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](http://sitaramc.github.com/gitolite).  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