gitolite/doc/index.mkd

F=index Hosting git repositories

Gitolite allows you to setup git hosting on a central server, with fine-grained access control and many (many!) more powerful features.

#qi quick install

If you're comfortable with Unix and ssh, the following steps should work.

• create a user called git. Login to this user.

• copy your ssh pubkey from your workstation. Rename it to YourName.pub.

• now run these commands:

  git clone git://github.com/sitaramc/gitolite
  gitolite/src/gl-system-install
  gl-setup ~/YourName.pub
  

You're done.

WARNING: do NOT add repos or users directly on the server! You MUST manage the server by cloning the special 'gitolite-admin' repo on your workstation (git clone git@server:gitolite-admin), making changes, and pushing them. Here's how to [add users and repos][add].

#rtfm what should you read?

The complete online documentation for gitolite is here. There's a lot of it, so here're some reading suggestions.

If you're a user (i.e., not a gitolite admin), you only need [this][user].

Otherwise, the suggested reading order is this:

• quick intro: this document, or at least the "[what is gitolite][gl_what]" section just below this one.
• installation: if the [quick install][qi] above did not work for you, then read the [INSTALL][install] document. The "[trouble][insttrouble]" section in it may be useful too.
• basic administration tasks: [adding users and repos][add].

When you have to use more features, look in the master table of contents (there's a link to it at the top of every document), and use your browser's search function to search for stuff.

F=other_docs what do the other docs contain

The master TOC (see link above) is really the only comprehensive list of what is there, but here's an attempt to give you an overview!

• understanding gitolite

  • gitolite install and basic admin in [pictures][]
  • gitolite.conf by [example][conf_examples]
  • gitolite and [ssh][gl_ssh]

• normal admin tasks done on the server

  • [admin][]: adding your own hooks, adding existing repos into gitolite, etc.
  • [rc][]: setting gitolite behaviour options (warning: some of the variables have a security impact if you're careless)

• normal admin tasks done by changing [gitolite.conf][conf]

  • basic access control
  • advanced access control
  • extras: personal branches, gitweb/git-daemon access, git config settings

• advanced use (experts only; you can shoot yourself in the foot nicely!)

  • [ADCs][]: allowing users to run specific shell commands (but not give them a shell)
  • (also, [sample ADCs][shipped_ADCs] that come with gitolite)
  • letting [users create][wild] their own repos and assign permissions
  • [delegating][deleg] admin rights
  • [mirroring][]

• special installation scenarios:

  • using smart-[http][] instead of ssh
  • [migrating][migr] from gitolite

Finally, [tips][] has a lot of useful information.

#gl_what what is gitolite?

Gitolite is an access control layer on top of git. Here's an "executive summary":

• use a single unix user ("real" user) on the server
• provide access to many gitolite users
  • they are not "real" users
  • they do not get shell access
• control access to many git repositories
  • read access controlled at the repo level
  • write access controlled at the branch/tag/file/directory level, including who can rewind, create, and delete branches/tags
• can be installed without root access, assuming git and perl are already installed
• authentication is most commonly done using sshd, but you can also use httpd if you prefer (this may require root access).
• several other neat features, too many to list here

F=need__ why is gitolite needed?

Gitolite is separate from git, and needs to be installed and configured. So... why do we bother?

Gitolite is useful in any server that is going to host multiple git repositories, each with many developers, where some sort of access control is required.

In theory, this can be done with plain old Unix permissions: each user is a member of one or more groups, each group "owns" one or more repositories, and using unix permissions (especially the setgid bit -- chmod g+s) you can allow/disallow users access to repos.

But there are several disadvantages here:

• every user needs a userid and password on the server. This is usually a killer, especially in tightly controlled environments
• adding/removing access rights involves complex usermod -G ... mumblings which most admins would rather not deal with
• viewing (aka auditing) the current set of permissions requires running multiple commands to list directories and their permissions/ownerships, users and their group memberships, and then correlating all these manually
• auditing historical permissions or permission changes is pretty much impossible without extraneous tools
• errors or omissions in setting the permissions exactly can cause problems of either kind: false accepts or false rejects
• without going into ACLs it is not possible to give some people read-only access while some others have read-write access to a repo (unless you make it world-readable). Group access just doesn't have enough granularity
• it is absolutely impossible to restrict pushing by branch name or tag name.

Gitolite does away with all this:

• it uses ssh magic to remove the need to give actual unix userids to developers
• it uses a simple but powerful config file format to specify access rights
• access control changes are affected by modifying this file, adding or removing user's public keys, and "compiling" the configuration
• this also makes auditing trivial -- all the data is in one place, and changes to the configuration are also logged, so you can audit them.
• finally, the config file allows distinguishing between read-only and read-write access, not only at the repository level, but at the branch level within repositories.

why did I write it?

The most important feature I needed was per-branch permissions. This is pretty much mandatory in a corporate environment, and is almost the single reason I started thinking about writing gitolite.

It's not just "read-only" versus "read-write". Rewinding a branch (aka "non fast forward push") is potentially dangerous, but sometimes needed. So is deleting a branch (which is really just an extreme form of rewind). I needed something in between allowing anyone to do it (the default) and disabling it completely (receive.denyNonFastForwards or receive.denyDeletes).

F=morefeatures__ some more features

Here're some more features.

• simple, yet powerful, config file syntax, including specifying gitweb/daemon access. You'll need this power if you manage lots of users+repos+combinations of access
• apart from branch-name based restrictions, you can also restrict by file/dir name changed (i.e., output of git diff --name-only)
• if your requirements are still too complex, you can split up the config file and delegate authority over parts of it
• easy to specify gitweb owner, description and gitweb/daemon access
• easy to sync gitweb (http) authorisation with gitolite's access config
• comprehensive logging [aka: management does not think "blame" is just a synonym for "annotate" :-)]
• "personal namespace" prefix for each dev
• migration guide and simple converter for gitosis conf file
• "exclude" (or "deny") rights at the branch/tag level
• specify repos using patterns (patterns may include creator's name)
• define powerful operations on the server side, even github-like forking

security

Due to the environment in which this was created and the need it fills, I consider this a "security" program, albeit a very modest one.

The first person to find a hole that allows a non-admin user to push a change to a repository that he is not allowed to, will get a modest reward of 5000 INR. The hole should not require enabling any of the options listed as having a [security impact][rcsecurity] in the rc file, nor obvious things like setting the umask too loose, etc.

contact and license

Gitolite is released under GPL v2. See COPYING for details.

• author: sitaramc@gmail.com, sitaram@atc.tcs.com
• mailing list: gitolite@googlegroups.com
• list subscribe address : gitolite+subscribe@googlegroups.com