gitolite/doc/admin-defined-commands.mkd

# admin defined commands

**WARNING:  Use this feature only if you really really know what you're doing.
If you come back to me saying this feature caused a problem, I will only
laugh.  The worse the problem, the louder I will laugh.  You won't actually
hear me laughing, but you'll feel it in your bones, trust me!**

There may be other such **WARNING** sections below.  **Read all of them**.

----

In this document:

  * <a href="#background">background</a>
  * <a href="#setting_it_up">setting it up</a>
  * <a href="#anatomy_of_a_command">anatomy of a command</a>
  * <a href="#example_uses_and_sample_commands_in_contrib">example uses and sample commands in contrib</a>
      * <a href="#fork">fork</a>
      * <a href="#rmrepo">rmrepo</a>
      * <a href="#enable_disable_push_access_temporarily">enable/disable push access temporarily</a>
      * <a href="#bonus_restricted_admin">(bonus) restricted admin</a>

----

<a name="background"></a>

### background

Gitolite was named to be short for "gitosis-lite".  Someone now wants to turn
it into a "github-lite" :-) and even had some code to start me off thinking.

Since my first impulse on being asked for a feature is to say no, I was
casting about for a reason when he gave me one: he first made some noises
about perl, then said something about rewriting it all in scheme.  Nice... I
resisted the urge to point him to [this][xkcd224], told him that's a great
idea and he should go for it, mentally blessing him for letting me off the
hook on coding it ;-) [Laziness][lazy] *is* the first virtue you know!

[xkcd224]: http://xkcd.com/224/
[lazy]: http://c2.com/cgi/wiki?LazinessImpatienceHubris

And that was that.  For a couple of days.

Soon, though, I realised that there could be a pretty big bonus in this for
tightly controlled setups, so I went and coded it all anyway.  See the section
on "restricted admin" for what's really exciting about this for *me*.

----

It may be a good idea to read [doc/4-wildcard-repositories.mkd][wild] before
you continue here though, because most of the uses of this feature also need
wildcard repos.  (This also means you must set `$GL_WILDREPOS` to "1" in the
rc file).

[wild]: http://github.com/sitaramc/gitolite/blob/pu/doc/4-wildcard-repositories.mkd

The wildcard repo feature is a way to create repositories matching a pattern
(even if it as simple as `personal/CREATOR/.+`), and a way to specify two
categories of permissions for each such user-created repo.

What we want now is more than that, as you'll see in the examples below.  And
I'm sure if you think of more uses you'll send them to me as "contrib"
entries, right?

<a name="setting_it_up"></a>

### setting it up

This can only be setup by someone who has shell access to the server.  Edit
the rc file and update the `$GL_ADC_PATH` variable to point to, say,
`/home/git/bin/adc`.  *Nothing happens unless this variable is set and
pointing to a directory*.  Then put in whatever such commands you create into
that directory.  If you have a command called "foo" in that directory, then a
user can invoke it by saying:

    ssh git@server foo argument list

**WARNING: When gitolite takes control, this directory is checked first, and
if the requested command exists, it is executed.  It is therefore quite easy
to inadvertently *hide* some of the "official" commands (like "info",
"expand", "setperms", etc., or worse, say "git-upload-pack"!) by creating
executable files with those names in this directory.  So don't do that -- you
have been warned!**

<a name="anatomy_of_a_command"></a>

### anatomy of a command

You can basically do whatever you want in such a command -- go wild!  It's
upto you to check the permissions of *each* repo that the user is manipulating
using your command -- you can `rm -rf $GL_REPO_BASE_ABS` if you like and
gitolite wouldn't stop you.

The current directory (`$PWD`) will be set to the `$HOME` of `git@server` (or
whatever id you're using).  It won't be any specific repo, it won't even be
the base directory of all the repos.

Gitolite defines a few environment variables, as well as allows you to
directly query the ownership and access permissions of any repository.

The environment variables available are:

  * `GL_USER` -- the name of the user invoking the command
  * `GL_BINDIR` -- the directory containing all the binaries (in particular,
    `gitolite.pm`, which is all we really care about here)
  * `GL_REPO_BASE_ABS` -- the absolute path of the base directory containing
    all the repos

There are a few other variables also available but the above are the only ones
you should rely on.  Please treat any other variables you notice as being
internal/undocumented/subject to change.

[Implementation note: some of the distro packagers don't seem to like
`GL_BINDIR`.  I have not tested this in those scenarios, but they probably put
`gitolite.pm` somewhere in perl's lib path anyway, so it ought to work].

