gitolite/doc/tips-notes.mkd

F=tips assorted tips and notes

common errors and mistakes

• adding repositories/ at the start of the repo name in the git clone. This error is typically made by the admin himself -- because he knows what $REPO_BASE is set to and thinks he has to provide that prefix on the client side also :-) In fact gitolite prepends $REPO_BASE internally, so you shouldn't also do the same thing!

• being able to clone but getting errors on push. Most likely caused by a combination of:

  • you already have shell access to the server, not just "gitolite" access, and

  • you cloned using git clone git@server:repositories/repo.git (notice there's an extra "repositories/" in there?)

  In other words, you used a key that completely bypassed gitolite and went straight to the shell to do the clone.

  Please see doc/ssh-troubleshooting.mkd for what all this means.

other errors, warnings, notes...

cloning an empty repo

Cloning an empty repo is only possible with clients greater than 1.6.2. So at least one of your clients needs to have a recent git. Once at least one commit has been made, older clients can also use it

When you clone an empty repo, git seems to complain about fatal: The remote end hung up unexpectedly. However, you can ignore this, since it doesn't seem to hurt anything. [Update 2009-09-14; this has been fixed in git 1.6.4.3]

@all syntax for repos

There is a way to use the @all syntax for repos also, as described in doc/gitolite.conf.mkd. However, there are a couple of minor cautions:

• don't use NAME/ or such restrictions on the special @all repo. Due to the potential for defeating a crucial optimisation and slowing down all access, we do not support this.

features

Apart from the big ones listed in the top level README, and subjective ones like "better config file format", gitolite has evolved to have many useful features than the original goal of branch-level access control.

syntax and normal usage

#multikey one user, many keys

If you have a user who has more than one pubkey (like from different machines) the simplest way to deal with it is to add subdirectories and add keys there. For example, I might have these files in keydir/:

sitaram.pub
home/sitaram.pub
laptop/sitaram.pub

F=oldmultikeys old style multi keys

This is an older method of enabling multi-keys. It will continue to work and be supported in code, simply because I prefer it. But I am not going to document it except for the example below, nor am I going to support it in terms of questions. Sorry. Apparently it was too complex to understand, even for some smart folks I know. This tells me it was probably ill thought out and should have been obsoleted as soon as e0fe73a was pushed.

Anyway, here's all the documentation for it -- some sample pubkey filenames and the corresponding derived usernames:

• plain username, no multikey

  sitaramc.pub                            sitaramc
  

• plain username, with multikeys

  sitaramc@laptop.pub                     sitaramc
  sitaramc@desktop.pub                    sitaramc
  

• email address as username, no multikey

  sitaramc@gmail.com.pub                  sitaramc@gmail.com
  

• email address as username, with multikeys

  sitaramc@gmail.com@laptop.pub           sitaramc@gmail.com
  sitaramc@gmail.com@desktop.pub          sitaramc@gmail.com
  

F=tipssec_ security, access control, and auditing

#2levels two levels of access rights checking

Gitolite has two levels of access checks. The first check is what I will call the pre-git level. At this stage, the gl-auth-command has been invoked by sshd, and it knows just three things:

• who,
• what repository, and
• what type of access (R or W)

Note that at this point no git program has entered the picture, and we have no way of knowing what ref (branch, tag, etc) he is trying to update, even if it is a "write" operation.

For a "read" operation to pass this check, the username (or @all users) must have read permission (i.e., R, RW, RW+, etc.) on at least one branch of the repo (or @all repos).

For a "write" operation, there is an additional restriction: lines specifying only R (read access) don't count. The user must have write access to some ref in the repo in order to pass this stage!

The second check is via a git update hook. This check only happens for write operations. By this time we know what "ref" he is trying to update, as well as the old and the new SHAs of that ref (by which we can also deduce whether it's a rewind or not). This is where the "per-branch" permissions come into play.

Each refex that allows W access (or + if this is a rewind) for this user, on this repo, is matched against the actual refname being updated. If any of the refexes match, the push succeeds. If none of them match, it fails.

Gitolite also allows "exclude" or "deny" rules. See later in this document for details.

better logging

If you have been too liberal with the permission to rewind, it has built-in logging as an emergency fallback if someone goes too far, or for audit purposes [*]. The logfile names and location are configurable, and can include the year/month/day etc in the filename for easy archival or further processing. The log file even tells you which pattern in the config file matched to allow that specific access to proceed.

