Automating svn<->git gateway

Hello Folks,

I want to set up a gateway between subversion and git, which would keep the master synchonized with subversion trunk, both ways, and allow working with any additional branches independent of subversion. For users it should behave as any other shared git repository accessed by push and pull. And it needs to be automatic.

Did anybody try to set up something like this?

Background:

At $work, we are considering switch from subversion to git. However to avoid big disruptions in the work, we need to do it gradually. So the idea is to switch to git one by one. The people who already switch need to be able to test the final workflow with git, while other people still commit to the subversion repository.

This basically rules out everybody just using git-svn, because individual conversions are incompatible (or is there some way to make them compatible?), so the people couldn't easily share their working branches.

That leaves me with creating one git-svn repository and having everybody clone from that. Keeping the repository up-to-date from subversion side seems trivial (just 'git svn fetch' to it from subversion's post-commit hook).

The trickier part is exporting changes pushed from the git side to subversion. My plan is to write a post-receive hook, that will 'git svn dcommit' to svn trunk.

I suppose I will have to get the rewritten commit back from subversion and merge it back to the master. I have not yet tested whether when dcommiting a merge will properly keep the second parent in the rewritten commit or not. I can do extra merge if it does not at the cost of slightly uglier history.

Thanks, Jan