In addition, all the arguments of the command are also available to you, so
you can define your own command syntaxes.  Gitolite checks these arguments to
make sure they fit a somewhat conservative pattern (see `$REPOPATT_PATT` in
`src/gitolite.pm`), so take that into consideration when designing your
commands and usage.

Finally, you can call gitolite to query ownership and permissions for the
current user (which may not necessarily be the owner).  This is done loosely
as follows (don't use this exact code yet though):

    perl -I$HOME/.gitolite/src -Mgitolite -e "cli_repo_rights('reponame')"

which will print two space-separated words, something like `_____R__W u1` or
maybe `____@R_@W <gitolite>`.  (The former is the response for a wildcard repo
created by user `u1`, the latter is for a non-wildcard repo)

But that's cumbersome.  There's a bash shell function called
`get_rights_and_owner` in `contrib/adc/adc.common-functions` that is much more
convenient.  See any of the other samples for how to use it.

If you don't like this, roll your own.  If you don't like bash, do the eqvt in
your language of choice.

<a name="example_uses_and_sample_commands_in_contrib"></a>

### example uses and sample commands in contrib

<a name="fork"></a>

#### fork

A user would use the fork command like this:

    ssh git@server fork from to

where "from" is a repo to which the user invoking the fork has "R" access, and
"to" is a repo that does not yet exist and to which he has "C" access.

(Reminder: these access checks are done by the "fork" script, **not** within
gitolite -- once again, you are responsible for making sure your scripts
maintain the security of the system!)

Strictly speaking this command is not really needed.  Even without all this
"admin-defined commands" setup you could still do the following, purely from
the client side:

    git clone git@server:from
    cd from
    git remote add new git@server:to
    git push new refs/*:refs/*

or some such incantation.

**Implementation note**: you might notice that this script does not just do a
"git clone ...".  This is because creating a repo has to be done via gitolite.
Otherwise, hooks won't get setup, and the all-important "gl-creater" file
showing who owns the repo won't get created.

So now we have an actual command to just create a repo and do nothing else:
`ssh git@server git-init \'reponame\'`.  [Yes; those single quotes are
required.  Deal with it.]

<a name="rmrepo"></a>

#### rmrepo

This is one thing that you really could not do before this setup was created.
Use it like this:

    ssh git@server rmrepo reponame

The script checks to make sure that the repo being deleted was *created* by
the user invoking it.

<a name="enable_disable_push_access_temporarily"></a>

#### enable/disable push access temporarily

If you want to disable push access to gitolite temporarily (maybe for
maintenance), anyone with write access to the gitolite-admin repo can do this:

    ssh git@server able dis @all    # able dis ==> dis able

To re-enable after the maint work is done:

    ssh git@server able en @all     # able en ==> en able

You can also do this for one or more individual repos; in place of `@all`,
just use a space separated list of reponames (exactly as they would appear in
the config file).  Wildcards are not supported; patches welcome ;-)

**NOTE: This needs a specific secondary update hook**.  Creating a secondary
update hook is described in the sections on "custom hooks" and "hook chaining"
in doc/2.  You need code like this in `update.secondary` (don't forget to
`chmod +x` the file):

    #!/bin/bash

    for f in $HOME/.gitolite.down $PWD/.gitolite.down
    do
        if [ -f $f ]
        then
            echo >&2
            echo '*** ABORT ***' >&2
            echo >&2
            cat $f >&2
            exit 1
        fi
    done

    exit 0

<a name="bonus_restricted_admin"></a>

#### (bonus) restricted admin

It's rather important to me (and presumably others in the "corporate" world)
to separate permission to push to the "gitolite-admin" repo from unrestricted
shell access to the server.  This issue has been visited often in the past.

Until now, though, this was binary -- you either had full shell access or none
at all.  If there were tasks that legitimately needed to be done from the
shell on the server, it often meant you had to break that separation or load
the few people who did have shell access already.

Now, however, it is possible to provide scripts to do what you want, and put
them in `$GL_ADC_PATH`.  `contrib/adc/restrict-admin` is a commented sample --
as you can see, it cleverly makes use of the fact that you can now check for
the invoking uses access to any repo in the system.  In this case it checks if
he has "W" access to the gitolite-admin repo, and if he does, allows the
script to proceed.

[Note that this particular use does not require `$GL_WILDREPOS` to be enabled,
because it's not using any wildcard repos].