At the recent GNU Hackers Meeting, I gave a talk about Woodchuck. (I'll publish another post when the video is made available.) The talk resulted in a lot of great feedback including a question from Arne Babenhauserheide whether Woodchuck could be used to automatically synchronize git or mercurial repositories.
I hadn't considered using Woodchuck to synchronize version control respoitories, but it is a fitting application of Woodchuck: some data is periodically transferred over the network in the background. I immediately saw two major applications in my own life: a means to periodically push changes to a personal back up repository; and automatically fetching change sets so that when I don't have network connectivity, I still have a recent version of a repository that I'm tracking.
I decided to implement Arne's suggestion. It's called VCS Sync. To configure it, you create a file in your home directory called .vcssync. The file is JSON-based with the extension that lines starting with // are accepted as comments. The file has the following shape:
{
"directory1": [ { action1 }, { action2 }, ..., { actionM } ],
"directory2": [ { action1 }, { action2 } ],
...
"directoryN": [ { action1 } ],
}
That is, there is a top-level hash mapping directories to arrays of actions. An action consists of four possible arguments: 'sync' (either 'push' or 'pull'), 'remote' (the remote repository, default: origin), 'refs' (the set of branches, e.g., +master:master, default: 'master') and 'freshness' (how often to perform the action, in hours).
Here's an example configuration file:
// To register changes, run 'vcssync -r'.
{
"~/src/woodchuck": [
// Pull daily.
{"sync": "pull", "remote": "origin", "freshness": 24},
// Backup every tracked branch every few hours.
{"sync": "push", "remote": "backups", "refs": "+*:*", "freshness": 3}
],
"~/src/gpodder": [
// Pull every few days.
{"sync": "pull", "remote": "origin", "freshness": 96}
]
}
VCS Sync automatically figures out the repository format and invokes the right tool (currently only git and mercurial are supported; patches for other VCSes are welcome).
After you install the configuration file, you need to run 'vcssync -r' to inform Woodchuck of any changes to the configuration file.
You can use this on the N900, however, because this is a programmer's tool and you need to edit a file to use it, it is not installable using the hildon application manager. Instead, you'll need to run 'apt-get install vcssync' from the command line (the package is in the same repository as the Woodchuck server). If you encounter problems, consult $HOME/.vcssync.log.
I also use this script on my laptop, which runs Debian. Building packages for Debian is easy, just check out woodchuck and use dpkg-buildpackage:
git clone http://hssl.cs.jhu.edu/~neal/woodchuck.git
cd woodchuck
dpkg-buildpackage -us -uc -rfakeroot
This (currently) generates eight packages. In addition to vcssync, you'll also need to install murmeltier (my Woodchuck implmentation), and pywoodchuck (a Python interface to Woodchuck).
CuteSoma is opensource and released under the GPL v.3 license. You can find the complete source code here: 
