gitosis-lite

In this document:

• "lite"?
• what's extra
• workflow

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"lite"?

I have been gitosis for a while, and have learnt a lot from it. But in a typical $DAYJOB setting, there are some issues. It's not always Linux, so you can't just "urpmi gitosis" and be done. "python-setuptools" isn't often installed (and on a Solaris 9 I was trying to help remotely, we never did manage it). And the most requested feature (see next section) had to be written anyway.

While I was pondering having to finally learn python (I hate whitespace based flow logic except for plain text; this is a personal opinion so pythonistas can back off :-), I also realised that:

• no one in $DAYJOB settings will use or approve access methods that work without any authentication, so I didn't need gitweb/daemon support in the tool
• the idea that you admin it by pushing to a special repo is cute and convenient, but not really necessary because of how rarely these changes are made.

All of this pointed to a rewrite. In perl, naturally.

I also gained (and used) an unfair advantage: gits newer than 1.6.2 can clone an empty repo, so I don't need complex logic in the permissions checking part to create the repo initially -- I just create an empty bare repo when I "compile" the config file (see "workflow" below).

what's extra?

A lot of people in my $DAYJOB type world want per-branch permissions, so I copied the basic idea from git.git:Documentation/howto/update-hook-example.txt. I think this is the most significant extra I have. This includes not just who can push to what branch, but also whether they are allowed to rewind it or not (non-ff push).

workflow

I took the opportunity to change the workflow significantly.

• all admin happens on the server, in a special directory
• after making any changes, one "compiles" the configuration. This refreshes ~/.ssh/authorized_keys, as well as puts a parsed form of the access list in a file for the other two pieces to use.

Why pre-parse? Because access control decisions are taken at two separate stages now:

• the program that is run via ~/.ssh/authorized_keys (called gl-auth-command, equivalent to gitosis-serve) decides whether even git should be allowed to run (basic R/W/no access)
• the update-hook on each repo, which decides the per-branch permissions.

But the user specifies only one access file, and he doesn't have to know these distinctions. So I avoid having to parse the access file in two completely different programs by pre-compiling it and storing it as a perl "variable".