So You Want to Contribute…

For general information on contributing to OpenStack, please check out the contributor guide to get started. It covers all the basics that are common to all OpenStack projects: the accounts you need, the basics of interacting with our Gerrit review system, how we communicate as a community, etc.

The cinderlib library is maintained by the OpenStack Cinder project. To understand our development process and how you can contribute to it, please look at the Cinder project’s general contributor’s page: http://docs.openstack.org/cinder/latest/contributor/contributing.html

Some cinderlib specific information is below.

cinderlib release model

The OpenStack release model for cinderlib is cycle-with-intermediary. This means that there can be multiple full releases of cinderlib from master during a development cycle. The deliverable type of cinderlib is ‘trailing’ which means that the final release of cinderlib for a development cycle must occur within 3 months after the official OpenStack coordinated release.

At the time of the final release, the stable branch is cut, and cinderlib releases from that branch follow the normal OpenStack stable release policy.

The primary thing to keep in mind here is that there is a period at the beginning of each OpenStack development cycle (for example, Zed) when the master branch in cinder and os-brick is open for Zed development, but cinderlib’s master branch is still being used for Yoga development.

cinderlib development model

Because cinderlib depends on cinder and os-brick, its tox.ini file is set up to use cinder and os-brick from source (not from released versions) so that changes in cinder and os-brick are immediately available for testing cinderlib.

We follow this practice both for cinderlib master and for the cinderlib stable branches.

cinderlib tox and zuul configuration maintenance

As mentioned above, cinderlib’s release schedule is offset from the OpenStack coordinated release schedule by about 3 months. Thus, once cinder and os-brick have had their final release for a cycle, their master branches become the development branch for the next cycle, whereas cinderlib’s master branch is still the development branch for the previous cycle.

This has an impact on both tox.ini, which controls your local development testing environment, and .zuul.yaml, which controls cinderlib’s CI environment. These files require manual maintenance at two points during each OpenStack development cycle:

  1. When the cinder (not cinderlib) master branch opens for n+1 cycle development. This happens when the first release candidate for release n is made and the stable branch for release n is created. At this time, cinderlib master is still being used for release n development, so cinderlib master is out of phase with cinder/os-brick master branch, and we must make adjustments to cinderlib master’s tox.ini and .zuul.yaml files.

  2. When the cinderlib release n is made, cinderlib master opens for release n+1 development. Thus, cinderlib’s master branch is back in phase with cinder/os-brick master branch, and we must make adjustments to cinderlib master’s tox.ini and .zuul.yaml files.

Although cinderlib’s requirements.txt file is not used by tox (and hence not by Zuul, either), we must maintain it for people who install cinderlib via pypi. Thus it must be checked for correctness before cinderlib is released.

Throughout this section, we’ll be talking about release ‘n’ and release ‘n+1’. The example we’ll use is ‘n’ is yoga and ‘n+1’ is zed.

cinderlib tox.ini maintenance

The items are listed below in the order you’ll find them in tox.ini.

[testenv]setenv

The environment variable CINDERLIB_RELEASE must be set to the name of the release that this is the development branch for.

  • What is this used by? It’s used by tools/special_install.sh to figure out what the appropriate upper-constraints file is.

  • When should it be changed? The requirements team has been setting up the redirect for https://releases.openstack.org/constraints/upper/{release} at the beginning of each OpenStack development cycle (that is, when master is Zed development, for example, the url https://releases.openstack.org/constraints/upper/zed redirects to the upper-constraints.txt in requirements master). Thus, you should only have to change the value of CINDERLIB_RELEASE in cinderlib master at the time it opens for release ‘n+1’.

[testenv]deps

  • While both the cinder and cinderlib master branches are the development branches for the ‘n’ release cycle (yoga, for example), the base testenv in tox.ini in master should look like this:

    # Use cinder and os-brick from the appropriate development branch instead of
# from PyPi.  Defining the egg name we won't overwrite the package installed
# by Zuul on jobs supporting cross-project dependencies (include Cinder in
# required-projects).  This allows us to also run local tests against the
# latest cinder/brick code instead of released code.
# NOTE: Functional tests may fail if host is missing bindeps from deps projects
deps= -r{toxinidir}/test-requirements.txt
      git+https://opendev.org/openstack/os-brick
      git+https://opendev.org/openstack/cinder

  • When the coordinated release for cycle ‘n’ has occurred, cinderlib’s tox.ini in master must be modified so that cinderlib is being tested against cinder and os-brick from the stable branches for the ‘n’ release (in this example, stable/yoga):

    deps = -r{toxinidir}/test-requirements.txt
       git+https://opendev.org/openstack/os-brick@stable/yoga
       git+https://opendev.org/openstack/cinder@stable/yoga

  • After the ‘n’ release of cinderlib occurs (and the stable/n branch is cut), all of cinder, os-brick, and cinderlib master branches are all ‘n+1’ cycle development branches, so:

    • The base testenv in tox.ini in master must be modified to use cinder and os-brick from master for testing, reverting the first code block change above.

[testenv:py{3,36,38}]install_command

Note: the actual list of versions may be different from what’s listed in the documentation heading above.

This testenv inherits from the base testenv and is the parent for all the unit tests. At the time cinderlib master opens for release ‘n+1’ development, check that all supported python versions for the release are listed between the braces (that is, { and }).

  • The tox term for this is “Generative section names”. See the tox docs for more information and the proper syntax.

  • The list of supported python runtimes can be found in the OpenStack governance documentation.

  • If the supported python runtimes have changed from the previous release, you may also need to update the python_requires and the “Programming Language” classifiers in cinderlib’s setup.cfg file.

