Using Subversion Hooks to send out build emails

The subversion version control system has a wonderfully handy feature called hooks. Hooks are essentially scripts that are triggered by a version control event (such as a commits, or revision property changes).

Subversion Hooks are located in your repository directory (so if you have multiple repositories you have to setup hooks for each one) in a directory called hooks, perhaps something like this: /home/svn/projectName/hooks. There are template files (.tmpl) in the directory for each event (these files are just examples). The events are:

• start-commit - run before commit transaction begins, can be used to do special permission checking
• pre-commit - run at the end of the transaction, but before commit. Often used to validate things such as a non zero length log message.
• post-commit - runs after the transaction has been committed. Can be used for sending emails, or backing up repository.
• pre-revprop-change - runs before a revision property change. Can be used to check permissions.
• post-revprop-change - runs after a revision property change. Can be used to email or backup these changes.

In your hooks directory you will find a .tmpl file with each of the event names, if you want to enable one of the hooks, copy the template file (without the .tmpl extension) and make it executable.

Note: On windows you need to rename the .tmpl file with an extension that is executable by windows such as an exe or bat file.

If you want to send out a build email on post-commit copy the post-commit.tmpl file to post-commit and make it executable. Edit the file, and add your email addresses.

Subversion comes with a few other pre-built hook scripts, there is a hot-backup.py script that can be used to make hot backups of your repository after commits.

You can find more info about this in the Version control with Subversion book which can also be found here

As with any server, you should also make sure your subversion server is patched for security vulnerabilities. A good way to keep updated on subversion vulnerabilities is with stack.watch. It will help you by sending you an email when new vulnerabilities are published.