Project Driver’s Guide

Branches

Projects might want to create branches for either prolonged development on specific branches, so called feature branches, or for maintenance of a release, these are called stable branches.

Some projects use the namespace feature/ for feature branches and stable/ for stable branches.

Branch Creation

If you are managing branches for your project you may have permission to do this yourself:

  • Go to https://review.opendev.org/ and sign in

  • Select ‘Admin’, ‘Projects’, then the project

  • Select ‘Branches’

  • Enter the name of your branch in the ‘Branch Name’ field, and HEAD as the ‘Initial Revision’, then press ‘Create Branch’. Alternatively, you may run git branch <new-branch> <sha> && git push gerrit <new-branch>

If you do not have the option to add a new branch, you will need to contact the OpenDev team to get the necessary permissions for the project.

Once this is done, you should push a change updating the defaultbranch in .gitreview to match the new name of the branch, so that “git review” automatically pushes to the right branch:

defaultbranch=<new-branch>

To check out the new branch in your local checkout, you can use:

git checkout master
git pull
git checkout <new-branch>

Feature Branches

There are times when prolonged development on specific features is easier on a feature branch rather than on master. In particular it organizes work to a location that interested parties can follow. Feature branches also move merge points to specific points in time rather than at every proposed change.

If more than one project is involved in a feature development effort, the same feature branch name should be used across all involved projects. This will cause integration testing with Zuul to use the respective feature branch from any project that carries it. Projects without an equivalently named feature branch will use master instead. Use care not to create a feature branch with the same name as a feature branch for an unrelated effort in another project.

One additional thing to keep in mind is that feature branches should be treated like master in most cases. They are specifically not for sustained long term development like stable branches.

Merge Commits

An important activity when using feature branches is syncing to and from the project’s master branch. During development on a feature branch a project will want to merge master into the feature branch periodically to keep up to date with changes over time. Then when development on the feature branch is complete, it will need to be merged into master.

Before this can happen the project team’s release group will need to have access to push merge commits in Gerrit:

[access "refs/for/refs/*"]
pushMerge = group <projectname>-release

Should be added to the project’s ACL file in the project-config repo.

Merge Master into Feature Branch

git remote update
git checkout feature-branch
git pull --ff-only origin feature-branch
git checkout -b merge-branch
git merge origin/master
# Amend the merge commit to automatically add a Change-ID to the commit message
GIT_EDITOR=/bin/true git commit --amend
git review -R feature-branch
git checkout master
git branch -D merge-branch

Merge Feature Branch into Master

git remote update
git checkout master
git pull --ff-only origin master
git checkout -b merge-branch
# Force a merge commit by not fast-forwarding, in case master hasn't updated:
git merge --no-ff origin/feature-branch
# Amend the merge commit to automatically add a Change-ID to the commit message:
GIT_EDITOR=/bin/true git commit --amend
git review -R
git checkout master
git branch -D merge-branch

How To Avoid Merging Specific Files

Sometimes you may have files on one branch you don’t want merged to or from another. An easy workaround for this is to checkout the file in question from the target branch and amend your merge commit before pushing it for review. For example, as in the last section you’ve just merged from origin/feature-branch into your local merge-branch but want to keep the .gitreview file from master because you don’t want defaultbranch=feature-branch added to it. Immediately before you git commit --amend do:

git checkout origin/master -- .gitreview

Stable or Maintenance Branches

If your project consists of several repositories or it is part of a larger group of projects, the same branch name should be used across all involved projects. This will cause integration testing with Zuul to use the respective stable branch from any project that carries it. Projects without an equivalently named stable branch will use master instead.

Authoring Changes for branches

Create topic branches as normal, but branch them from the feature or stable branch rather than master:

git checkout <branch>
git pull
git checkout -b <topic branch>

Generally the defaultbranch in .gitreview is adjusted on the new branch so that you can directly use git review. If not, changes for stable/* should be submitted with:

git review <branch>

Submit Changes in master to a stable branch

If a change to master should also be included in a stable branch, use this procedure to cherry-pick that change and submit it for review:

git checkout <stable-branch>
git pull
git checkout -b master-to-mp
git cherry-pick -x <SHA1 or "master">
git review <stable-branch>
git checkout master
git branch -D master-to-mp

git cherry-pick master will pick the most recent commit from master to apply, if you want a different patch, use the SHA1 of the commit instead.