[*] setting core.logAllRefUpdates true does provide a safety net against over-zealous rewinds, but it does not tell you "who". And strangely, management does not seem to share the view that "blame" is just a synonym for "annotate" ;-)]

The log lines look like this:

2009-09-19.10:24:37  +  b4e76569659939  4fb16f2a88d8b5  myrepo refs/heads/master       user2   refs/heads/master

The "+" at the start indicates a non-fast forward update, in this case from b4e76569659939 to 4fb16f2a88d8b5. So b4e76569659939 is the one to restore! Can it get easier?

The other parts of the log line are the name of the repo, the refname being updated, the user updating it, and the refex pattern (from the config file) that matched, in case you need to debug the config file itself.

delegating parts of the config file

You can now split up the config file and delegate the authority to specify access control for their own pieces. See [delegation][deleg] for details.

F=tnconv_ convenience features

what repos do I have access to?

Sometimes there are too many repos, maybe even named similarly, or with the potential for typos, confusion about hyphens/underscores or upper/lower case, etc. You'd just like a simple way to know what repos you have access to.

Gitolite provides two commands ([info][info] and [expand][expand]) to help you find this information.

support for git installed outside default PATH

The normal solution is to add to the system default PATH somehow, either by munging /etc/profile or by enabling PermitUserEnvironment in /etc/ssh/sshd_config and then setting the PATH in ~/.ssh/.environment. All these are security risks because they allow a lot more than just you and your git install :-)

And if you don't have root, you can't do this anyway.

The only solution till now has been to ask every client to set the config parameters remote.<name>.receivepack and remote.<name>.uploadpack. But telling every client to do so is a pain...

Gitolite lets you specify the directory in which git binaries are to be found, via a new variable ($GIT_PATH) in the "rc" file. If this variable is non-empty, it will be appended to the PATH environment variable before attempting to run git stuff.

Very easy, very simple, and completely transparent to the users :-)

Note: sometimes you have a system that already has an older "git" installed in one of the system PATHs, but you've installed a newer git in some non-standard location and want that picked up. Because of security reasons, gitolite will not prepend GIT_PATH to the PATH variable, so the older git comes first and it gets kinda frustrating!

Here's a simple workaround. Ignore the GIT_PATH variable, and directly set the full PATH in the rc file, like so:

$ENV{PATH} = "/home/sitaram/bin:$ENV{PATH}";

#pers "personal" branches

"personal" branches are great for corporate environments, where unauthenticated pull/clone is a no-no. Since a dev workstation cannot do authentication, even work shared just between 2 devs has to go via the server. This causes the same branch name clutter as in a centralised VCS, plus setting up permissions for this becomes a chore for the admin.

Personal branches exist in a namespace of their own. The syntax is

    RW+ personal/USER/  =   @userlist

where the "personal" can be anything you like (but cannot be empty), and the "/USER/" part is necessary (including both slashes). A user "alice" (if she's in the userlist) can then push any branches inside personal/alice/. Which means she can push personal/alice/foo and personal/alice/bar, but NOT personal/alice.

(Background: at runtime the "USER" component will be replaced by the name of the invoking user. Access is determined by the right hand side, as usual).

custom hooks and custom git config

You can specify hooks that you want to propagate to all repos, as well as per-repo "gitconfig" settings. Please see doc/2-admin.mkd and doc/gitolite.conf.mkd for details.

bypassing gitolite

Sometimes you'll need to access one of the gitolite-managed repos directly on the server, without going through gitolite. Reasons may be some automatic updates or some other ad hoc purposes you can dream up.

Cloning a gitolite-controlled repo is easy enough -- just use the full path (typically ~/repositories/reponame.git) instead of just reponame, to compensate for gitolite not sitting in between and adding those things to the repo path.

But when you push, the update hook (which git will invoke anyway) will fail because it needs all sorts of access control info that it now doesn't have, because the push was invoked without going through gitolite.

In order to bypass the update hook, just set the GL_BYPASS_UPDATE_HOOK environment variable to "1" or something, export it, and push. I prefer not to set that variable permanently, preferring this mode instead:

GL_BYPASS_UPDATE_HOOK=1 git push

F=adminpush gl-admin-push: bypassing gitolite for the gitolite-admin repo

The method described in the previous section (setting GL_BYPASS_UPDATE_HOOK) will work for all the repos managed by gitolite, except for the special gitolite-admin repo. For that you will need some extra magic, because there is also a post-update hook that runs here, and this needs additional information which is NOT available if you bypass gitolite.

(Note: If your gitolite is too old to have the gl-admin-push program, try gl-dont-panic; run it without arguments for usage info. If you don't even have that, it may be best to [clean][] things out more thoroughly!)

