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Get started with launchpadlib

·2 mins

In my spare time, I sometimes talk to people about how they can get started with launchpadlib hacking.

launchpadlib is the Python client-side library that talks to Launchpad’s own REST API. It turns out that customize scripted control of a bug-tracker-code-hosting-translation-distribution-building-cross-project-collaboration thing is actually quite handy.

If you want to get started hacking with launchpadlib, and you have Ubuntu, then install ‘python-launchpadlib’ now. I’m pretty sure you can also get it from PyPI.

You can check that it works by running:

$ python>>> import launchpadlib>>> launchpadlib.__version__'1.5.1'

I’ll be assuming you’re running 1.5.1 or later.

I’ve written a very simple launchpadlib application that you can get with ‘bzr branch lp:~jml/+junk/bugstats’. Each revision shows a meaningful launchpadlib script. You can get at the old revisions with ‘bzr revert -r1’ or ‘bzr revert -r2’ or ‘-r3’.

Here’s what the simplest launchpadlib script that I could think of looks like:

import osimport sysfrom launchpadlib.launchpad import Launchpad, STAGING_SERVICE_ROOTAPP_NAME = 'jml-bug-stats'CACHE_DIR = os.path.expanduser('~/.launchpadlib/cache')SERVICE_ROOT = STAGING_SERVICE_ROOTlaunchpad = Launchpad.login_with(APP_NAME, SERVICE_ROOT, CACHE_DIR)print launchpad.bugs[1].title

(Adapted from r2 of the above branch).

A few points.

  • We use STAGING_SERVICE_ROOT, which means that we’re pointing
    at Launchpad’s staging service,
    just in case we screw up any data.
  • We give the application a name, when you run the application, launchpadlib
    opens up a browser window letting you decide how far the application
    can act on your behalf.
  • We provide a cache directory. Credentials, among other things, get stored
    here.
  • We then login and get an object that represents a Launchpad instance
  • Once we’ve got it, we look at the collection of bugs, get Bug #1 and then
    print the title

Very simple. To learn how to write this application, I looked at the main Launchpad API help page, the
examples page and the reference documentation. You’ll notice that I had to translate the reference documentation from REST-speak into Python-speak.

Already you have enough to go exploring with the Launchpad API and think of cool things to do. A bunch of people are already doing cool stuff and there are many projects that use launchpadlib.

Next up, I hope to show you some more complex things you can do with the API.

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