} is like Darcs, in that
each branch is stored in a separate repository. The @code{repourl},
@code{baseURL}, and @code{defaultBranch} arguments are all handled the
same way as with Darcs. The ``revision'', however, is the hash
identifier returned by @command{hg identify}.

@uref{http://git.or.cz/, Git} also follows a decentralized model, and
each repository can have several branches and tags. The source Step is
configured with a static @code{repourl} which specifies the location
of the repository. In addition, an optional @code{branch} parameter
can be specified to check out code from a specific branch instead of
the default ``master'' branch. The ``revision'' is specified as a SHA1
hash as returned by e.g. @command{git rev-parse}. No attempt is made
to ensure that the specified revision is actually a subset of the
specified branch.


@node Attributes of Changes,  , How Different VC Systems Specify Sources, Version Control Systems
@subsection Attributes of Changes

@heading Who

Each Change has a @code{who} attribute, which specifies which
developer is responsible for the change. This is a string which comes
from a namespace controlled by the VC repository. Frequently this
means it is a username on the host which runs the repository, but not
all VC systems require this (Arch, for example, uses a fully-qualified
@code{Arch ID}, which looks like an email address, as does Darcs).
Each StatusNotifier will map the @code{who} attribute into something
appropriate for their particular means of communication: an email
address, an IRC handle, etc.

@heading Files

It also has a list of @code{files}, which are just the tree-relative
filenames of any files that were added, deleted, or modified for this
Change. These filenames are used by the @code{fileIsImportant}
function (in the Scheduler) to decide whether it is worth triggering a
new build or not, e.g. the function could use the following function
to only run a build if a C file were checked in:

@example
def has_C_files(change):
    for name in change.files:
        if name.endswith(".c"):
            return True
    return False
@end example

Certain BuildSteps can also use the list of changed files
to run a more targeted series of tests, e.g. the
@code{python_twisted.Trial} step can run just the unit tests that
provide coverage for the modified .py files instead of running the
full test suite.

@heading Comments

The Change also has a @code{comments} attribute, which is a string
containing any checkin comments.

@heading Revision

Each Change can have a @code{revision} attribute, which describes how
to get a tree with a specific state: a tree which includes this Change
(and all that came before it) but none that come after it. If this
information is unavailable, the @code{.revision} attribute will be
@code{None}. These revisions are provided by the ChangeSource, and
consumed by the @code{computeSourceRevision} method in the appropriate
@code{step.Source} class.

@table @samp
@item CVS
@code{revision} is an int, seconds since the epoch
@item SVN
@code{revision} is an int, the changeset number (r%d)
@item Darcs
@code{revision} is a large string, the output of @code{darcs changes --context}
@item Mercurial
@code{revision} is a short string (a hash ID), the output of @code{hg identify}
@item Arch/Bazaar
@code{revision} is the full revision ID (ending in --patch-%d)
@item P4
@code{revision} is an int, the transaction number
@item Git
@code{revision} is a short string (a SHA1 hash), the output of e.g.
@code{git rev-parse}
@end table

@heading Branches

The Change might also have a @code{branch} attribute. This indicates
that all of the Change's files are in the same named branch. The
Schedulers get to decide whether the branch should be built or not.

For VC systems like CVS, Arch, Monotone, and Git, the @code{branch}
name is unrelated to the filename. (that is, the branch name and the
filename inhabit unrelated namespaces). For SVN, branches are
expressed as subdirectories of the repository, so the file's
``svnurl'' is a combination of some base URL, the branch name, and the
filename within the branch. (In a sense, the branch name and the
filename inhabit the same namespace). Darcs branches are
subdirectories of a base URL just like SVN. Mercurial branches are the
same as Darcs.

@table @samp
@item CVS
branch='warner-newfeature', files=['src/foo.c']
@item SVN
branch='branches/warner-newfeature', files=['src/foo.c']
@item Darcs
branch='warner-newfeature', files=['src/foo.c']
@item Mercurial
branch='warner-newfeature', files=['src/foo.c']
@item Arch/Bazaar
branch='buildbot--usebranches--0', files=['buildbot/master.py']
@item Git
branch='warner-newfeature', files=['src/foo.c']
@end table

@heading Links

@c TODO: who is using 'links'? how is it being used?

Finally, the Change might have a @code{links} list, which is intended
to provide a list of URLs to a @emph{viewcvs}-style web page that
provides more detail for this Change, perhaps including the full file
diffs.


@node Schedulers, BuildSet, Version Control Systems, Concepts
@section Schedulers

@cindex Scheduler

Each Buildmaster has a set of @code{Scheduler} objects, each of which
gets a copy of every incoming Change. The Schedulers are responsible
for deciding when Builds should be run. Some Buildbot installations
might have a single Scheduler, while others may have several, each for
a different purpose.

For example, a ``quick'' scheduler might exist to give immediate
feedback to developers, hoping to catch obvious problems in the code
that can be detected quickly. These typically do not run the full test
suite, nor do they run on a wide variety of platforms. They also
usually do a VC update rather than performing a brand-new checkout
each time. You could have a ``quick'' scheduler which used a 30 second
timeout, and feeds a single ``quick'' Builder that uses a VC
@code{mode='update'} setting.

A separate ``full'' scheduler would run more comprehensive tests a
little while later, to catch more subtle problems. This scheduler
would have a longer tree-stable-timer, maybe 30 minutes, and would
feed multiple Builders (with a @code{mode=} of @code{'copy'},
@code{'clobber'}, or @code{'export'}).

The @code{tree-stable-timer} and @code{fileIsImportant} decisions are
made by the Scheduler. Dependencies are also implemented here.
Periodic builds (those which are run every N seconds rather than after
new Changes arrive) are triggered by a special @code{Periodic}
Scheduler subclass. The default Scheduler class can also be told to
watch for specific branches, ignoring Changes on other branches. This
may be useful if you have a trunk and a few release branches which
should be tracked, but when you don't want to have the Buildbot pay
attention to several dozen private user branches.

When the setup has multiple sources of Changes the @code{category}
can be used for @code{Scheduler} objects to filter out a subset
of the Changes.  Note that not all change sources can attach a category.

Some Schedulers may trigger builds for other reasons, other than
recent Changes. For example, a Scheduler subclass could connect to a
remote buildmaster and watch for builds of a library to succeed before
triggering a local build that uses that library.

Each Scheduler creates and submits @code{BuildSet} objects to the
@code{BuildMaster}, which is then responsible for making sure the
individual @code{BuildRequests} are delivered to the target
@code{Builders}.

@code{Scheduler} instances are activated by placing them in the
@code{c['schedulers']} list in the buildmaster config file. Each
Scheduler has a unique name.


@node BuildSet, BuildRequest, Schedulers, Concepts
@section BuildSet

@cindex BuildSet

A @code{BuildSet} is the name given to a set of Builds that all
compile/test the same version of the tree on multiple Builders. In
general, all these component Builds will perform the same sequence of
Steps, using the same source code, but on different platforms or
against a different set of libraries.

The @code{BuildSet} is tracked as a single unit, which fails if any of
the component Builds have failed, and therefore can succeed only if
@emph{all} of the component Builds have succeeded. There are two kinds
of status notification messages that can be emitted for a BuildSet:
the @code{firstFailure} type (which fires as soon as we know the
BuildSet will fail), and the @code{Finished} type (which fires once
the BuildSet has completely finished, regardless of whether the
overall set passed or failed).

A @code{BuildSet} is created with a @emph{source stamp} tuple of
(branch, revision, changes, patch), some of which may be None, and a
list of Builders on which it is to be run. They are then given to the
BuildMaster, which is responsible for creating a separate
@code{BuildRequest} for each Builder.

There are a couple of different likely values for the
@code{SourceStamp}:

@table @code
@item (revision=None, changes=[CHANGES], patch=None)
This is a @code{SourceStamp} used when a series of Changes have
triggered a build. The VC step will attempt to check out a tree that
contains CHANGES (and any changes that occurred before CHANGES, but
not any that occurred after them).

@item (revision=None, changes=None, patch=None)
This builds the most recent code on the default branch. This is the
sort of @code{SourceStamp} that would be used on a Build that was
triggered by a user request, or a Periodic scheduler. It is also
possible to configure the VC Source Step to always check out the
latest sources rather than paying attention to the Changes in the
SourceStamp, which will result in same behavior as this.

@item (branch=BRANCH, revision=None, changes=None, patch=None)
This builds the most recent code on the given BRANCH. Again, this is
generally triggered by a user request or Periodic build.

@item (revision=REV, changes=None, patch=(LEVEL, DIFF))
This checks out the tree at the given revision REV, then applies a
patch (using @code{patch -pLEVEL <DIFF}). The @ref{try} feature uses
this kind of @code{SourceStamp}. If @code{patch} is None, the patching
step is bypassed.

@end table

The buildmaster is responsible for turning the @code{BuildSet} into a
set of @code{BuildRequest} objects and queueing them on the
appropriate Builders.


@node BuildRequest, Builder, BuildSet, Concepts
@section BuildRequest

@cindex BuildRequest

A @code{BuildRequest} is a request to build a specific set of sources
on a single specific @code{Builder}. Each @code{Builder} runs the
@code{BuildRequest} as soon as it can (i.e. when an associated
buildslave becomes free). @code{BuildRequest}s are prioritized from
oldest to newest, so when a buildslave becomes free, the
@code{Builder} with the oldest @code{BuildRequest} is run.

The @code{BuildRequest} contains the @code{SourceStamp} specification.
The actual process of running the build (the series of Steps that will
be executed) is implemented by the @code{Build} object. In this future
this might be changed, to have the @code{Build} define @emph{what}
gets built, and a separate @code{BuildProcess} (provided by the
Builder) to define @emph{how} it gets built.

@code{BuildRequest} is created with optional @code{Properties}.  One
of these, @code{owner}, is collected by the resultant @code{Build} and
added to the set of @emph{interested users} to which status
notifications will be sent, depending on the configuration for each
status object.

The @code{BuildRequest} may be mergeable with other compatible
@code{BuildRequest}s. Builds that are triggered by incoming Changes
will generally be mergeable. Builds that are triggered by user
requests are generally not, unless they are multiple requests to build
the @emph{latest sources} of the same branch.

@node Builder, Users, BuildRequest, Concepts
@section Builder

@cindex Builder

The @code{Builder} is a long-lived object which controls all Builds of
a given type. Each one is created when the config file is first
parsed, and lives forever (or rather until it is removed from the
config file). It mediates the connections to the buildslaves that do
all the work, and is responsible for creating the @code{Build} objects
that decide @emph{how} a build is performed (i.e., which steps are
executed in what order).

Each @code{Builder} gets a unique name, and the path name of a
directory where it gets to do all its work (there is a
buildmaster-side directory for keeping status information, as well as
a buildslave-side directory where the actual checkout/compile/test
commands are executed). It also gets a @code{BuildFactory}, which is
responsible for creating new @code{Build} instances: because the
@code{Build} instance is what actually performs each build, choosing
the @code{BuildFactory} is the way to specify what happens each time a
build is done.

Each @code{Builder} is associated with one of more @code{BuildSlaves}.
A @code{Builder} which is used to perform OS-X builds (as opposed to
Linux or Solaris builds) should naturally be associated with an
OS-X-based buildslave.

A @code{Builder} may be given a set of environment variables to be used
in its @pxref{ShellCommand}s. These variables will override anything in the
buildslave's environment. Variables passed directly to a ShellCommand will
override variables of the same name passed to the Builder.

For example, if you a pool of identical slaves it is often easier to manage
variables like PATH from Buildbot rather than manually editing it inside of
the slaves' environment.

@example
f = factory.BuildFactory
f.addStep(ShellCommand(
              command=['bash', './configure']))
f.addStep(Compile())

c['builders'] = [
  @{'name': 'test', 'slavenames': ['slave1', 'slave2', 'slave3', 'slave4',
                                   'slave5', 'slave6'],
    'builddir': 'test', 'factory': f',
    'env': @{'PATH': '/opt/local/bin:/opt/app/bin:/usr/local/bin:/usr/bin'@}@}

@end example

@node Users, Build Properties, Builder, Concepts
@section Users

@cindex Users

Buildbot has a somewhat limited awareness of @emph{users}. It assumes
the world consists of a set of developers, each of whom can be
described by a couple of simple attributes. These developers make
changes to the source code, causing builds which may succeed or fail.

Each developer is primarily known through the source control system. Each
Change object that arrives is tagged with a @code{who} field that
typically gives the account name (on the repository machine) of the user
responsible for that change. This string is the primary key by which the
User is known, and is displayed on the HTML status pages and in each Build's
``blamelist''.

To do more with the User than just refer to them, this username needs to
be mapped into an address of some sort. The responsibility for this mapping
is left up to the status module which needs the address. The core code knows
nothing about email addresses or IRC nicknames, just user names.

@menu
* Doing Things With Users::
* Email Addresses::
* IRC Nicknames::
* Live Status Clients::
@end menu

@node Doing Things With Users, Email Addresses, Users, Users
@subsection Doing Things With Users

Each Change has a single User who is responsible for that Change. Most
Builds have a set of Changes: the Build represents the first time these
Changes have been built and tested by the Buildbot. The build has a
``blamelist'' that consists of a simple union of the Users responsible
for all the Build's Changes.

The Build provides (through the IBuildStatus interface) a list of Users
who are ``involved'' in the build. For now this is equal to the
blamelist, but in the future it will be expanded to include a ``build
sheriff'' (a person who is ``on duty'' at that time and responsible for
watching over all builds that occur during their shift), as well as
per-module owners who simply want to keep watch over their domain (chosen by
subdirectory or a regexp matched against the filenames pulled out of the
Changes). The Involved Users are those who probably have an interest in the
results of any given build.

In the future, Buildbot will acquire the concept of ``Problems'',
which last longer than builds and have beginnings and ends. For example, a
test case which passed in one build and then failed in the next is a
Problem. The Problem lasts until the test case starts passing again, at
which point the Problem is said to be ``resolved''.

If there appears to be a code change that went into the tree at the
same time as the test started failing, that Change is marked as being
resposible for the Problem, and the user who made the change is added
to the Problem's ``Guilty'' list. In addition to this user, there may
be others who share responsibility for the Problem (module owners,
sponsoring developers). In addition to the Responsible Users, there
may be a set of Interested Users, who take an interest in the fate of
the Problem.

Problems therefore have sets of Users who may want to be kept aware of
the condition of the problem as it changes over time. If configured, the
Buildbot can pester everyone on the Responsible list with increasing
harshness until the problem is resolved, with the most harshness reserved
for the Guilty parties themselves. The Interested Users may merely be told
when the problem starts and stops, as they are not actually responsible for
fixing anything.

@node Email Addresses, IRC Nicknames, Doing Things With Users, Users
@subsection Email Addresses

The @code{buildbot.status.mail.MailNotifier} class
(@pxref{MailNotifier}) provides a status target which can send email
about the results of each build. It accepts a static list of email
addresses to which each message should be delivered, but it can also
be configured to send mail to the Build's Interested Users. To do
this, it needs a way to convert User names into email addresses.

For many VC systems, the User Name is actually an account name on the
system which hosts the repository. As such, turning the name into an
email address is a simple matter of appending
``@@repositoryhost.com''. Some projects use other kinds of mappings
(for example the preferred email address may be at ``project.org''
despite the repository host being named ``cvs.project.org''), and some
VC systems have full separation between the concept of a user and that
of an account on the repository host (like Perforce). Some systems
(like Arch) put a full contact email address in every change.

To convert these names to addresses, the MailNotifier uses an EmailLookup
object. This provides a .getAddress method which accepts a name and
(eventually) returns an address. The default @code{MailNotifier}
module provides an EmailLookup which simply appends a static string,
configurable when the notifier is created. To create more complex behaviors
(perhaps using an LDAP lookup, or using ``finger'' on a central host to
determine a preferred address for the developer), provide a different object
as the @code{lookup} argument.

In the future, when the Problem mechanism has been set up, the Buildbot
will need to send mail to arbitrary Users. It will do this by locating a
MailNotifier-like object among all the buildmaster's status targets, and
asking it to send messages to various Users. This means the User-to-address
mapping only has to be set up once, in your MailNotifier, and every email
message the buildbot emits will take advantage of it.

@node IRC Nicknames, Live Status Clients, Email Addresses, Users
@subsection IRC Nicknames

Like MailNotifier, the @code{buildbot.status.words.IRC} class
provides a status target which can announce the results of each build. It
also provides an interactive interface by responding to online queries
posted in the channel or sent as private messages.

In the future, the buildbot can be configured map User names to IRC
nicknames, to watch for the recent presence of these nicknames, and to
deliver build status messages to the interested parties. Like
@code{MailNotifier} does for email addresses, the @code{IRC} object
will have an @code{IRCLookup} which is responsible for nicknames. The
mapping can be set up statically, or it can be updated by online users
themselves (by claiming a username with some kind of ``buildbot: i am
user warner'' commands).

Once the mapping is established, the rest of the buildbot can ask the
@code{IRC} object to send messages to various users. It can report on
the likelihood that the user saw the given message (based upon how long the
user has been inactive on the channel), which might prompt the Problem
Hassler logic to send them an email message instead.

@node Live Status Clients,  , IRC Nicknames, Users
@subsection Live Status Clients

The Buildbot also offers a PB-based status client interface which can
display real-time build status in a GUI panel on the developer's desktop.
This interface is normally anonymous, but it could be configured to let the
buildmaster know @emph{which} developer is using the status client. The
status client could then be used as a message-delivery service, providing an
alternative way to deliver low-latency high-interruption messages to the
developer (like ``hey, you broke the build'').

@node Build Properties,  , Users, Concepts
@section Build Properties
@cindex Properties

Each build has a set of ``Build Properties'', which can be used by its
BuildStep to modify their actions.  These properties, in the form of
key-value pairs, provide a general framework for dynamically altering
the behavior of a build based on its circumstances.

Properties come from a number of places:
@itemize
@item global configuration --
These properties apply to all builds.
@item schedulers --
A scheduler can specify properties available to all the builds it
starts.
@item buildslaves --
A buildslave can pass properties on to the builds it performs.
@item builds --
A build automatically sets a number of properties on itself.
@item steps --
Steps of a build can set properties that are available to subsequent
steps.  In particular, source steps set a number of properties.
@end itemize

Properties are very flexible, and can be used to implement all manner
of functionality.  Here are some examples:

Most Source steps record the revision that they checked out in
the @code{got_revision} property.  A later step could use this
property to specify the name of a fully-built tarball, dropped in an
easily-acessible directory for later testing.

Some projects want to perform nightly builds as well as in response
to committed changes.  Such a project would run two schedulers,
both pointing to the same set of builders, but could provide an
@code{is_nightly} property so that steps can distinguish the nightly
builds, perhaps to run more resource-intensive tests.

Some projects have different build processes on different systems.
Rather than create a build factory for each slave, the steps can use
buildslave properties to identify the unique aspects of each slave
and adapt the build process dynamically.

@node Configuration, Getting Source Code Changes, Concepts, Top
@chapter Configuration

@cindex Configuration

The buildbot's behavior is defined by the ``config file'', which
normally lives in the @file{master.cfg} file in the buildmaster's base
directory (but this can be changed with an option to the
@code{buildbot create-master} command). This file completely specifies
which Builders are to be run, which slaves they should use, how
Changes should be tracked, and where the status information is to be
sent. The buildmaster's @file{buildbot.tac} file names the base
directory; everything else comes from the config file.

A sample config file was installed for you when you created the
buildmaster, but you will need to edit it before your buildbot will do
anything useful.

This chapter gives an overview of the format of this file and the
various sections in it. You will need to read the later chapters to
understand how to fill in each section properly.

@menu
* Config File Format::
* Loading the Config File::
* Testing the Config File::
* Defining the Project::
* Change Sources and Schedulers::
* Merging BuildRequests::
* Setting the slaveport::
* Buildslave Specifiers::
* On-Demand ("Latent") Buildslaves::
* Defining Global Properties::
* Defining Builders::
* Defining Status Targets::
* Debug options::
@end menu

@node Config File Format, Loading the Config File, Configuration, Configuration
@section Config File Format

The config file is, fundamentally, just a piece of Python code which
defines a dictionary named @code{BuildmasterConfig}, with a number of
keys that are treated specially. You don't need to know Python to do
basic configuration, though, you can just copy the syntax of the
sample file. If you @emph{are} comfortable writing Python code,
however, you can use all the power of a full programming language to
achieve more complicated configurations.

The @code{BuildmasterConfig} name is the only one which matters: all
other names defined during the execution of the file are discarded.
When parsing the config file, the Buildmaster generally compares the
old configuration with the new one and performs the minimum set of
actions necessary to bring the buildbot up to date: Builders which are
not changed are left untouched, and Builders which are modified get to
keep their old event history.

Basic Python syntax: comments start with a hash character (``#''),
tuples are defined with @code{(parenthesis, pairs)}, arrays are
defined with @code{[square, brackets]}, tuples and arrays are mostly
interchangeable. Dictionaries (data structures which map ``keys'' to
``values'') are defined with curly braces: @code{@{'key1': 'value1',
'key2': 'value2'@} }. Function calls (and object instantiation) can use
named parameters, like @code{w = html.Waterfall(http_port=8010)}.

The config file starts with a series of @code{import} statements,
which make various kinds of Steps and Status targets available for
later use. The main @code{BuildmasterConfig} dictionary is created,
then it is populated with a variety of keys. These keys are broken
roughly into the following sections, each of which is documented in
the rest of this chapter:

@itemize @bullet
@item
Project Definitions
@item
Change Sources / Schedulers
@item
Slaveport
@item
Buildslave Configuration
@item
Builders / Interlocks
@item
Status Targets
@item
Debug options
@end itemize

The config file can use a few names which are placed into its namespace:

@table @code
@item basedir
the base directory for the buildmaster. This string has not been
expanded, so it may start with a tilde. It needs to be expanded before
use. The config file is located in
@code{os.path.expanduser(os.path.join(basedir, 'master.cfg'))}

@end table


@node Loading the Config File, Testing the Config File, Config File Format, Configuration
@section Loading the Config File

The config file is only read at specific points in time. It is first
read when the buildmaster is launched. Once it is running, there are
various ways to ask it to reload the config file. If you are on the
system hosting the buildmaster, you can send a @code{SIGHUP} signal to
it: the @command{buildbot} tool has a shortcut for this:

@example
buildbot reconfig @var{BASEDIR}
@end example

This command will show you all of the lines from @file{twistd.log}
that relate to the reconfiguration. If there are any problems during
the config-file reload, they will be displayed in these lines.

The debug tool (@code{buildbot debugclient --master HOST:PORT}) has a
``Reload .cfg'' button which will also trigger a reload. In the
future, there will be other ways to accomplish this step (probably a
password-protected button on the web page, as well as a privileged IRC
command).

When reloading the config file, the buildmaster will endeavor to
change as little as possible about the running system. For example,
although old status targets may be shut down and new ones started up,
any status targets that were not changed since the last time the
config file was read will be left running and untouched. Likewise any
Builders which have not been changed will be left running. If a
Builder is modified (say, the build process is changed) while a Build
is currently running, that Build will keep running with the old
process until it completes. Any previously queued Builds (or Builds
which get queued after the reconfig) will use the new process.

@node Testing the Config File, Defining the Project, Loading the Config File, Configuration
@section Testing the Config File

To verify that the config file is well-formed and contains no
deprecated or invalid elements, use the ``checkconfig'' command:

@example
% buildbot checkconfig master.cfg
Config file is good!
@end example

If the config file has deprecated features (perhaps because you've
upgraded the buildmaster and need to update the config file to match),
they will be announced by checkconfig. In this case, the config file
will work, but you should really remove the deprecated items and use
the recommended replacements instead:

@example
% buildbot checkconfig master.cfg
/usr/lib/python2.4/site-packages/buildbot/master.py:559: DeprecationWarning: c['sources'] is
deprecated as of 0.7.6 and will be removed by 0.8.0 . Please use c['change_source'] instead.
  warnings.warn(m, DeprecationWarning)
Config file is good!
@end example

If the config file is simply broken, that will be caught too:

@example
% buildbot checkconfig master.cfg
Traceback (most recent call last):
  File "/usr/lib/python2.4/site-packages/buildbot/scripts/runner.py", line 834, in doCheckConfig
    ConfigLoader(configFile)
  File "/usr/lib/python2.4/site-packages/buildbot/scripts/checkconfig.py", line 31, in __init__
    self.loadConfig(configFile)
  File "/usr/lib/python2.4/site-packages/buildbot/master.py", line 480, in loadConfig
    exec f in localDict
  File "/home/warner/BuildBot/master/foolscap/master.cfg", line 90, in ?
    c[bogus] = "stuff"
NameError: name 'bogus' is not defined
@end example


@node Defining the Project, Change Sources and Schedulers, Testing the Config File, Configuration
@section Defining the Project

There are a couple of basic settings that you use to tell the buildbot
what project it is working on. This information is used by status
reporters to let users find out more about the codebase being
exercised by this particular Buildbot installation.

@example
c['projectName'] = "Buildbot"
c['projectURL'] = "http://buildbot.sourceforge.net/"
c['buildbotURL'] = "http://localhost:8010/"
@end example

@bcindex c['projectName']
@code{projectName} is a short string will be used to describe the
project that this buildbot is working on. For example, it is used as
the title of the waterfall HTML page.

@bcindex c['projectURL']
@code{projectURL} is a string that gives a URL for the project as a
whole. HTML status displays will show @code{projectName} as a link to
@code{projectURL}, to provide a link from buildbot HTML pages to your
project's home page.

@bcindex c['buildbotURL']
The @code{buildbotURL} string should point to the location where the
buildbot's internal web server (usually the @code{html.Waterfall}
page) is visible. This typically uses the port number set when you
create the @code{Waterfall} object: the buildbot needs your help to
figure out a suitable externally-visible host name.

When status notices are sent to users (either by email or over IRC),
@code{buildbotURL} will be used to create a URL to the specific build
or problem that they are being notified about. It will also be made
available to queriers (over IRC) who want to find out where to get
more information about this buildbot.

@bcindex c['logCompressionLimit']
The @code{logCompressionLimit} enables bz2-compression of build logs on
disk for logs that are bigger than the given size, or disables that
completely if given @code{False}. The default value is 4k, which should
be a reasonable default on most file systems. This setting has no impact
on status plugins, and merely affects the required disk space on the
master for build logs.


@node Change Sources and Schedulers, Merging BuildRequests, Defining the Project, Configuration
@section Change Sources and Schedulers

@bcindex c['sources']
@bcindex c['change_source']

The @code{c['change_source']} key is the ChangeSource
instance@footnote{To be precise, it is an object or a list of objects
which all implement the @code{buildbot.interfaces.IChangeSource}
Interface. It is unusual to have multiple ChangeSources, so this key
accepts either a single ChangeSource or a sequence of them.} that
defines how the buildmaster learns about source code changes. More
information about what goes here is available in @xref{Getting Source
Code Changes}.

@example
from buildbot.changes.pb import PBChangeSource
c['change_source'] = PBChangeSource()
@end example
@bcindex c['schedulers']

(note: in buildbot-0.7.5 and earlier, this key was named
@code{c['sources']}, and required a list. @code{c['sources']} is
deprecated as of buildbot-0.7.6 and is scheduled to be removed in a
future release).

@code{c['schedulers']} is a list of Scheduler instances, each
of which causes builds to be started on a particular set of
Builders. The two basic Scheduler classes you are likely to start
with are @code{Scheduler} and @code{Periodic}, but you can write a
customized subclass to implement more complicated build scheduling.

Scheduler arguments
should always be specified by name (as keyword arguments), to allow
for future expansion:

@example
sched = Scheduler(name="quick", builderNames=['lin', 'win'])
@end example

All schedulers have several arguments in common:

@table @code
@item name

Each Scheduler must have a unique name. This is used in status
displays, and is also available in the build property @code{scheduler}.

@item builderNames

This is the set of builders which this scheduler should trigger, specified
as a list of names (strings).

@item properties
@cindex Properties

This is a dictionary specifying properties that will be transmitted
to all builds started by this scheduler.

@end table

Here is a brief catalog of the available Scheduler types. All these
Schedulers are classes in @code{buildbot.scheduler}, and the
docstrings there are the best source of documentation on the arguments
taken by each one.

@menu
* Scheduler Scheduler::
* AnyBranchScheduler::
* Dependent Scheduler::
* Periodic Scheduler::
* Nightly Scheduler::
* Try Schedulers::
* Triggerable Scheduler::
@end menu

@node Scheduler Scheduler, AnyBranchScheduler, Change Sources and Schedulers, Change Sources and Schedulers
@subsection Scheduler Scheduler
@slindex buildbot.scheduler.Scheduler

This is the original and still most popular Scheduler class. It follows
exactly one branch, and starts a configurable tree-stable-timer after
each change on that branch. When the timer expires, it starts a build
on some set of Builders. The Scheduler accepts a @code{fileIsImportant}
function which can be used to ignore some Changes if they do not
affect any ``important'' files.

The arguments to this scheduler are:

@table @code
@item name

@item builderNames

@item properties

@item branch
This Scheduler will pay attention to a single branch, ignoring Changes
that occur on other branches. Setting @code{branch} equal to the
special value of @code{None} means it should only pay attention to
the default branch. Note that @code{None} is a keyword, not a string,
so you want to use @code{None} and not @code{"None"}.

@item treeStableTimer
The Scheduler will wait for this many seconds before starting the
build. If new changes are made during this interval, the timer will be
restarted, so really the build will be started after a change and then
after this many seconds of inactivity.

@item fileIsImportant
A callable which takes one argument, a Change instance, and returns
@code{True} if the change is worth building, and @code{False} if
it is not.  Unimportant Changes are accumulated until the build is
triggered by an important change.  The default value of None means
that all Changes are important.

@item categories
A list of categories of changes that this scheduler will respond to.  If this
is specified, then any non-matching changes are ignored.

@end table

Example:

@example
from buildbot import scheduler
quick = scheduler.Scheduler(name="quick",
                    branch=None,
                    treeStableTimer=60,
                    builderNames=["quick-linux", "quick-netbsd"])
full = scheduler.Scheduler(name="full",
                    branch=None,
                    treeStableTimer=5*60,
                    builderNames=["full-linux", "full-netbsd", "full-OSX"])
c['schedulers'] = [quick, full]
@end example

In this example, the two ``quick'' builders are triggered 60 seconds
after the tree has been changed. The ``full'' builds do not run quite
so quickly (they wait 5 minutes), so hopefully if the quick builds
fail due to a missing file or really simple typo, the developer can
discover and fix the problem before the full builds are started. Both
Schedulers only pay attention to the default branch: any changes
on other branches are ignored by these Schedulers. Each Scheduler
triggers a different set of Builders, referenced by name.