Use the gl-admin-push program to make changes to the admin repo directly on the server. Here's how:

• clone the repo to some safe location and cd to it:

  cd /tmp
  git clone ~/repositories/gitolite-admin.git
  cd gitolite-admin
  

• make whatever changes you want to that clone and commit. You can add new keys, change the conf file, or anything at all that needs fixing up. You can even reset to an older commit (rewind) if that is the simplest way to fix up some config problem that may have lost you your access.

• when done, instead of git push <push arguments>, use this program instead. For example, instead of git push -f, use gl-admin-push -f.

Note that this method will work for any repo, not just the special admin repo.

#disable disabling write access to take backups

If you want to take normal, OS-level, backups of the system, you might want git to be quiescent during that time, so that the backup is clean. The best way to do this is to disable write-access to the server for the duration of the backup.

Here's how:

cd $HOME    # if running as "git" user, else "cd ~git" or whatever
echo writes disabled during backup window > .gitolite.down

# << RUN YOUR BACKUP COMMAND(s) HERE >>

rm .gitolite.down

I leave it to you to

• make sure that if the backup script fails, the .gitolite.down file is still removed (or not; maybe your policy is that if the backup failed, no further writes are allowed. Whatever...)
• if you're extremely paranoid (even I wouldn't worry about this!) make sure that no push is in progress by checking for any git-receive-pack processes in a ps output.

INconvenience features

#repodel deleting a repo

By design, there is no code in gitolite to delete a repo if the repo was specified by name in the config file. (Wildcard repos can be deleted by the user; see [here][wild_repodel] for details).

If you do want to permanently delete a non-wildcard repo, here's what you do:

• remove the repo from the gitolite-admin repo clone's conf/gitolite.conf file. "add" the change, commit, and push.

• then remove the repo from ~/repositories on the server (or whatever you set $REPO_BASE to in the ~/.gitolite.rc)

renaming a repo

This is similar; there's no code to do this in gitolite. What you do is:

• log on to the server, cd $REPO_BASE (default: cd ~/repositories), and mv old-name.git new-name.git
• back on your gitolite-admin clone, edit conf/gitolite.conf and replace all occurrences of old-name with new-name. Then add, commit, and push as usual.

The order of these 2 steps is important; do not reverse them :-)

helping with gitweb

Although gitweb is a completely separate program, gitolite can do quite a lot to help you manage gitweb access as well; once the initial setup is complete, you can do it all from within the gitolite config file!

If you just want gitweb to show some repositories, see [here][gwd] for how to specify which repos to show.

#gitwebauth easier to link gitweb authorisation with gitolite

Over and above whether a repo is even shown by gitweb, you may want to further restrict people, allowing them to view only those repos for which they have been given read access by gitolite.

This requires that:

• you have to have some sort of HTTP auth on your web server (out of my scope, sorry!)
• the HTTP auth should use the same username (like "sitaram") as used in the gitolite config (for the corresponding user)

Normally a superuser sets up passwords for users using the "htpasswd" command, but this is an administrative chore.

Robin Smidsrød had the great idea that, since each user already has pubkey access to git@server, this gives us a very neat way of using gitolite to let the users manage their own HTTP passwords. Here's how:

• setup apache so that the htaccess file it looks for is owned by the "git" user
• in the ~/.gitolite.rc file, look for the variable $HTPASSWD_FILE and point it to this file
• tell your users to type in ssh git@server htpasswd to set or change their HTTP passwords

Of course some other authentication method can be used (e.g. mod_ldap) as long as the usernames match.

Gitweb allows you to specify a subroutine to decide on access. We use that feature and tie it to gitolite. Configuration example can be found in contrib/gitweb/.

#umask umask setting

Gitweb not able to read your repos? You can change the umask for newly created repos to something more relaxed -- see the REPO_UMASK setting in the [rc file documentation][rc].

advanced features

There are some really cool features that are now in pretty wide use.

• [repos named with wildcards][wild] is useful when some or most of your repos fit a pattern, avoiding the need to name repos individually in the config file. New repos matching the pattern can be created by any user (if you give them rights to), with a set of permissions assigned to "roles", and the creator can then place users into those roles.

• [admin defined commands][ADCs] allow controlled access to specific commands and scripts without giving users full shell access.

odds and ends

"poking" the admin repo to force a compile

Sometimes you need to force a compile, as if you pushed the gitolite-admin repo. I have a git alias that looks like this:

[alias]
    poke = !git ls-remote origin | grep -w refs/heads/poke && git push origin :poke || git push origin master:poke

so I just run git poke. This toggles between deleting and creating a dummy branch called "poke". Either operation will trigger the hooks.