[testenv:docs]install_command

  • The docs testenv sets a default value for TOX_CONSTRAINTS_FILE as part of the install_command. This only needs to be changed at the time cinderlib master opens for release ‘n+1’. See the discussion above about setting the value for CINDERLIB_RELEASE; the same considerations apply here.

    The [testenv:docs]install_command is referred to by the other documentation-like testenvs, so you should only have to change the value of TOX_CONSTRAINTS_FILE in one place. (But do a scan of tox.ini to be sure, and if you find another, please update this page.)

cinderlib .zuul.yaml maintenance

A few things to note about the cinderlib .zuul.yaml file.

  • The OpenStack QA team defines “templates” that can be used for testing. A template defines a set of jobs that are run in the check and the gate, and the QA team takes the responsibility to make sure that the template for a release includes all the appropriate tests.

    We don’t use the ‘openstack-python3-{release}-jobs’ template; instead, we directly configure the jobs that are listed in the template. The reason for this is that during cinderlib’s trailing development phase (when cinderlib master is the development branch for release ‘n’ while cinder and os-brick master is the development branch for release ‘n+1’, we need to make sure that zuul installs the correct cinder and os-brick branch to test against. We can do this by specifying an ‘override-checkout’ for cinder, os-brick, and requirements in the job definitions.

    We need to do this even though the zuul jobs will ultimately call cinderlib’s tox.ini, where we have already configured the correct branches to use. That’s because Zuul doesn’t simply call tox; it does a bunch of setup work to download packages and configure the environment, and if we don’t specifically tell Zuul what branches to use, when we run a job on a cinderlib master patch, Zuul figures that all components are supposed to be installed from their master branch – including openstack requirements, which specifies the upper-constraints for the release.

  • The QA testing templates are defined here: https://opendev.org/openstack/openstack-zuul-jobs/src/branch/master/zuul.d/project-templates.yaml

    The openstack-zuul-jobs repo is not branched, so that file will contain the testing templates for all stable branches for which OpenStack CI is still supported.

    After the cinderlib ‘n’ release, you will open cinderlib for ‘n+1’ development. For example, after the yoga release, you will open cinderlib for zed development. For the reasons outlined above, we won’t use the zed template directly, but you need to look at it to see what jobs it includes, and make sure that cinderlib’s .zuul.yaml uses equivalent jobs in each of the check, gate, and post pipelines.

    • What’s meant by “equivalent jobs” is best explained by an example. The openstack-python3-zed-jobs template contains (among other things) an openstack-tox-py39 job. We don’t use that job directly, but instead have an cinderlib-tox-py39 job defined in the cinderlib .zuul.yaml that has openstack-tox-py39 as a parent. (If the equivalent job you need doesn’t exist, you must create it, using the other jobs as examples.)

      We need these cinderlib-specific jobs for running unit tests in the CI because the tests run using the development versions of cinder and os-brick, not released versions, so we need to tell Zuul that it needs to have the code repositories for cinder and os-brick available. (We also tell it to have the requirements repo available; it will be needed during cinderlib’s cycle-trailing development phase.)

With that background, here are the .zuul.yaml maintenance tasks.

  • When the coordinated release for cycle ‘n’ has occurred, the jobs in cinderlib’s .zuul.yaml in master must be updated to use the ‘n’ stable branch for each of its sibling projects. Letting ‘n’ be the Yoga relase, what this means is that the jobs will change from looking like this:

    - job:
    name: cinderlib-tox-py39
    parent: openstack-tox-py39
    required-projects:
      - name: openstack/os-brick
      - name: openstack/cinder
      - name: openstack/requirements

    to looking like this:

    - job:
    name: cinderlib-tox-py39
    parent: openstack-tox-py39
    required-projects:
      - name: openstack/os-brick
        override-checkout: stable/yoga
      - name: openstack/cinder
        override-checkout: stable/yoga
      - name: openstack/requirements
        override-checkout: stable/yoga

    Additionally, instead of running the os-brick-src-tempest-lvm-lio-barbican job (which is defined in the os-brick repository), we will need to run a special version of that job will be defined in cinderlib’s .zuul.yaml. This job should already be defined in the file, and will be named cinderlib-os-brick-src-tempest-lvm-lio-barbican-{release}. Verify that the job has the correct branch specified for override-checkout, and then configure the check and gate sections to run this job.

  • After the ‘n’ release of cinderlib, when cinderlib master has become the ‘n+1’ development branch and is once again in sync with the master branches of cinder and os-brick:

    • remove the override-checkout specification from the cinderlib-tox-* job definitions

    • take a look at the ‘n+1’ release testing template (as discussed above) and make sure that cinderlib is running the correct jobs for the cycle

    • run os-brick-src-tempest-lvm-lio-barbican in the check and gate

    • update the definition for the ‘cinderlib-os-brick-src-tempest-lvm-lio-barbican-{release}’ job so that it will be ready when you need it later in the cycle.

cinderlib requirements.txt maintenance

  • When the coordinated release for cycle ‘n’ has occurred, cinderlib’s requirements.txt in master must be updated to use only ‘n’ deliverables (in this example, yoga):

    # restrict cinder to the yoga release only
cinder>=20.0.0.0,<21.0.0  # Apache-2.0
# brick upper bound is controlled by yoga/upper-constraints
os-brick>=5.2.0  # Apache-2.0

  • After the ‘n’ release of cinderlib, when cinderlib master has become the ‘n+1’ development branch, requirements.txt can again be updated:

    • Remove the upper bound from cinder.

    • The release team likes to push an early release of os-brick from master early in the development cycle. Check to see if that has happened already, and if so, update the minimum version of os-brick to the latest release and make appropriate adjustments to the comments in the file.