Automatic versioning of python packages with Jenkins

I maintain a few internal python libraries at Pinterest, and for some of them, we try to maintain properly versioned pip packages. There’s no real method to my madness of versioning things, I start with 0.1 and if I need to make changes that require me to reinstall the package somewhere we’ll soon see a 0.1.1.

Occasionally there’ll be a big change, maybe a new script, and we’ll see 0.2.0.

The small changes, however got obnoxious. My workflow would be like this:

1. Run my package.
2. Find a bug.
3. Fix the bug.
4. Increment the version.
5. Build a package.
6. Reinstall package.

Repeat if necessary.

At least step 5 was automatic, Jenkins happily will run python setup.py sdist and upload those bits to S3. Step 4 was a bit annoying, since it was often editing setup.py to change the version number.

So I changed some things around. Jenkins uses nice monotonically increasing numbers. Part of my build step involves doing this:

echo $BUILD_NUMBER > build.info

build.info gets packaged with my library by adding it to the MANIFEST.in file.

In setup.py I do the following:

def __path(filename):
    return os.path.join(os.path.dirname(__file__),
                        filename)

build = 0

if os.path.exists(__path('build.info')):
    build = open(__path('build.info')).read().strip()

version= '0.6.{}'.format(build)

I can then pass version to the setup() method.

Now my version numbers are 0.1.$JENKINS_BUILD which eliminates step 4 in my bug fix cycle. The one downside is this number will never reach “0”, so if I do a major change I’ll jump from 0.1.12 to 0.2.13. That functionally works for me, but I’d love to improve this.