@node AnyBranchScheduler, Dependent Scheduler, Scheduler Scheduler, Change Sources and Schedulers
@subsection AnyBranchScheduler
@slindex buildbot.scheduler.AnyBranchScheduler

This scheduler uses a tree-stable-timer like the default one, but
follows multiple branches at once. Each branch gets a separate timer.

The arguments to this scheduler are:

@table @code
@item name

@item builderNames

@item properties

@item branches
This Scheduler will pay attention to any number of branches, ignoring
Changes that occur on other branches. Branches are specified just as
for the @code{Scheduler} class.

@item treeStableTimer
The Scheduler will wait for this many seconds before starting the
build. If new changes are made during this interval, the timer will be
restarted, so really the build will be started after a change and then
after this many seconds of inactivity.

@item fileIsImportant
A callable which takes one argument, a Change instance, and returns
@code{True} if the change is worth building, and @code{False} if
it is not.  Unimportant Changes are accumulated until the build is
triggered by an important change.  The default value of None means
that all Changes are important.
@end table

@node Dependent Scheduler, Periodic Scheduler, AnyBranchScheduler, Change Sources and Schedulers
@subsection Dependent Scheduler
@cindex Dependent
@cindex Dependencies
@slindex buildbot.scheduler.Dependent

It is common to wind up with one kind of build which should only be
performed if the same source code was successfully handled by some
other kind of build first. An example might be a packaging step: you
might only want to produce .deb or RPM packages from a tree that was
known to compile successfully and pass all unit tests. You could put
the packaging step in the same Build as the compile and testing steps,
but there might be other reasons to not do this (in particular you
might have several Builders worth of compiles/tests, but only wish to
do the packaging once). Another example is if you want to skip the
``full'' builds after a failing ``quick'' build of the same source
code. Or, if one Build creates a product (like a compiled library)
that is used by some other Builder, you'd want to make sure the
consuming Build is run @emph{after} the producing one.

You can use ``Dependencies'' to express this relationship
to the Buildbot. There is a special kind of Scheduler named
@code{scheduler.Dependent} that will watch an ``upstream'' Scheduler
for builds to complete successfully (on all of its Builders). Each time
that happens, the same source code (i.e. the same @code{SourceStamp})
will be used to start a new set of builds, on a different set of
Builders. This ``downstream'' scheduler doesn't pay attention to
Changes at all. It only pays attention to the upstream scheduler.

If the build fails on any of the Builders in the upstream set,
the downstream builds will not fire.  Note that, for SourceStamps
generated by a ChangeSource, the @code{revision} is None, meaning HEAD.
If any changes are committed between the time the upstream scheduler
begins its build and the time the dependent scheduler begins its
build, then those changes will be included in the downstream build.
See the @pxref{Triggerable Scheduler} for a more flexible dependency
mechanism that can avoid this problem.

The arguments to this scheduler are:

@table @code
@item name

@item builderNames

@item properties

@item upstream
The upstream scheduler to watch.  Note that this is an ``instance'',
not the name of the scheduler.
@end table

Example:

@example
from buildbot import scheduler
tests = scheduler.Scheduler("just-tests", None, 5*60,
                            ["full-linux", "full-netbsd", "full-OSX"])
package = scheduler.Dependent("build-package",
                              tests, # upstream scheduler -- no quotes!
                              ["make-tarball", "make-deb", "make-rpm"])
c['schedulers'] = [tests, package]
@end example

@node Periodic Scheduler, Nightly Scheduler, Dependent Scheduler, Change Sources and Schedulers
@subsection Periodic Scheduler
@slindex buildbot.scheduler.Periodic

This simple scheduler just triggers a build every N seconds.

The arguments to this scheduler are:

@table @code
@item name

@item builderNames

@item properties

@item periodicBuildTimer
The time, in seconds, after which to start a build.
@end table

Example:

@example
from buildbot import scheduler
nightly = scheduler.Periodic(name="nightly",
                builderNames=["full-solaris"],
                periodicBuildTimer=24*60*60)
c['schedulers'] = [nightly]
@end example

The Scheduler in this example just runs the full solaris build once
per day. Note that this Scheduler only lets you control the time
between builds, not the absolute time-of-day of each Build, so this
could easily wind up a ``daily'' or ``every afternoon'' scheduler
depending upon when it was first activated.

@node Nightly Scheduler, Try Schedulers, Periodic Scheduler, Change Sources and Schedulers
@subsection Nightly Scheduler
@slindex buildbot.scheduler.Nightly

This is highly configurable periodic build scheduler, which triggers
a build at particular times of day, week, month, or year. The
configuration syntax is very similar to the well-known @code{crontab}
format, in which you provide values for minute, hour, day, and month
(some of which can be wildcards), and a build is triggered whenever
the current time matches the given constraints. This can run a build
every night, every morning, every weekend, alternate Thursdays,
on your boss's birthday, etc.

Pass some subset of @code{minute}, @code{hour}, @code{dayOfMonth},
@code{month}, and @code{dayOfWeek}; each may be a single number or
a list of valid values. The builds will be triggered whenever the
current time matches these values. Wildcards are represented by a
'*' string. All fields default to a wildcard except 'minute', so
with no fields this defaults to a build every hour, on the hour.
The full list of parameters is:

@table @code
@item name

@item builderNames

@item properties

@item branch
The branch to build, just as for @code{Scheduler}.

@item minute
The minute of the hour on which to start the build.  This defaults
to 0, meaning an hourly build.

@item hour
The hour of the day on which to start the build, in 24-hour notation.
This defaults to *, meaning every hour.

@item month
The month in which to start the build, with January = 1.  This defaults
to *, meaning every month.

@item dayOfWeek
The day of the week to start a build, with Monday = 0.  This defauls
to *, meaning every day of the week.

@item onlyIfChanged
If this is true, then builds will not be scheduled at the designated time
unless the source has changed since the previous build.
@end table

For example, the following master.cfg clause will cause a build to be
started every night at 3:00am:

@example
s = scheduler.Nightly(name='nightly',
        builderNames=['builder1', 'builder2'],
        hour=3,
        minute=0)
@end example

This scheduler will perform a build each monday morning at 6:23am and
again at 8:23am, but only if someone has committed code in the interim:

@example
s = scheduler.Nightly(name='BeforeWork',
         builderNames=['builder1'],
         dayOfWeek=0,
         hour=[6,8],
         minute=23,
         onlyIfChanged=True)
@end example

The following runs a build every two hours, using Python's @code{range}
function:

@example
s = Nightly(name='every2hours',
        builderNames=['builder1'],
        hour=range(0, 24, 2))
@end example

Finally, this example will run only on December 24th:

@example
s = Nightly(name='SleighPreflightCheck',
        builderNames=['flying_circuits', 'radar'],
        month=12,
        dayOfMonth=24,
        hour=12,
        minute=0)
@end example

@node Try Schedulers, Triggerable Scheduler, Nightly Scheduler, Change Sources and Schedulers
@subsection Try Schedulers
@slindex buildbot.scheduler.Try_Jobdir
@slindex buildbot.scheduler.Try_Userpass

This scheduler allows developers to use the @code{buildbot try}
command to trigger builds of code they have not yet committed. See
@ref{try} for complete details.

Two implementations are available: @code{Try_Jobdir} and
@code{Try_Userpass}.  The former monitors a job directory, specified
by the @code{jobdir} parameter, while the latter listens for PB
connections on a specific @code{port}, and authenticates against
@code{userport}.

@node Triggerable Scheduler,  , Try Schedulers, Change Sources and Schedulers
@subsection Triggerable Scheduler
@cindex Triggers
@slindex buildbot.scheduler.Triggerable

The @code{Triggerable} scheduler waits to be triggered by a Trigger
step (see @ref{Triggering Schedulers}) in another build. That step
can optionally wait for the scheduler's builds to complete. This
provides two advantages over Dependent schedulers. First, the same
scheduler can be triggered from multiple builds. Second, the ability
to wait for a Triggerable's builds to complete provides a form of
"subroutine call", where one or more builds can "call" a scheduler
to perform some work for them, perhaps on other buildslaves.

The parameters are just the basics:

@table @code
@item name
@item builderNames
@item properties
@end table

This class is only useful in conjunction with the @code{Trigger} step.
Here is a fully-worked example:

@example
from buildbot import scheduler
from buildbot.process import factory
from buildbot.steps import trigger

checkin = scheduler.Scheduler(name="checkin",
            branch=None,
            treeStableTimer=5*60,
            builderNames=["checkin"])
nightly = scheduler.Nightly(name='nightly',
            builderNames=['nightly'],
            hour=3,
            minute=0)

mktarball = scheduler.Triggerable(name="mktarball",
                builderNames=["mktarball"])
build = scheduler.Triggerable(name="build-all-platforms",
                builderNames=["build-all-platforms"])
test = scheduler.Triggerable(name="distributed-test",
                builderNames=["distributed-test"])
package = scheduler.Triggerable(name="package-all-platforms",
                builderNames=["package-all-platforms"])

c['schedulers'] = [checkin, nightly, build, test, package]

# on checkin, make a tarball, build it, and test it
checkin_factory = factory.BuildFactory()
checkin_factory.addStep(trigger.Trigger(schedulerNames=['mktarball'],
                                       waitForFinish=True))
checkin_factory.addStep(trigger.Trigger(schedulerNames=['build-all-platforms'],
                                   waitForFinish=True))
checkin_factory.addStep(trigger.Trigger(schedulerNames=['distributed-test'],
                                  waitForFinish=True))

# and every night, make a tarball, build it, and package it
nightly_factory = factory.BuildFactory()
nightly_factory.addStep(trigger.Trigger(schedulerNames=['mktarball'],
                                       waitForFinish=True))
nightly_factory.addStep(trigger.Trigger(schedulerNames=['build-all-platforms'],
                                   waitForFinish=True))
nightly_factory.addStep(trigger.Trigger(schedulerNames=['package-all-platforms'],
                                     waitForFinish=True))
@end example

@node Merging BuildRequests, Setting the slaveport, Change Sources and Schedulers, Configuration
@section Merging BuildRequests

@bcindex c['mergeRequests']

By default, buildbot merges BuildRequests that have the compatible
SourceStamps. This behaviour can be customized with the
@code{c['mergeRequests']} configuration key.  This key specifies a function
which is caleld with three arguments: a @code{Builder} and two
@code{BuildRequest} objects.  It should return true if the requests can be
merged.  For example:

@example
def mergeRequests(builder, req1, req2):
    """Don't merge buildrequest at all"""
    return False
c['mergeRequests'] = mergeRequests
@end example

In many cases, the details of the SourceStamps and BuildRequests are important.
In this example, only BuildRequests with the same "reason" are merged; thus
developers forcing builds for different reasons will see distinct builds.

@example
def mergeRequests(builder, req1, req2):
    if req1.source.canBeMergedWith(req2.source) and  req1.reason == req2.reason:
       return True
    return False
c['mergeRequests'] = mergeRequests
@end example

@node Setting the slaveport, Buildslave Specifiers, Merging BuildRequests, Configuration
@section Setting the slaveport

@bcindex c['slavePortnum']

The buildmaster will listen on a TCP port of your choosing for
connections from buildslaves. It can also use this port for
connections from remote Change Sources, status clients, and debug
tools. This port should be visible to the outside world, and you'll
need to tell your buildslave admins about your choice.

It does not matter which port you pick, as long it is externally
visible, however you should probably use something larger than 1024,
since most operating systems don't allow non-root processes to bind to
low-numbered ports. If your buildmaster is behind a firewall or a NAT
box of some sort, you may have to configure your firewall to permit
inbound connections to this port.

@example
c['slavePortnum'] = 10000
@end example

@code{c['slavePortnum']} is a @emph{strports} specification string,
defined in the @code{twisted.application.strports} module (try
@command{pydoc twisted.application.strports} to get documentation on
the format). This means that you can have the buildmaster listen on a
localhost-only port by doing:

@example
c['slavePortnum'] = "tcp:10000:interface=127.0.0.1"
@end example

This might be useful if you only run buildslaves on the same machine,
and they are all configured to contact the buildmaster at
@code{localhost:10000}.


@node Buildslave Specifiers, On-Demand ("Latent") Buildslaves, Setting the slaveport, Configuration
@section Buildslave Specifiers
@bcindex c['slaves']

The @code{c['slaves']} key is a list of known buildslaves. In the common case,
each buildslave is defined by an instance of the BuildSlave class.  It
represents a standard, manually started machine that will try to connect to
the buildbot master as a slave.  Contrast these with the "on-demand" latent
buildslaves, such as the Amazon Web Service Elastic Compute Cloud latent
buildslave discussed below.

The BuildSlave class is instantiated with two values: (slavename,
slavepassword). These are the same two values that need to be provided to the
buildslave administrator when they create the buildslave.

The slavenames must be unique, of course. The password exists to
prevent evildoers from interfering with the buildbot by inserting
their own (broken) buildslaves into the system and thus displacing the
real ones.

Buildslaves with an unrecognized slavename or a non-matching password
will be rejected when they attempt to connect, and a message
describing the problem will be put in the log file (see @ref{Logfiles}).

@example
from buildbot.buildslave import BuildSlave
c['slaves'] = [BuildSlave('bot-solaris', 'solarispasswd')
               BuildSlave('bot-bsd', 'bsdpasswd')
              ]
@end example

@cindex Properties
@code{BuildSlave} objects can also be created with an optional
@code{properties} argument, a dictionary specifying properties that
will be available to any builds performed on this slave.  For example:

@example
from buildbot.buildslave import BuildSlave
c['slaves'] = [BuildSlave('bot-solaris', 'solarispasswd',
                    properties=@{'os':'solaris'@}),
              ]
@end example

The @code{BuildSlave} constructor can also take an optional
@code{max_builds} parameter to limit the number of builds that it
will execute simultaneously:

@example
from buildbot.buildslave import BuildSlave
c['slaves'] = [BuildSlave("bot-linux", "linuxpassword", max_builds=2)]
@end example

Historical note: in buildbot-0.7.5 and earlier, the @code{c['bots']}
key was used instead, and it took a list of (name, password) tuples.
This key is accepted for backwards compatibility, but is deprecated as
of 0.7.6 and will go away in some future release.

@menu
* When Buildslaves Go Missing::
@end menu

@node When Buildslaves Go Missing, , , Buildslave Specifiers
@subsection When Buildslaves Go Missing

Sometimes, the buildslaves go away. One very common reason for this is
when the buildslave process is started once (manually) and left
running, but then later the machine reboots and the process is not
automatically restarted.

If you'd like to have the administrator of the buildslave (or other
people) be notified by email when the buildslave has been missing for
too long, just add the @code{notify_on_missing=} argument to the
@code{BuildSlave} definition:

@example
c['slaves'] = [BuildSlave('bot-solaris', 'solarispasswd',
                          notify_on_missing="bob@@example.com"),
              ]
@end example

By default, this will send email when the buildslave has been
disconnected for more than one hour. Only one email per
connection-loss event will be sent. To change the timeout, use
@code{missing_timeout=} and give it a number of seconds (the default
is 3600).

You can have the buildmaster send email to multiple recipients: just
provide a list of addresses instead of a single one:

@example
c['slaves'] = [BuildSlave('bot-solaris', 'solarispasswd',
                          notify_on_missing=["bob@@example.com",
                                             "alice@@example.org"],
                          missing_timeout=300, # notify after 5 minutes
                          ),
              ]
@end example

The email sent this way will use a MailNotifier (@pxref{MailNotifier})
status target, if one is configured. This provides a way for you to
control the ``from'' address of the email, as well as the relayhost
(aka ``smarthost'') to use as an SMTP server. If no MailNotifier is
configured on this buildmaster, the buildslave-missing emails will be
sent using a default configuration.

Note that if you want to have a MailNotifier for buildslave-missing
emails but not for regular build emails, just create one with
builders=[], as follows:

@example
from buildbot.status import mail
m = mail.MailNotifier(fromaddr="buildbot@@localhost", builders=[],
                      relayhost="smtp.example.org")
c['status'].append(m)
c['slaves'] = [BuildSlave('bot-solaris', 'solarispasswd',
                          notify_on_missing="bob@@example.com"),
              ]
@end example

@node On-Demand ("Latent") Buildslaves, Defining Global Properties, Buildslave Specifiers, Configuration
@section On-Demand ("Latent") Buildslaves

The standard buildbot model has slaves started manually.  The previous section
described how to configure the master for this approach.

Another approach is to let the buildbot master start slaves when builds are
ready, on-demand.  Thanks to services such as Amazon Web Services' Elastic
Compute Cloud ("AWS EC2"), this is relatively easy to set up, and can be
very useful for some situations.

The buildslaves that are started on-demand are called "latent" buildslaves.
As of this writing, buildbot ships with an abstract base class for building
latent buildslaves, and a concrete implementation for AWS EC2.

@menu
* Amazon Web Services Elastic Compute Cloud ("AWS EC2")::
* Dangers with Latent Buildslaves::
* Writing New Latent Buildslaves::
@end menu

@node Amazon Web Services Elastic Compute Cloud ("AWS EC2"), Dangers with Latent Buildslaves, , On-Demand ("Latent") Buildslaves
@subsection Amazon Web Services Elastic Compute Cloud ("AWS EC2")

@url{http://aws.amazon.com/ec2/,,AWS EC2} is a web service that allows you to
start virtual machines in an Amazon data center. Please see their website for
details, incuding costs. Using the AWS EC2 latent buildslaves involves getting
an EC2 account with AWS and setting up payment; customizing one or more EC2
machine images ("AMIs") on your desired operating system(s) and publishing
them (privately if needed); and configuring the buildbot master to know how to
start your customized images for "substantiating" your latent slaves.

@menu
* Get an AWS EC2 Account::
* Create an AMI::
* Configure the Master with an EC2LatentBuildSlave::
@end menu

@node Get an AWS EC2 Account, Create an AMI, , Amazon Web Services Elastic Compute Cloud ("AWS EC2")
@subsubsection Get an AWS EC2 Account

To start off, to use the AWS EC2 latent buildslave, you need to get an AWS
developer account and sign up for EC2. These instructions may help you get
started:

@itemize @bullet
@item
Go to http://aws.amazon.com/ and click to "Sign Up Now" for an AWS account.

@item
Once you are logged into your account, you need to sign up for EC2.
Instructions for how to do this have changed over time because Amazon changes
their website, so the best advice is to hunt for it. After signing up for EC2,
it may say it wants you to upload an x.509 cert. You will need this to create
images (see below) but it is not technically necessary for the buildbot master
configuration.

@item
You must enter a valid credit card before you will be able to use EC2. Do that
under 'Payment Method'.

@item
Make sure you're signed up for EC2 by going to 'Your Account'->'Account
Activity' and verifying EC2 is listed.
@end itemize

@node Create an AMI, Configure the Master with an EC2LatentBuildSlave, Get an AWS EC2 Account, Amazon Web Services Elastic Compute Cloud ("AWS EC2")
@subsubsection Create an AMI

Now you need to create an AMI and configure the master.  You may need to
run through this cycle a few times to get it working, but these instructions
should get you started.

Creating an AMI is out of the scope of this document.  The
@url{http://docs.amazonwebservices.com/AWSEC2/latest/GettingStartedGuide/,,EC2 Getting Started Guide}
is a good resource for this task.  Here are a few additional hints.

@itemize @bullet
@item
When an instance of the image starts, it needs to automatically start a
buildbot slave that connects to your master (to create a buildbot slave,
@pxref{Creating a buildslave}; to make a daemon,
@pxref{Launching the daemons}).

@item
You may want to make an instance of the buildbot slave, configure it as a
standard buildslave in the master (i.e., not as a latent slave), and test and
debug it that way before you turn it into an AMI and convert to a latent
slave in the master.
@end itemize

@node Configure the Master with an EC2LatentBuildSlave, , Create an AMI, Amazon Web Services Elastic Compute Cloud ("AWS EC2")
@subsubsection Configure the Master with an EC2LatentBuildSlave

Now let's assume you have an AMI that should work with the
EC2LatentBuildSlave.  It's now time to set up your buildbot master
configuration.

You will need some information from your AWS account: the "Access Key Id" and
the "Secret Access Key".  If you've built the AMI yourself, you probably
already are familiar with these values.  If you have not, and someone has
given you access to an AMI, these hints may help you find the necessary
values:

@itemize @bullet
@item
While logged into your AWS account, find the "Access Identifiers" link (either
on the left, or via "Your Account" -> "Access Identifiers".

@item
On the page, you'll see alphanumeric values for "Your Access Key Id:" and
"Your Secret Access Key:". Make a note of these. Later on, we'll call the
first one your "identifier" and the second one your "secret_identifier."
@end itemize

When creating an EC2LatentBuildSlave in the buildbot master configuration,
the first three arguments are required.  The name and password are the first
two arguments, and work the same as with normal buildslaves.  The next
argument specifies the type of the EC2 virtual machine (available options as
of this writing include "m1.small", "m1.large", 'm1.xlarge", "c1.medium",
and "c1.xlarge"; see the EC2 documentation for descriptions of these
machines).

Here is the simplest example of configuring an EC2 latent buildslave. It
specifies all necessary remaining values explicitly in the instantiation.

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
c['slaves'] = [EC2LatentBuildSlave('bot1', 'sekrit', 'm1.large',
                                   ami='ami-12345',
                                   identifier='publickey',
                                   secret_identifier='privatekey'
                                   )]
@end example

The "ami" argument specifies the AMI that the master should start.  The
"identifier" argument specifies the AWS "Access Key Id," and the
"secret_identifier" specifies the AWS "Secret Access Key." Both the AMI and
the account information can be specified in alternate ways.

Note that whoever has your identifier and secret_identifier values can request
AWS work charged to your account, so these values need to be carefully
protected. Another way to specify these access keys is to put them in a
separate file. You can then make the access privileges stricter for this
separate file, and potentially let more people read your main configuration
file.

By default, you can make an .ec2 directory in the home folder of the user
running the buildbot master. In that directory, create a file called aws_id.
The first line of that file should be your access key id; the second line
should be your secret access key id. Then you can instantiate the build slave
as follows.

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
c['slaves'] = [EC2LatentBuildSlave('bot1', 'sekrit', 'm1.large',
                                   ami='ami-12345')]
@end example

If you want to put the key information in another file, use the
"aws_id_file_path" initialization argument.

Previous examples used a particular AMI.  If the Buildbot master will be
deployed in a process-controlled environment, it may be convenient to
specify the AMI more flexibly.  Rather than specifying an individual AMI,
specify one or two AMI filters.

In all cases, the AMI that sorts last by its location (the S3 bucket and
manifest name) will be preferred.

One available filter is to specify the acceptable AMI owners, by AWS account
number (the 12 digit number, usually rendered in AWS with hyphens like
"1234-5678-9012", should be entered as in integer).

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
bot1 = EC2LatentBuildSlave('bot1', 'sekrit', 'm1.large',
                           valid_ami_owners=[11111111111,
                                             22222222222],
                           identifier='publickey',
                           secret_identifier='privatekey'
                           )
@end example

The other available filter is to provide a regular expression string that
will be matched against each AMI's location (the S3 bucket and manifest name).

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
bot1 = EC2LatentBuildSlave(
    'bot1', 'sekrit', 'm1.large',
    valid_ami_location_regex=r'buildbot\-.*/image.manifest.xml',
    identifier='publickey', secret_identifier='privatekey')
@end example

The regular expression can specify a group, which will be preferred for the
sorting.  Only the first group is used; subsequent groups are ignored.

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
bot1 = EC2LatentBuildSlave(
    'bot1', 'sekrit', 'm1.large',
    valid_ami_location_regex=r'buildbot\-.*\-(.*)/image.manifest.xml',
    identifier='publickey', secret_identifier='privatekey')
@end example

If the group can be cast to an integer, it will be.  This allows 10 to sort
after 1, for instance.

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
bot1 = EC2LatentBuildSlave(
    'bot1', 'sekrit', 'm1.large',
    valid_ami_location_regex=r'buildbot\-.*\-(\d+)/image.manifest.xml',
    identifier='publickey', secret_identifier='privatekey')
@end example

In addition to using the password as a handshake between the master and the
slave, you may want to use a firewall to assert that only machines from a
specific IP can connect as slaves.  This is possible with AWS EC2 by using
the Elastic IP feature.  To configure, generate a Elastic IP in AWS, and then
specify it in your configuration using the "elastic_ip" argument.

@example
from buildbot.ec2buildslave import EC2LatentBuildSlave
c['slaves'] = [EC2LatentBuildSlave('bot1', 'sekrit', 'm1.large',
                                   'ami-12345',
                                   identifier='publickey',
                                   secret_identifier='privatekey',
                                   elastic_ip='208.77.188.166'
                                   )]
@end example

The EC2LatentBuildSlave supports all other configuration from the standard
BuildSlave.  The "missing_timeout" and "notify_on_missing" specify how long
to wait for an EC2 instance to attach before considering the attempt to have
failed, and email addresses to alert, respectively.  "missing_timeout"
defaults to 20 minutes.

The "build_wait_timeout" allows you to specify how long an EC2LatentBuildSlave
should wait after a build for another build before it shuts down the EC2
instance.  It defaults to 10 minutes.

"keypair_name" and "security_name" allow you to specify different names for
these AWS EC2 values.  They both default to "latent_buildbot_slave".

@node Dangers with Latent Buildslaves, Writing New Latent Buildslaves, Amazon Web Services Elastic Compute Cloud ("AWS EC2"), On-Demand ("Latent") Buildslaves
@subsection Dangers with Latent Buildslaves

Any latent build slave that interacts with a for-fee service, such as the
EC2LatentBuildSlave, brings significant risks. As already identified, the
configuraton will need access to account information that, if obtained by a
criminal, can be used to charge services to your account. Also, bugs in the
buildbot software may lead to unnecessary charges. In particular, if the
master neglects to shut down an instance for some reason, a virtual machine
may be running unnecessarily, charging against your account. Manual and/or
automatic (e.g. nagios with a plugin using a library like boto)
double-checking may be appropriate.

A comparitively trivial note is that currently if two instances try to attach
to the same latent buildslave, it is likely that the system will become
confused.  This should not occur, unless, for instance, you configure a normal
build slave to connect with the authentication of a latent buildbot.  If the
situation occurs, stop all attached instances and restart the master.

@node Writing New Latent Buildslaves, , Dangers with Latent Buildslaves, On-Demand ("Latent") Buildslaves
@subsection Writing New Latent Buildslaves

Writing a new latent buildslave should only require subclassing
@code{buildbot.buildslave.AbstractLatentBuildSlave} and implementing
start_instance and stop_instance.

@example
def start_instance(self):
    # responsible for starting instance that will try to connect with this
    # master. Should return deferred. Problems should use an errback. The
    # callback value can be None, or can be an iterable of short strings to
    # include in the "substantiate success" status message, such as
    # identifying the instance that started.
    raise NotImplementedError

def stop_instance(self, fast=False):
    # responsible for shutting down instance. Return a deferred. If `fast`,
    # we're trying to shut the master down, so callback as soon as is safe.
    # Callback value is ignored.
    raise NotImplementedError
@end example

See @code{buildbot.ec2buildslave.EC2LatentBuildSlave} for an example, or see the
test example @code{buildbot.test_slaves.FakeLatentBuildSlave}.

@node Defining Global Properties, Defining Builders, On-Demand ("Latent") Buildslaves, Configuration
@section Defining Global Properties
@bcindex c['properties']
@cindex Properties

The @code{'properties'} configuration key defines a dictionary
of properties that will be available to all builds started by the
buildmaster:

@example
c['properties'] = @{
    'Widget-version' : '1.2',
    'release-stage' : 'alpha'
@}
@end example

@node Defining Builders, Defining Status Targets, Defining Global Properties, Configuration
@section Defining Builders

@bcindex c['builders']

The @code{c['builders']} key is a list of dictionaries which specify
the Builders. The Buildmaster runs a collection of Builders, each of
which handles a single type of build (e.g. full versus quick), on a
single build slave. A Buildbot which makes sure that the latest code
(``HEAD'') compiles correctly across four separate architecture will
have four Builders, each performing the same build but on different
slaves (one per platform).

Each Builder gets a separate column in the waterfall display. In
general, each Builder runs independently (although various kinds of
interlocks can cause one Builder to have an effect on another).

Each Builder specification dictionary has several required keys:

@table @code
@item name
This specifies the Builder's name, which is used in status
reports.

@item slavename
This specifies which buildslave will be used by this Builder.
@code{slavename} must appear in the @code{c['slaves']} list. Each
buildslave can accomodate multiple Builders.

@item slavenames
If you provide @code{slavenames} instead of @code{slavename}, you can
give a list of buildslaves which are capable of running this Builder.
If multiple buildslaves are available for any given Builder, you will
have some measure of redundancy: in case one slave goes offline, the
others can still keep the Builder working. In addition, multiple
buildslaves will allow multiple simultaneous builds for the same
Builder, which might be useful if you have a lot of forced or ``try''
builds taking place.

If you use this feature, it is important to make sure that the
buildslaves are all, in fact, capable of running the given build. The
slave hosts should be configured similarly, otherwise you will spend a
lot of time trying (unsuccessfully) to reproduce a failure that only
occurs on some of the buildslaves and not the others. Different
platforms, operating systems, versions of major programs or libraries,
all these things mean you should use separate Builders.

@item builddir
This specifies the name of a subdirectory (under the base directory)
in which everything related to this builder will be placed. On the
buildmaster, this holds build status information. On the buildslave,
this is where checkouts, compiles, and tests are run.

@item factory
This is a @code{buildbot.process.factory.BuildFactory} instance which
controls how the build is performed. Full details appear in their own
chapter, @xref{Build Process}. Parameters like the location of the CVS
repository and the compile-time options used for the build are
generally provided as arguments to the factory's constructor.

@end table

Other optional keys may be set on each Builder:

@table @code

@item category
If provided, this is a string that identifies a category for the
builder to be a part of. Status clients can limit themselves to a
subset of the available categories. A common use for this is to add
new builders to your setup (for a new module, or for a new buildslave)
that do not work correctly yet and allow you to integrate them with
the active builders. You can put these new builders in a test
category, make your main status clients ignore them, and have only
private status clients pick them up. As soon as they work, you can
move them over to the active category.

@end table


@node Defining Status Targets, Debug options, Defining Builders, Configuration
@section Defining Status Targets

The Buildmaster has a variety of ways to present build status to
various users. Each such delivery method is a ``Status Target'' object
in the configuration's @code{status} list. To add status targets, you
just append more objects to this list:

@bcindex c['status']

@example
c['status'] = []

from buildbot.status import html
c['status'].append(html.Waterfall(http_port=8010))

from buildbot.status import mail
m = mail.MailNotifier(fromaddr="buildbot@@localhost",
                      extraRecipients=["builds@@lists.example.com"],
                      sendToInterestedUsers=False)
c['status'].append(m)

from buildbot.status import words
c['status'].append(words.IRC(host="irc.example.com", nick="bb",
                             channels=["#example"]))
@end example

Status delivery has its own chapter, @xref{Status Delivery}, in which
all the built-in status targets are documented.


