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Automate Creating Branches

Include the URL of your StoryBoard story:

https://storyboard.openstack.org/?#!/story/2000722

The release management team would like to manage branches through a reviewable process, like we do with tags.

Problem Description

The process for creating stable and feature branches is manual and ill-defined, both of which make it error-prone. We have partially automated the process of creating the stable branches, but a release manager has to remember to run the script after tagging an RC1 release for a project. We would like to manage the branches using deliverable files in openstack/releases, like we do now with tags.

Proposed Change

Extend the schema of the deliverable files in openstack/releases to include information about branches as well as releases. Add a new “branches” key at the top level, parallel to “releases”. The contents of the “branches” section are a list of branches with “name” and “location” values.

The “name” is a string value that will become the name of the new branch without any modifications made to it (no prefix added automatically, no lower-casing, etc.).

The “location” value depends on the name. If a branch name starts with stable/ then the location must be either an existing version tag or the most recently added version number under the “releases” list (allowing a tag and branch to be submitted together).

If a branch name starts with feature/ then the “location” must be a mapping between the target repository name and the SHA of a commit already in the target repository.

The names of branches will be reviewed by human reviewers.

Even after implemented we would retain the ability for humans to create branches manually, but this process should make most branch creation simpler and more reliable.

Alternatives

  1. Continue to create branches by hand, using the informal request system (email or IRC) and RC1 tagging.

    This approach remains error prone.

  2. Add a “branch” key to the releases section of the deliverable file.

    This approach would not support feature branches.

Implementation

Assignee(s)

Primary assignee: doughellmann

Gerrit Topic

Use Gerrit topic “branch-automation” for all patches related to this spec.

git-review -t branch-automation

Work Items

  1. Extend the validation of deliverable files to cover branches, using the rules described above.

  2. Extend the validation of deliverable files to ensure that RC1 versions also have stable branches added at the same time.

  3. Extend the validation of deliverable files to ensure that if a branch exists, it starts at the point specified in the location. (This ensures that we import old data correctly.)

  4. Either extend the tag-releases job (or add a new job) to look at the branch list in the deliverable file and create the last one in the list if it does not exist. This approach is consistent with our treatment of adding tags one at a time.

    Some relevant code for working with branches already exists in openstack-infra/project-config/jenkins/scripts/release-tools/make_stable_branch.sh, .../branch_from_yaml.sh, and openstack-infra/release-tools/make_feature_branch.sh. Those scripts will be reused or obsoleted by this work.

    Some projects, like devstack and grenade, may require extra work when a branch is created. We could use a hook script from inside of the repository being branched to make additional changes in the repository after it is branched, or we could embed that logic in the branching script itself using repository-specific logic. The latter is more secure, but the former is more flexible.

Repositories

No new repositories needed.

Servers

The branching will be done by the same signing node that currently applies tags.

DNS Entries

No new entries.

Documentation

  1. Update the README.rst in openstack/releases to describe the schema.
  2. Update the project team guide to cover the new procedure for requesting a branch.

Security

The signing node should not need any additional credentials, though the associated gerrit account may need more permissions than it has.

Testing

We can automate the testing of the validation code and manually test creating the branches using the openstack/release-test repository.

Dependencies

None