The -x flag will ensure the commit message records the SHA1 hash of the original commit in master.

If there are conflicts when cherry-picking, do not delete the ‘Conflicts’ lines git adds to the commit message. These are valuable to reviewers to identify files which need extra attention.

Tagging a Release

If you are managing your own releases, your ACLs need to be setup to have have permission to tag a relase.

Tag the tip of the appropriate branch with a release tag and push that tag to Gerrit by running the following commands:

git checkout <branch name>
git pull --ff-only
git tag -s <version number>
git push gerrit <version number>

Note

  • Pushing the tag will trigger the release pipeline in zuul, but without proper configuration no release will happen. A publishing job is required. One common way to do this is to use a publish-to-pypi template in openstack/project-config. The publishing jobs are one of the Central Config Exceptions.

  • Tags can’t be effectively deleted once pushed, so make absolutely certain they’re correct (ideally by locally testing release artifact generation commands and inspecting the results between the tag and push steps above).

  • Git won’t have a remote named gerrit until the first time git-review runs. You may need to run git review -s before the push.

  • The -s option to git tag signs the tag using GnuPG, so it’s important to ensure that the person making the release has a suitable OpenPGP key.

  • Make sure you’re only adding a single tag when pushing to gerrit, like in the example above.

  • After a tag is created the release build will generate a source code tarball and may publish it to a repository such as PyPI.

  • Tags need to follow the format of PEP 440 which consists for final releases of one or more non-negative integer values, separated by dots. Be aware that pbr needs a three component version, like 1.0.0 or 1.2.3.

    If you need to support other version schemes, you might need to use the tag pipeline instead of the default release pipeline. Best discuss this with the OpenDev team.

Gerrit IRC Notifications

The intent of this section is to detail how to set up notifications about all the projects that are hosted on OpenDev Gerrit in the appropriate IRC channels.

GerritBot is an IRC bot that listens to the OpenDev Gerrit server for events and notifies those on Freenode’s channels.

GerritBot is able to notify the channel for events like creation of patchsets, changes merged, comments added to patchsets and updates to refs. These event notifications can be configured per project, so the channel can have multiple notifications per project.

Before you can configure GerritBot, you need to give channel permissions with an accessbot configuration specific to the channel where you want notifications posted. The configuration file is hosted in openstack/project-config. Edit accessbot/channels.yaml to add your IRC channel if it is not already listed.

In order for GerritBot to post notifications on the IRC channel of the project you are configuring, you need to add your GerritBot configuration into gerritbot/channels.yaml. This file is hosted in openstack/project-config.

The syntax for configuring the notifications is:

<IRC channel>:
      events:
        - patchset-created
        - change-merged
        - comment-added
        - ref-updated
      projects:
        - <project name>
      branches:
        - <branch name>

Please note that the text between the angle brackets are placeholder values. Multiple projects and branches can be listed in the YAML file.

Running Jobs with Zuul

Those looking to write and run jobs with Zuul can refer to Zuul’s documentation in order to get started.

Retiring a Project

If you need to retire a project and no longer accept patches, it is important to communicate that to both users and contributors. The following steps will help you wind down a project gracefully.

Note

The following sections are really separate steps. If your project has jobs set up, you need to submit several different changes as explained below. We recommend to link these changes with “Depends-On:” and “Needed-By:” headers.

Prerequirement: Announce Retirement

Use mailing lists or other channels to announce to users and contributors that the project is being retired. Be sure to include a date upon which maintenance will end, if that date is in the future.

