delegating access control responsibilities
[Thanks to jeromeag for forcing me to think through this...]
lots of repos, lots of users
Gitolite tries to make it easy to manage access to lots of users and repos, exploiting commonalities wherever possible. (The example in this section should give you an idea). As you can see, it lets you specify bits and pieces of the access control separately -- i.e., all the access specs for a certain repo need not be together; they can be scattered, which makes it easier to manage the sort of slice and dice needed in that example.
But eventually the config file will become too big. If you let only one person have control, he could become a bottleneck. If you give it to multiple people, they might make mistakes or stomp on each others' work accidentally.
The best way is to divide up the config file and give parts of it to different people.
Ideally, we would delegate authority for groups of repos, not individual repos, otherwise it doesn't scale. It would also be nice if we could prevent an admin from creating access rules for any repo in the system -- i.e., set limits on what repos he can control. This would be a nice "security" feature.
Delegation offers a way to do all that. Note that delegated admins cannot create or remove users, not can they define new repos. They can only define access control rules for a set of repos they have been given authority for.
It's easier to show how it all works with an example instead of long descriptions.
splitting up the set of repos into groups
To start with, recall that gitolite allows you to specify groups (of users
or repos, same syntax). So the basic idea is that the main config file
conf/gitolite.conf in your admin repo clone) will specify some repo groups:
# group your projects/repos however you want @webbrowser_repos = firefox lynx @webserver_repos = apache nginx @malware_repos = conficker storm # any other config as usual, including access control lines for any of the # above projects or groups
delegating ownership of groups of repos
Once the repos are grouped, give each person charge of one or more groups. For example, Alice may be in charge of all web browser development projects, Bob takes care of web servers, and Mallory, as tradition dictates, is in charge of malware ;-)
You do this by adding branches to the
# the admin repo access was probably like this to start with: repo gitolite-admin RW+ = sitaram # now add these lines to the config for the admin repo RW = alice bob mallory RW+ NAME/ = sitaram RW NAME/conf/fragments/webbrowser_repos = alice RW NAME/conf/fragments/webserver_repos = bob RW NAME/conf/fragments/malware_repos = mallory
This uses gitolite's ability to restrict pushes by file/dir name being changed
-- the syntax you see above ensures that, while "sitaram" does not have any
NAME based restrictions, the other 3 users do. See
syntax and notes.
As you can see, for each repo group you want to delegate authority over,
there's a rule for a corresponding file in
conf/fragments in the
gitolite-admin repo. If you have write access to that file, you are allowed
to define rules for repos in that repo group.
In other words, we use gitolite's file/dir NAME-based permissions to "enforce" the separation between the delegated configs!
Here's how to use this in practice:
Alice clones the
gitolite-adminrepo, and adds a file called
she writes in this file any access control rules for the "firefox" and "lynx" repos. She should not write access rules for any other project -- they will be ignored
Alice then commits and pushes to the
Naturally, a successful push invokes the post-update hook that the admin repo has, which eventually runs the compile script. The net effect is as if you appended the contents of all the "fragment" files, in alphabetical order, to the bottom of the main file.
The delegation feature is meant only for access control rules, not pubkeys. Adding/removing pubkeys is a much more significant event than changing branch level permissions for people already on staff, and only the main admin should be allowed to do it.
Gitolite's "userids" all live in the same namespace. This is unlikely to change, so please don't ask -- it gets real complicated to do otherwise. Allowing delegated admins to add users means username collisions, which also means security problems (admin-A creates a pubkey for Admin-B, thus gaining access to all of Admin-B's stuff).
If you feel the need to delegate even that, please just go the whole hog and give them separate gitolite instances! It's pretty easy to setup the software itself system-wide, so that many users can use it without all the "easy install" fuss. See the "system install / user setup" section in doc/0-INSTALL.mkd for details.