@node Debug options,  , Defining Status Targets, Configuration
@section Debug options


@bcindex c['debugPassword']
If you set @code{c['debugPassword']}, then you can connect to the
buildmaster with the diagnostic tool launched by @code{buildbot
debugclient MASTER:PORT}. From this tool, you can reload the config
file, manually force builds, and inject changes, which may be useful
for testing your buildmaster without actually commiting changes to
your repository (or before you have the Change Sources set up). The
debug tool uses the same port number as the slaves do:
@code{c['slavePortnum']}, and is authenticated with this password.

@example
c['debugPassword'] = "debugpassword"
@end example

@bcindex c['manhole']
If you set @code{c['manhole']} to an instance of one of the classes in
@code{buildbot.manhole}, you can telnet or ssh into the buildmaster
and get an interactive Python shell, which may be useful for debugging
buildbot internals. It is probably only useful for buildbot
developers. It exposes full access to the buildmaster's account
(including the ability to modify and delete files), so it should not
be enabled with a weak or easily guessable password.

There are three separate @code{Manhole} classes. Two of them use SSH,
one uses unencrypted telnet. Two of them use a username+password
combination to grant access, one of them uses an SSH-style
@file{authorized_keys} file which contains a list of ssh public keys.

@table @code
@item manhole.AuthorizedKeysManhole
You construct this with the name of a file that contains one SSH
public key per line, just like @file{~/.ssh/authorized_keys}. If you
provide a non-absolute filename, it will be interpreted relative to
the buildmaster's base directory.

@item manhole.PasswordManhole
This one accepts SSH connections but asks for a username and password
when authenticating. It accepts only one such pair.


@item manhole.TelnetManhole
This accepts regular unencrypted telnet connections, and asks for a
username/password pair before providing access. Because this
username/password is transmitted in the clear, and because Manhole
access to the buildmaster is equivalent to granting full shell
privileges to both the buildmaster and all the buildslaves (and to all
accounts which then run code produced by the buildslaves), it is
highly recommended that you use one of the SSH manholes instead.

@end table

@example
# some examples:
from buildbot import manhole
c['manhole'] = manhole.AuthorizedKeysManhole(1234, "authorized_keys")
c['manhole'] = manhole.PasswordManhole(1234, "alice", "mysecretpassword")
c['manhole'] = manhole.TelnetManhole(1234, "bob", "snoop_my_password_please")
@end example

The @code{Manhole} instance can be configured to listen on a specific
port. You may wish to have this listening port bind to the loopback
interface (sometimes known as ``lo0'', ``localhost'', or 127.0.0.1) to
restrict access to clients which are running on the same host.

@example
from buildbot.manhole import PasswordManhole
c['manhole'] = PasswordManhole("tcp:9999:interface=127.0.0.1","admin","passwd")
@end example

To have the @code{Manhole} listen on all interfaces, use
@code{"tcp:9999"} or simply 9999. This port specification uses
@code{twisted.application.strports}, so you can make it listen on SSL
or even UNIX-domain sockets if you want.

Note that using any Manhole requires that the TwistedConch package be
installed, and that you be using Twisted version 2.0 or later.

The buildmaster's SSH server will use a different host key than the
normal sshd running on a typical unix host. This will cause the ssh
client to complain about a ``host key mismatch'', because it does not
realize there are two separate servers running on the same host. To
avoid this, use a clause like the following in your @file{.ssh/config}
file:

@example
Host remotehost-buildbot
 HostName remotehost
 HostKeyAlias remotehost-buildbot
 Port 9999
 # use 'user' if you use PasswordManhole and your name is not 'admin'.
 # if you use AuthorizedKeysManhole, this probably doesn't matter.
 User admin
@end example


@node Getting Source Code Changes, Build Process, Configuration, Top
@chapter Getting Source Code Changes

The most common way to use the Buildbot is centered around the idea of
@code{Source Trees}: a directory tree filled with source code of some form
which can be compiled and/or tested. Some projects use languages that don't
involve any compilation step: nevertheless there may be a @code{build} phase
where files are copied or rearranged into a form that is suitable for
installation. Some projects do not have unit tests, and the Buildbot is
merely helping to make sure that the sources can compile correctly. But in
all of these cases, the thing-being-tested is a single source tree.

A Version Control System mantains a source tree, and tells the
buildmaster when it changes. The first step of each Build is typically
to acquire a copy of some version of this tree.

This chapter describes how the Buildbot learns about what Changes have
occurred. For more information on VC systems and Changes, see
@ref{Version Control Systems}.


@menu
* Change Sources::
* Choosing ChangeSources::
* CVSToys - PBService::
* Mail-parsing ChangeSources::
* PBChangeSource::
* P4Source::
* BonsaiPoller::
* SVNPoller::
* MercurialHook::
* Bzr Hook::
* Bzr Poller::
@end menu



@node Change Sources, Choosing ChangeSources, Getting Source Code Changes, Getting Source Code Changes
@section Change Sources

@c TODO: rework this, the one-buildmaster-one-tree thing isn't quite
@c so narrow-minded anymore

Each Buildmaster watches a single source tree. Changes can be provided
by a variety of ChangeSource types, however any given project will
typically have only a single ChangeSource active. This section
provides a description of all available ChangeSource types and
explains how to set up each of them.

There are a variety of ChangeSources available, some of which are
meant to be used in conjunction with other tools to deliver Change
events from the VC repository to the buildmaster.

@itemize @bullet

@item CVSToys
This ChangeSource opens a TCP connection from the buildmaster to a
waiting FreshCVS daemon that lives on the repository machine, and
subscribes to hear about Changes.

@item MaildirSource
This one watches a local maildir-format inbox for email sent out by
the repository when a change is made. When a message arrives, it is
parsed to create the Change object. A variety of parsing functions are
available to accomodate different email-sending tools.

@item PBChangeSource
This ChangeSource listens on a local TCP socket for inbound
connections from a separate tool. Usually, this tool would be run on
the VC repository machine in a commit hook. It is expected to connect
to the TCP socket and send a Change message over the network
connection. The @command{buildbot sendchange} command is one example
of a tool that knows how to send these messages, so you can write a
commit script for your VC system that calls it to deliver the Change.
There are other tools in the contrib/ directory that use the same
protocol.

@end itemize

As a quick guide, here is a list of VC systems and the ChangeSources
that might be useful with them. All of these ChangeSources are in the
@code{buildbot.changes} module.

@table @code
@item CVS

@itemize @bullet
@item freshcvs.FreshCVSSource (connected via TCP to the freshcvs daemon)
@item mail.FCMaildirSource (watching for email sent by a freshcvs daemon)
@item mail.BonsaiMaildirSource (watching for email sent by Bonsai)
@item mail.SyncmailMaildirSource (watching for email sent by syncmail)
@item pb.PBChangeSource (listening for connections from @code{buildbot
sendchange} run in a loginfo script)
@item pb.PBChangeSource (listening for connections from a long-running
@code{contrib/viewcvspoll.py} polling process which examines the ViewCVS
database directly
@end itemize

@item SVN
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/svn_buildbot.py} run in a postcommit script)
@item pb.PBChangeSource (listening for connections from a long-running
@code{contrib/svn_watcher.py} or @code{contrib/svnpoller.py} polling
process
@item mail.SVNCommitEmailMaildirSource (watching for email sent by commit-email.pl)
@item svnpoller.SVNPoller (polling the SVN repository)
@end itemize

@item Darcs
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/darcs_buildbot.py} in a commit script
@end itemize

@item Mercurial
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/hg_buildbot.py} run in an 'incoming' hook)
@item pb.PBChangeSource (listening for connections from
@code{buildbot/changes/hgbuildbot.py} run as an in-process 'changegroup'
hook)
@end itemize

@item Arch/Bazaar
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/arch_buildbot.py} run in a commit hook)
@end itemize

@item Bzr (the newer Bazaar)
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/bzr_buildbot.py} run in a post-change-branch-tip or commit hook)
@item @code{contrib/bzr_buildbot.py}'s BzrPoller (polling the Bzr repository)
@end itemize

@item Git
@itemize @bullet
@item pb.PBChangeSource (listening for connections from
@code{contrib/git_buildbot.py} run in the post-receive hook)
@end itemize

@end table

All VC systems can be driven by a PBChangeSource and the
@code{buildbot sendchange} tool run from some form of commit script.
If you write an email parsing function, they can also all be driven by
a suitable @code{MaildirSource}.


@node Choosing ChangeSources, CVSToys - PBService, Change Sources, Getting Source Code Changes
@section Choosing ChangeSources

The @code{master.cfg} configuration file has a dictionary key named
@code{BuildmasterConfig['change_source']}, which holds the active
@code{IChangeSource} object. The config file will typically create an
object from one of the classes described below and stuff it into this
key.

Each buildmaster typically has just a single ChangeSource, since it is
only watching a single source tree. But if, for some reason, you need
multiple sources, just set @code{c['change_source']} to a list of
ChangeSources.. it will accept that too.

@example
s = FreshCVSSourceNewcred(host="host", port=4519,
                          user="alice", passwd="secret",
                          prefix="Twisted")
BuildmasterConfig['change_source'] = [s]
@end example

Each source tree has a nominal @code{top}. Each Change has a list of
filenames, which are all relative to this top location. The
ChangeSource is responsible for doing whatever is necessary to
accomplish this. Most sources have a @code{prefix} argument: a partial
pathname which is stripped from the front of all filenames provided to
that @code{ChangeSource}. Files which are outside this sub-tree are
ignored by the changesource: it does not generate Changes for those
files.


@node CVSToys - PBService, Mail-parsing ChangeSources, Choosing ChangeSources, Getting Source Code Changes
@section CVSToys - PBService

@csindex buildbot.changes.freshcvs.FreshCVSSource

The @uref{http://purl.net/net/CVSToys, CVSToys} package provides a
server which runs on the machine that hosts the CVS repository it
watches. It has a variety of ways to distribute commit notifications,
and offers a flexible regexp-based way to filter out uninteresting
changes. One of the notification options is named @code{PBService} and
works by listening on a TCP port for clients. These clients subscribe
to hear about commit notifications.

The buildmaster has a CVSToys-compatible @code{PBService} client built
in. There are two versions of it, one for old versions of CVSToys
(1.0.9 and earlier) which used the @code{oldcred} authentication
framework, and one for newer versions (1.0.10 and later) which use
@code{newcred}. Both are classes in the
@code{buildbot.changes.freshcvs} package.

@code{FreshCVSSourceNewcred} objects are created with the following
parameters:

@table @samp

@item @code{host} and @code{port}
these specify where the CVSToys server can be reached

@item @code{user} and @code{passwd}
these specify the login information for the CVSToys server
(@code{freshcvs}). These must match the server's values, which are
defined in the @code{freshCfg} configuration file (which lives in the
CVSROOT directory of the repository).

@item @code{prefix}
this is the prefix to be found and stripped from filenames delivered
by the CVSToys server. Most projects live in sub-directories of the
main repository, as siblings of the CVSROOT sub-directory, so
typically this prefix is set to that top sub-directory name.

@end table

@heading Example

To set up the freshCVS server, add a statement like the following to
your @file{freshCfg} file:

@example
pb = ConfigurationSet([
    (None, None, None, PBService(userpass=('foo', 'bar'), port=4519)),
    ])
@end example

This will announce all changes to a client which connects to port 4519
using a username of 'foo' and a password of 'bar'.

Then add a clause like this to your buildmaster's @file{master.cfg}:

@example
BuildmasterConfig['change_source'] = FreshCVSSource("cvs.example.com", 4519,
                                                    "foo", "bar",
                                                    prefix="glib/")
@end example

where "cvs.example.com" is the host that is running the FreshCVS daemon, and
"glib" is the top-level directory (relative to the repository's root) where
all your source code lives. Most projects keep one or more projects in the
same repository (along with CVSROOT/ to hold admin files like loginfo and
freshCfg); the prefix= argument tells the buildmaster to ignore everything
outside that directory, and to strip that common prefix from all pathnames
it handles.


@node Mail-parsing ChangeSources, PBChangeSource, CVSToys - PBService, Getting Source Code Changes
@section Mail-parsing ChangeSources

Many projects publish information about changes to their source tree
by sending an email message out to a mailing list, frequently named
PROJECT-commits or PROJECT-changes. Each message usually contains a
description of the change (who made the change, which files were
affected) and sometimes a copy of the diff. Humans can subscribe to
this list to stay informed about what's happening to the source tree.

The Buildbot can also be subscribed to a -commits mailing list, and
can trigger builds in response to Changes that it hears about. The
buildmaster admin needs to arrange for these email messages to arrive
in a place where the buildmaster can find them, and configure the
buildmaster to parse the messages correctly. Once that is in place,
the email parser will create Change objects and deliver them to the
Schedulers (see @pxref{Change Sources and Schedulers}) just
like any other ChangeSource.

There are two components to setting up an email-based ChangeSource.
The first is to route the email messages to the buildmaster, which is
done by dropping them into a ``maildir''. The second is to actually
parse the messages, which is highly dependent upon the tool that was
used to create them. Each VC system has a collection of favorite
change-emailing tools, and each has a slightly different format, so
each has a different parsing function. There is a separate
ChangeSource variant for each parsing function.

Once you've chosen a maildir location and a parsing function, create
the change source and put it in @code{c['change_source']}:

@example
from buildbot.changes.mail import SyncmailMaildirSource
c['change_source'] = SyncmailMaildirSource("~/maildir-buildbot",
                                           prefix="/trunk/")
@end example

@menu
* Subscribing the Buildmaster::
* Using Maildirs::
* Parsing Email Change Messages::
@end menu

@node Subscribing the Buildmaster, Using Maildirs, Mail-parsing ChangeSources, Mail-parsing ChangeSources
@subsection Subscribing the Buildmaster

The recommended way to install the buildbot is to create a dedicated
account for the buildmaster. If you do this, the account will probably
have a distinct email address (perhaps
@email{buildmaster@@example.org}). Then just arrange for this
account's email to be delivered to a suitable maildir (described in
the next section).

If the buildbot does not have its own account, ``extension addresses''
can be used to distinguish between email intended for the buildmaster
and email intended for the rest of the account. In most modern MTAs,
the e.g. @code{foo@@example.org} account has control over every email
address at example.org which begins with "foo", such that email
addressed to @email{account-foo@@example.org} can be delivered to a
different destination than @email{account-bar@@example.org}. qmail
does this by using separate .qmail files for the two destinations
(@file{.qmail-foo} and @file{.qmail-bar}, with @file{.qmail}
controlling the base address and @file{.qmail-default} controlling all
other extensions). Other MTAs have similar mechanisms.

Thus you can assign an extension address like
@email{foo-buildmaster@@example.org} to the buildmaster, and retain
@email{foo@@example.org} for your own use.


@node Using Maildirs, Parsing Email Change Messages, Subscribing the Buildmaster, Mail-parsing ChangeSources
@subsection Using Maildirs

A ``maildir'' is a simple directory structure originally developed for
qmail that allows safe atomic update without locking. Create a base
directory with three subdirectories: ``new'', ``tmp'', and ``cur''.
When messages arrive, they are put into a uniquely-named file (using
pids, timestamps, and random numbers) in ``tmp''. When the file is
complete, it is atomically renamed into ``new''. Eventually the
buildmaster notices the file in ``new'', reads and parses the
contents, then moves it into ``cur''. A cronjob can be used to delete
files in ``cur'' at leisure.

Maildirs are frequently created with the @command{maildirmake} tool,
but a simple @command{mkdir -p ~/MAILDIR/@{cur,new,tmp@}} is pretty much
equivalent.

Many modern MTAs can deliver directly to maildirs. The usual .forward
or .procmailrc syntax is to name the base directory with a trailing
slash, so something like @code{~/MAILDIR/} . qmail and postfix are
maildir-capable MTAs, and procmail is a maildir-capable MDA (Mail
Delivery Agent).

For MTAs which cannot put files into maildirs directly, the
``safecat'' tool can be executed from a .forward file to accomplish
the same thing.

The Buildmaster uses the linux DNotify facility to receive immediate
notification when the maildir's ``new'' directory has changed. When
this facility is not available, it polls the directory for new
messages, every 10 seconds by default.

@node Parsing Email Change Messages,  , Using Maildirs, Mail-parsing ChangeSources
@subsection Parsing Email Change Messages

The second component to setting up an email-based ChangeSource is to
parse the actual notices. This is highly dependent upon the VC system
and commit script in use.

A couple of common tools used to create these change emails are:

@table @samp

@item CVS
@table @samp
@item CVSToys MailNotifier
@ref{FCMaildirSource}
@item Bonsai notification
@ref{BonsaiMaildirSource}
@item syncmail
@ref{SyncmailMaildirSource}
@end table

@item SVN
@table @samp
@item svnmailer
http://opensource.perlig.de/en/svnmailer/
@item commit-email.pl
@ref{SVNCommitEmailMaildirSource}
@end table

@item Mercurial
@table @samp
@item NotifyExtension
http://www.selenic.com/mercurial/wiki/index.cgi/NotifyExtension
@end table

@item Git
@table @samp
@item post-receive-email
http://git.kernel.org/?p=git/git.git;a=blob;f=contrib/hooks/post-receive-email;hb=HEAD
@end table

@end table


The following sections describe the parsers available for each of
these tools.

Most of these parsers accept a @code{prefix=} argument, which is used
to limit the set of files that the buildmaster pays attention to. This
is most useful for systems like CVS and SVN which put multiple
projects in a single repository (or use repository names to indicate
branches). Each filename that appears in the email is tested against
the prefix: if the filename does not start with the prefix, the file
is ignored. If the filename @emph{does} start with the prefix, that
prefix is stripped from the filename before any further processing is
done. Thus the prefix usually ends with a slash.

@menu
* FCMaildirSource::
* SyncmailMaildirSource::
* BonsaiMaildirSource::
* SVNCommitEmailMaildirSource::
@end menu

@node FCMaildirSource, SyncmailMaildirSource, Parsing Email Change Messages, Parsing Email Change Messages
@subsubsection FCMaildirSource


@csindex buildbot.changes.mail.FCMaildirSource

http://twistedmatrix.com/users/acapnotic/wares/code/CVSToys/

This parser works with the CVSToys @code{MailNotification} action,
which will send email to a list of recipients for each commit. This
tends to work better than using @code{/bin/mail} from within the
CVSROOT/loginfo file directly, as CVSToys will batch together all
files changed during the same CVS invocation, and can provide more
information (like creating a ViewCVS URL for each file changed).

The Buildbot's @code{FCMaildirSource} knows for to parse these CVSToys
messages and turn them into Change objects. It can be given two
parameters: the directory name of the maildir root, and the prefix to
strip.

@example
from buildbot.changes.mail import FCMaildirSource
c['change_source'] = FCMaildirSource("~/maildir-buildbot")
@end example

@node SyncmailMaildirSource, BonsaiMaildirSource, FCMaildirSource, Parsing Email Change Messages
@subsubsection SyncmailMaildirSource

@csindex buildbot.changes.mail.SyncmailMaildirSource

http://sourceforge.net/projects/cvs-syncmail

@code{SyncmailMaildirSource} knows how to parse the message format used by
the CVS ``syncmail'' script.

@example
from buildbot.changes.mail import SyncmailMaildirSource
c['change_source'] = SyncmailMaildirSource("~/maildir-buildbot")
@end example

@node BonsaiMaildirSource, SVNCommitEmailMaildirSource, SyncmailMaildirSource, Parsing Email Change Messages
@subsubsection BonsaiMaildirSource

@csindex buildbot.changes.mail.BonsaiMaildirSource

http://www.mozilla.org/bonsai.html

@code{BonsaiMaildirSource} parses messages sent out by Bonsai, the CVS
tree-management system built by Mozilla.

@example
from buildbot.changes.mail import BonsaiMaildirSource
c['change_source'] = BonsaiMaildirSource("~/maildir-buildbot")
@end example

@node SVNCommitEmailMaildirSource,  , BonsaiMaildirSource, Parsing Email Change Messages
@subsubsection SVNCommitEmailMaildirSource

@csindex buildbot.changes.mail.SVNCommitEmailMaildirSource

@code{SVNCommitEmailMaildirSource} parses message sent out by the
@code{commit-email.pl} script, which is included in the Subversion
distribution.

It does not currently handle branches: all of the Change objects that
it creates will be associated with the default (i.e. trunk) branch.

@example
from buildbot.changes.mail import SVNCommitEmailMaildirSource
c['change_source'] = SVNCommitEmailMaildirSource("~/maildir-buildbot")
@end example


@node PBChangeSource, P4Source, Mail-parsing ChangeSources, Getting Source Code Changes
@section PBChangeSource

@csindex buildbot.changes.pb.PBChangeSource

The last kind of ChangeSource actually listens on a TCP port for
clients to connect and push change notices @emph{into} the
Buildmaster. This is used by the built-in @code{buildbot sendchange}
notification tool, as well as the VC-specific
@file{contrib/svn_buildbot.py}, @file{contrib/arch_buildbot.py},
@file{contrib/hg_buildbot.py} tools, and the
@code{buildbot.changes.hgbuildbot} hook. These tools are run by the
repository (in a commit hook script), and connect to the buildmaster
directly each time a file is comitted. This is also useful for
creating new kinds of change sources that work on a @code{push} model
instead of some kind of subscription scheme, for example a script
which is run out of an email .forward file.

This ChangeSource can be configured to listen on its own TCP port, or
it can share the port that the buildmaster is already using for the
buildslaves to connect. (This is possible because the
@code{PBChangeSource} uses the same protocol as the buildslaves, and
they can be distinguished by the @code{username} attribute used when
the initial connection is established). It might be useful to have it
listen on a different port if, for example, you wanted to establish
different firewall rules for that port. You could allow only the SVN
repository machine access to the @code{PBChangeSource} port, while
allowing only the buildslave machines access to the slave port. Or you
could just expose one port and run everything over it. @emph{Note:
this feature is not yet implemented, the PBChangeSource will always
share the slave port and will always have a @code{user} name of
@code{change}, and a passwd of @code{changepw}. These limitations will
be removed in the future.}.


The @code{PBChangeSource} is created with the following arguments. All
are optional.

@table @samp
@item @code{port}
which port to listen on. If @code{None} (which is the default), it
shares the port used for buildslave connections. @emph{Not
Implemented, always set to @code{None}}.

@item @code{user} and @code{passwd}
The user/passwd account information that the client program must use
to connect. Defaults to @code{change} and @code{changepw}. @emph{Not
Implemented, @code{user} is currently always set to @code{change},
@code{passwd} is always set to @code{changepw}}.

@item @code{prefix}
The prefix to be found and stripped from filenames delivered over the
connection. Any filenames which do not start with this prefix will be
removed. If all the filenames in a given Change are removed, the that
whole Change will be dropped. This string should probably end with a
directory separator.

This is useful for changes coming from version control systems that
represent branches as parent directories within the repository (like
SVN and Perforce). Use a prefix of 'trunk/' or
'project/branches/foobranch/' to only follow one branch and to get
correct tree-relative filenames. Without a prefix, the PBChangeSource
will probably deliver Changes with filenames like @file{trunk/foo.c}
instead of just @file{foo.c}. Of course this also depends upon the
tool sending the Changes in (like @command{buildbot sendchange}) and
what filenames it is delivering: that tool may be filtering and
stripping prefixes at the sending end.

@end table

@node P4Source, BonsaiPoller, PBChangeSource, Getting Source Code Changes
@section P4Source

@csindex buildbot.changes.p4poller.P4Source

The @code{P4Source} periodically polls a @uref{http://www.perforce.com/,
Perforce} depot for changes. It accepts the following arguments:

@table @samp
@item @code{p4base}
The base depot path to watch, without the trailing '/...'.

@item @code{p4port}
The Perforce server to connect to (as host:port).

@item @code{p4user}
The Perforce user.

@item @code{p4passwd}
The Perforce password.

@item @code{p4bin}
An optional string parameter. Specify the location of the perforce command 
line binary (p4).  You only need to do this if the perforce binary is not 
in the path of the buildbot user.  Defaults to ``p4''.

@item @code{split_file}
A function that maps a pathname, without the leading @code{p4base}, to a
(branch, filename) tuple. The default just returns (None, branchfile),
which effectively disables branch support. You should supply a function
which understands your repository structure.

@item @code{pollinterval}
How often to poll, in seconds. Defaults to 600 (10 minutes).

@item @code{histmax}
The maximum number of changes to inspect at a time. If more than this
number occur since the last poll, older changes will be silently
ignored.
@end table

@heading Example

This configuration uses the @code{P4PORT}, @code{P4USER}, and @code{P4PASSWD}
specified in the buildmaster's environment. It watches a project in which the
branch name is simply the next path component, and the file is all path
components after.

@example
import buildbot.changes.p4poller
s = p4poller.P4Source(p4base='//depot/project/',
                      split_file=lambda branchfile: branchfile.split('/',1),
                     )
c['change_source'] = s
@end example

@node BonsaiPoller, SVNPoller, P4Source, Getting Source Code Changes
@section BonsaiPoller

@csindex buildbot.changes.bonsaipoller.BonsaiPoller

The @code{BonsaiPoller} periodically polls a Bonsai server. This is a
CGI script accessed through a web server that provides information
about a CVS tree, for example the Mozilla bonsai server at
@uref{http://bonsai.mozilla.org}. Bonsai servers are usable by both
humans and machines. In this case, the buildbot's change source forms
a query which asks about any files in the specified branch which have
changed since the last query.

Please take a look at the BonsaiPoller docstring for details about the
arguments it accepts.


@node SVNPoller, MercurialHook, BonsaiPoller, Getting Source Code Changes
@section SVNPoller

@csindex buildbot.changes.svnpoller.SVNPoller

The @code{buildbot.changes.svnpoller.SVNPoller} is a ChangeSource
which periodically polls a @uref{http://subversion.tigris.org/,
Subversion} repository for new revisions, by running the @code{svn
log} command in a subshell. It can watch a single branch or multiple
branches.

@code{SVNPoller} accepts the following arguments:

@table @code
@item svnurl
The base URL path to watch, like
@code{svn://svn.twistedmatrix.com/svn/Twisted/trunk}, or
@code{http://divmod.org/svn/Divmod/}, or even
@code{file:///home/svn/Repository/ProjectA/branches/1.5/}. This must
include the access scheme, the location of the repository (both the
hostname for remote ones, and any additional directory names necessary
to get to the repository), and the sub-path within the repository's
virtual filesystem for the project and branch of interest.

The @code{SVNPoller} will only pay attention to files inside the
subdirectory specified by the complete svnurl.

@item split_file
A function to convert pathnames into (branch, relative_pathname)
tuples. Use this to explain your repository's branch-naming policy to
@code{SVNPoller}. This function must accept a single string and return
a two-entry tuple. There are a few utility functions in
@code{buildbot.changes.svnpoller} that can be used as a
@code{split_file} function, see below for details.

The default value always returns (None, path), which indicates that
all files are on the trunk.

Subclasses of @code{SVNPoller} can override the @code{split_file}
method instead of using the @code{split_file=} argument.

@item svnuser
An optional string parameter. If set, the @code{--user} argument will
be added to all @code{svn} commands. Use this if you have to
authenticate to the svn server before you can do @code{svn info} or
@code{svn log} commands.

@item svnpasswd
Like @code{svnuser}, this will cause a @code{--password} argument to
be passed to all svn commands.

@item pollinterval
How often to poll, in seconds. Defaults to 600 (checking once every 10
minutes). Lower this if you want the buildbot to notice changes
faster, raise it if you want to reduce the network and CPU load on
your svn server. Please be considerate of public SVN repositories by
using a large interval when polling them.

@item histmax
The maximum number of changes to inspect at a time. Every POLLINTERVAL
seconds, the @code{SVNPoller} asks for the last HISTMAX changes and
looks through them for any ones it does not already know about. If
more than HISTMAX revisions have been committed since the last poll,
older changes will be silently ignored. Larger values of histmax will
cause more time and memory to be consumed on each poll attempt.
@code{histmax} defaults to 100.

@item svnbin
This controls the @code{svn} executable to use. If subversion is
installed in a weird place on your system (outside of the
buildmaster's @code{$PATH}), use this to tell @code{SVNPoller} where
to find it. The default value of ``svn'' will almost always be
sufficient.

@end table

@heading Branches

Each source file that is tracked by a Subversion repository has a
fully-qualified SVN URL in the following form:
(REPOURL)(PROJECT-plus-BRANCH)(FILEPATH). When you create the
@code{SVNPoller}, you give it a @code{svnurl} value that includes all
of the REPOURL and possibly some portion of the PROJECT-plus-BRANCH
string. The @code{SVNPoller} is responsible for producing Changes that
contain a branch name and a FILEPATH (which is relative to the top of
a checked-out tree). The details of how these strings are split up
depend upon how your repository names its branches.

@subheading PROJECT/BRANCHNAME/FILEPATH repositories

One common layout is to have all the various projects that share a
repository get a single top-level directory each. Then under a given
project's directory, you get two subdirectories, one named ``trunk''
and another named ``branches''. Under ``branches'' you have a bunch of
other directories, one per branch, with names like ``1.5.x'' and
``testing''. It is also common to see directories like ``tags'' and
``releases'' next to ``branches'' and ``trunk''.

For example, the Twisted project has a subversion server on
``svn.twistedmatrix.com'' that hosts several sub-projects. The
repository is available through a SCHEME of ``svn:''. The primary
sub-project is Twisted, of course, with a repository root of
``svn://svn.twistedmatrix.com/svn/Twisted''. Another sub-project is
Informant, with a root of
``svn://svn.twistedmatrix.com/svn/Informant'', etc. Inside any
checked-out Twisted tree, there is a file named bin/trial (which is
used to run unit test suites).

The trunk for Twisted is in
``svn://svn.twistedmatrix.com/svn/Twisted/trunk'', and the
fully-qualified SVN URL for the trunk version of @code{trial} would be
``svn://svn.twistedmatrix.com/svn/Twisted/trunk/bin/trial''. The same
SVNURL for that file on a branch named ``1.5.x'' would be
``svn://svn.twistedmatrix.com/svn/Twisted/branches/1.5.x/bin/trial''.

To set up a @code{SVNPoller} that watches the Twisted trunk (and
nothing else), we would use the following:

@example
from buildbot.changes.svnpoller import SVNPoller
c['change_source'] = SVNPoller("svn://svn.twistedmatrix.com/svn/Twisted/trunk")
@end example

In this case, every Change that our @code{SVNPoller} produces will
have @code{.branch=None}, to indicate that the Change is on the trunk.
No other sub-projects or branches will be tracked.