Step 1: End Project Gating

Check out a copy of the openstack/project-config repository and edit zuul.d/projects.yaml. Find the section for your project and change it to look like this:

- project:
  name: <namespace>/<projectname>
  templates:
    - noop-jobs

Also, remove any jobs and templates you have defined. These can be defined in openstack/project-config repository in the directory zuul.d, or in openstack/openstack-zuul-jobs repository or in your own repository.

Submit that change and make sure to mention in the commit message that you are ending project gating for the purposes of retiring the project. Wait for that change to merge and then proceed.

Step 2: Remove Project Content

Once Zuul is no longer running tests on your project, prepare a change that removes all of the files from your project except the README. Double check that all dot files (such as .gitignore and .testr.conf) except .gitreview are also removed.

Note

Removing the .gitreview file from the master branch of a repository breaks much of the OpenStack release tools, so it will be harder to continue to tag releases on existing stable branches. Take care to remove all files other than README.rst and .gitreview.

Replace the contents of the README with a message such as this:

This project is no longer maintained.

The contents of this repository are still available in the Git
source code management system.  To see the contents of this
repository before it reached its end of life, please check out the
previous commit with "git checkout HEAD^1".

(Optional:)
For an alternative project, please see <alternative project name> at
<alternative project URL>.

For any further questions, please email
openstack-discuss@lists.openstack.org or join #openstack-dev on
Freenode.

Merge this commit to your project.

If any users missed the announcement that the project is being retired, removing the content of the repository will cause any users who continuously deploy the software as well as users who track changes to the repository to notice the retirement. While this may be disruptive, it is generally considered better than continuing to deploy unmaintained software. Potential contributors who may not have otherwise read the README will in this case, as it is the only file in the repository.

Step 3: Remove Project from Infrastructure Systems

Once your repository is in its final state, prepare a second change to the openstack/project-config repository that does the following:

  • Remove your project from zuul.d/projects.yaml and zuul/main.yaml.

  • By default, project ACLs are defined in a file called gerrit/acls/<namespace>/<projectname>.config. If this file exists, remove it.

  • Now adjust the project configuration and use the shared read-only ACLs. Find the entry for your project in gerrit/projects.yaml and look for the line which defines the acl-config, update or add it so that it contents is:

    acl-config: /home/gerrit2/acls/openstack/retired.config
    

    Also prefix the project description with RETIRED,:

    description: RETIRED, existing  project description
    
  • Remove your project from gerritbot/channels.yaml.

Note

If there is a need to unretire a project, most steps here can be done in reverse. This step has some caveats to be aware of when going in reverse.

With the removal of ACLs from the Gerrit project, the project gets marked as read-only. Adding those ACLs back to the configuration files does not switch it back to read-write. Manual intervention will be required from the infra team to restore the project status back to “Active” in Gerrit before ACLs can be reapplied successfully.

Package Requirements

The OpenDev infrastructure sets up nodes for testing that contain a minimal system and a number of convenience distribution packages.

If you want to add additional packages, you have several options.

If you run Python tests using tox, you can install them using requirements.txt and test-requirements.txt files (for OpenStack projects, see also the global requirements process). If these Python tests need additional distribution packages installed as well and if those are not in the nodes used for testing, they have to be installed explicitly.

If you are building documentation, the file doc/requirements.txt is used instead to install Python packages.

If you run devstack based tests, then list missing binary packages below the files directory of devstack.

For non-devstack based tests, add a bindep.txt file containing listing the required distribution packages. It is a cross-platform list of all dependencies needed for running tests. The bindep utility will be used to install the right dependencies per distribution when running in the OpenDev infrastructure.

If you use bindep, create a bindep tox environment as well:

[testenv:bindep]
# Do not install any requirements. We want this to be fast and work even if
# system dependencies are missing, since it's used to tell you what system
# dependencies are missing! This also means that bindep must be installed
# separately, outside of the requirements files.
deps = bindep
commands = bindep test

This way a developer can just run bindep to get a list of missing packages for their own system:

$ tox -e bindep

The output of this can then be fed into the distribution package manager like apt-get, dnf, yum, or zypper to install missing binary packages.

