Find Git branch name in post-update hook

Question

I'm executing a programme to alert CruiseControl each time an update is sent to our remote repository. I'm using a Git post-update hook for this.

It would be great if I could find out which branch had been committed so I could use that to inform CruiseControl which branch to build. Is there any way to access the branch name within a post-update hook?

Answer 1

The first parameter to the post-update hook is the branch reference in full - for instance I see 'refs/heads/master' for a push to 'origin master'. So an example hook script that just prints the branch modified is:

#!/bin/sh
branch=$(git rev-parse --symbolic --abbrev-ref $1)
echo Update pushed to branch $branch
exec git update-server-info

To illustrate, when the above is placed into your remote repository hooks/post-update file the following is printed when performing a push:

% git push origin master
Counting objects: 5, done
Writing objects: 100% (3/3), 247 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
remote: Update pushed to branch master
To /tmp/xx/a
    e02d9cd..ab14a08  master -> master

The new line beginning 'remote:' was output by our hook script.