If we want our ChangeSource to follow multiple branches, we have to do
two things. First we have to change our @code{svnurl=} argument to
watch more than just ``.../Twisted/trunk''. We will set it to
``.../Twisted'' so that we'll see both the trunk and all the branches.
Second, we have to tell @code{SVNPoller} how to split the
(PROJECT-plus-BRANCH)(FILEPATH) strings it gets from the repository
out into (BRANCH) and (FILEPATH) pairs.

We do the latter by providing a ``split_file'' function. This function
is responsible for splitting something like
``branches/1.5.x/bin/trial'' into @code{branch}=''branches/1.5.x'' and
@code{filepath}=''bin/trial''. This function is always given a string
that names a file relative to the subdirectory pointed to by the
@code{SVNPoller}'s @code{svnurl=} argument. It is expected to return a
(BRANCHNAME, FILEPATH) tuple (in which FILEPATH is relative to the
branch indicated), or None to indicate that the file is outside any
project of interest.

(note that we want to see ``branches/1.5.x'' rather than just
``1.5.x'' because when we perform the SVN checkout, we will probably
append the branch name to the baseURL, which requires that we keep the
``branches'' component in there. Other VC schemes use a different
approach towards branches and may not require this artifact.)

If your repository uses this same PROJECT/BRANCH/FILEPATH naming
scheme, the following function will work:

@example
def split_file_branches(path):
    pieces = path.split('/')
    if pieces[0] == 'trunk':
        return (None, '/'.join(pieces[1:]))
    elif pieces[0] == 'branches':
        return ('/'.join(pieces[0:2]),
                '/'.join(pieces[2:]))
    else:
        return None
@end example

This function is provided as
@code{buildbot.changes.svnpoller.split_file_branches} for your
convenience. So to have our Twisted-watching @code{SVNPoller} follow
multiple branches, we would use this:

@example
from buildbot.changes.svnpoller import SVNPoller, split_file_branches
c['change_source'] = SVNPoller("svn://svn.twistedmatrix.com/svn/Twisted",
                               split_file=split_file_branches)
@end example

Changes for all sorts of branches (with names like ``branches/1.5.x'',
and None to indicate the trunk) will be delivered to the Schedulers.
Each Scheduler is then free to use or ignore each branch as it sees
fit.

@subheading BRANCHNAME/PROJECT/FILEPATH repositories

Another common way to organize a Subversion repository is to put the
branch name at the top, and the projects underneath. This is
especially frequent when there are a number of related sub-projects
that all get released in a group.

For example, Divmod.org hosts a project named ``Nevow'' as well as one
named ``Quotient''. In a checked-out Nevow tree there is a directory
named ``formless'' that contains a python source file named
``webform.py''. This repository is accessible via webdav (and thus
uses an ``http:'' scheme) through the divmod.org hostname. There are
many branches in this repository, and they use a
(BRANCHNAME)/(PROJECT) naming policy.

The fully-qualified SVN URL for the trunk version of webform.py is
@code{http://divmod.org/svn/Divmod/trunk/Nevow/formless/webform.py}.
You can do an @code{svn co} with that URL and get a copy of the latest
version. The 1.5.x branch version of this file would have a URL of
@code{http://divmod.org/svn/Divmod/branches/1.5.x/Nevow/formless/webform.py}.
The whole Nevow trunk would be checked out with
@code{http://divmod.org/svn/Divmod/trunk/Nevow}, while the Quotient
trunk would be checked out using
@code{http://divmod.org/svn/Divmod/trunk/Quotient}.

Now suppose we want to have an @code{SVNPoller} that only cares about
the Nevow trunk. This case looks just like the PROJECT/BRANCH layout
described earlier:

@example
from buildbot.changes.svnpoller import SVNPoller
c['change_source'] = SVNPoller("http://divmod.org/svn/Divmod/trunk/Nevow")
@end example

But what happens when we want to track multiple Nevow branches? We
have to point our @code{svnurl=} high enough to see all those
branches, but we also don't want to include Quotient changes (since
we're only building Nevow). To accomplish this, we must rely upon the
@code{split_file} function to help us tell the difference between
files that belong to Nevow and those that belong to Quotient, as well
as figuring out which branch each one is on.

@example
from buildbot.changes.svnpoller import SVNPoller
c['change_source'] = SVNPoller("http://divmod.org/svn/Divmod",
                               split_file=my_file_splitter)
@end example

The @code{my_file_splitter} function will be called with
repository-relative pathnames like:

@table @code
@item trunk/Nevow/formless/webform.py
This is a Nevow file, on the trunk. We want the Change that includes this
to see a filename of @code{formless/webform.py"}, and a branch of None

@item branches/1.5.x/Nevow/formless/webform.py
This is a Nevow file, on a branch. We want to get
branch=''branches/1.5.x'' and filename=''formless/webform.py''.

@item trunk/Quotient/setup.py
This is a Quotient file, so we want to ignore it by having
@code{my_file_splitter} return None.

@item branches/1.5.x/Quotient/setup.py
This is also a Quotient file, which should be ignored.
@end table

The following definition for @code{my_file_splitter} will do the job:

@example
def my_file_splitter(path):
    pieces = path.split('/')
    if pieces[0] == 'trunk':
        branch = None
        pieces.pop(0) # remove 'trunk'
    elif pieces[0] == 'branches':
        pieces.pop(0) # remove 'branches'
        # grab branch name
        branch = 'branches/' + pieces.pop(0)
    else:
        return None # something weird
    projectname = pieces.pop(0)
    if projectname != 'Nevow':
        return None # wrong project
    return (branch, '/'.join(pieces))
@end example

@node MercurialHook,  Bzr Hook, SVNPoller, Getting Source Code Changes
@section MercurialHook

Since Mercurial is written in python, the hook script can invoke
Buildbot's @code{sendchange} function directly, rather than having to
spawn an external process. This function delivers the same sort of
changes as @code{buildbot sendchange} and the various hook scripts in
contrib/, so you'll need to add a @code{pb.PBChangeSource} to your
buildmaster to receive these changes.

To set this up, first choose a Mercurial repository that represents
your central ``official'' source tree. This will be the same
repository that your buildslaves will eventually pull from. Install
Buildbot on the machine that hosts this repository, using the same
version of python as Mercurial is using (so that the Mercurial hook
can import code from buildbot). Then add the following to the
@code{.hg/hgrc} file in that repository, replacing the buildmaster
hostname/portnumber as appropriate for your buildbot:

@example
[hooks]
changegroup.buildbot = python:buildbot.changes.hgbuildbot.hook

[hgbuildbot]
master = buildmaster.example.org:9987
@end example

(Note that Mercurial lets you define multiple @code{changegroup} hooks
by giving them distinct names, like @code{changegroup.foo} and
@code{changegroup.bar}, which is why we use
@code{changegroup.buildbot} in this example. There is nothing magical
about the ``buildbot'' suffix in the hook name. The
@code{[hgbuildbot]} section @emph{is} special, however, as it is the
only section that the buildbot hook pays attention to.)

Also note that this runs as a @code{changegroup} hook, rather than as
an @code{incoming} hook. The @code{changegroup} hook is run with
multiple revisions at a time (say, if multiple revisions are being
pushed to this repository in a single @command{hg push} command),
whereas the @code{incoming} hook is run with just one revision at a
time. The @code{hgbuildbot.hook} function will only work with the
@code{changegroup} hook.

The @code{[hgbuildbot]} section has two other parameters that you
might specify, both of which control the name of the branch that is
attached to the changes coming from this hook.

One common branch naming policy for Mercurial repositories is to use
it just like Darcs: each branch goes into a separate repository, and
all the branches for a single project share a common parent directory.
For example, you might have @file{/var/repos/PROJECT/trunk/} and
@file{/var/repos/PROJECT/release}. To use this style, use the
@code{branchtype = dirname} setting, which simply uses the last
component of the repository's enclosing directory as the branch name:

@example
[hgbuildbot]
master = buildmaster.example.org:9987
branchtype = dirname
@end example

Another approach is to use Mercurial's built-in branches (the kind
created with @command{hg branch} and listed with @command{hg
branches}). This feature associates persistent names with particular
lines of descent within a single repository. (note that the buildbot
@code{source.Mercurial} checkout step does not yet support this kind
of branch). To have the commit hook deliver this sort of branch name
with the Change object, use @code{branchtype = inrepo}:

@example
[hgbuildbot]
master = buildmaster.example.org:9987
branchtype = inrepo
@end example

Finally, if you want to simply specify the branchname directly, for
all changes, use @code{branch = BRANCHNAME}. This overrides
@code{branchtype}:

@example
[hgbuildbot]
master = buildmaster.example.org:9987
branch = trunk
@end example

If you use @code{branch=} like this, you'll need to put a separate
.hgrc in each repository. If you use @code{branchtype=}, you may be
able to use the same .hgrc for all your repositories, stored in
@file{~/.hgrc} or @file{/etc/mercurial/hgrc}.


@node Bzr Hook, Bzr Poller, MercurialHook, Getting Source Code Changes
@section Bzr Hook

Bzr is also written in Python, and the Bzr hook depends on Twisted to send the
changes.

To install, put @code{contrib/bzr_buildbot.py} in one of your plugins
locations a bzr plugins directory (e.g.,
@code{~/.bazaar/plugins}). Then, in one of your bazaar conf files (e.g.,
@code{~/.bazaar/locations.conf}), set the location you want to connect with buildbot
with these keys:

@table @code
@item buildbot_on
one of 'commit', 'push, or 'change'. Turns the plugin on to report changes via
commit, changes via push, or any changes to the trunk. 'change' is
recommended.

@item buildbot_server
(required to send to a buildbot master) the URL of the buildbot master to
which you will connect (as of this writing, the same server and port to which
slaves connect).

@item buildbot_port
(optional, defaults to 9989) the port of the buildbot master to which you will
connect (as of this writing, the same server and port to which slaves connect)

@item buildbot_pqm
(optional, defaults to not pqm) Normally, the user that commits the revision
is the user that is responsible for the change. When run in a pqm (Patch Queue
Manager, see https://launchpad.net/pqm) environment, the user that commits is
the Patch Queue Manager, and the user that committed the *parent* revision is
responsible for the change. To turn on the pqm mode, set this value to any of
(case-insensitive) "Yes", "Y", "True", or "T".

@item buildbot_dry_run
(optional, defaults to not a dry run) Normally, the post-commit hook will
attempt to communicate with the configured buildbot server and port. If this
parameter is included and any of (case-insensitive) "Yes", "Y", "True", or
"T", then the hook will simply print what it would have sent, but not attempt
to contact the buildbot master.

@item buildbot_send_branch_name
(optional, defaults to not sending the branch name) If your buildbot's bzr
source build step uses a repourl, do *not* turn this on. If your buildbot's
bzr build step uses a baseURL, then you may set this value to any of
(case-insensitive) "Yes", "Y", "True", or "T" to have the buildbot master
append the branch name to the baseURL.

@end table

When buildbot no longer has a hardcoded password, it will be a configuration
option here as well.

Here's a simple example that you might have in your
@code{~/.bazaar/locations.conf}.

@example
[chroot-*:///var/local/myrepo/mybranch]
buildbot_on = change
buildbot_server = localhost
@end example

@node Bzr Poller, , Bzr Hook, Getting Source Code Changes
@section Bzr Poller

If you cannot insert a Bzr hook in the server, you can use the Bzr Poller. To
use, put @code{contrib/bzr_buildbot.py} somewhere that your buildbot
configuration can import it. Even putting it in the same directory as the master.cfg
should work. Install the poller in the buildbot configuration as with any
other change source. Minimally, provide a URL that you want to poll (bzr://,
bzr+ssh://, or lp:), though make sure the buildbot user has necessary
privileges. You may also want to specify these optional values.

@table @code
@item poll_interval
The number of seconds to wait between polls.  Defaults to 10 minutes.

@item branch_name
Any value to be used as the branch name. Defaults to None, or specify a
string, or specify the constants from @code{bzr_buildbot.py} SHORT or FULL to
get the short branch name or full branch address.

@item blame_merge_author
normally, the user that commits the revision is the user that is responsible
for the change. When run in a pqm (Patch Queue Manager, see
https://launchpad.net/pqm) environment, the user that commits is the Patch
Queue Manager, and the user that committed the merged, *parent* revision is
responsible for the change. set this value to True if this is pointed against
a PQM-managed branch.
@end table

@node Build Process, Status Delivery, Getting Source Code Changes, Top
@chapter Build Process

A @code{Build} object is responsible for actually performing a build.
It gets access to a remote @code{SlaveBuilder} where it may run
commands, and a @code{BuildStatus} object where it must emit status
events. The @code{Build} is created by the Builder's
@code{BuildFactory}.

The default @code{Build} class is made up of a fixed sequence of
@code{BuildSteps}, executed one after another until all are complete
(or one of them indicates that the build should be halted early). The
default @code{BuildFactory} creates instances of this @code{Build}
class with a list of @code{BuildSteps}, so the basic way to configure
the build is to provide a list of @code{BuildSteps} to your
@code{BuildFactory}.

More complicated @code{Build} subclasses can make other decisions:
execute some steps only if certain files were changed, or if certain
previous steps passed or failed. The base class has been written to
allow users to express basic control flow without writing code, but
you can always subclass and customize to achieve more specialized
behavior.

@menu
* Build Steps::
* Interlocks::
* Build Factories::
@end menu

@node Build Steps, Interlocks, Build Process, Build Process
@section Build Steps

@code{BuildStep}s are usually specified in the buildmaster's
configuration file, in a list that goes into the @code{BuildFactory}.
The @code{BuildStep} instances in this list are used as templates to
construct new independent copies for each build (so that state can be
kept on the @code{BuildStep} in one build without affecting a later
build). Each @code{BuildFactory} can be created with a list of steps,
or the factory can be created empty and then steps added to it using
the @code{addStep} method:

@example
from buildbot.steps import source, shell
from buildbot.process import factory

f = factory.BuildFactory()
f.addStep(source.SVN(svnurl="http://svn.example.org/Trunk/"))
f.addStep(shell.ShellCommand(command=["make", "all"]))
f.addStep(shell.ShellCommand(command=["make", "test"]))
@end example

In earlier versions (0.7.5 and older), these steps were specified with
a tuple of (step_class, keyword_arguments). Steps can still be
specified this way, but the preferred form is to pass actual
@code{BuildStep} instances to @code{addStep}, because that gives the
@code{BuildStep} class a chance to do some validation on the
arguments.

If you have a common set of steps which are used in several factories, the
@code{addSteps} method may be handy.  It takes an iterable of @code{BuildStep}
instances.

@example
setup_steps = [
    source.SVN(svnurl="http://svn.example.org/Trunk/")
    shell.ShellCommand(command="./setup")
]
quick = factory.BuildFactory()
quick.addSteps(setup_steps)
quick.addStep(shell.shellCommand(command="make quick"))
@end example

The rest of this section lists all the standard BuildStep objects
available for use in a Build, and the parameters which can be used to
control each.

@menu
* Common Parameters::
* Using Build Properties::
* Source Checkout::
* ShellCommand::
* Simple ShellCommand Subclasses::
* Python BuildSteps::
* Transferring Files::
* Steps That Run on the Master::
* Triggering Schedulers::
* Writing New BuildSteps::
@end menu

@node Common Parameters, Using Build Properties, Build Steps, Build Steps
@subsection Common Parameters

The standard @code{Build} runs a series of @code{BuildStep}s in order,
only stopping when it runs out of steps or if one of them requests
that the build be halted. It collects status information from each one
to create an overall build status (of SUCCESS, WARNINGS, or FAILURE).

All BuildSteps accept some common parameters. Some of these control
how their individual status affects the overall build. Others are used
to specify which @code{Locks} (see @pxref{Interlocks}) should be
acquired before allowing the step to run.

Arguments common to all @code{BuildStep} subclasses:


@table @code
@item name
the name used to describe the step on the status display. It is also
used to give a name to any LogFiles created by this step.

@item haltOnFailure
if True, a FAILURE of this build step will cause the build to halt
immediately. Steps with @code{alwaysRun=True} are still run. Generally
speaking, haltOnFailure implies flunkOnFailure (the default for most
BuildSteps). In some cases, particularly series of tests, it makes sense
to haltOnFailure if something fails early on but not flunkOnFailure.
This can be achieved with haltOnFailure=True, flunkOnFailure=False.

@item flunkOnWarnings
when True, a WARNINGS or FAILURE of this build step will mark the
overall build as FAILURE. The remaining steps will still be executed.

@item flunkOnFailure
when True, a FAILURE of this build step will mark the overall build as
a FAILURE. The remaining steps will still be executed.

@item warnOnWarnings
when True, a WARNINGS or FAILURE of this build step will mark the
overall build as having WARNINGS. The remaining steps will still be
executed.

@item warnOnFailure
when True, a FAILURE of this build step will mark the overall build as
having WARNINGS. The remaining steps will still be executed.

@item alwaysRun
if True, this build step will always be run, even if a previous buildstep
with @code{haltOnFailure=True} has failed.

@item locks
a list of Locks (instances of @code{buildbot.locks.SlaveLock} or
@code{buildbot.locks.MasterLock}) that should be acquired before
starting this Step. The Locks will be released when the step is
complete. Note that this is a list of actual Lock instances, not
names. Also note that all Locks must have unique names.

@end table

@node Using Build Properties, Source Checkout, Common Parameters, Build Steps
@subsection Using Build Properties
@cindex Properties

Build properties are a generalized way to provide configuration
information to build steps; see @ref{Build Properties}.

Some build properties are inherited from external sources -- global
properties, schedulers, or buildslaves.  Some build properties are
set when the build starts, such as the SourceStamp information. Other
properties can be set by BuildSteps as they run, for example the
various Source steps will set the @code{got_revision} property to the
source revision that was actually checked out (which can be useful
when the SourceStamp in use merely requested the ``latest revision'':
@code{got_revision} will tell you what was actually built).

In custom BuildSteps, you can get and set the build properties with
the @code{getProperty}/@code{setProperty} methods. Each takes a string
for the name of the property, and returns or accepts an
arbitrary@footnote{Build properties are serialized along with the
build results, so they must be serializable. For this reason, the
value of any build property should be simple inert data: strings,
numbers, lists, tuples, and dictionaries. They should not contain
class instances.} object. For example:

@example
class MakeTarball(ShellCommand):
    def start(self):
        if self.getProperty("os") == "win":
            self.setCommand([ ... ]) # windows-only command
        else:
            self.setCommand([ ... ]) # equivalent for other systems
        ShellCommand.start(self)
@end example

@heading WithProperties
@cindex WithProperties

You can use build properties in ShellCommands by using the
@code{WithProperties} wrapper when setting the arguments of
the ShellCommand. This interpolates the named build properties
into the generated shell command.  Most step parameters accept
@code{WithProperties}.  Please file bugs for any parameters which
do not.

@example
from buildbot.steps.shell import ShellCommand
from buildbot.process.properties import WithProperties

f.addStep(ShellCommand(
          command=["tar", "czf",
                   WithProperties("build-%s.tar.gz", "revision"),
                   "source"]))
@end example

If this BuildStep were used in a tree obtained from Subversion, it
would create a tarball with a name like @file{build-1234.tar.gz}.

The @code{WithProperties} function does @code{printf}-style string
interpolation, using strings obtained by calling
@code{build.getProperty(propname)}. Note that for every @code{%s} (or
@code{%d}, etc), you must have exactly one additional argument to
indicate which build property you want to insert.

You can also use python dictionary-style string interpolation by using
the @code{%(propname)s} syntax. In this form, the property name goes
in the parentheses, and WithProperties takes @emph{no} additional
arguments:

@example
f.addStep(ShellCommand(
          command=["tar", "czf",
                   WithProperties("build-%(revision)s.tar.gz"),
                   "source"]))
@end example

Don't forget the extra ``s'' after the closing parenthesis! This is
the cause of many confusing errors.

The dictionary-style interpolation supports a number of more advanced
syntaxes, too.

@table @code

@item propname:-replacement
If @code{propname} exists, substitute its value; otherwise,
substitute @code{replacement}.  @code{replacement} may be empty
(@code{%(propname:-)s})

@item propname:+replacement
If @code{propname} exists, substitute @code{replacement}; otherwise,
substitute an empty string.

@end table

Although these are similar to shell substitutions, no other
substitutions are currently supported, and @code{replacement} in the
above cannot contain more substitutions.

Note: like python, you can either do positional-argument interpolation
@emph{or} keyword-argument interpolation, not both. Thus you cannot use
a string like @code{WithProperties("foo-%(revision)s-%s", "branch")}.

@heading Common Build Properties

The following build properties are set when the build is started, and
are available to all steps.

@table @code
@item branch

This comes from the build's SourceStamp, and describes which branch is
being checked out. This will be @code{None} (which interpolates into
@code{WithProperties} as an empty string) if the build is on the
default branch, which is generally the trunk. Otherwise it will be a
string like ``branches/beta1.4''. The exact syntax depends upon the VC
system being used.

@item revision

This also comes from the SourceStamp, and is the revision of the source code
tree that was requested from the VC system. When a build is requested of a
specific revision (as is generally the case when the build is triggered by
Changes), this will contain the revision specification. This is always a
string, although the syntax depends upon the VC system in use: for SVN it is an
integer, for Mercurial it is a short string, for Darcs it is a rather large
string, etc.

If the ``force build'' button was pressed, the revision will be @code{None},
which means to use the most recent revision available.  This is a ``trunk
build''. This will be interpolated as an empty string.

@item got_revision

This is set when a Source step checks out the source tree, and
provides the revision that was actually obtained from the VC system.
In general this should be the same as @code{revision}, except for
trunk builds, where @code{got_revision} indicates what revision was
current when the checkout was performed. This can be used to rebuild
the same source code later.

Note that for some VC systems (Darcs in particular), the revision is a
large string containing newlines, and is not suitable for interpolation
into a filename.

@item buildername

This is a string that indicates which Builder the build was a part of.
The combination of buildername and buildnumber uniquely identify a
build.

@item buildnumber

Each build gets a number, scoped to the Builder (so the first build
performed on any given Builder will have a build number of 0). This
integer property contains the build's number.

@item slavename

This is a string which identifies which buildslave the build is
running on.

@item scheduler

If the build was started from a scheduler, then this property will
contain the name of that scheduler.

@end table


@node Source Checkout, ShellCommand, Using Build Properties, Build Steps
@subsection Source Checkout

The first step of any build is typically to acquire the source code
from which the build will be performed. There are several classes to
handle this, one for each of the different source control system that
Buildbot knows about. For a description of how Buildbot treats source
control in general, see @ref{Version Control Systems}.

All source checkout steps accept some common parameters to control how
they get the sources and where they should be placed. The remaining
per-VC-system parameters are mostly to specify where exactly the
sources are coming from.

@table @code
@item mode

a string describing the kind of VC operation that is desired. Defaults
to @code{update}.

@table @code
@item update
specifies that the CVS checkout/update should be performed directly
into the workdir. Each build is performed in the same directory,
allowing for incremental builds. This minimizes disk space, bandwidth,
and CPU time. However, it may encounter problems if the build process
does not handle dependencies properly (sometimes you must do a ``clean
build'' to make sure everything gets compiled), or if source files are
deleted but generated files can influence test behavior (e.g. python's
.pyc files), or when source directories are deleted but generated
files prevent CVS from removing them. Builds ought to be correct
regardless of whether they are done ``from scratch'' or incrementally,
but it is useful to test both kinds: this mode exercises the
incremental-build style.

@item copy
specifies that the CVS workspace should be maintained in a separate
directory (called the 'copydir'), using checkout or update as
necessary. For each build, a new workdir is created with a copy of the
source tree (rm -rf workdir; cp -r copydir workdir). This doubles the
disk space required, but keeps the bandwidth low (update instead of a
full checkout). A full 'clean' build is performed each time. This
avoids any generated-file build problems, but is still occasionally
vulnerable to CVS problems such as a repository being manually
rearranged, causing CVS errors on update which are not an issue with a
full checkout.

@c TODO: something is screwy about this, revisit. Is it the source
@c directory or the working directory that is deleted each time?

@item clobber
specifes that the working directory should be deleted each time,
necessitating a full checkout for each build. This insures a clean
build off a complete checkout, avoiding any of the problems described
above. This mode exercises the ``from-scratch'' build style.

@item export
this is like @code{clobber}, except that the 'cvs export' command is
used to create the working directory. This command removes all CVS
metadata files (the CVS/ directories) from the tree, which is
sometimes useful for creating source tarballs (to avoid including the
metadata in the tar file).
@end table

@item workdir
like all Steps, this indicates the directory where the build will take
place. Source Steps are special in that they perform some operations
outside of the workdir (like creating the workdir itself).

@item alwaysUseLatest
if True, bypass the usual ``update to the last Change'' behavior, and
always update to the latest changes instead.

@item retry
If set, this specifies a tuple of @code{(delay, repeats)} which means
that when a full VC checkout fails, it should be retried up to
@var{repeats} times, waiting @var{delay} seconds between attempts. If
you don't provide this, it defaults to @code{None}, which means VC
operations should not be retried. This is provided to make life easier
for buildslaves which are stuck behind poor network connections.

@end table


My habit as a developer is to do a @code{cvs update} and @code{make} each
morning. Problems can occur, either because of bad code being checked in, or
by incomplete dependencies causing a partial rebuild to fail where a
complete from-scratch build might succeed. A quick Builder which emulates
this incremental-build behavior would use the @code{mode='update'}
setting.

On the other hand, other kinds of dependency problems can cause a clean
build to fail where a partial build might succeed. This frequently results
from a link step that depends upon an object file that was removed from a
later version of the tree: in the partial tree, the object file is still
around (even though the Makefiles no longer know how to create it).

``official'' builds (traceable builds performed from a known set of
source revisions) are always done as clean builds, to make sure it is
not influenced by any uncontrolled factors (like leftover files from a
previous build). A ``full'' Builder which behaves this way would want
to use the @code{mode='clobber'} setting.

Each VC system has a corresponding source checkout class: their
arguments are described on the following pages.


@menu
* CVS::
* SVN::
* Darcs::
* Mercurial::
* Arch::
* Bazaar::
* Bzr::
* P4::
* Git::
@end menu

@node CVS, SVN, Source Checkout, Source Checkout
@subsubsection CVS
@cindex CVS Checkout
@bsindex buildbot.steps.source.CVS


The @code{CVS} build step performs a @uref{http://www.nongnu.org/cvs/,
CVS} checkout or update. It takes the following arguments:

@table @code
@item cvsroot
(required): specify the CVSROOT value, which points to a CVS
repository, probably on a remote machine. For example, the cvsroot
value you would use to get a copy of the Buildbot source code is
@code{:pserver:anonymous@@cvs.sourceforge.net:/cvsroot/buildbot}

@item cvsmodule
(required): specify the cvs @code{module}, which is generally a
subdirectory of the CVSROOT. The cvsmodule for the Buildbot source
code is @code{buildbot}.

@item branch
a string which will be used in a @code{-r} argument. This is most
useful for specifying a branch to work on. Defaults to @code{HEAD}.

@item global_options
a list of flags to be put before the verb in the CVS command.

@item checkoutDelay
if set, the number of seconds to put between the timestamp of the last
known Change and the value used for the @code{-D} option. Defaults to
half of the parent Build's treeStableTimer.

@end table


@node SVN, Darcs, CVS, Source Checkout
@subsubsection SVN

@cindex SVN Checkout
@bsindex buildbot.steps.source.SVN


The @code{SVN} build step performs a
@uref{http://subversion.tigris.org, Subversion} checkout or update.
There are two basic ways of setting up the checkout step, depending
upon whether you are using multiple branches or not.

If all of your builds use the same branch, then you should create the
@code{SVN} step with the @code{svnurl} argument:

@table @code
@item svnurl
(required): this specifies the @code{URL} argument that will be given
to the @code{svn checkout} command. It dictates both where the
repository is located and which sub-tree should be extracted. In this
respect, it is like a combination of the CVS @code{cvsroot} and
@code{cvsmodule} arguments. For example, if you are using a remote
Subversion repository which is accessible through HTTP at a URL of
@code{http://svn.example.com/repos}, and you wanted to check out the
@code{trunk/calc} sub-tree, you would use
@code{svnurl="http://svn.example.com/repos/trunk/calc"} as an argument
to your @code{SVN} step.
@end table

If, on the other hand, you are building from multiple branches, then
you should create the @code{SVN} step with the @code{baseURL} and
@code{defaultBranch} arguments instead:

@table @code
@item baseURL
(required): this specifies the base repository URL, to which a branch
name will be appended. It should probably end in a slash.

@item defaultBranch
this specifies the name of the branch to use when a Build does not
provide one of its own. This will be appended to @code{baseURL} to
create the string that will be passed to the @code{svn checkout}
command.

@item username
if specified, this will be passed to the @code{svn} binary with a
@code{--username} option.

@item password
if specified, this will be passed to the @code{svn} binary with a
@code{--password} option.  The password itself will be suitably obfuscated in
the logs.

@end table

If you are using branches, you must also make sure your
@code{ChangeSource} will report the correct branch names.

@heading branch example

Let's suppose that the ``MyProject'' repository uses branches for the
trunk, for various users' individual development efforts, and for
several new features that will require some amount of work (involving
multiple developers) before they are ready to merge onto the trunk.
Such a repository might be organized as follows:

@example
svn://svn.example.org/MyProject/trunk
svn://svn.example.org/MyProject/branches/User1/foo
svn://svn.example.org/MyProject/branches/User1/bar
svn://svn.example.org/MyProject/branches/User2/baz
svn://svn.example.org/MyProject/features/newthing
svn://svn.example.org/MyProject/features/otherthing
@end example

Further assume that we want the Buildbot to run tests against the
trunk and against all the feature branches (i.e., do a
checkout/compile/build of branch X when a file has been changed on
branch X, when X is in the set [trunk, features/newthing,
features/otherthing]). We do not want the Buildbot to automatically
build any of the user branches, but it should be willing to build a
user branch when explicitly requested (most likely by the user who
owns that branch).

There are three things that need to be set up to accomodate this
system. The first is a ChangeSource that is capable of identifying the
branch which owns any given file. This depends upon a user-supplied
function, in an external program that runs in the SVN commit hook and
connects to the buildmaster's @code{PBChangeSource} over a TCP
connection. (you can use the ``@code{buildbot sendchange}'' utility
for this purpose, but you will still need an external program to
decide what value should be passed to the @code{--branch=} argument).
For example, a change to a file with the SVN url of
``svn://svn.example.org/MyProject/features/newthing/src/foo.c'' should
be broken down into a Change instance with
@code{branch='features/newthing'} and @code{file='src/foo.c'}.

The second piece is an @code{AnyBranchScheduler} which will pay
attention to the desired branches. It will not pay attention to the
user branches, so it will not automatically start builds in response
to changes there. The AnyBranchScheduler class requires you to
explicitly list all the branches you want it to use, but it would not
be difficult to write a subclass which used
@code{branch.startswith('features/'} to remove the need for this
explicit list. Or, if you want to build user branches too, you can use
AnyBranchScheduler with @code{branches=None} to indicate that you want
it to pay attention to all branches.

