GitLab PushD is a Ruby + Rack implementation of a simple daemon to push git repos to elsewhere as triggered by a GitLab web hook.
To install for deployment, you can do:
RUBY=/path/to/ruby
$RUBY/bin/gem install bundler -i vendor/gem -n bin
bin/bundle install --deployment --binstubs --shebang $RUBY/bin/ruby
You will also need to create a config.rb file for your environment. There is an example provided.
There is also an example Upstart config to show how you can run it as a service.
Run pushd on the host where your central git repositories live, and make a config.rb file as outlined in the included example.
In GitLab, then add a web hook that points to the running pushd application uri.
Given that GitLab just talks JSON, if you want to trigger the pushd daemon directly from a git hook, you can use the update hook, and do something like:
#!/bin/sh
repouri=git@git.example.org:myrepo.git
pushd=http://git.example.org:29224
curl --data '{"repository":{"url":"'$repouri'"}}' $pushd
The repouri only needs to match whatever you listed in the config.rb file, i.e. just some unique identifier of your choosing.