94 lines
3.7 KiB
Markdown
94 lines
3.7 KiB
Markdown
# gitosis-lite
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gitosis-lite is the bare essentials of gitosis, with a completely different
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config file that allows (at last!) access control down to the branch level,
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including specifying who can and cannot *rewind* a given branch.
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In this document:
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* why
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* what's gone
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* what's new
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* the workflow
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----
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### why
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I have been using gitosis for a while, and have learnt a lot from it. But in
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a typical $DAYJOB setting, there are some issues:
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* it's not always Linux; you can't just "urpmi gitosis" (or yum or apt-get)
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and be done
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* often, "python-setuptools" isn't installed (and on a Solaris9 I was trying
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to help remotely, we never did manage to install it eventually)
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* the most requested feature (see "what's extra?") had to be written anyway
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### what's gone
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While I was pondering the need to finally learn python[1] , I also realised
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that:
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* no one in $DAYJOB type environments will use or approve access methods
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that work without any authentication, so I didn't need gitweb/daemon
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support in the tool or in the config file
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* the idea that you admin it by pushing to a special repo is nice, but not
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really necessary because of how rarely these changes are made, especially
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considering how much code is involved in that piece
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All of this pointed to a rewrite. In perl, naturally :-)
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### what's extra?
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Per-branch permissions. You will not believe how often I am asked this at
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$DAYJOB. This is almost the single reason I started *thinking* about rolling
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my own gitosis in the first place.
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Take a look at the example config file in the repo to see how I do this. I
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copied the basic idea from `update-hook-example.txt` (it's one of the "howto"s
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that come with the git source tree). This includes not just who can push to
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what branch, but also whether they are allowed to rewind it or not (non-ff
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push).
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However, please note the difference in the size and complexity of the
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*operational code* between the update hook in that example, and in mine :-)
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The reason is in the next section.
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### the workflow
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In order to get per-branch access, you *must* use an update hook. However,
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that only gets invoked on a push; "read" access still has to be controlled
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right at the beginning, before git even enters the scene (just the way gitosis
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currently works).
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So: either split the access control into two config files, or have two
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completely different programs *both* parse the same one and pick what they
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want. Crap... I definitely don't want the hook doing any parsing, (and it
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would be nice if the auth-control program didn't have to either).
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So I changed the workflow completely:
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* all admin changes happen *on the server*, in a special directory that
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contains the config and the users' pubkeys. But there's no commit and
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push afterward. Nothing prevents you from version-controlling that
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directory if you wish to, but it's not *required*
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* instead, after making changes, you "compile" the configuration. This
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refreshes `~/.ssh/authorized_keys`, as well as puts a parsed form of the
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access list in a file for the other two pieces to use.
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The pre-parsed form is basically a huge perl variable. It's human readable
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too (never mind what the python guys say!)
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Advantages: all the complexity of parsing and error checking the parse is done
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away from the two places where the actual access control happens, which are:
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* the program that is run via `~/.ssh/authorized_keys` (I call it
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`gl-auth-command`, equivalent to `gitosis-serve`); this decides whether
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git should even be allowed to run (basic R/W/no access)
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* the update-hook on each repo, which decides the per-branch permissions
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----
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[1] I hate whitespace to mean anything significant except for text; this is a
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personal opinion *only*, so pythonistas please back off :-)
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