The third piece is an @code{SVN} checkout step that is configured to
handle the branches correctly, with a @code{baseURL} value that
matches the way the ChangeSource splits each file's URL into base,
branch, and file.

@example
from buildbot.changes.pb import PBChangeSource
from buildbot.scheduler import AnyBranchScheduler
from buildbot.process import source, factory
from buildbot.steps import source, shell

c['change_source'] = PBChangeSource()
s1 = AnyBranchScheduler('main',
                        ['trunk', 'features/newthing', 'features/otherthing'],
                        10*60, ['test-i386', 'test-ppc'])
c['schedulers'] = [s1]

f = factory.BuildFactory()
f.addStep(source.SVN(mode='update',
                     baseURL='svn://svn.example.org/MyProject/',
                     defaultBranch='trunk'))
f.addStep(shell.Compile(command="make all"))
f.addStep(shell.Test(command="make test"))

c['builders'] = [
  @{'name':'test-i386', 'slavename':'bot-i386', 'builddir':'test-i386',
                       'factory':f @},
  @{'name':'test-ppc', 'slavename':'bot-ppc', 'builddir':'test-ppc',
                      'factory':f @},
 ]
@end example

In this example, when a change arrives with a @code{branch} attribute
of ``trunk'', the resulting build will have an SVN step that
concatenates ``svn://svn.example.org/MyProject/'' (the baseURL) with
``trunk'' (the branch name) to get the correct svn command. If the
``newthing'' branch has a change to ``src/foo.c'', then the SVN step
will concatenate ``svn://svn.example.org/MyProject/'' with
``features/newthing'' to get the svnurl for checkout.

@node Darcs, Mercurial, SVN, Source Checkout
@subsubsection Darcs

@cindex Darcs Checkout
@bsindex buildbot.steps.source.Darcs


The @code{Darcs} build step performs a
@uref{http://darcs.net/, Darcs} checkout or update.

Like @xref{SVN}, this step can either be configured to always check
out a specific tree, or set up to pull from a particular branch that
gets specified separately for each build. Also like SVN, the
repository URL given to Darcs is created by concatenating a
@code{baseURL} with the branch name, and if no particular branch is
requested, it uses a @code{defaultBranch}. The only difference in
usage is that each potential Darcs repository URL must point to a
fully-fledged repository, whereas SVN URLs usually point to sub-trees
of the main Subversion repository. In other words, doing an SVN
checkout of @code{baseURL} is legal, but silly, since you'd probably
wind up with a copy of every single branch in the whole repository.
Doing a Darcs checkout of @code{baseURL} is just plain wrong, since
the parent directory of a collection of Darcs repositories is not
itself a valid repository.

The Darcs step takes the following arguments:

@table @code
@item repourl
(required unless @code{baseURL} is provided): the URL at which the
Darcs source repository is available.

@item baseURL
(required unless @code{repourl} is provided): the base repository URL,
to which a branch name will be appended. It should probably end in a
slash.

@item defaultBranch
(allowed if and only if @code{baseURL} is provided): this specifies
the name of the branch to use when a Build does not provide one of its
own. This will be appended to @code{baseURL} to create the string that
will be passed to the @code{darcs get} command.
@end table

@node Mercurial, Arch, Darcs, Source Checkout
@subsubsection Mercurial

@cindex Mercurial Checkout
@bsindex buildbot.steps.source.Mercurial


The @code{Mercurial} build step performs a
@uref{http://selenic.com/mercurial, Mercurial} (aka ``hg'') checkout
or update.

Branches are handled just like @xref{Darcs}.

The Mercurial step takes the following arguments:

@table @code
@item repourl
(required unless @code{baseURL} is provided): the URL at which the
Mercurial source repository is available.

@item baseURL
(required unless @code{repourl} is provided): the base repository URL,
to which a branch name will be appended. It should probably end in a
slash.

@item defaultBranch
(allowed if and only if @code{baseURL} is provided): this specifies
the name of the branch to use when a Build does not provide one of its
own. This will be appended to @code{baseURL} to create the string that
will be passed to the @code{hg clone} command.
@end table


@node Arch, Bazaar, Mercurial, Source Checkout
@subsubsection Arch

@cindex Arch Checkout
@bsindex buildbot.steps.source.Arch


The @code{Arch} build step performs an @uref{http://gnuarch.org/,
Arch} checkout or update using the @code{tla} client. It takes the
following arguments:

@table @code
@item url
(required): this specifies the URL at which the Arch source archive is
available.

@item version
(required): this specifies which ``development line'' (like a branch)
should be used. This provides the default branch name, but individual
builds may specify a different one.

@item archive
(optional): Each repository knows its own archive name. If this
parameter is provided, it must match the repository's archive name.
The parameter is accepted for compatibility with the @code{Bazaar}
step, below.

@end table

@node Bazaar, Bzr, Arch, Source Checkout
@subsubsection Bazaar

@cindex Bazaar Checkout
@bsindex buildbot.steps.source.Bazaar


@code{Bazaar} is an alternate implementation of the Arch VC system,
which uses a client named @code{baz}. The checkout semantics are just
different enough from @code{tla} that there is a separate BuildStep for
it.

It takes exactly the same arguments as @code{Arch}, except that the
@code{archive=} parameter is required. (baz does not emit the archive
name when you do @code{baz register-archive}, so we must provide it
ourselves).


@node Bzr, P4, Bazaar, Source Checkout
@subsubsection Bzr

@cindex Bzr Checkout
@bsindex buildbot.steps.source.Bzr

@code{bzr} is a descendant of Arch/Baz, and is frequently referred to
as simply ``Bazaar''. The repository-vs-workspace model is similar to
Darcs, but it uses a strictly linear sequence of revisions (one
history per branch) like Arch. Branches are put in subdirectories.
This makes it look very much like Mercurial, so it takes the same
arguments:

@table @code

@item repourl
(required unless @code{baseURL} is provided): the URL at which the
Bzr source repository is available.

@item baseURL
(required unless @code{repourl} is provided): the base repository URL,
to which a branch name will be appended. It should probably end in a
slash.

@item defaultBranch
(allowed if and only if @code{baseURL} is provided): this specifies
the name of the branch to use when a Build does not provide one of its
own. This will be appended to @code{baseURL} to create the string that
will be passed to the @code{bzr checkout} command.
@end table



@node P4, Git, Bzr, Source Checkout
@subsubsection P4

@cindex Perforce Update
@bsindex buildbot.steps.source.P4
@c TODO @bsindex buildbot.steps.source.P4Sync


The @code{P4} build step creates a @uref{http://www.perforce.com/,
Perforce} client specification and performs an update.

@table @code
@item p4base
A view into the Perforce depot without branch name or trailing "...".
Typically "//depot/proj/".
@item defaultBranch
A branch name to append on build requests if none is specified.
Typically "trunk".
@item p4port
(optional): the host:port string describing how to get to the P4 Depot
(repository), used as the -p argument for all p4 commands.
@item p4user
(optional): the Perforce user, used as the -u argument to all p4
commands.
@item p4passwd
(optional): the Perforce password, used as the -p argument to all p4
commands.
@item p4extra_views
(optional): a list of (depotpath, clientpath) tuples containing extra
views to be mapped into the client specification. Both will have
"/..." appended automatically. The client name and source directory
will be prepended to the client path.
@item p4client
(optional): The name of the client to use. In mode='copy' and
mode='update', it's particularly important that a unique name is used
for each checkout directory to avoid incorrect synchronization. For
this reason, Python percent substitution will be performed on this value
to replace %(slave)s with the slave name and %(builder)s with the
builder name. The default is "buildbot_%(slave)s_%(build)s".
@end table


@node Git,  , P4, Source Checkout
@subsubsection Git

@cindex Git Checkout
@bsindex buildbot.steps.source.Git

The @code{Git} build step clones or updates a @uref{http://git.or.cz/,
Git} repository and checks out the specified branch or revision. Note
that the buildbot supports Git version 1.2.0 and later: earlier
versions (such as the one shipped in Ubuntu 'Dapper') do not support
the @command{git init} command that the buildbot uses.

The Git step takes the following arguments:

@table @code
@item repourl
(required): the URL of the upstream Git repository.

@item branch
(optional): this specifies the name of the branch to use when a Build
does not provide one of its own. If this this parameter is not
specified, and the Build does not provide a branch, the ``master''
branch will be used.
@end table


@node ShellCommand, Simple ShellCommand Subclasses, Source Checkout, Build Steps
@subsection ShellCommand

@bsindex buildbot.steps.shell.ShellCommand
@c TODO @bsindex buildbot.steps.shell.TreeSize

This is a useful base class for just about everything you might want
to do during a build (except for the initial source checkout). It runs
a single command in a child shell on the buildslave. All stdout/stderr
is recorded into a LogFile. The step finishes with a status of FAILURE
if the command's exit code is non-zero, otherwise it has a status of
SUCCESS.

The preferred way to specify the command is with a list of argv strings,
since this allows for spaces in filenames and avoids doing any fragile
shell-escaping. You can also specify the command with a single string, in
which case the string is given to '/bin/sh -c COMMAND' for parsing.

On Windows, commands are run via @code{cmd.exe /c} which works well. However,
if you're running a batch file, the error level does not get propagated
correctly unless you add 'call' before your batch file's name:
@code{cmd=['call', 'myfile.bat', ...]}.

All ShellCommands are run by default in the ``workdir'', which
defaults to the ``@file{build}'' subdirectory of the slave builder's
base directory. The absolute path of the workdir will thus be the
slave's basedir (set as an option to @code{buildbot create-slave},
@pxref{Creating a buildslave}) plus the builder's basedir (set in the
builder's @code{c['builddir']} key in master.cfg) plus the workdir
itself (a class-level attribute of the BuildFactory, defaults to
``@file{build}'').

@code{ShellCommand} arguments:

@table @code
@item command
a list of strings (preferred) or single string (discouraged) which
specifies the command to be run. A list of strings is preferred
because it can be used directly as an argv array. Using a single
string (with embedded spaces) requires the buildslave to pass the
string to /bin/sh for interpretation, which raises all sorts of
difficult questions about how to escape or interpret shell
metacharacters.

@item env
a dictionary of environment strings which will be added to the child
command's environment. For example, to run tests with a different i18n
language setting, you might use

@example
f.addStep(ShellCommand(command=["make", "test"],
                       env=@{'LANG': 'fr_FR'@}))
@end example

These variable settings will override any existing ones in the
buildslave's environment or the environment specified in the
Builder. The exception is PYTHONPATH, which is merged
with (actually prepended to) any existing $PYTHONPATH setting. The
value is treated as a list of directories to prepend, and a single
string is treated like a one-item list. For example, to prepend both
@file{/usr/local/lib/python2.3} and @file{/home/buildbot/lib/python}
to any existing $PYTHONPATH setting, you would do something like the
following:

@example
f.addStep(ShellCommand(
              command=["make", "test"],
              env=@{'PYTHONPATH': ["/usr/local/lib/python2.3",
                                   "/home/buildbot/lib/python"] @}))
@end example

@item want_stdout
if False, stdout from the child process is discarded rather than being
sent to the buildmaster for inclusion in the step's LogFile.

@item want_stderr
like @code{want_stdout} but for stderr. Note that commands run through
a PTY do not have separate stdout/stderr streams: both are merged into
stdout.

@item usePTY
Should this command be run in a @code{pty}?  The default is to observe the
configuration of the client (@pxref{Buildslave Options}), but specifying
@code{True} or @code{False} here will override the default.

The advantage of using a PTY is that ``grandchild'' processes are more likely
to be cleaned up if the build is interrupted or times out (since it enables the
use of a ``process group'' in which all child processes will be placed). The
disadvantages: some forms of Unix have problems with PTYs, some of your unit
tests may behave differently when run under a PTY (generally those which check
to see if they are being run interactively), and PTYs will merge the stdout and
stderr streams into a single output stream (which means the red-vs-black
coloring in the logfiles will be lost).

@item logfiles
Sometimes commands will log interesting data to a local file, rather
than emitting everything to stdout or stderr. For example, Twisted's
``trial'' command (which runs unit tests) only presents summary
information to stdout, and puts the rest into a file named
@file{_trial_temp/test.log}. It is often useful to watch these files
as the command runs, rather than using @command{/bin/cat} to dump
their contents afterwards.

The @code{logfiles=} argument allows you to collect data from these
secondary logfiles in near-real-time, as the step is running. It
accepts a dictionary which maps from a local Log name (which is how
the log data is presented in the build results) to a remote filename
(interpreted relative to the build's working directory). Each named
file will be polled on a regular basis (every couple of seconds) as
the build runs, and any new text will be sent over to the buildmaster.

@example
f.addStep(ShellCommand(
              command=["make", "test"],
              logfiles=@{"triallog": "_trial_temp/test.log"@}))
@end example


@item timeout
if the command fails to produce any output for this many seconds, it
is assumed to be locked up and will be killed.

@item description
This will be used to describe the command (on the Waterfall display)
while the command is still running. It should be a single
imperfect-tense verb, like ``compiling'' or ``testing''. The preferred
form is a list of short strings, which allows the HTML Waterfall
display to create narrower columns by emitting a <br> tag between each
word. You may also provide a single string.

@item descriptionDone
This will be used to describe the command once it has finished. A
simple noun like ``compile'' or ``tests'' should be used. Like
@code{description}, this may either be a list of short strings or a
single string.

If neither @code{description} nor @code{descriptionDone} are set, the
actual command arguments will be used to construct the description.
This may be a bit too wide to fit comfortably on the Waterfall
display.

@example
f.addStep(ShellCommand(command=["make", "test"],
                       description=["testing"],
                       descriptionDone=["tests"]))
@end example

@item logEnviron
If this option is true (the default), then the step's logfile will describe the
environment variables on the slave.  In situations where the environment is not
relevant and is long, it may be easier to set @code{logEnviron=False}.

@end table

@node Simple ShellCommand Subclasses, Python BuildSteps, ShellCommand, Build Steps
@subsection Simple ShellCommand Subclasses

Several subclasses of ShellCommand are provided as starting points for
common build steps. These are all very simple: they just override a few
parameters so you don't have to specify them yourself, making the master.cfg
file less verbose.

@menu
* Configure::
* Compile::
* Test::
* TreeSize::
* PerlModuleTest::
* SetProperty::
@end menu

@node Configure, Compile, Simple ShellCommand Subclasses, Simple ShellCommand Subclasses
@subsubsection Configure

@bsindex buildbot.steps.shell.Configure

This is intended to handle the @code{./configure} step from
autoconf-style projects, or the @code{perl Makefile.PL} step from perl
MakeMaker.pm-style modules. The default command is @code{./configure}
but you can change this by providing a @code{command=} parameter.

@node Compile, Test, Configure, Simple ShellCommand Subclasses
@subsubsection Compile

@bsindex buildbot.steps.shell.Compile

This is meant to handle compiling or building a project written in C.
The default command is @code{make all}. When the compile is finished,
the log file is scanned for GCC warning messages, a summary log is
created with any problems that were seen, and the step is marked as
WARNINGS if any were discovered. The number of warnings is stored in a
Build Property named ``warnings-count'', which is accumulated over all
Compile steps (so if two warnings are found in one step, and three are
found in another step, the overall build will have a
``warnings-count'' property of 5.

The default regular expression used to detect a warning is
@code{'.*warning[: ].*'} , which is fairly liberal and may cause
false-positives. To use a different regexp, provide a
@code{warningPattern=} argument, or use a subclass which sets the
@code{warningPattern} attribute:

@example
f.addStep(Compile(command=["make", "test"],
                  warningPattern="^Warning: "))
@end example

The @code{warningPattern=} can also be a pre-compiled python regexp
object: this makes it possible to add flags like @code{re.I} (to use
case-insensitive matching).

(TODO: this step needs to be extended to look for GCC error messages
as well, and collect them into a separate logfile, along with the
source code filenames involved).


@node Test, TreeSize, Compile, Simple ShellCommand Subclasses
@subsubsection Test

@bsindex buildbot.steps.shell.Test

This is meant to handle unit tests. The default command is @code{make
test}, and the @code{warnOnFailure} flag is set.

@node TreeSize, PerlModuleTest, Test, Simple ShellCommand Subclasses
@subsubsection TreeSize

@bsindex buildbot.steps.shell.TreeSize

This is a simple command that uses the 'du' tool to measure the size
of the code tree. It puts the size (as a count of 1024-byte blocks,
aka 'KiB' or 'kibibytes') on the step's status text, and sets a build
property named 'tree-size-KiB' with the same value.

@node PerlModuleTest, SetProperty, TreeSize, Simple ShellCommand Subclasses
@subsubsection PerlModuleTest

@bsindex buildbot.steps.shell.PerlModuleTest

This is a simple command that knows how to run tests of perl modules.
It parses the output to determine the number of tests passed and
failed and total number executed, saving the results for later query.

@node SetProperty,  , PerlModuleTest, Simple ShellCommand Subclasses
@subsubsection SetProperty

@bsindex buildbot.steps.shell.SetProperty

This buildstep is similar to ShellCommand, except that it captures the
output of the command into a property.  It is usually used like this:

@example
f.addStep(SetProperty(command="uname -a", property="uname"))
@end example

This runs @code{uname -a} and captures its stdout, stripped of leading
and trailing whitespace, in the property "uname".  To avoid stripping,
add @code{strip=False}.  The @code{property} argument can be specified
as a @code{WithProperties} object.

The more advanced usage allows you to specify a function to extract
properties from the command output.  Here you can use regular
expressions, string interpolation, or whatever you would like.
The function is called with three arguments: the exit status of the
command, its standard output as a string, and its standard error as
a string.  It should return a dictionary containing all new properties.

@example
def glob2list(rc, stdout, stderr):
    jpgs = [ l.strip() for l in stdout.split('\n') ]
    return @{ 'jpgs' : jpgs @}
f.addStep(SetProperty(command="ls -1 *.jpg", extract_fn=glob2list))
@end example

Note that any ordering relationship of the contents of stdout and
stderr is lost.  For example, given

@example
f.addStep(SetProperty(
    command="echo output1; echo error >&2; echo output2",
    extract_fn=my_extract))
@end example

Then @code{my_extract} will see @code{stdout="output1\noutput2\n"}
and @code{stderr="error\n"}.

@node Python BuildSteps, Transferring Files, Simple ShellCommand Subclasses, Build Steps
@subsection Python BuildSteps

Here are some BuildSteps that are specifcally useful for projects
implemented in Python.

@menu
* BuildEPYDoc::
* PyFlakes::
* PyLint::
@end menu

@node BuildEPYDoc
@subsubsection BuildEPYDoc

@bsindex buildbot.steps.python.BuildEPYDoc

@url{http://epydoc.sourceforge.net/, epydoc} is a tool for generating
API documentation for Python modules from their docstrings. It reads
all the .py files from your source tree, processes the docstrings
therein, and creates a large tree of .html files (or a single .pdf
file).

The @code{buildbot.steps.python.BuildEPYDoc} step will run
@command{epydoc} to produce this API documentation, and will count the
errors and warnings from its output.

You must supply the command line to be used. The default is
@command{make epydocs}, which assumes that your project has a Makefile
with an ``epydocs'' target. You might wish to use something like
@command{epydoc -o apiref source/PKGNAME} instead. You might also want
to add @command{--pdf} to generate a PDF file instead of a large tree
of HTML files.

The API docs are generated in-place in the build tree (under the
workdir, in the subdirectory controlled by the ``-o'' argument). To
make them useful, you will probably have to copy them to somewhere
they can be read. A command like @command{rsync -ad apiref/
dev.example.com:~public_html/current-apiref/} might be useful. You
might instead want to bundle them into a tarball and publish it in the
same place where the generated install tarball is placed.

@example
from buildbot.steps.python import BuildEPYDoc

...
f.addStep(BuildEPYDoc(command=["epydoc", "-o", "apiref", "source/mypkg"]))
@end example


@node PyFlakes
@subsubsection PyFlakes

@bsindex buildbot.steps.python.PyFlakes

@url{http://divmod.org/trac/wiki/DivmodPyflakes, PyFlakes} is a tool
to perform basic static analysis of Python code to look for simple
errors, like missing imports and references of undefined names. It is
like a fast and simple form of the C ``lint'' program. Other tools
(like pychecker) provide more detailed results but take longer to run.

The @code{buildbot.steps.python.PyFlakes} step will run pyflakes and
count the various kinds of errors and warnings it detects.

You must supply the command line to be used. The default is
@command{make pyflakes}, which assumes you have a top-level Makefile
with a ``pyflakes'' target. You might want to use something like
@command{pyflakes .} or @command{pyflakes src}.

@example
from buildbot.steps.python import PyFlakes

...
f.addStep(PyFlakes(command=["pyflakes", "src"]))
@end example

@node PyLint
@subsubsection PyLint

@bsindex buildbot.steps.python.PyLint

Similarly, the @code{buildbot.steps.python.PyLint} step will run pylint and
analyze the results.

You must supply the command line to be used. There is no default.

@example
from buildbot.steps.python import PyLint

...
f.addStep(PyLint(command=["pylint", "src"]))
@end example


@node Transferring Files
@subsection Transferring Files

@cindex File Transfer
@bsindex buildbot.steps.transfer.FileUpload
@bsindex buildbot.steps.transfer.FileDownload
@bsindex buildbot.steps.transfer.DirectoryUpload

Most of the work involved in a build will take place on the
buildslave. But occasionally it is useful to do some work on the
buildmaster side. The most basic way to involve the buildmaster is
simply to move a file from the slave to the master, or vice versa.
There are a pair of BuildSteps named @code{FileUpload} and
@code{FileDownload} to provide this functionality. @code{FileUpload}
moves a file @emph{up to} the master, while @code{FileDownload} moves
a file @emph{down from} the master.

As an example, let's assume that there is a step which produces an
HTML file within the source tree that contains some sort of generated
project documentation. We want to move this file to the buildmaster,
into a @file{~/public_html} directory, so it can be visible to
developers. This file will wind up in the slave-side working directory
under the name @file{docs/reference.html}. We want to put it into the
master-side @file{~/public_html/ref.html}.

@example
from buildbot.steps.shell import ShellCommand
from buildbot.steps.transfer import FileUpload

f.addStep(ShellCommand(command=["make", "docs"]))
f.addStep(FileUpload(slavesrc="docs/reference.html",
                     masterdest="~/public_html/ref.html"))
@end example

The @code{masterdest=} argument will be passed to os.path.expanduser,
so things like ``~'' will be expanded properly. Non-absolute paths
will be interpreted relative to the buildmaster's base directory.
Likewise, the @code{slavesrc=} argument will be expanded and
interpreted relative to the builder's working directory.


To move a file from the master to the slave, use the
@code{FileDownload} command. For example, let's assume that some step
requires a configuration file that, for whatever reason, could not be
recorded in the source code repository or generated on the buildslave
side:

@example
from buildbot.steps.shell import ShellCommand
from buildbot.steps.transfer import FileUpload

f.addStep(FileDownload(mastersrc="~/todays_build_config.txt",
                       slavedest="build_config.txt"))
f.addStep(ShellCommand(command=["make", "config"]))
@end example

Like @code{FileUpload}, the @code{mastersrc=} argument is interpreted
relative to the buildmaster's base directory, and the
@code{slavedest=} argument is relative to the builder's working
directory. If the buildslave is running in @file{~buildslave}, and the
builder's ``builddir'' is something like @file{tests-i386}, then the
workdir is going to be @file{~buildslave/tests-i386/build}, and a
@code{slavedest=} of @file{foo/bar.html} will get put in
@file{~buildslave/tests-i386/build/foo/bar.html}. Both of these commands
will create any missing intervening directories.

@subheading Other Parameters

The @code{maxsize=} argument lets you set a maximum size for the file
to be transferred. This may help to avoid surprises: transferring a
100MB coredump when you were expecting to move a 10kB status file
might take an awfully long time. The @code{blocksize=} argument
controls how the file is sent over the network: larger blocksizes are
slightly more efficient but also consume more memory on each end, and
there is a hard-coded limit of about 640kB.

The @code{mode=} argument allows you to control the access permissions
of the target file, traditionally expressed as an octal integer. The
most common value is probably 0755, which sets the ``x'' executable
bit on the file (useful for shell scripts and the like). The default
value for @code{mode=} is None, which means the permission bits will
default to whatever the umask of the writing process is. The default
umask tends to be fairly restrictive, but at least on the buildslave
you can make it less restrictive with a --umask command-line option at
creation time (@pxref{Buildslave Options}).

@subheading Transfering Directories

To transfer complete directories from the buildslave to the master, there
is a BuildStep named @code{DirectoryUpload}. It works like @code{FileUpload},
just for directories. However it does not support the @code{maxsize},
@code{blocksize} and @code{mode} arguments. As an example, let's assume an
generated project documentation, which consists of many files (like the output
of doxygen or epydoc). We want to move the entire documentation to the
buildmaster, into a @code{~/public_html/docs} directory. On the slave-side
the directory can be found under @code{docs}:

@example
from buildbot.steps.shell import ShellCommand
from buildbot.steps.transfer import DirectoryUpload

f.addStep(ShellCommand(command=["make", "docs"]))
f.addStep(DirectoryUpload(slavesrc="docs",
                                masterdest="~/public_html/docs"))
@end example

The DirectoryUpload step will create all necessary directories and
transfers empty directories, too.

@node Steps That Run on the Master
@subsection Steps That Run on the Master

Occasionally, it is useful to execute some task on the master, for example to
create a directory, deploy a build result, or trigger some other centralized
processing.  This is possible, in a limited fashion, with the
@code{MasterShellCommand} step.

This step operates similarly to a regular @code{ShellCommand}, but executes on
the master, instead of the slave.  To be clear, the enclosing @code{Build}
object must still have a slave object, just as for any other step -- only, in
this step, the slave does not do anything.

In this example, the step renames a tarball based on the day of the week.

@example
from buildbot.steps.transfer import FileUpload
from buildbot.steps.master import MasterShellCommand

f.addStep(FileUpload(slavesrc="widgetsoft.tar.gz",
                     masterdest="/var/buildoutputs/widgetsoft-new.tar.gz"))
f.addStep(MasterShellCommand(command="""
    cd /var/buildoutputs;
    mv widgetsoft-new.tar.gz widgetsoft-`date +%a`.tar.gz"""))
@end example

@node Triggering Schedulers
@subsection Triggering Schedulers

The counterpart to the Triggerable described in section
@pxref{Triggerable Scheduler} is the Trigger BuildStep.

@example
from buildbot.steps.trigger import Trigger
f.addStep(Trigger(schedulerNames=['build-prep'],
                  waitForFinish=True,
                  updateSourceStamp=True))
@end example

The @code{schedulerNames=} argument lists the Triggerables
that should be triggered when this step is executed.  Note that
it is possible, but not advisable, to create a cycle where a build
continually triggers itself, because the schedulers are specified
by name.

If @code{waitForFinish} is True, then the step will not finish until
all of the builds from the triggered schedulers have finished. If this
argument is False (the default) or not given, then the buildstep
succeeds immediately after triggering the schedulers.

If @code{updateSourceStamp} is True (the default), then step updates
the SourceStamp given to the Triggerables to include
@code{got_revision} (the revision actually used in this build) as
@code{revision} (the revision to use in the triggered builds). This is
useful to ensure that all of the builds use exactly the same
SourceStamp, even if other Changes have occurred while the build was
running.

@node Writing New BuildSteps
@subsection Writing New BuildSteps

While it is a good idea to keep your build process self-contained in
the source code tree, sometimes it is convenient to put more
intelligence into your Buildbot configuration. One way to do this is
to write a custom BuildStep. Once written, this Step can be used in
the @file{master.cfg} file.

The best reason for writing a custom BuildStep is to better parse the
results of the command being run. For example, a BuildStep that knows
about JUnit could look at the logfiles to determine which tests had
been run, how many passed and how many failed, and then report more
detailed information than a simple @code{rc==0} -based ``good/bad''
decision.

@menu
* Writing BuildStep Constructors::
* BuildStep LogFiles::
* Reading Logfiles::
* Adding LogObservers::
* BuildStep URLs::
@end menu

@node Writing BuildStep Constructors
@subsubsection Writing BuildStep Constructors

BuildStep classes have some extra equipment, because they are their own
factories.  Consider the use of a BuildStep in @file{master.cfg}:

@example
f.addStep(MyStep(someopt="stuff", anotheropt=1))
@end example

This creates a single instance of class @code{MyStep}.  However, Buildbot needs
a new object each time the step is executed.  this is accomplished by storing
the information required to instantiate a new object in the @code{factory}
attribute.  When the time comes to construct a new Build, BuildFactory consults
this attribute (via @code{getStepFactory}) and instantiates a new step object.

When writing a new step class, then, keep in mind are that you cannot do
anything "interesting" in the constructor -- limit yourself to checking and
storing arguments.  To ensure that these arguments are provided to any new
objects, call @code{self.addFactoryArguments} with any keyword arguments your
constructor needs.

Keep a @code{**kwargs} argument on the end of your options, and pass that up to
the parent class's constructor.

The whole thing looks like this:

@example
class Frobinfy(LoggingBuildStep):
    def __init__(self,
            frob_what="frobee",
            frob_how_many=None,
            frob_how=None,
            **kwargs)

        # check
        if frob_how_many is None:
            raise TypeError("Frobinfy argument how_many is required")

        # call parent
        LoggingBuildStep.__init__(self, **kwargs)

        # and record arguments for later
        self.addFactoryArguments(
            frob_what=frob_what,
            frob_how_many=frob_how_many,
            frob_how=frob_how)

class FastFrobnify(Frobnify):
    def __init__(self,
            speed=5,
            **kwargs)
        Frobnify.__init__(self, **kwargs)
        self.addFactoryArguments(
            speed=speed)
@end example

@node BuildStep LogFiles
@subsubsection BuildStep LogFiles

Each BuildStep has a collection of ``logfiles''. Each one has a short
name, like ``stdio'' or ``warnings''. Each LogFile contains an
arbitrary amount of text, usually the contents of some output file
generated during a build or test step, or a record of everything that
was printed to stdout/stderr during the execution of some command.

These LogFiles are stored to disk, so they can be retrieved later.

Each can contain multiple ``channels'', generally limited to three
basic ones: stdout, stderr, and ``headers''. For example, when a
ShellCommand runs, it writes a few lines to the ``headers'' channel to
indicate the exact argv strings being run, which directory the command
is being executed in, and the contents of the current environment
variables. Then, as the command runs, it adds a lot of ``stdout'' and
``stderr'' messages. When the command finishes, a final ``header''
line is added with the exit code of the process.

