Girocco

Petr Baudis <pasky@ucw.cz>

This is the duct tape that ties repo.or.cz together, codenamed Girocco. It is packaged here for easy re-deployment - just follow the INSTALL file for brief deployment instructions; you may hit some obstacle here or there, though, so be prepared.

Girocco is an Open Source project covered by the GNU General Public License. See the file COPYING for further details.

About Girocco

Girocco is a Git hosting solution, designed to allow users easily create and access repositories over the web, either in mirror mode (Girocco maintains a clone of the given repository locally) or in push mode (Girocco maintains a secure chroot with ssh inside for push-only access). A well-known feature is forking support, where users can easily publish modifications of projects they don't own, and mob user support, allowing a sandbox within a project where anonymous pushing is allowed.

Typical scenarios are:

• Full-blown hosting site with both mirroring and ssh push access (like repo.or.cz)
• Internal Git hosting site with no mirroring, but users being able to easily set up projects to push to (corporate deployment with no networked homes)
• Internal Git hosting site with no pushing, instead mirroring specified projects from people's home directories for others to easily access and fork (corporate deployment especially suitable for NFS homes and UNIX-savvy users)

Girocco itself comprises of a terse documentation, somewhat customized gitweb instance, CGI scripts for user and project management, and several management scripts for the hosting site maintenance.

Girocco vs...

• Gitorious: Gitorious is very slick hosting solution, but without mirroring support (thus less flexible for both public and corporate deployment) and offering different project model and interface nice for Web 2.0 fans but not for those who prefer the raw beauty and terseness of gitweb.

• GitHub: Like Gitorious, but actually not open-source at all.

• Gitosis, gitolite: Not really a hosting solution, just a clever way to give multiple users push access over SSH without giving them actual UNIX accounts on the system. It could be used as an alternative to chroot for push access support in Girocco, though that is unfortunately not yet implemented.

Requirements and setup

You will need git pre-installed, or you can build and install one from the git.git subdirectory; normally, Girocco will use only gitweb from there. However, some bits of Girocco (e.g. the chroot setup) will rely on /usr/bin/git regardless of cmd_git settings; for chroot you will also need /bin/nc.openbsd (netcat-openbsd debian package). You will need to add the right users to the right groups (a dedicated Girocco user and the CGI user, at least); root access or root user cooperation will be probably essential unless you have good suexec setup. Girocco is designed to be run only with single instance within one system. If you want git protocol access, you will need to set up git-daemon independently, but it's very easy with inetd.

After configuring Girocco (editing Girocco/Config.pm and possibly other files), you should try to run make install and carefully look at any errors. See INSTALL for details. The installation procedure (especially chroot setup) is tuned for Debian systems, elsewhere you might need to adjust few things.

You should be running jobd.pl at all times - it will periodically check all the repositories and check if any need garbage collection, but also update them if the mirroring mode is enabled.

If you enable mirror support or want to have push notifications, you must also be running taskd.pl - it will listen to clone requests and perform the actual clone operations, and listen to notification messages from repository post-receive hooks and perform notifications.

If you enable push support, you will have to run sshd as root from within the chroot setup by make install; no special setup of the sshd is necessary, up to specifying a port to listen at in etc/ssh/sshd_config within the chroot (if the port is not to be 22).

Alternately, you can use push support with extremely relaxed security, but using the system-wide password database and not requiring a chroot. Or you could implement Gitosis permission model and send me a patch. ;-)

History and naming

Until Jul 2008, we called all the repo.or.cz machinery just 'repo', however that is not very good name, especially since the machinery is now suitable for universal usage even outside of repo.or.cz. Thankfully, Jan Engelhart invented a nice name 'Girocco', standing for 'GIt Repo.Or.Cz COdebase'.

At that time, the machinery was a set of ugly cronjobs completely specific for repo.or.cz. However, Novartis sponsored an internship for Pasky to generalize the framework and adapt it for an internally suitable usage. And another year later, Pasky finally finished the job by porting Girocco back to useable state for repo.or.cz and further cleaning it up.

Forks

An important Girocco concept is a project fork - anyone can fork any project (including a fork of another project), the fork resides in the directory structure as PARENT/FORK.git. Forks are meant as a place for people to freely publish their modifications for the project, even if they don't have push permissions to the parent. To save space and bandwidth, the fork will reuse objects in the parent project, garbage collection is done in a clever way not to prune objects used in forks.

Implementation of project database

(All uids and gids are allocated from range 65536..infty. All passwords are stored in DES crypt(3) format because Apache is moronic - in the past the group file was also used as htpasswd file.)

When you register a project, it will get a gid allocation and you will set a password for it. The triple is stored in a group(5) file (but containing just the project groups):

    projname:crypt:gid:list,of,users

When you register a user, it will get a uid allocation and you will upload an ssh public key for it. The user is stored in a passwd(5) file (but containing just the repo.or.cz users; 65534 is nogroup):

    username:x:uid:65534:email:/:/bin/git-shell

The authorized keys are stored in /etc/sshkeys/username.

When you (un)assign user to a project, you just manipulate the list of users for the project in /etc/group. The web interface for the project administration is protected by the group password.

If the given project is in push mode, that is indicated by having a .nofetch file in the repository. If the given project is in mirror mode on the other hand, that is indicated by the absence of .nofetch and by having double colon after the gid in the group(5) file - this prevents listed users to actually have write access to the repository.