Open Stack

This message is a summary of the discussion about enabling integration testing under Python 3 from the summit. The full notes are in https://etherpad.openstack.org/p/liberty-cross-project-python3 and the spec is up at https://review.openstack.org/#/c/177375/

tl;dr: Most of our libraries now support Python 3, and run their unit tests there. We have several application-level projects ready to start porting their code to Python 3 as well. Running unit tests for the application code under Python 3 will be an important step, but won’t be sufficient to claim Python 3 support. The proposed changes to devstack allow each application project to add a test job to run their code under Python 3 when they think they are ready, allowing applications to port one at a time.


We agreed that we need to keep supporting Python 2.7 and 3.x simultaneously for some time, until we are at a point where we can reliably tell deployers to shift most/all of their stack. We are explicitly putting off discussion of more detailed criteria for that until we actually have *any* project that runs fully on Python 3.

We agreed that we would only support one version of python 3 at a time. Some distros may choose to package 3.5 when it is available (soon), but we agreed that we would continue working with python 3.4 because it is more widely supported on our platforms (directly, or through supported extra repositories). Ubuntu has an issue with their 3.4 package due to missing a backport that causes segfaults under some circumstances. The packagers are aware of the issue, and zul is going to work with them to raise the priority of updating the package. If the update isn’t released in a reasonable amount of time, we can fall back to testing on Debian Jessie instead, but that will take some work from the infra team.

We agreed to use environment markers in our packaging metadata to control version-specific requirements, and remove the use of version-specific requirements*.txt files. The current release of pbr understands environment markers in setup.cfg, but we still need to update projects with version-specific requirements to list their dependencies there instead of requirements.txt and to fix up the global-requirements tools to update setup.cfg instead of the requirements files. I think lifeless has signed up for some of that work, but maybe not all of it?

We agreed to move to PyMySQL as our database driver, since the one we are using now appears to be unmaintained and does not support Python 3. sdague has a series of patches up for devstack to make this change, starting with https://review.openstack.org/#/c/184489 and we will need to update the dependencies of oslo.db as well.

We still need to approve the spec (https://review.openstack.org/#/c/177375/) and I need to set up the job template so that projects can turn the job on when they are ready to try it out.

Please let me know if you think I missed any details, or misunderstood something as agreed to. Or, of course, if you weren’t there and see something wrong with the plan after looking at it now.

Doug