Status display plugins can format these different channels in
different ways. For example, the web page shows LogFiles as text/html,
with header lines in blue text, stdout in black, and stderr in red. A
different URL is available which provides a text/plain format, in
which stdout and stderr are collapsed together, and header lines are
stripped completely. This latter option makes it easy to save the
results to a file and run @command{grep} or whatever against the
output.

Each BuildStep contains a mapping (implemented in a python dictionary)
from LogFile name to the actual LogFile objects. Status plugins can
get a list of LogFiles to display, for example, a list of HREF links
that, when clicked, provide the full contents of the LogFile.

@heading Using LogFiles in custom BuildSteps

The most common way for a custom BuildStep to use a LogFile is to
summarize the results of a ShellCommand (after the command has
finished running). For example, a compile step with thousands of lines
of output might want to create a summary of just the warning messages.
If you were doing this from a shell, you would use something like:

@example
grep "warning:" output.log >warnings.log
@end example

In a custom BuildStep, you could instead create a ``warnings'' LogFile
that contained the same text. To do this, you would add code to your
@code{createSummary} method that pulls lines from the main output log
and creates a new LogFile with the results:

@example
    def createSummary(self, log):
        warnings = []
        for line in log.readlines():
            if "warning:" in line:
                warnings.append()
        self.addCompleteLog('warnings', "".join(warnings))
@end example

This example uses the @code{addCompleteLog} method, which creates a
new LogFile, puts some text in it, and then ``closes'' it, meaning
that no further contents will be added. This LogFile will appear in
the HTML display under an HREF with the name ``warnings'', since that
is the name of the LogFile.

You can also use @code{addHTMLLog} to create a complete (closed)
LogFile that contains HTML instead of plain text. The normal LogFile
will be HTML-escaped if presented through a web page, but the HTML
LogFile will not. At the moment this is only used to present a pretty
HTML representation of an otherwise ugly exception traceback when
something goes badly wrong during the BuildStep.

In contrast, you might want to create a new LogFile at the beginning
of the step, and add text to it as the command runs. You can create
the LogFile and attach it to the build by calling @code{addLog}, which
returns the LogFile object. You then add text to this LogFile by
calling methods like @code{addStdout} and @code{addHeader}. When you
are done, you must call the @code{finish} method so the LogFile can be
closed. It may be useful to create and populate a LogFile like this
from a LogObserver method @xref{Adding LogObservers}.

The @code{logfiles=} argument to @code{ShellCommand} (see
@pxref{ShellCommand}) creates new LogFiles and fills them in realtime
by asking the buildslave to watch a actual file on disk. The
buildslave will look for additions in the target file and report them
back to the BuildStep. These additions will be added to the LogFile by
calling @code{addStdout}. These secondary LogFiles can be used as the
source of a LogObserver just like the normal ``stdio'' LogFile.

@node Reading Logfiles
@subsubsection Reading Logfiles

Once a LogFile has been added to a BuildStep with @code{addLog()},
@code{addCompleteLog()}, @code{addHTMLLog()}, or @code{logfiles=},
your BuildStep can retrieve it by using @code{getLog()}:

@example
class MyBuildStep(ShellCommand):
    logfiles = @{ "nodelog": "_test/node.log" @}

    def evaluateCommand(self, cmd):
        nodelog = self.getLog("nodelog")
        if "STARTED" in nodelog.getText():
            return SUCCESS
        else:
            return FAILURE
@end example

For a complete list of the methods you can call on a LogFile, please
see the docstrings on the @code{IStatusLog} class in
@file{buildbot/interfaces.py}.


@node Adding LogObservers, BuildStep URLs, Reading Logfiles, Writing New BuildSteps
@subsubsection Adding LogObservers

@cindex LogObserver
@cindex LogLineObserver

Most shell commands emit messages to stdout or stderr as they operate,
especially if you ask them nicely with a @code{--verbose} flag of some
sort. They may also write text to a log file while they run. Your
BuildStep can watch this output as it arrives, to keep track of how
much progress the command has made. You can get a better measure of
progress by counting the number of source files compiled or test cases
run than by merely tracking the number of bytes that have been written
to stdout. This improves the accuracy and the smoothness of the ETA
display.

To accomplish this, you will need to attach a @code{LogObserver} to
one of the log channels, most commonly to the ``stdio'' channel but
perhaps to another one which tracks a log file. This observer is given
all text as it is emitted from the command, and has the opportunity to
parse that output incrementally. Once the observer has decided that
some event has occurred (like a source file being compiled), it can
use the @code{setProgress} method to tell the BuildStep about the
progress that this event represents.

There are a number of pre-built @code{LogObserver} classes that you
can choose from (defined in @code{buildbot.process.buildstep}, and of
course you can subclass them to add further customization. The
@code{LogLineObserver} class handles the grunt work of buffering and
scanning for end-of-line delimiters, allowing your parser to operate
on complete stdout/stderr lines. (Lines longer than a set maximum
length are dropped; the maximum defaults to 16384 bytes, but you can
change it by calling @code{setMaxLineLength()} on your
@code{LogLineObserver} instance.  Use @code{sys.maxint} for effective
infinity.)

For example, let's take a look at the @code{TrialTestCaseCounter},
which is used by the Trial step to count test cases as they are run.
As Trial executes, it emits lines like the following:

@example
buildbot.test.test_config.ConfigTest.testDebugPassword ... [OK]
buildbot.test.test_config.ConfigTest.testEmpty ... [OK]
buildbot.test.test_config.ConfigTest.testIRC ... [FAIL]
buildbot.test.test_config.ConfigTest.testLocks ... [OK]
@end example

When the tests are finished, trial emits a long line of ``======'' and
then some lines which summarize the tests that failed. We want to
avoid parsing these trailing lines, because their format is less
well-defined than the ``[OK]'' lines.

The parser class looks like this:

@example
from buildbot.process.buildstep import LogLineObserver

class TrialTestCaseCounter(LogLineObserver):
    _line_re = re.compile(r'^([\w\.]+) \.\.\. \[([^\]]+)\]$')
    numTests = 0
    finished = False

    def outLineReceived(self, line):
        if self.finished:
            return
        if line.startswith("=" * 40):
            self.finished = True
            return

        m = self._line_re.search(line.strip())
        if m:
            testname, result = m.groups()
            self.numTests += 1
            self.step.setProgress('tests', self.numTests)
@end example

This parser only pays attention to stdout, since that's where trial
writes the progress lines. It has a mode flag named @code{finished} to
ignore everything after the ``===='' marker, and a scary-looking
regular expression to match each line while hopefully ignoring other
messages that might get displayed as the test runs.

Each time it identifies a test has been completed, it increments its
counter and delivers the new progress value to the step with
@code{self.step.setProgress}. This class is specifically measuring
progress along the ``tests'' metric, in units of test cases (as
opposed to other kinds of progress like the ``output'' metric, which
measures in units of bytes). The Progress-tracking code uses each
progress metric separately to come up with an overall completion
percentage and an ETA value.

To connect this parser into the @code{Trial} BuildStep,
@code{Trial.__init__} ends with the following clause:

@example
        # this counter will feed Progress along the 'test cases' metric
        counter = TrialTestCaseCounter()
        self.addLogObserver('stdio', counter)
        self.progressMetrics += ('tests',)
@end example

This creates a TrialTestCaseCounter and tells the step that the
counter wants to watch the ``stdio'' log. The observer is
automatically given a reference to the step in its @code{.step}
attribute.

@subheading A Somewhat Whimsical Example

Let's say that we've got some snazzy new unit-test framework called
Framboozle. It's the hottest thing since sliced bread. It slices, it
dices, it runs unit tests like there's no tomorrow. Plus if your unit
tests fail, you can use its name for a Web 2.1 startup company, make
millions of dollars, and hire engineers to fix the bugs for you, while
you spend your afternoons lazily hang-gliding along a scenic pacific
beach, blissfully unconcerned about the state of your
tests.@footnote{framboozle.com is still available. Remember, I get 10%
:).}

To run a Framboozle-enabled test suite, you just run the 'framboozler'
command from the top of your source code tree. The 'framboozler'
command emits a bunch of stuff to stdout, but the most interesting bit
is that it emits the line "FNURRRGH!" every time it finishes running a
test case@footnote{Framboozle gets very excited about running unit
tests.}. You'd like to have a test-case counting LogObserver that
watches for these lines and counts them, because counting them will
help the buildbot more accurately calculate how long the build will
take, and this will let you know exactly how long you can sneak out of
the office for your hang-gliding lessons without anyone noticing that
you're gone.

This will involve writing a new BuildStep (probably named
"Framboozle") which inherits from ShellCommand. The BuildStep class
definition itself will look something like this:

@example
# START
from buildbot.steps.shell import ShellCommand
from buildbot.process.buildstep import LogLineObserver

class FNURRRGHCounter(LogLineObserver):
    numTests = 0
    def outLineReceived(self, line):
        if "FNURRRGH!" in line:
            self.numTests += 1
            self.step.setProgress('tests', self.numTests)

class Framboozle(ShellCommand):
    command = ["framboozler"]

    def __init__(self, **kwargs):
        ShellCommand.__init__(self, **kwargs)   # always upcall!
        counter = FNURRRGHCounter())
        self.addLogObserver('stdio', counter)
        self.progressMetrics += ('tests',)
# FINISH
@end example

So that's the code that we want to wind up using. How do we actually
deploy it?

You have a couple of different options.

Option 1: The simplest technique is to simply put this text
(everything from START to FINISH) in your master.cfg file, somewhere
before the BuildFactory definition where you actually use it in a
clause like:

@example
f = BuildFactory()
f.addStep(SVN(svnurl="stuff"))
f.addStep(Framboozle())
@end example

Remember that master.cfg is secretly just a python program with one
job: populating the BuildmasterConfig dictionary. And python programs
are allowed to define as many classes as they like. So you can define
classes and use them in the same file, just as long as the class is
defined before some other code tries to use it.

This is easy, and it keeps the point of definition very close to the
point of use, and whoever replaces you after that unfortunate
hang-gliding accident will appreciate being able to easily figure out
what the heck this stupid "Framboozle" step is doing anyways. The
downside is that every time you reload the config file, the Framboozle
class will get redefined, which means that the buildmaster will think
that you've reconfigured all the Builders that use it, even though
nothing changed. Bleh.

Option 2: Instead, we can put this code in a separate file, and import
it into the master.cfg file just like we would the normal buildsteps
like ShellCommand and SVN.

Create a directory named ~/lib/python, put everything from START to
FINISH in ~/lib/python/framboozle.py, and run your buildmaster using:

@example
 PYTHONPATH=~/lib/python buildbot start MASTERDIR
@end example

or use the @file{Makefile.buildbot} to control the way
@command{buildbot start} works. Or add something like this to
something like your ~/.bashrc or ~/.bash_profile or ~/.cshrc:

@example
 export PYTHONPATH=~/lib/python
@end example

Once we've done this, our master.cfg can look like:

@example
from framboozle import Framboozle
f = BuildFactory()
f.addStep(SVN(svnurl="stuff"))
f.addStep(Framboozle())
@end example

or:

@example
import framboozle
f = BuildFactory()
f.addStep(SVN(svnurl="stuff"))
f.addStep(framboozle.Framboozle())
@end example

(check out the python docs for details about how "import" and "from A
import B" work).

What we've done here is to tell python that every time it handles an
"import" statement for some named module, it should look in our
~/lib/python/ for that module before it looks anywhere else. After our
directories, it will try in a bunch of standard directories too
(including the one where buildbot is installed). By setting the
PYTHONPATH environment variable, you can add directories to the front
of this search list.

Python knows that once it "import"s a file, it doesn't need to
re-import it again. This means that reconfiguring the buildmaster
(with "buildbot reconfig", for example) won't make it think the
Framboozle class has changed every time, so the Builders that use it
will not be spuriously restarted. On the other hand, you either have
to start your buildmaster in a slightly weird way, or you have to
modify your environment to set the PYTHONPATH variable.


Option 3: Install this code into a standard python library directory

Find out what your python's standard include path is by asking it:

@example
80:warner@@luther% python
Python 2.4.4c0 (#2, Oct  2 2006, 00:57:46)
[GCC 4.1.2 20060928 (prerelease) (Debian 4.1.1-15)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> import pprint
>>> pprint.pprint(sys.path)
['',
 '/usr/lib/python24.zip',
 '/usr/lib/python2.4',
 '/usr/lib/python2.4/plat-linux2',
 '/usr/lib/python2.4/lib-tk',
 '/usr/lib/python2.4/lib-dynload',
 '/usr/local/lib/python2.4/site-packages',
 '/usr/lib/python2.4/site-packages',
 '/usr/lib/python2.4/site-packages/Numeric',
 '/var/lib/python-support/python2.4',
 '/usr/lib/site-python']
@end example

In this case, putting the code into
/usr/local/lib/python2.4/site-packages/framboozle.py would work just
fine. We can use the same master.cfg "import framboozle" statement as
in Option 2. By putting it in a standard include directory (instead of
the decidedly non-standard ~/lib/python), we don't even have to set
PYTHONPATH to anything special. The downside is that you probably have
to be root to write to one of those standard include directories.


Option 4: Submit the code for inclusion in the Buildbot distribution

Make a fork of buildbot on http://github.com/djmitche/buildbot or post a patch
in a bug at http://buildbot.net.  In either case, post a note about your patch
to the mailing list, so others can provide feedback and, eventually, commit it.

@example
from buildbot.steps import framboozle
f = BuildFactory()
f.addStep(SVN(svnurl="stuff"))
f.addStep(framboozle.Framboozle())
@end example

And then you don't even have to install framboozle.py anywhere on your
system, since it will ship with Buildbot. You don't have to be root,
you don't have to set PYTHONPATH. But you do have to make a good case
for Framboozle being worth going into the main distribution, you'll
probably have to provide docs and some unit test cases, you'll need to
figure out what kind of beer the author likes, and then you'll have to
wait until the next release. But in some environments, all this is
easier than getting root on your buildmaster box, so the tradeoffs may
actually be worth it.



Putting the code in master.cfg (1) makes it available to that
buildmaster instance. Putting it in a file in a personal library
directory (2) makes it available for any buildmasters you might be
running. Putting it in a file in a system-wide shared library
directory (3) makes it available for any buildmasters that anyone on
that system might be running. Getting it into the buildbot's upstream
repository (4) makes it available for any buildmasters that anyone in
the world might be running. It's all a matter of how widely you want
to deploy that new class.



@node BuildStep URLs,  , Adding LogObservers, Writing New BuildSteps
@subsubsection BuildStep URLs

@cindex links
@cindex BuildStep URLs
@cindex addURL

Each BuildStep has a collection of ``links''. Like its collection of
LogFiles, each link has a name and a target URL. The web status page
creates HREFs for each link in the same box as it does for LogFiles,
except that the target of the link is the external URL instead of an
internal link to a page that shows the contents of the LogFile.

These external links can be used to point at build information hosted
on other servers. For example, the test process might produce an
intricate description of which tests passed and failed, or some sort
of code coverage data in HTML form, or a PNG or GIF image with a graph
of memory usage over time. The external link can provide an easy way
for users to navigate from the buildbot's status page to these
external web sites or file servers. Note that the step itself is
responsible for insuring that there will be a document available at
the given URL (perhaps by using @command{scp} to copy the HTML output
to a @file{~/public_html/} directory on a remote web server). Calling
@code{addURL} does not magically populate a web server.

To set one of these links, the BuildStep should call the @code{addURL}
method with the name of the link and the target URL. Multiple URLs can
be set.

In this example, we assume that the @command{make test} command causes
a collection of HTML files to be created and put somewhere on the
coverage.example.org web server, in a filename that incorporates the
build number.

@example
class TestWithCodeCoverage(BuildStep):
    command = ["make", "test",
               WithProperties("buildnum=%s" % "buildnumber")]

    def createSummary(self, log):
        buildnumber = self.getProperty("buildnumber")
        url = "http://coverage.example.org/builds/%s.html" % buildnumber
        self.addURL("coverage", url)
@end example

You might also want to extract the URL from some special message
output by the build process itself:

@example
class TestWithCodeCoverage(BuildStep):
    command = ["make", "test",
               WithProperties("buildnum=%s" % "buildnumber")]

    def createSummary(self, log):
        output = StringIO(log.getText())
        for line in output.readlines():
            if line.startswith("coverage-url:"):
                url = line[len("coverage-url:"):].strip()
                self.addURL("coverage", url)
                return
@end example

Note that a build process which emits both stdout and stderr might
cause this line to be split or interleaved between other lines. It
might be necessary to restrict the getText() call to only stdout with
something like this:

@example
        output = StringIO("".join([c[1]
                                   for c in log.getChunks()
                                   if c[0] == LOG_CHANNEL_STDOUT]))
@end example

Of course if the build is run under a PTY, then stdout and stderr will
be merged before the buildbot ever sees them, so such interleaving
will be unavoidable.


@node Interlocks, Build Factories, Build Steps, Build Process
@section Interlocks

@cindex locks
@slindex buildbot.locks.MasterLock
@slindex buildbot.locks.SlaveLock
@slindex buildbot.locks.LockAccess

Until now, we assumed that a master can run builds at any slave whenever
needed or desired.  Some times, you want to enforce additional constraints on
builds. For reasons like limited network bandwidth, old slave machines, or a
self-willed data base server, you may want to limit the number of builds (or
build steps) that can access a resource.

The mechanism used by Buildbot is known as the read/write lock.@footnote{See
http://en.wikipedia.org/wiki/Read/write_lock_pattern for more information.} It
allows either many readers or a single writer but not a combination of readers
and writers. The general lock has been modified and extended for use in
Buildbot. Firstly, the general lock allows an infinite number of readers. In
Buildbot, we often want to put an upper limit on the number of readers, for
example allowing two out of five possible builds at the same time. To do this,
the lock counts the number of active readers. Secondly, the terms @emph{read
mode} and @emph{write mode} are confusing in Buildbot context. They have been
replaced by @emph{counting mode} (since the lock counts them) and @emph{exclusive
mode}.  As a result of these changes, locks in Buildbot allow a number of
builds (upto some fixed number) in counting mode, or they allow one build in
exclusive mode.

Often, not all slaves are equal. To allow for this situation, Buildbot allows
to have a separate upper limit on the count for each slave. In this way, you
can have at most 3 concurrent builds at a fast slave, 2 at a slightly older
slave, and 1 at all other slaves.

The final thing you can specify when you introduce a new lock is its scope.
Some constraints are global -- they must be enforced over all slaves. Other
constraints are local to each slave.  A @emph{master lock} is used for the
global constraints. You can ensure for example that at most one build (of all
builds running at all slaves) accesses the data base server. With a
@emph{slave lock} you can add a limit local to each slave. With such a lock,
you can for example enforce an upper limit to the number of active builds at a
slave, like above.

Time for a few examples. Below a master lock is defined to protect a data base,
and a slave lock is created to limit the number of builds at each slave.

@example
from buildbot import locks

db_lock = locks.MasterLock("database")
build_lock = locks.SlaveLock("slave_builds",
                             maxCount = 1,
                             maxCountForSlave = @{ 'fast': 3, 'new': 2 @})
@end example

After importing locks from buildbot, @code{db_lock} is defined to be a master
lock. The @code{"database"} string is used for uniquely identifying the lock.
At the next line, a slave lock called @code{build_lock} is created. It is
identified by the @code{"slave_builds"} string. Since the requirements of the
lock are a bit more complicated, two optional arguments are also specified. The
@code{maxCount} parameter sets the default limit for builds in counting mode to
@code{1}. For the slave called @code{'fast'} however, we want to have at most
three builds, and for the slave called @code{'new'} the upper limit is two
builds running at the same time.

The next step is using the locks in builds.  Buildbot allows a lock to be used
during an entire build (from beginning to end), or only during a single build
step. In the latter case, the lock is claimed for use just before the step
starts, and released again when the step ends. To prevent
deadlocks,@footnote{Deadlock is the situation where two or more slaves each
hold a lock in exclusive mode, and in addition want to claim the lock held by
the other slave exclusively as well. Since locks allow at most one exclusive
user, both slaves will wait forever.} it is not possible to claim or release
locks at other times.

To use locks, you should add them with a @code{locks} argument.
Each use of a lock is either in counting mode (that is, possibly shared with
other builds) or in exclusive mode. A build or build step proceeds only when it
has acquired all locks. If a build or step needs a lot of locks, it may be
starved@footnote{Starving is the situation that only a few locks are available,
and they are immediately grabbed by another build. As a result, it may take a
long time before all locks needed by the starved build are free at the same
time.} by other builds that need fewer locks.

To illustrate use of locks, a few examples.

@example
from buildbot import locks
from buildbot.steps import source, shell
from buildbot.process import factory

db_lock = locks.MasterLock("database")
build_lock = locks.SlaveLock("slave_builds",
                             maxCount = 1,
                             maxCountForSlave = @{ 'fast': 3, 'new': 2 @})

f = factory.BuildFactory()
f.addStep(source.SVN(svnurl="http://example.org/svn/Trunk"))
f.addStep(shell.ShellCommand(command="make all"))
f.addStep(shell.ShellCommand(command="make test",
                             locks=[db_lock.access('exclusive')]))

b1 = @{'name': 'full1', 'slavename': 'fast',  'builddir': 'f1', 'factory': f,
       'locks': [build_lock.access('counting')] @}

b2 = @{'name': 'full2', 'slavename': 'new',   'builddir': 'f2', 'factory': f.
       'locks': [build_lock.access('counting')] @}

b3 = @{'name': 'full3', 'slavename': 'old',   'builddir': 'f3', 'factory': f.
       'locks': [build_lock.access('counting')] @}

b4 = @{'name': 'full4', 'slavename': 'other', 'builddir': 'f4', 'factory': f.
       'locks': [build_lock.access('counting')] @}

c['builders'] = [b1, b2, b3, b4]
@end example

Here we have four slaves @code{b1}, @code{b2}, @code{b3}, and @code{b4}. Each
slave performs the same checkout, make, and test build step sequence.
We want to enforce that at most one test step is executed between all slaves due
to restrictions with the data base server. This is done by adding the
@code{locks=} parameter with the third step. It takes a list of locks with their
access mode. In this case only the @code{db_lock} is needed. The exclusive
access mode is used to ensure there is at most one slave that executes the test
step.

In addition to exclusive accessing the data base, we also want slaves to stay
responsive even under the load of a large number of builds being triggered.
For this purpose, the slave lock called @code{build_lock} is defined. Since
the restraint holds for entire builds, the lock is specified in the builder
with @code{'locks': [build_lock.access('counting')]}.
@node Build Factories,  , Interlocks, Build Process
@section Build Factories


Each Builder is equipped with a ``build factory'', which is
responsible for producing the actual @code{Build} objects that perform
each build. This factory is created in the configuration file, and
attached to a Builder through the @code{factory} element of its
dictionary.

The standard @code{BuildFactory} object creates @code{Build} objects
by default. These Builds will each execute a collection of BuildSteps
in a fixed sequence. Each step can affect the results of the build,
but in general there is little intelligence to tie the different steps
together. You can create subclasses of @code{Build} to implement more
sophisticated build processes, and then use a subclass of
@code{BuildFactory} (or simply set the @code{buildClass} attribute) to
create instances of your new Build subclass.


@menu
* BuildStep Objects::
* BuildFactory::
* Process-Specific build factories::
@end menu

@node BuildStep Objects, BuildFactory, Build Factories, Build Factories
@subsection BuildStep Objects

The steps used by these builds are all subclasses of @code{BuildStep}.
The standard ones provided with Buildbot are documented later,
@xref{Build Steps}. You can also write your own subclasses to use in
builds.

The basic behavior for a @code{BuildStep} is to:

@itemize @bullet
@item
run for a while, then stop
@item
possibly invoke some RemoteCommands on the attached build slave
@item
possibly produce a set of log files
@item
finish with a status described by one of four values defined in
buildbot.status.builder: SUCCESS, WARNINGS, FAILURE, SKIPPED
@item
provide a list of short strings to describe the step
@item
define a color (generally green, orange, or red) with which the
step should be displayed
@end itemize


More sophisticated steps may produce additional information and
provide it to later build steps, or store it in the factory to provide
to later builds.


@menu
* BuildFactory Attributes::
* Quick builds::
@end menu

@node BuildFactory, Process-Specific build factories, BuildStep Objects, Build Factories
@subsection BuildFactory

@bfindex buildbot.process.factory.BuildFactory
@bfindex buildbot.process.factory.BasicBuildFactory
@c TODO: what is BasicSVN anyway?
@bfindex buildbot.process.factory.BasicSVN

The default @code{BuildFactory}, provided in the
@code{buildbot.process.factory} module, contains an internal list of
``BuildStep specifications'': a list of @code{(step_class, kwargs)}
tuples for each. These specification tuples are constructed when the
config file is read, by asking the instances passed to @code{addStep}
for their subclass and arguments.

When asked to create a Build, the @code{BuildFactory} puts a copy of
the list of step specifications into the new Build object. When the
Build is actually started, these step specifications are used to
create the actual set of BuildSteps, which are then executed one at a
time. This serves to give each Build an independent copy of each step.
For example, a build which consists of a CVS checkout followed by a
@code{make build} would be constructed as follows:

@example
from buildbot.steps import source, shell
from buildbot.process import factory

f = factory.BuildFactory()
f.addStep(source.CVS(cvsroot=CVSROOT, cvsmodule="project", mode="update"))
f.addStep(shell.Compile(command=["make", "build"]))
@end example

(To support config files from buildbot-0.7.5 and earlier,
@code{addStep} also accepts the @code{f.addStep(shell.Compile,
command=["make","build"])} form, although its use is discouraged
because then the @code{Compile} step doesn't get to validate or
complain about its arguments until build time. The modern
pass-by-instance approach allows this validation to occur while the
config file is being loaded, where the admin has a better chance of
noticing problems).

It is also possible to pass a list of steps into the
@code{BuildFactory} when it is created. Using @code{addStep} is
usually simpler, but there are cases where is is more convenient to
create the list of steps ahead of time.:

@example
from buildbot.steps import source, shell
from buildbot.process import factory

all_steps = [source.CVS(cvsroot=CVSROOT, cvsmodule="project", mode="update"),
             shell.Compile(command=["make", "build"]),
            ]
f = factory.BuildFactory(all_steps)
@end example


Each step can affect the build process in the following ways:

@itemize @bullet
@item
If the step's @code{haltOnFailure} attribute is True, then a failure
in the step (i.e. if it completes with a result of FAILURE) will cause
the whole build to be terminated immediately: no further steps will be
executed, with the exception of steps with @code{alwaysRun} set to
True. @code{haltOnFailure} is useful for setup steps upon which the
rest of the build depends: if the CVS checkout or @code{./configure}
process fails, there is no point in trying to compile or test the
resulting tree.

@item
If the step's @code{alwaysRun} attribute is True, then it will always
be run, regardless of if previous steps have failed. This is useful
for cleanup steps that should always be run to return the build
directory or build slave into a good state.

@item
If the @code{flunkOnFailure} or @code{flunkOnWarnings} flag is set,
then a result of FAILURE or WARNINGS will mark the build as a whole as
FAILED. However, the remaining steps will still be executed. This is
appropriate for things like multiple testing steps: a failure in any
one of them will indicate that the build has failed, however it is
still useful to run them all to completion.

@item
Similarly, if the @code{warnOnFailure} or @code{warnOnWarnings} flag
is set, then a result of FAILURE or WARNINGS will mark the build as
having WARNINGS, and the remaining steps will still be executed. This
may be appropriate for certain kinds of optional build or test steps.
For example, a failure experienced while building documentation files
should be made visible with a WARNINGS result but not be serious
enough to warrant marking the whole build with a FAILURE.

@end itemize

In addition, each Step produces its own results, may create logfiles,
etc. However only the flags described above have any effect on the
build as a whole.

The pre-defined BuildSteps like @code{CVS} and @code{Compile} have
reasonably appropriate flags set on them already. For example, without
a source tree there is no point in continuing the build, so the
@code{CVS} class has the @code{haltOnFailure} flag set to True. Look
in @file{buildbot/steps/*.py} to see how the other Steps are
marked.

Each Step is created with an additional @code{workdir} argument that
indicates where its actions should take place. This is specified as a
subdirectory of the slave builder's base directory, with a default
value of @code{build}. This is only implemented as a step argument (as
opposed to simply being a part of the base directory) because the
CVS/SVN steps need to perform their checkouts from the parent
directory.

@menu
* BuildFactory Attributes::
* Quick builds::
@end menu

@node BuildFactory Attributes, Quick builds, BuildFactory, BuildFactory
@subsubsection BuildFactory Attributes

Some attributes from the BuildFactory are copied into each Build.

@cindex treeStableTimer

@table @code
@item useProgress
(defaults to True): if True, the buildmaster keeps track of how long
each step takes, so it can provide estimates of how long future builds
will take. If builds are not expected to take a consistent amount of
time (such as incremental builds in which a random set of files are
recompiled or tested each time), this should be set to False to
inhibit progress-tracking.

@end table


@node Quick builds,  , BuildFactory Attributes, BuildFactory
@subsubsection Quick builds

@bfindex buildbot.process.factory.QuickBuildFactory

The difference between a ``full build'' and a ``quick build'' is that
quick builds are generally done incrementally, starting with the tree
where the previous build was performed. That simply means that the
source-checkout step should be given a @code{mode='update'} flag, to
do the source update in-place.

In addition to that, the @code{useProgress} flag should be set to
False. Incremental builds will (or at least the ought to) compile as
few files as necessary, so they will take an unpredictable amount of
time to run. Therefore it would be misleading to claim to predict how
long the build will take.


@node Process-Specific build factories,  , BuildFactory, Build Factories
@subsection Process-Specific build factories

Many projects use one of a few popular build frameworks to simplify
the creation and maintenance of Makefiles or other compilation
structures. Buildbot provides several pre-configured BuildFactory
subclasses which let you build these projects with a minimum of fuss.

@menu
* GNUAutoconf::
* CPAN::
* Python distutils::
* Python/Twisted/trial projects::
@end menu

@node GNUAutoconf, CPAN, Process-Specific build factories, Process-Specific build factories
@subsubsection GNUAutoconf

@bfindex buildbot.process.factory.GNUAutoconf

@uref{http://www.gnu.org/software/autoconf/, GNU Autoconf} is a
software portability tool, intended to make it possible to write
programs in C (and other languages) which will run on a variety of
UNIX-like systems. Most GNU software is built using autoconf. It is
frequently used in combination with GNU automake. These tools both
encourage a build process which usually looks like this:

@example
% CONFIG_ENV=foo ./configure --with-flags
% make all
% make check
# make install
@end example

(except of course the Buildbot always skips the @code{make install}
part).

The Buildbot's @code{buildbot.process.factory.GNUAutoconf} factory is
designed to build projects which use GNU autoconf and/or automake. The
configuration environment variables, the configure flags, and command
lines used for the compile and test are all configurable, in general
the default values will be suitable.

