Monday, 16 August 2010

Distutils2 Summer of Code

This summer, I took part in Google Summer of Code project as a student. I worked on distutils2 project implementing new commands and improving the existing ones. In poarticular, my tasks were:

  • to implement a test command (similar to the one from setuptools/distribute
  • implement command hooks
  • port the upload_docs command
  • enhance the check command
I started with a low hanging fruit: porting upload_docs. This didn't take very long. In fact I spent most of my time with the test code, implementing mock PyPI server, which - I'm proud to say - turned out quite useful for other student's tests (although, my initial implementation used wsgiref - not available in Python 2.4 and Alexis refactored practically all of it, so it's rather his child).

After that, I started working on the test command. The new command's API is a little bit different than the one you might know from setuptools/distribute: the options "test-suite" and "test-loader" got replaced with "suite" and "runner". You would use "suite" option in place of "test-suite", but setting the "runner" to a dotted path to a Python callable will cause the test command to invoke that callable in place of default unittest test runner. In absence of both options, the test command will invoke test discovery as implemented in unittest (Python 2.7, 3.2 and newer) or unittest2 (if installed, for older Python versions).

The next task was to implement command hooks. The command pre- and post-hooks are Python callables that accept the command instance (giving it access to all its options). You specify them in your setup.cfg file as the command's options. In addition to that, you have to specify a postfix for you hook, so that it wouldn't override hooks from other files:

  pre-hook.my_postfix =

The improvements to the check command were arguably most neglected task in my project. I gathered the optional checks (originally only check for validity of ReStructuredText in package's description) under a single option --all, and implemented additional check: one that validates importability of the hooks.

Not all changes are upstream yet. The hooks and the upload_docs command are already in the central repo. The test command and check improvements are waiting for the merge. Tomorrow, I'm leaving for my summer kayak trip, but I'm looking forward to contributing more to distutils in the future.

Overall, I am very happy with the time I spent working on the project. Even in spite of some problems in my way, I enjoyed the experience of working with a team of extremely smart guys. The regular IRC meetings were instructive and enjoyable. I would also like to thank my mentor: Fred Drake, who offered all the help and feedback I needed.