redirecting pushes

Please read carefully; there are security implications if you enable this for mirrors NOT under your control.

When a user pushes to a non-native repo, it is possible to transparently redirect the push to the correct master server. This is a very neat feature, because now all your users just use one URL (the mirror nearest to them). They don't need to know where the actual master is, and more importantly, if you and the other admins change it, they don't need to know it changed!

The gitolite.mirror.redirectOK config variable decides where this redirection is OK. If it is set to 'true', any valid 'slave' can redirect an incoming non-native push from a developer. Otherwise, it contains a list of slaves that are permitted to redirect pushes (this might happen if you don't trust some of your slaves enough to accept a redirected push from them).

Warning: like gitolite.mirror.slaves, this key also should have only hosts, no keys, in it.

This check needs to pass on both the master and slave servers; both have a say in deciding if this is allowed. (The master may have real reasons not to allow this; see below. I cannot think of any real reason for the slave to disable this, but it's there in case some admin doesn't like it).

There are some potential issues that you MUST consider before enabling this:

(security) If the slave and master server are so different or autonomous that a user, say "alice", on the slave is not guaranteed to be the same one as "alice" on the master, then the master admin should NOT enable this feature.

This is because, in this scheme, authentication happens on the slave, but authorisation is on the master. The slave-authenticated userid (alice) is passed to the master.

(If you know ssh well enough, you know that the ssh authentication has already happened, so all we can do is ensure authorisation happens with whatever username we know so far).
If your slave is out of sync with the master for whatever reason, then the user will get confusing results. A git fetch may say everything is upto-date but the push fails saying it is not a fast-forward push. (Of course there's a way to fix this; see the "commands to (re-)sync mirrors" section above).
We cannot redirect non-git commands like ADC, setperms, etc because we don't really have a way of knowing what repo he's talking about (different commands have different syntaxes, some have more than one reponame...). Any user who needs to do that should access the end server directly. It should be easy enough to write an ADC to do the forwarding, in case the slave server is the only one that can reach the real master due to network or firewall setup.

Ideally, I recommend that ad hoc repos not be mirrored at all. Keep mirroring for "blessed" repos only.