Example:

@example
# use the s() convenience function defined earlier
f = factory.GNUAutoconf(source=s(step.SVN, svnurl=URL, mode="copy"),
                        flags=["--disable-nls"])
@end example

Required Arguments:

@table @code
@item source
This argument must be a step specification tuple that provides a
BuildStep to generate the source tree.
@end table

Optional Arguments:

@table @code
@item configure
The command used to configure the tree. Defaults to
@code{./configure}. Accepts either a string or a list of shell argv
elements.

@item configureEnv
The environment used for the initial configuration step. This accepts
a dictionary which will be merged into the buildslave's normal
environment. This is commonly used to provide things like
@code{CFLAGS="-O2 -g"} (to turn off debug symbols during the compile).
Defaults to an empty dictionary.

@item configureFlags
A list of flags to be appended to the argument list of the configure
command. This is commonly used to enable or disable specific features
of the autoconf-controlled package, like @code{["--without-x"]} to
disable windowing support. Defaults to an empty list.

@item compile
this is a shell command or list of argv values which is used to
actually compile the tree. It defaults to @code{make all}. If set to
None, the compile step is skipped.

@item test
this is a shell command or list of argv values which is used to run
the tree's self-tests. It defaults to @code{make check}. If set to
None, the test step is skipped.

@end table


@node CPAN, Python distutils, GNUAutoconf, Process-Specific build factories
@subsubsection CPAN

@bfindex buildbot.process.factory.CPAN

Most Perl modules available from the @uref{http://www.cpan.org/, CPAN}
archive use the @code{MakeMaker} module to provide configuration,
build, and test services. The standard build routine for these modules
looks like:

@example
% perl Makefile.PL
% make
% make test
# make install
@end example

(except again Buildbot skips the install step)

Buildbot provides a @code{CPAN} factory to compile and test these
projects.


Arguments:
@table @code
@item source
(required): A step specification tuple, like that used by GNUAutoconf.

@item perl
A string which specifies the @code{perl} executable to use. Defaults
to just @code{perl}.

@end table


@node Python distutils, Python/Twisted/trial projects, CPAN, Process-Specific build factories
@subsubsection Python distutils

@bfindex buildbot.process.factory.Distutils

Most Python modules use the @code{distutils} package to provide
configuration and build services. The standard build process looks
like:

@example
% python ./setup.py build
% python ./setup.py install
@end example

Unfortunately, although Python provides a standard unit-test framework
named @code{unittest}, to the best of my knowledge @code{distutils}
does not provide a standardized target to run such unit tests. (Please
let me know if I'm wrong, and I will update this factory.)

The @code{Distutils} factory provides support for running the build
part of this process. It accepts the same @code{source=} parameter as
the other build factories.


Arguments:
@table @code
@item source
(required): A step specification tuple, like that used by GNUAutoconf.

@item python
A string which specifies the @code{python} executable to use. Defaults
to just @code{python}.

@item test
Provides a shell command which runs unit tests. This accepts either a
string or a list. The default value is None, which disables the test
step (since there is no common default command to run unit tests in
distutils modules).

@end table


@node Python/Twisted/trial projects,  , Python distutils, Process-Specific build factories
@subsubsection Python/Twisted/trial projects

@bfindex buildbot.process.factory.Trial
@c TODO: document these steps better
@bsindex buildbot.steps.python_twisted.HLint
@bsindex buildbot.steps.python_twisted.Trial
@bsindex buildbot.steps.python_twisted.ProcessDocs
@bsindex buildbot.steps.python_twisted.BuildDebs
@bsindex buildbot.steps.python_twisted.RemovePYCs

Twisted provides a unit test tool named @code{trial} which provides a
few improvements over Python's built-in @code{unittest} module. Many
python projects which use Twisted for their networking or application
services also use trial for their unit tests. These modules are
usually built and tested with something like the following:

@example
% python ./setup.py build
% PYTHONPATH=build/lib.linux-i686-2.3 trial -v PROJECTNAME.test
% python ./setup.py install
@end example

Unfortunately, the @file{build/lib} directory into which the
built/copied .py files are placed is actually architecture-dependent,
and I do not yet know of a simple way to calculate its value. For many
projects it is sufficient to import their libraries ``in place'' from
the tree's base directory (@code{PYTHONPATH=.}).

In addition, the @var{PROJECTNAME} value where the test files are
located is project-dependent: it is usually just the project's
top-level library directory, as common practice suggests the unit test
files are put in the @code{test} sub-module. This value cannot be
guessed, the @code{Trial} class must be told where to find the test
files.

The @code{Trial} class provides support for building and testing
projects which use distutils and trial. If the test module name is
specified, trial will be invoked. The library path used for testing
can also be set.

One advantage of trial is that the Buildbot happens to know how to
parse trial output, letting it identify which tests passed and which
ones failed. The Buildbot can then provide fine-grained reports about
how many tests have failed, when individual tests fail when they had
been passing previously, etc.

Another feature of trial is that you can give it a series of source
.py files, and it will search them for special @code{test-case-name}
tags that indicate which test cases provide coverage for that file.
Trial can then run just the appropriate tests. This is useful for
quick builds, where you want to only run the test cases that cover the
changed functionality.

Arguments:
@table @code
@item source
(required): A step specification tuple, like that used by GNUAutoconf.

@item buildpython
A list (argv array) of strings which specifies the @code{python}
executable to use when building the package. Defaults to just
@code{['python']}. It may be useful to add flags here, to supress
warnings during compilation of extension modules. This list is
extended with @code{['./setup.py', 'build']} and then executed in a
ShellCommand.

@item testpath
Provides a directory to add to @code{PYTHONPATH} when running the unit
tests, if tests are being run. Defaults to @code{.} to include the
project files in-place. The generated build library is frequently
architecture-dependent, but may simply be @file{build/lib} for
pure-python modules.

@item trialpython
Another list of strings used to build the command that actually runs
trial. This is prepended to the contents of the @code{trial} argument
below. It may be useful to add @code{-W} flags here to supress
warnings that occur while tests are being run. Defaults to an empty
list, meaning @code{trial} will be run without an explicit
interpreter, which is generally what you want if you're using
@file{/usr/bin/trial} instead of, say, the @file{./bin/trial} that
lives in the Twisted source tree.

@item trial
provides the name of the @code{trial} command. It is occasionally
useful to use an alternate executable, such as @code{trial2.2} which
might run the tests under an older version of Python. Defaults to
@code{trial}.

@item tests
Provides a module name or names which contain the unit tests for this
project. Accepts a string, typically @code{PROJECTNAME.test}, or a
list of strings. Defaults to None, indicating that no tests should be
run. You must either set this or @code{useTestCaseNames} to do anyting
useful with the Trial factory.

@item useTestCaseNames
Tells the Step to provide the names of all changed .py files to trial,
so it can look for test-case-name tags and run just the matching test
cases. Suitable for use in quick builds. Defaults to False.

@item randomly
If @code{True}, tells Trial (with the @code{--random=0} argument) to
run the test cases in random order, which sometimes catches subtle
inter-test dependency bugs. Defaults to @code{False}.

@item recurse
If @code{True}, tells Trial (with the @code{--recurse} argument) to
look in all subdirectories for additional test cases. It isn't clear
to me how this works, but it may be useful to deal with the
unknown-PROJECTNAME problem described above, and is currently used in
the Twisted buildbot to accomodate the fact that test cases are now
distributed through multiple twisted.SUBPROJECT.test directories.

@end table

Unless one of @code{trialModule} or @code{useTestCaseNames}
are set, no tests will be run.

Some quick examples follow. Most of these examples assume that the
target python code (the ``code under test'') can be reached directly
from the root of the target tree, rather than being in a @file{lib/}
subdirectory.

@example
#  Trial(source, tests="toplevel.test") does:
#   python ./setup.py build
#   PYTHONPATH=. trial -to toplevel.test

#  Trial(source, tests=["toplevel.test", "other.test"]) does:
#   python ./setup.py build
#   PYTHONPATH=. trial -to toplevel.test other.test

#  Trial(source, useTestCaseNames=True) does:
#   python ./setup.py build
#   PYTHONPATH=. trial -to --testmodule=foo/bar.py..  (from Changes)

#  Trial(source, buildpython=["python2.3", "-Wall"], tests="foo.tests"):
#   python2.3 -Wall ./setup.py build
#   PYTHONPATH=. trial -to foo.tests

#  Trial(source, trialpython="python2.3", trial="/usr/bin/trial",
#        tests="foo.tests") does:
#   python2.3 -Wall ./setup.py build
#   PYTHONPATH=. python2.3 /usr/bin/trial -to foo.tests

# For running trial out of the tree being tested (only useful when the
# tree being built is Twisted itself):
#  Trial(source, trialpython=["python2.3", "-Wall"], trial="./bin/trial",
#        tests="foo.tests") does:
#   python2.3 -Wall ./setup.py build
#   PYTHONPATH=. python2.3 -Wall ./bin/trial -to foo.tests
@end example

If the output directory of @code{./setup.py build} is known, you can
pull the python code from the built location instead of the source
directories. This should be able to handle variations in where the
source comes from, as well as accomodating binary extension modules:

@example
# Trial(source,tests="toplevel.test",testpath='build/lib.linux-i686-2.3')
# does:
#  python ./setup.py build
#  PYTHONPATH=build/lib.linux-i686-2.3 trial -to toplevel.test
@end example


@node Status Delivery, Command-line tool, Build Process, Top
@chapter Status Delivery

More details are available in the docstrings for each class, use a
command like @code{pydoc buildbot.status.html.WebStatus} to see them.
Most status delivery objects take a @code{categories=} argument, which
can contain a list of ``category'' names: in this case, it will only
show status for Builders that are in one of the named categories.

(implementor's note: each of these objects should be a
service.MultiService which will be attached to the BuildMaster object
when the configuration is processed. They should use
@code{self.parent.getStatus()} to get access to the top-level IStatus
object, either inside @code{startService} or later. They may call
@code{status.subscribe()} in @code{startService} to receive
notifications of builder events, in which case they must define
@code{builderAdded} and related methods. See the docstrings in
@file{buildbot/interfaces.py} for full details.)

@menu
* WebStatus::
* MailNotifier::
* IRC Bot::
* PBListener::
* Writing New Status Plugins::
@end menu

@c @node Email Delivery,  , Status Delivery, Status Delivery
@c @subsection Email Delivery

@c DOCUMENT THIS


@node WebStatus, MailNotifier, Status Delivery, Status Delivery
@section WebStatus

@cindex WebStatus
@stindex buildbot.status.web.baseweb.WebStatus

The @code{buildbot.status.html.WebStatus} status target runs a small
web server inside the buildmaster. You can point a browser at this web
server and retrieve information about every build the buildbot knows
about, as well as find out what the buildbot is currently working on.

The first page you will see is the ``Welcome Page'', which contains
links to all the other useful pages. This page is simply served from
the @file{public_html/index.html} file in the buildmaster's base
directory, where it is created by the @command{buildbot create-master}
command along with the rest of the buildmaster.

The most complex resource provided by @code{WebStatus} is the
``Waterfall Display'', which shows a time-based chart of events. This
somewhat-busy display provides detailed information about all steps of
all recent builds, and provides hyperlinks to look at individual build
logs and source changes. By simply reloading this page on a regular
basis, you will see a complete description of everything the buildbot
is currently working on.

There are also pages with more specialized information. For example,
there is a page which shows the last 20 builds performed by the
buildbot, one line each. Each line is a link to detailed information
about that build. By adding query arguments to the URL used to reach
this page, you can narrow the display to builds that involved certain
branches, or which ran on certain Builders. These pages are described
in great detail below.


When the buildmaster is created, a subdirectory named
@file{public_html/} is created in its base directory. By default, @code{WebStatus}
will serve files from this directory: for example, when a user points
their browser at the buildbot's @code{WebStatus} URL, they will see
the contents of the @file{public_html/index.html} file. Likewise,
@file{public_html/robots.txt}, @file{public_html/buildbot.css}, and
@file{public_html/favicon.ico} are all useful things to have in there.
The first time a buildmaster is created, the @file{public_html}
directory is populated with some sample files, which you will probably
want to customize for your own project. These files are all static:
the buildbot does not modify them in any way as it serves them to HTTP
clients.

@example
from buildbot.status.html import WebStatus
c['status'].append(WebStatus(8080))
@end example

Note that the initial robots.txt file has Disallow lines for all of
the dynamically-generated buildbot pages, to discourage web spiders
and search engines from consuming a lot of CPU time as they crawl
through the entire history of your buildbot. If you are running the
buildbot behind a reverse proxy, you'll probably need to put the
robots.txt file somewhere else (at the top level of the parent web
server), and replace the URL prefixes in it with more suitable values.

If you would like to use an alternative root directory, add the
@code{public_html=..} option to the @code{WebStatus} creation:

@example
c['status'].append(WebStatus(8080, public_html="/var/www/buildbot"))
@end example

In addition, if you are familiar with twisted.web @emph{Resource
Trees}, you can write code to add additional pages at places inside
this web space. Just use @code{webstatus.putChild} to place these
resources.

The following section describes the special URLs and the status views
they provide.


@menu
* WebStatus Configuration Parameters::
* Buildbot Web Resources::
* XMLRPC server::
* HTML Waterfall::
@end menu

@node WebStatus Configuration Parameters, Buildbot Web Resources, WebStatus, WebStatus
@subsection WebStatus Configuration Parameters

The most common way to run a @code{WebStatus} is on a regular TCP
port. To do this, just pass in the TCP port number when you create the
@code{WebStatus} instance; this is called the @code{http_port} argument:

@example
from buildbot.status.html import WebStatus
c['status'].append(WebStatus(8080))
@end example

The @code{http_port} argument is actually a ``strports specification''
for the port that the web server should listen on. This can be a
simple port number, or a string like
@code{tcp:8080:interface=127.0.0.1} (to limit connections to the
loopback interface, and therefore to clients running on the same
host)@footnote{It may even be possible to provide SSL access by using
a specification like
@code{"ssl:12345:privateKey=mykey.pen:certKey=cert.pem"}, but this is
completely untested}.

If instead (or in addition) you provide the @code{distrib_port}
argument, a twisted.web distributed server will be started either on a
TCP port (if @code{distrib_port} is like @code{"tcp:12345"}) or more
likely on a UNIX socket (if @code{distrib_port} is like
@code{"unix:/path/to/socket"}).

The @code{distrib_port} option means that, on a host with a
suitably-configured twisted-web server, you do not need to consume a
separate TCP port for the buildmaster's status web page. When the web
server is constructed with @code{mktap web --user}, URLs that point to
@code{http://host/~username/} are dispatched to a sub-server that is
listening on a UNIX socket at @code{~username/.twisted-web-pb}. On
such a system, it is convenient to create a dedicated @code{buildbot}
user, then set @code{distrib_port} to
@code{"unix:"+os.path.expanduser("~/.twistd-web-pb")}. This
configuration will make the HTML status page available at
@code{http://host/~buildbot/} . Suitable URL remapping can make it
appear at @code{http://host/buildbot/}, and the right virtual host
setup can even place it at @code{http://buildbot.host/} .

The other @code{WebStatus} argument is @code{allowForce}. If set to
True, then the web page will provide a ``Force Build'' button that
allows visitors to manually trigger builds. This is useful for
developers to re-run builds that have failed because of intermittent
problems in the test suite, or because of libraries that were not
installed at the time of the previous build. You may not wish to allow
strangers to cause a build to run: in that case, set this to False to
remove these buttons. The default value is False.



@node Buildbot Web Resources, XMLRPC server, WebStatus Configuration Parameters, WebStatus
@subsection Buildbot Web Resources

Certain URLs are ``magic'', and the pages they serve are created by
code in various classes in the @file{buildbot.status.web} package
instead of being read from disk. The most common way to access these
pages is for the buildmaster admin to write or modify the
@file{index.html} page to contain links to them. Of course other
project web pages can contain links to these buildbot pages as well.

Many pages can be modified by adding query arguments to the URL. For
example, a page which shows the results of the most recent build
normally does this for all builders at once. But by appending
``?builder=i386'' to the end of the URL, the page will show only the
results for the ``i386'' builder. When used in this way, you can add
multiple ``builder='' arguments to see multiple builders. Remembering
that URL query arguments are separated @emph{from each other} with
ampersands, a URL that ends in ``?builder=i386&builder=ppc'' would
show builds for just those two Builders.

The @code{branch=} query argument can be used on some pages. This
filters the information displayed by that page down to only the builds
or changes which involved the given branch. Use @code{branch=trunk} to
reference the trunk: if you aren't intentionally using branches,
you're probably using trunk. Multiple @code{branch=} arguments can be
used to examine multiple branches at once (so appending
@code{?branch=foo&branch=bar} to the URL will show builds involving
either branch). No @code{branch=} arguments means to show builds and
changes for all branches.

Some pages may include the Builder name or the build number in the
main part of the URL itself. For example, a page that describes Build
#7 of the ``i386'' builder would live at @file{/builders/i386/builds/7}.

The table below lists all of the internal pages and the URLs that can
be used to access them.

NOTE: of the pages described here, @code{/slave_status_timeline} and
@code{/last_build} have not yet been implemented, and @code{/xmlrpc}
has only a few methods so far. Future releases will improve this.

@table @code

@item /waterfall

This provides a chronologically-oriented display of the activity of
all builders. It is the same display used by the Waterfall display.

By adding one or more ``builder='' query arguments, the Waterfall is
restricted to only showing information about the given Builders. By
adding one or more ``branch='' query arguments, the display is
restricted to showing information about the given branches. In
addition, adding one or more ``category='' query arguments to the URL
will limit the display to Builders that were defined with one of the
given categories.

A 'show_events=true' query argument causes the display to include
non-Build events, like slaves attaching and detaching, as well as
reconfiguration events. 'show_events=false' hides these events. The
default is to show them.

The @code{last_time=}, @code{first_time=}, and @code{show_time=}
arguments will control what interval of time is displayed. The default
is to show the latest events, but these can be used to look at earlier
periods in history. The @code{num_events=} argument also provides a
limit on the size of the displayed page.

The Waterfall has references to resources many of the other portions
of the URL space: @file{/builders} for access to individual builds,
@file{/changes} for access to information about source code changes,
etc.

@item /rss

This provides a rss feed summarizing all failed builds. The same
query-arguments used by 'waterfall' can be added to filter the
feed output.

@item /atom

This provides an atom feed summarizing all failed builds. The same
query-arguments used by 'waterfall' can be added to filter the feed
output.

@item /builders/$BUILDERNAME

This describes the given Builder, and provides buttons to force a build.

@item /builders/$BUILDERNAME/builds/$BUILDNUM

This describes a specific Build.

@item /builders/$BUILDERNAME/builds/$BUILDNUM/steps/$STEPNAME

This describes a specific BuildStep.

@item /builders/$BUILDERNAME/builds/$BUILDNUM/steps/$STEPNAME/logs/$LOGNAME

This provides an HTML representation of a specific logfile.

@item /builders/$BUILDERNAME/builds/$BUILDNUM/steps/$STEPNAME/logs/$LOGNAME/text

This returns the logfile as plain text, without any HTML coloring
markup. It also removes the ``headers'', which are the lines that
describe what command was run and what the environment variable
settings were like. This maybe be useful for saving to disk and
feeding to tools like 'grep'.

@item /changes

This provides a brief description of the ChangeSource in use
(@pxref{Change Sources}).

@item /changes/NN

This shows detailed information about the numbered Change: who was the
author, what files were changed, what revision number was represented,
etc.

@item /buildslaves

This summarizes each BuildSlave, including which Builders are
configured to use it, whether the buildslave is currently connected or
not, and host information retrieved from the buildslave itself.

@item /one_line_per_build

This page shows one line of text for each build, merging information
from all Builders@footnote{Apparently this is the same way
http://buildd.debian.org displays build status}. Each line specifies
the name of the Builder, the number of the Build, what revision it
used, and a summary of the results. Successful builds are in green,
while failing builds are in red. The date and time of the build are
added to the right-hand edge of the line. The lines are ordered by
build finish timestamp.

One or more @code{builder=} or @code{branch=} arguments can be used to
restrict the list. In addition, a @code{numbuilds=} argument will
control how many lines are displayed (20 by default).

@item /one_box_per_builder

This page shows a small table, with one box for each Builder,
containing the results of the most recent Build. It does not show the
individual steps, or the current status. This is a simple summary of
buildbot status: if this page is green, then all tests are passing.

As with @code{/one_line_per_build}, this page will also honor
@code{builder=} and @code{branch=} arguments.

@item /about

This page gives a brief summary of the Buildbot itself: software
version, versions of some libraries that the Buildbot depends upon,
etc. It also contains a link to the buildbot.net home page.

@item /slave_status_timeline

(note: this page has not yet been implemented)

This provides a chronological display of configuration and operational
events: master startup/shutdown, slave connect/disconnect, and
config-file changes. When a config-file reload is abandoned because of
an error in the config file, the error is displayed on this page.

This page does not show any builds.

@item /last_build/$BUILDERNAME/status.png

This returns a PNG image that describes the results of the most recent
build, which can be referenced in an IMG tag by other pages, perhaps
from a completely different site. Use it as you would a webcounter.

@end table

There are also a set of web-status resources that are intended for use
by other programs, rather than humans.

@table @code

@item /xmlrpc

This runs an XML-RPC server which can be used to query status
information about various builds. See @ref{XMLRPC server} for more
details.

@end table

@node XMLRPC server, HTML Waterfall, Buildbot Web Resources, WebStatus
@subsection XMLRPC server

When using WebStatus, the buildbot runs an XML-RPC server at
@file{/xmlrpc} that can be used by other programs to query build
status. The following table lists the methods that can be invoked
using this interface.

@table @code
@item getAllBuildsInInterval(start, stop)

Return a list of builds that have completed after the 'start'
timestamp and before the 'stop' timestamp. This looks at all Builders.

The timestamps are integers, interpreted as standard unix timestamps
(seconds since epoch).

Each Build is returned as a tuple in the form: @code{(buildername,
buildnumber, build_end, branchname, revision, results, text)}

The buildnumber is an integer. 'build_end' is an integer (seconds
since epoch) specifying when the build finished.

The branchname is a string, which may be an empty string to indicate
None (i.e. the default branch). The revision is a string whose meaning
is specific to the VC system in use, and comes from the 'got_revision'
build property. The results are expressed as a string, one of
('success', 'warnings', 'failure', 'exception'). The text is a list of
short strings that ought to be joined by spaces and include slightly
more data about the results of the build.

@item getBuild(builder_name, build_number)

Return information about a specific build.

This returns a dictionary (aka ``struct'' in XMLRPC terms) with
complete information about the build. It does not include the contents
of the log files, but it has just about everything else.

@end table

@node HTML Waterfall,  , XMLRPC server, WebStatus
@subsection HTML Waterfall

@cindex Waterfall
@stindex buildbot.status.html.Waterfall

The @code{Waterfall} status target, deprecated as of 0.7.6, is a
subset of the regular @code{WebStatus} resource (@pxref{WebStatus}).
This section (and the @code{Waterfall} class itself) will be removed
from a future release.

@example
from buildbot.status import html
w = html.WebStatus(http_port=8080)
c['status'].append(w)
@end example



@node MailNotifier, IRC Bot, WebStatus, Status Delivery
@section MailNotifier

@cindex email
@cindex mail
@stindex buildbot.status.mail.MailNotifier

The buildbot can also send email when builds finish. The most common
use of this is to tell developers when their change has caused the
build to fail. It is also quite common to send a message to a mailing
list (usually named ``builds'' or similar) about every build.

The @code{MailNotifier} status target is used to accomplish this. You
configure it by specifying who mail should be sent to, under what
circumstances mail should be sent, and how to deliver the mail. It can
be configured to only send out mail for certain builders, and only
send messages when the build fails, or when the builder transitions
from success to failure. It can also be configured to include various
build logs in each message.


By default, the message will be sent to the Interested Users list
(@pxref{Doing Things With Users}), which includes all developers who
made changes in the build. You can add additional recipients with the
extraRecipients argument.

Each MailNotifier sends mail to a single set of recipients. To send
different kinds of mail to different recipients, use multiple
MailNotifiers.

The following simple example will send an email upon the completion of
each build, to just those developers whose Changes were included in
the build. The email contains a description of the Build, its results,
and URLs where more information can be obtained.

@example
from buildbot.status.mail import MailNotifier
mn = MailNotifier(fromaddr="buildbot@@example.org", lookup="example.org")
c['status'].append(mn)
@end example

To get a simple one-message-per-build (say, for a mailing list), use
the following form instead. This form does not send mail to individual
developers (and thus does not need the @code{lookup=} argument,
explained below), instead it only ever sends mail to the ``extra
recipients'' named in the arguments:

@example
mn = MailNotifier(fromaddr="buildbot@@example.org",
                  sendToInterestedUsers=False,
                  extraRecipients=['listaddr@@example.org'])
@end example

In some cases it is desirable to have different information then what
is provided in a standard MailNotifier message. For this purpose 
MailNotifier provides the argument customMesg (a function) which allows 
for the creation of messages with unique content.

For example it can be useful to display the last few lines of a log file 
and recent changes when a builder fails:

@example
def message(attrs):
    logLines = 10
    text = list()
    text.append("STATUS: %s" % attrs['result'].title())
    text.append("")
    text.extend([c.asText() for c in attrs['changes']])
    text.append("")
    name, url, lines = attrs['logs'][-1]
    text.append("Last %d lines of '%s':" % (logLines, name))
    text.extend(["\t%s\n" % line for line in lines[len(lines)-logLines:]])
    text.append("")
    text.append("-buildbot")
    return ("\n".join(text), 'plain')

mn = MailNotifier(fromaddr="buildbot@@example.org",
                  sendToInterestedUsers=False,
                  mode='problem',
                  extraRecipients=['listaddr@@example.org'],
                  customMesg=message)
@end example

A customMesg function takes a single dict argument (see below) and returns a 
tuple of strings. The first string is the complete text of the message and the
second is the message type ('plain' or 'html'). The 'html' type should be used
when generating an HTML message: 

@example
def message(attrs):
    logLines = 10
    text = list()
    text.append('<h4>Build status %s.</h4>' % (attrs['result'].title()))
    if attrs['changes']:
        text.append('<h4>Recent Changes:</h4>')
        text.extend([c.asHTML() for c in attrs['changes']])
    name, url, lines = attrs['logs'][-1]
    text.append('<h4>Last %d lines of "%s":</h4>' % (logLines, name))
    text.append('<p>')
    text.append('<br>'.join([line for line in lines[len(lines)-logLines:]]))
    text.append('</p>')
    text.append('<br><br>')
    text.append('Full log at: %s' % url)
    text.append('<br><br>')
    text.append('<b>-buildbot</b>')
    return ('\n'.join(text), 'html')
@end example 

@heading MailNotifier arguments

@table @code
@item fromaddr
The email address to be used in the 'From' header.

@item sendToInterestedUsers
(boolean). If True (the default), send mail to all of the Interested
Users. If False, only send mail to the extraRecipients list.

@item extraRecipients
(tuple of strings). A list of email addresses to which messages should
be sent (in addition to the InterestedUsers list, which includes any
developers who made Changes that went into this build). It is a good
idea to create a small mailing list and deliver to that, then let
subscribers come and go as they please.

@item subject
(string). A string to be used as the subject line of the message.
@code{%(builder)s} will be replaced with the name of the builder which
provoked the message.

@item mode
(string). Default to 'all'. One of:
@table @code
@item all
Send mail about all builds, bothpassing and failing
@item failing
Only send mail about builds which fail
@item problem
Only send mail about a build which failed when the previous build has passed.
If your builds usually pass, then this will only send mail when a problem
occurs.
@end table

@item builders
(list of strings). A list of builder names for which mail should be
sent. Defaults to None (send mail for all builds). Use either builders
or categories, but not both.

@item categories
(list of strings). A list of category names to serve status
information for. Defaults to None (all categories). Use either
builders or categories, but not both.

@item addLogs
(boolean). If True, include all build logs as attachments to the
messages. These can be quite large. This can also be set to a list of
log names, to send a subset of the logs. Defaults to False.

@item relayhost
(string). The host to which the outbound SMTP connection should be
made. Defaults to 'localhost'

@item lookup
(implementor of @code{IEmailLookup}). Object which provides
IEmailLookup, which is responsible for mapping User names (which come
from the VC system) into valid email addresses. If not provided, the
notifier will only be able to send mail to the addresses in the
extraRecipients list. Most of the time you can use a simple Domain
instance. As a shortcut, you can pass as string: this will be treated
as if you had provided Domain(str). For example,
lookup='twistedmatrix.com' will allow mail to be sent to all
developers whose SVN usernames match their twistedmatrix.com account
names. See buildbot/status/mail.py for more details.

@item customMesg
This is a optional function that can be used to generate a custom mail 
message. The customMesg function takes a single dict and must return a 
tuple containing the message text and type ('html' or 'plain'). Below is a list 
of availale keys in the dict passed to customMesg:

@table @code
@item builderName 
(str) Name of the builder that generated this event.
@item projectName 
(str) Name of the project.
@item mode 
(str) Mode set in MailNotifier. (failing, passing, problem).
@item result 
(str) Builder result as a string. 'success', 'warnings', 'failure', 'skipped', or 'exception'
@item buildURL 
(str) URL to build page.
@item buildbotURL 
(str) URL to buildbot main page.
@item buildText 
(str) Build text from build.getText().
@item slavename 
(str) Slavename.
@item reason 
(str) Build reason from build.getReason().
@item responsibleUsers 
(List of str) List of responsible users.
@item branch 
(str) Name of branch used. If no SourceStamp exists branch
is an empty string.
@item revision 
(str) Name of revision used. If no SourceStamp exists revision
is an empty string.
@item patch 
(str) Name of patch used. If no SourceStamp exists patch
is an empty string.
@item changes
(list of objs) List of change objects from SourceStamp. A change
object has the following useful information:
@table @code
@item who
(str) who made this change
@item revision 
(str) what VC revision is this change
@item branch 
(str) on what branch did this change occur
@item when 
(str) when did this change occur
@item files 
(list of str) what files were affected in this change
@item comments 
(str) comments reguarding the change.
@end table
The functions asText and asHTML return a list of strings with
the above information formatted. 
@item logs
(List of Tuples) List of tuples where each tuple contains the log name, log url,
and log contents as a list of strings.
@end table
@end table

@node IRC Bot, PBListener, MailNotifier, Status Delivery
@section IRC Bot

@cindex IRC
@stindex buildbot.status.words.IRC


The @code{buildbot.status.words.IRC} status target creates an IRC bot
which will attach to certain channels and be available for status
queries. It can also be asked to announce builds as they occur, or be
told to shut up.

@example
from buildbot.status import words
irc = words.IRC("irc.example.org", "botnickname",
                channels=["channel1", "channel2"],
                password="mysecretpassword",
                notify_events=@{
                  'exception': 1,
                  'successToFailure': 1,
                  'failureToSuccess': 1,
                @})
c['status'].append(irc)
@end example

Take a look at the docstring for @code{words.IRC} for more details on
configuring this service. The @code{password} argument, if provided,
will be sent to Nickserv to claim the nickname: some IRC servers will
not allow clients to send private messages until they have logged in
with a password.

To use the service, you address messages at the buildbot, either
normally (@code{botnickname: status}) or with private messages
(@code{/msg botnickname status}). The buildbot will respond in kind.

Some of the commands currently available:

@table @code

@item list builders
Emit a list of all configured builders
@item status BUILDER
Announce the status of a specific Builder: what it is doing right now.
@item status all
Announce the status of all Builders
@item watch BUILDER
If the given Builder is currently running, wait until the Build is
finished and then announce the results.
@item last BUILDER
Return the results of the last build to run on the given Builder.
@item join CHANNEL
Join the given IRC channel
@item leave CHANNEL
Leave the given IRC channel
@item notify on|off|list EVENT
Report events relating to builds.  If the command is issued as a
private message, then the report will be sent back as a private
message to the user who issued the command.  Otherwise, the report
will be sent to the channel.  Available events to be notified are:

@table @code
@item started
A build has started
@item finished
A build has finished
@item success
A build finished successfully
@item failed
A build failed
@item exception
A build generated and exception
@item xToY
The previous build was x, but this one is Y, where x and Y are each
one of success, warnings, failure, exception (except Y is
capitalized).  For example: successToFailure will notify if the
previous build was successful, but this one failed
@end table

@item help COMMAND
Describe a command. Use @code{help commands} to get a list of known
commands.
@item source
Announce the URL of the Buildbot's home page.
@item version
Announce the version of this Buildbot.
@end table

Additionally, the config file may specify default notification options
as shown in the example earlier.

If the @code{allowForce=True} option was used, some addtional commands
will be available:

@table @code
@item force build BUILDER REASON
Tell the given Builder to start a build of the latest code. The user
requesting the build and REASON are recorded in the Build status. The
buildbot will announce the build's status when it finishes.

@item stop build BUILDER REASON
Terminate any running build in the given Builder. REASON will be added
to the build status to explain why it was stopped. You might use this
if you committed a bug, corrected it right away, and don't want to
wait for the first build (which is destined to fail) to complete
before starting the second (hopefully fixed) build.
@end table

@node PBListener, Writing New Status Plugins, IRC Bot, Status Delivery
@section PBListener

@cindex PBListener
@stindex buildbot.status.client.PBListener


@example
import buildbot.status.client
pbl = buildbot.status.client.PBListener(port=int, user=str,
                                        passwd=str)
c['status'].append(pbl)
@end example

This sets up a PB listener on the given TCP port, to which a PB-based
status client can connect and retrieve status information.
@code{buildbot statusgui} (@pxref{statusgui}) is an example of such a
status client. The @code{port} argument can also be a strports
specification string.

@node Writing New Status Plugins,  , PBListener, Status Delivery
@section Writing New Status Plugins

TODO: this needs a lot more examples

Each status plugin is an object which provides the
@code{twisted.application.service.IService} interface, which creates a
tree of Services with the buildmaster at the top [not strictly true].
The status plugins are all children of an object which implements
@code{buildbot.interfaces.IStatus}, the main status object. From this
object, the plugin can retrieve anything it wants about current and
past builds. It can also subscribe to hear about new and upcoming
builds.

Status plugins which only react to human queries (like the Waterfall
display) never need to subscribe to anything: they are idle until
someone asks a question, then wake up and extract the information they
need to answer it, then they go back to sleep. Plugins which need to
act spontaneously when builds complete (like the MailNotifier plugin)
need to subscribe to hear about new builds.

If the status plugin needs to run network services (like the HTTP
server used by the Waterfall plugin), they can be attached as Service
children of the plugin itself, using the @code{IServiceCollection}
interface.



@node Command-line tool, Resources, Status Delivery, Top
@chapter Command-line tool

The @command{buildbot} command-line tool can be used to start or stop a
buildmaster or buildbot, and to interact with a running buildmaster.
Some of its subcommands are intended for buildmaster admins, while
some are for developers who are editing the code that the buildbot is
monitoring.

@menu
* Administrator Tools::
* Developer Tools::
* Other Tools::
* .buildbot config directory::
@end menu

@node Administrator Tools, Developer Tools, Command-line tool, Command-line tool
@section Administrator Tools

The following @command{buildbot} sub-commands are intended for
buildmaster administrators:

@heading create-master

This creates a new directory and populates it with files that allow it
to be used as a buildmaster's base directory.

@example
buildbot create-master BASEDIR
@end example

@heading create-slave

This creates a new directory and populates it with files that let it
be used as a buildslave's base directory. You must provide several
arguments, which are used to create the initial @file{buildbot.tac}
file.

@example
buildbot create-slave @var{BASEDIR} @var{MASTERHOST}:@var{PORT} @var{SLAVENAME} @var{PASSWORD}
@end example

@heading start

This starts a buildmaster or buildslave which was already created in
the given base directory. The daemon is launched in the background,
with events logged to a file named @file{twistd.log}.

@example
buildbot start BASEDIR
@end example

@heading stop

This terminates the daemon (either buildmaster or buildslave) running
in the given directory.

@example
buildbot stop BASEDIR
@end example

@heading sighup

This sends a SIGHUP to the buildmaster running in the given directory,
which causes it to re-read its @file{master.cfg} file.

@example
buildbot sighup BASEDIR
@end example

@node Developer Tools, Other Tools, Administrator Tools, Command-line tool
@section Developer Tools

These tools are provided for use by the developers who are working on
the code that the buildbot is monitoring.

@menu
* statuslog::
* statusgui::
* try::
@end menu

@node statuslog, statusgui, Developer Tools, Developer Tools
@subsection statuslog

@example
buildbot statuslog --master @var{MASTERHOST}:@var{PORT}
@end example

This command starts a simple text-based status client, one which just
prints out a new line each time an event occurs on the buildmaster.

The @option{--master} option provides the location of the
@code{buildbot.status.client.PBListener} status port, used to deliver
build information to realtime status clients. The option is always in
the form of a string, with hostname and port number separated by a
colon (@code{HOSTNAME:PORTNUM}). Note that this port is @emph{not} the
same as the slaveport (although a future version may allow the same
port number to be used for both purposes). If you get an error message
to the effect of ``Failure: twisted.cred.error.UnauthorizedLogin:'',
this may indicate that you are connecting to the slaveport rather than
a @code{PBListener} port.

The @option{--master} option can also be provided by the
@code{masterstatus} name in @file{.buildbot/options} (@pxref{.buildbot
config directory}).

@node statusgui, try, statuslog, Developer Tools
@subsection statusgui

@cindex statusgui

If you have set up a PBListener (@pxref{PBListener}), you will be able
to monitor your Buildbot using a simple Gtk+ application invoked with
the @code{buildbot statusgui} command:

@example
buildbot statusgui --master @var{MASTERHOST}:@var{PORT}
@end example

This command starts a simple Gtk+-based status client, which contains
a few boxes for each Builder that change color as events occur. It
uses the same @option{--master} argument as the @command{buildbot
statuslog} command (@pxref{statuslog}).

@node try,  , statusgui, Developer Tools
@subsection try

This lets a developer to ask the question ``What would happen if I
committed this patch right now?''. It runs the unit test suite (across
multiple build platforms) on the developer's current code, allowing
them to make sure they will not break the tree when they finally
commit their changes.

The @command{buildbot try} command is meant to be run from within a
developer's local tree, and starts by figuring out the base revision
of that tree (what revision was current the last time the tree was
updated), and a patch that can be applied to that revision of the tree
to make it match the developer's copy. This (revision, patch) pair is
then sent to the buildmaster, which runs a build with that
SourceStamp. If you want, the tool will emit status messages as the
builds run, and will not terminate until the first failure has been
detected (or the last success).

There is an alternate form which accepts a pre-made patch file
(typically the output of a command like 'svn diff'). This ``--diff''
form does not require a local tree to run from. See @xref{try --diff}.

For this command to work, several pieces must be in place:


@heading TryScheduler

@slindex buildbot.scheduler.Try_Jobdir
@slindex buildbot.scheduler.Try_Userpass

The buildmaster must have a @code{scheduler.Try} instance in
the config file's @code{c['schedulers']} list. This lets the
administrator control who may initiate these ``trial'' builds, which
branches are eligible for trial builds, and which Builders should be
used for them.

The @code{TryScheduler} has various means to accept build requests:
all of them enforce more security than the usual buildmaster ports do.
Any source code being built can be used to compromise the buildslave
accounts, but in general that code must be checked out from the VC
repository first, so only people with commit privileges can get
control of the buildslaves. The usual force-build control channels can
waste buildslave time but do not allow arbitrary commands to be
executed by people who don't have those commit privileges. However,
the source code patch that is provided with the trial build does not
have to go through the VC system first, so it is important to make
sure these builds cannot be abused by a non-committer to acquire as
much control over the buildslaves as a committer has. Ideally, only
developers who have commit access to the VC repository would be able
to start trial builds, but unfortunately the buildmaster does not, in
general, have access to VC system's user list.

As a result, the @code{TryScheduler} requires a bit more
configuration. There are currently two ways to set this up:

@table @strong
@item jobdir (ssh)

This approach creates a command queue directory, called the
``jobdir'', in the buildmaster's working directory. The buildmaster
admin sets the ownership and permissions of this directory to only
grant write access to the desired set of developers, all of whom must
have accounts on the machine. The @code{buildbot try} command creates
a special file containing the source stamp information and drops it in
the jobdir, just like a standard maildir. When the buildmaster notices
the new file, it unpacks the information inside and starts the builds.

The config file entries used by 'buildbot try' either specify a local
queuedir (for which write and mv are used) or a remote one (using scp
and ssh).

The advantage of this scheme is that it is quite secure, the
disadvantage is that it requires fiddling outside the buildmaster
config (to set the permissions on the jobdir correctly). If the
buildmaster machine happens to also house the VC repository, then it
can be fairly easy to keep the VC userlist in sync with the
trial-build userlist. If they are on different machines, this will be
much more of a hassle. It may also involve granting developer accounts
on a machine that would not otherwise require them.

To implement this, the buildslave invokes 'ssh -l username host
buildbot tryserver ARGS', passing the patch contents over stdin. The
arguments must include the inlet directory and the revision
information.

@item user+password (PB)

In this approach, each developer gets a username/password pair, which
are all listed in the buildmaster's configuration file. When the
developer runs @code{buildbot try}, their machine connects to the
buildmaster via PB and authenticates themselves using that username
and password, then sends a PB command to start the trial build.

The advantage of this scheme is that the entire configuration is
performed inside the buildmaster's config file. The disadvantages are
that it is less secure (while the ``cred'' authentication system does
not expose the password in plaintext over the wire, it does not offer
most of the other security properties that SSH does). In addition, the
buildmaster admin is responsible for maintaining the username/password
list, adding and deleting entries as developers come and go.

@end table


For example, to set up the ``jobdir'' style of trial build, using a
command queue directory of @file{MASTERDIR/jobdir} (and assuming that
all your project developers were members of the @code{developers} unix
group), you would first create that directory (with @command{mkdir
MASTERDIR/jobdir MASTERDIR/jobdir/new MASTERDIR/jobdir/cur
MASTERDIR/jobdir/tmp; chgrp developers MASTERDIR/jobdir
MASTERDIR/jobdir/*; chmod g+rwx,o-rwx MASTERDIR/jobdir
MASTERDIR/jobdir/*}), and then use the following scheduler in the
buildmaster's config file:

@example
from buildbot.scheduler import Try_Jobdir
s = Try_Jobdir("try1", ["full-linux", "full-netbsd", "full-OSX"],
               jobdir="jobdir")
c['schedulers'] = [s]
@end example

Note that you must create the jobdir before telling the buildmaster to
use this configuration, otherwise you will get an error. Also remember
that the buildmaster must be able to read and write to the jobdir as
well. Be sure to watch the @file{twistd.log} file (@pxref{Logfiles})
as you start using the jobdir, to make sure the buildmaster is happy
with it.

To use the username/password form of authentication, create a
@code{Try_Userpass} instance instead. It takes the same
@code{builderNames} argument as the @code{Try_Jobdir} form, but
accepts an addtional @code{port} argument (to specify the TCP port to
listen on) and a @code{userpass} list of username/password pairs to
accept. Remember to use good passwords for this: the security of the
buildslave accounts depends upon it:

@example
from buildbot.scheduler import Try_Userpass
s = Try_Userpass("try2", ["full-linux", "full-netbsd", "full-OSX"],
                 port=8031, userpass=[("alice","pw1"), ("bob", "pw2")] )
c['schedulers'] = [s]
@end example

Like most places in the buildbot, the @code{port} argument takes a
strports specification. See @code{twisted.application.strports} for
details.


@heading locating the master

The @command{try} command needs to be told how to connect to the
@code{TryScheduler}, and must know which of the authentication
approaches described above is in use by the buildmaster. You specify
the approach by using @option{--connect=ssh} or @option{--connect=pb}
(or @code{try_connect = 'ssh'} or @code{try_connect = 'pb'} in
@file{.buildbot/options}).

For the PB approach, the command must be given a @option{--master}
argument (in the form HOST:PORT) that points to TCP port that you
picked in the @code{Try_Userpass} scheduler. It also takes a
@option{--username} and @option{--passwd} pair of arguments that match
one of the entries in the buildmaster's @code{userpass} list. These
arguments can also be provided as @code{try_master},
@code{try_username}, and @code{try_password} entries in the
@file{.buildbot/options} file.

For the SSH approach, the command must be given @option{--tryhost},
@option{--username}, and optionally @option{--password} (TODO:
really?) to get to the buildmaster host. It must also be given
@option{--trydir}, which points to the inlet directory configured
above. The trydir can be relative to the user's home directory, but
most of the time you will use an explicit path like
@file{~buildbot/project/trydir}. These arguments can be provided in
@file{.buildbot/options} as @code{try_host}, @code{try_username},
@code{try_password}, and @code{try_dir}.

In addition, the SSH approach needs to connect to a PBListener status
port, so it can retrieve and report the results of the build (the PB
approach uses the existing connection to retrieve status information,
so this step is not necessary). This requires a @option{--master}
argument, or a @code{masterstatus} entry in @file{.buildbot/options},
in the form of a HOSTNAME:PORT string.


@heading choosing the Builders

A trial build is performed on multiple Builders at the same time, and
the developer gets to choose which Builders are used (limited to a set
selected by the buildmaster admin with the TryScheduler's
@code{builderNames=} argument). The set you choose will depend upon
what your goals are: if you are concerned about cross-platform
compatibility, you should use multiple Builders, one from each
platform of interest. You might use just one builder if that platform
has libraries or other facilities that allow better test coverage than
what you can accomplish on your own machine, or faster test runs.

The set of Builders to use can be specified with multiple
@option{--builder} arguments on the command line. It can also be
specified with a single @code{try_builders} option in
@file{.buildbot/options} that uses a list of strings to specify all
the Builder names:

@example
try_builders = ["full-OSX", "full-win32", "full-linux"]
@end example

@heading specifying the VC system

The @command{try} command also needs to know how to take the
developer's current tree and extract the (revision, patch)
source-stamp pair. Each VC system uses a different process, so you
start by telling the @command{try} command which VC system you are
using, with an argument like @option{--vc=cvs} or @option{--vc=tla}.
This can also be provided as @code{try_vc} in
@file{.buildbot/options}.

The following names are recognized: @code{cvs} @code{svn} @code{baz}
@code{tla} @code{hg} @code{darcs}


@heading finding the top of the tree

Some VC systems (notably CVS and SVN) track each directory
more-or-less independently, which means the @command{try} command
needs to move up to the top of the project tree before it will be able
to construct a proper full-tree patch. To accomplish this, the
@command{try} command will crawl up through the parent directories
until it finds a marker file. The default name for this marker file is
@file{.buildbot-top}, so when you are using CVS or SVN you should
@code{touch .buildbot-top} from the top of your tree before running
@command{buildbot try}. Alternatively, you can use a filename like
@file{ChangeLog} or @file{README}, since many projects put one of
these files in their top-most directory (and nowhere else). To set
this filename, use @option{--try-topfile=ChangeLog}, or set it in the
options file with @code{try_topfile = 'ChangeLog'}.

You can also manually set the top of the tree with
@option{--try-topdir=~/trees/mytree}, or @code{try_topdir =
'~/trees/mytree'}. If you use @code{try_topdir}, in a
@file{.buildbot/options} file, you will need a separate options file
for each tree you use, so it may be more convenient to use the
@code{try_topfile} approach instead.

Other VC systems which work on full projects instead of individual
directories (tla, baz, darcs, monotone, mercurial, git) do not require
@command{try} to know the top directory, so the @option{--try-topfile}
and @option{--try-topdir} arguments will be ignored.
@c is this true? I think I currently require topdirs all the time.

If the @command{try} command cannot find the top directory, it will
abort with an error message.

@heading determining the branch name

Some VC systems record the branch information in a way that ``try''
can locate it, in particular Arch (both @command{tla} and
@command{baz}). For the others, if you are using something other than
the default branch, you will have to tell the buildbot which branch
your tree is using. You can do this with either the @option{--branch}
argument, or a @option{try_branch} entry in the
@file{.buildbot/options} file.

@heading determining the revision and patch

Each VC system has a separate approach for determining the tree's base
revision and computing a patch.

@table @code

@item CVS

@command{try} pretends that the tree is up to date. It converts the
current time into a @code{-D} time specification, uses it as the base
revision, and computes the diff between the upstream tree as of that
point in time versus the current contents. This works, more or less,
but requires that the local clock be in reasonably good sync with the
repository.

@item SVN
@command{try} does a @code{svn status -u} to find the latest
repository revision number (emitted on the last line in the ``Status
against revision: NN'' message). It then performs an @code{svn diff
-rNN} to find out how your tree differs from the repository version,
and sends the resulting patch to the buildmaster. If your tree is not
up to date, this will result in the ``try'' tree being created with
the latest revision, then @emph{backwards} patches applied to bring it
``back'' to the version you actually checked out (plus your actual
code changes), but this will still result in the correct tree being
used for the build.

@item baz
@command{try} does a @code{baz tree-id} to determine the
fully-qualified version and patch identifier for the tree
(ARCHIVE/VERSION--patch-NN), and uses the VERSION--patch-NN component
as the base revision. It then does a @code{baz diff} to obtain the
patch.

@item tla
@command{try} does a @code{tla tree-version} to get the
fully-qualified version identifier (ARCHIVE/VERSION), then takes the
first line of @code{tla logs --reverse} to figure out the base
revision. Then it does @code{tla changes --diffs} to obtain the patch.

@item Darcs
@code{darcs changes --context} emits a text file that contains a list
of all patches back to and including the last tag was made. This text
file (plus the location of a repository that contains all these
patches) is sufficient to re-create the tree. Therefore the contents
of this ``context'' file @emph{are} the revision stamp for a
Darcs-controlled source tree.

So @command{try} does a @code{darcs changes --context} to determine
what your tree's base revision is, and then does a @code{darcs diff
-u} to compute the patch relative to that revision.

@item Mercurial
@code{hg identify} emits a short revision ID (basically a truncated
SHA1 hash of the current revision's contents), which is used as the
base revision. @code{hg diff} then provides the patch relative to that
revision. For @command{try} to work, your working directory must only
have patches that are available from the same remotely-available
repository that the build process' @code{step.Mercurial} will use.

@item Git
@code{git branch -v} lists all the branches available in the local
repository along with the revision ID it points to and a short summary
of the last commit. The line containing the currently checked out
branch begins with '* ' (star and space) while all the others start
with '  ' (two spaces). @command{try} scans for this line and extracts
the branch name and revision from it. Then it generates a diff against
the base revision.
@c TODO: I'm not sure if this actually works the way it's intended
@c since the extracted base revision might not actually exist in the
@c upstream repository. Perhaps we need to add a --remote option to
@c specify the remote tracking branch to generate a diff against.

@c TODO: monotone
@end table

@heading waiting for results

If you provide the @option{--wait} option (or @code{try_wait = True}
in @file{.buildbot/options}), the @command{buildbot try} command will
wait until your changes have either been proven good or bad before
exiting. Unless you use the @option{--quiet} option (or
@code{try_quiet=True}), it will emit a progress message every 60
seconds until the builds have completed.

@menu
* try --diff::
@end menu

@node try --diff,  , try, try
@subsubsection try --diff

Sometimes you might have a patch from someone else that you want to
submit to the buildbot. For example, a user may have created a patch
to fix some specific bug and sent it to you by email. You've inspected
the patch and suspect that it might do the job (and have at least
confirmed that it doesn't do anything evil). Now you want to test it
out.

One approach would be to check out a new local tree, apply the patch,
run your local tests, then use ``buildbot try'' to run the tests on
other platforms. An alternate approach is to use the @command{buildbot
try --diff} form to have the buildbot test the patch without using a
local tree.

This form takes a @option{--diff} argument which points to a file that
contains the patch you want to apply. By default this patch will be
applied to the TRUNK revision, but if you give the optional
@option{--baserev} argument, a tree of the given revision will be used
as a starting point instead of TRUNK.

You can also use @command{buildbot try --diff=-} to read the patch
from stdin.

Each patch has a ``patchlevel'' associated with it. This indicates the
number of slashes (and preceding pathnames) that should be stripped
before applying the diff. This exactly corresponds to the @option{-p}
or @option{--strip} argument to the @command{patch} utility. By
default @command{buildbot try --diff} uses a patchlevel of 0, but you
can override this with the @option{-p} argument.

When you use @option{--diff}, you do not need to use any of the other
options that relate to a local tree, specifically @option{--vc},
@option{--try-topfile}, or @option{--try-topdir}. These options will
be ignored. Of course you must still specify how to get to the
buildmaster (with @option{--connect}, @option{--tryhost}, etc).


@node Other Tools, .buildbot config directory, Developer Tools, Command-line tool
@section Other Tools

These tools are generally used by buildmaster administrators.

@menu
* sendchange::
* debugclient::
@end menu

@node sendchange, debugclient, Other Tools, Other Tools
@subsection sendchange

This command is used to tell the buildmaster about source changes. It
is intended to be used from within a commit script, installed on the
VC server. It requires that you have a PBChangeSource
(@pxref{PBChangeSource}) running in the buildmaster (by being set in
@code{c['change_source']}).


@example
buildbot sendchange --master @var{MASTERHOST}:@var{PORT} --username @var{USER} @var{FILENAMES..}
@end example

There are other (optional) arguments which can influence the
@code{Change} that gets submitted:

@table @code
@item --branch
This provides the (string) branch specifier. If omitted, it defaults
to None, indicating the ``default branch''. All files included in this
Change must be on the same branch.

@item --category
This provides the (string) category specifier. If omitted, it defaults
to None, indicating ``no category''. The category property is used
by Schedulers to filter what changes they listen to.

@item --revision_number
This provides a (numeric) revision number for the change, used for VC systems
that use numeric transaction numbers (like Subversion).

@item --revision
This provides a (string) revision specifier, for VC systems that use
strings (Arch would use something like patch-42 etc).

@item --revision_file
This provides a filename which will be opened and the contents used as
the revision specifier. This is specifically for Darcs, which uses the
output of @command{darcs changes --context} as a revision specifier.
This context file can be a couple of kilobytes long, spanning a couple
lines per patch, and would be a hassle to pass as a command-line
argument.

@item --comments
This provides the change comments as a single argument. You may want
to use @option{--logfile} instead.

@item --logfile
This instructs the tool to read the change comments from the given
file. If you use @code{-} as the filename, the tool will read the
change comments from stdin.
@end table


@node debugclient,  , sendchange, Other Tools
@subsection debugclient

@example
buildbot debugclient --master @var{MASTERHOST}:@var{PORT} --passwd @var{DEBUGPW}
@end example

This launches a small Gtk+/Glade-based debug tool, connecting to the
buildmaster's ``debug port''. This debug port shares the same port
number as the slaveport (@pxref{Setting the slaveport}), but the
@code{debugPort} is only enabled if you set a debug password in the
buildmaster's config file (@pxref{Debug options}). The
@option{--passwd} option must match the @code{c['debugPassword']}
value.

@option{--master} can also be provided in @file{.debug/options} by the
@code{master} key. @option{--passwd} can be provided by the
@code{debugPassword} key.

The @code{Connect} button must be pressed before any of the other
buttons will be active. This establishes the connection to the
buildmaster. The other sections of the tool are as follows:

@table @code
@item Reload .cfg
Forces the buildmaster to reload its @file{master.cfg} file. This is
equivalent to sending a SIGHUP to the buildmaster, but can be done
remotely through the debug port. Note that it is a good idea to be
watching the buildmaster's @file{twistd.log} as you reload the config
file, as any errors which are detected in the config file will be
announced there.

@item Rebuild .py
(not yet implemented). The idea here is to use Twisted's ``rebuild''
facilities to replace the buildmaster's running code with a new
version. Even if this worked, it would only be used by buildbot
developers.

@item poke IRC
This locates a @code{words.IRC} status target and causes it to emit a
message on all the channels to which it is currently connected. This
was used to debug a problem in which the buildmaster lost the
connection to the IRC server and did not attempt to reconnect.

@item Commit
This allows you to inject a Change, just as if a real one had been
delivered by whatever VC hook you are using. You can set the name of
the committed file and the name of the user who is doing the commit.
Optionally, you can also set a revision for the change. If the
revision you provide looks like a number, it will be sent as an
integer, otherwise it will be sent as a string.

@item Force Build
This lets you force a Builder (selected by name) to start a build of
the current source tree.

@item Currently
(obsolete). This was used to manually set the status of the given
Builder, but the status-assignment code was changed in an incompatible
way and these buttons are no longer meaningful.

@end table


@node .buildbot config directory,  , Other Tools, Command-line tool
@section .buildbot config directory

Many of the @command{buildbot} tools must be told how to contact the
buildmaster that they interact with. This specification can be
provided as a command-line argument, but most of the time it will be
easier to set them in an ``options'' file. The @command{buildbot}
command will look for a special directory named @file{.buildbot},
starting from the current directory (where the command was run) and
crawling upwards, eventually looking in the user's home directory. It
will look for a file named @file{options} in this directory, and will
evaluate it as a python script, looking for certain names to be set.
You can just put simple @code{name = 'value'} pairs in this file to
set the options.

For a description of the names used in this file, please see the
documentation for the individual @command{buildbot} sub-commands. The
following is a brief sample of what this file's contents could be.

@example
# for status-reading tools
masterstatus = 'buildbot.example.org:12345'
# for 'sendchange' or the debug port
master = 'buildbot.example.org:18990'
debugPassword = 'eiv7Po'
@end example

@table @code
@item masterstatus
Location of the @code{client.PBListener} status port, used by
@command{statuslog} and @command{statusgui}.

@item master
Location of the @code{debugPort} (for @command{debugclient}). Also the
location of the @code{pb.PBChangeSource} (for @command{sendchange}).
Usually shares the slaveport, but a future version may make it
possible to have these listen on a separate port number.

@item debugPassword
Must match the value of @code{c['debugPassword']}, used to protect the
debug port, for the @command{debugclient} command.

@item username
Provides a default username for the @command{sendchange} command.

@end table


The following options are used by the @code{buildbot try} command
(@pxref{try}):

@table @code
@item try_connect
This specifies how the ``try'' command should deliver its request to
the buildmaster. The currently accepted values are ``ssh'' and ``pb''.
@item try_builders
Which builders should be used for the ``try'' build.
@item try_vc
This specifies the version control system being used.
@item try_branch
This indicates that the current tree is on a non-trunk branch.
@item try_topdir
@item try_topfile
Use @code{try_topdir} to explicitly indicate the top of your working
tree, or @code{try_topfile} to name a file that will only be found in
that top-most directory.

@item try_host
@item try_username
@item try_dir
When try_connect is ``ssh'', the command will pay attention to
@code{try_host}, @code{try_username}, and @code{try_dir}.

@item try_username
@item try_password
@item try_master
Instead, when @code{try_connect} is ``pb'', the command will pay
attention to @code{try_username}, @code{try_password}, and
@code{try_master}.

@item try_wait
@item masterstatus
@code{try_wait} and @code{masterstatus} are used to ask the ``try''
command to wait for the requested build to complete.

@end table



@node Resources, Developer's Appendix, Command-line tool, Top
@chapter Resources

The Buildbot's home page is at @uref{http://buildbot.sourceforge.net/}

For configuration questions and general discussion, please use the
@code{buildbot-devel} mailing list. The subscription instructions and
archives are available at
@uref{http://lists.sourceforge.net/lists/listinfo/buildbot-devel}

@node Developer's Appendix, Index of Useful Classes, Resources, Top
@unnumbered Developer's Appendix

This appendix contains random notes about the implementation of the
Buildbot, and is likely to only be of use to people intending to
extend the Buildbot's internals.

The buildmaster consists of a tree of Service objects, which is shaped
as follows:

@example
BuildMaster
 ChangeMaster  (in .change_svc)
  [IChangeSource instances]
 [IScheduler instances]  (in .schedulers)
 BotMaster  (in .botmaster)
  [IBuildSlave instances]
 [IStatusTarget instances]  (in .statusTargets)
@end example

The BotMaster has a collection of Builder objects as values of its
@code{.builders} dictionary.


@node Index of Useful Classes, Index of master.cfg keys, Developer's Appendix, Top
@unnumbered Index of Useful Classes

This is a list of all user-visible classes. There are the ones that
are useful in @file{master.cfg}, the buildmaster's configuration file.
Classes that are not listed here are generally internal things that
admins are unlikely to have much use for.


@heading Change Sources
@printindex cs

@heading Schedulers and Locks
@printindex sl

@heading Build Factories
@printindex bf

@heading Build Steps
@printindex bs

@c undocumented steps
@bsindex buildbot.steps.source.Git
@bsindex buildbot.steps.maxq.MaxQ


@heading Status Targets
@printindex st

@c TODO: undocumented targets

@node Index of master.cfg keys, Index, Index of Useful Classes, Top
@unnumbered Index of master.cfg keys

This is a list of all of the significant keys in master.cfg . Recall
that master.cfg is effectively a small python program with exactly one
responsibility: create a dictionary named @code{BuildmasterConfig}.
The keys of this dictionary are listed here. The beginning of the
master.cfg file typically starts with something like:

@example
BuildmasterConfig = c = @{@}
@end example

Therefore a config key of @code{change_source} will usually appear in
master.cfg as @code{c['change_source']}.

@printindex bc


@node Index,  , Index of master.cfg keys, Top
@unnumbered Index

@printindex cp


@bye