The OpenDev infrastructure will install packages marked for a profile named “test” along with any packages belonging to the default profile of the bindep.txt file. Add any build time requirements and any requirements specific to the test jobs to the “test” profile, add any requirements specific to documentation building to the “doc” profile, add requirements for test, runtime, and documentation to the base profile:

# A runtime dependency
libffi6
# A build time dependency
libffi-devel [test]
# A documentation dependency
graphviz [doc]

Submodules

The use of git submodules is not supported. The tools that we use do not all work correctly with submodules and we have found that submodules can be very confusing even for experienced developers. If your project depends on another project, please express that as an external dependency on a released package (i.e., through requirements.txt, bindep.txt, or similar mechanism).

Unit Test Set up

Projects might need special set up for unit tests which can be done via the script tools/test-setup.sh that needs to reside in the repository.

Python unit tests are tests like coverage, python27, python35, and pypy which are run using python’s tox package as well as tests using the template openstack-tox-{envlist} or tox-{envlist}. For these tests, the script tools/test-setup.sh is run if it exists in the repository and is executable after package installation. The script has sudo access and can set up the test environment as needed. For example, it should be used to set up the openstack_citest databases for testing.

Consistent Naming for Zuul Jobs

This document describes a consistent naming scheme for Zuul jobs. The goal is to give job developer and reviewers of jobs a common document as reference. This is particularly important because all jobs within a Zuul tenant share a common global namespace. Adhering to these guidelines avoids collisions between jobs defined in various repositories within a Zuul tenant.

Warning

This is a living document, it may get updates as our use of Zuul changes over time.

Job Naming Scheme

  • The general pattern is {prefix-}MAINPURPOSE-DETAILS{-}{node}.

  • Jobs in specific pipelines have no special prefix, there’s no need to use gate- or periodic as it was done with Zuul v2.

  • There is in general no need to give the name of the repository as part of the job as it was done with Zuul v2, unless the job is defined in a specific repo.

  • Publishing jobs, like documentation or tarball uploads, have a prefix of publish like publish-tarball and publish-sphinx-docs.

    These jobs are normally run in a post pipeline.

  • Jobs that build an artifact without uploading build like build-sphinx-docs.

  • Jobs have the optional suffixes {node} which is used when a test should be run on different platforms like on CentOS, Fedora, openSUSE, or Ubuntu - or on different versions of these. For jobs that are only run on one platform, the suffix {node} should be avoided. The suffix {node} is the name for the node the job runs on. If this is a a multi-node job, it’s the name of the underlying single node.

  • Use consistent names like “integration”, “functional”, “rally”, “tempest”, “grenade”, “devstack” (what do we need? Those should be explained) as MAINPURPOSE.

  • Components of job names are separated by -.

  • Do not use “.” for versions, just cat them together like 35 for Python 3.5.

  • Since Zuul allows overriding of job and definition of jobs, care should be taken not to use the same name for different jobs:

    • If you override a generic Zuul job for project specific usage prefix it with PROJECT-. For example, OpenStack creates versions of generic jobs intended to be used globally within OpenStack and prefixes them with openstack-.

    • If you define a job in a specific repo, the name of the job should use the repository name as prefix or as first part of it.

Examples of job names using these rules:

  • tox-py27 or openstack-py27

  • tox-py35 or openstack-py35

  • grenade-neutron-forward

  • neutron-api (or neutron-api-ubuntu-xenial if multiple OSes need to be tested)

  • tempest-neutron-full-ssh

  • build-sphinx-docs

  • publish-sphinx-docs

Outbound Third-Party Testing

Many organizations generously donate cloud computing resources to OpenDev for use by its testing and automation system so that we can maintain and improve the quality of the hosted software. We are stewards of these resources and strive to use them wisely and responsibly.

These resources are available to perform integration testing with Open-Source projects which are direct dependencies or direct downstream consumers of hosted projects. If you want to set up an integration test with a non-hosted project that meets these criteria, follow the instructions below.

Currently, Zuul is able to report on changes proposed to Gerrit systems or GitHub. If the project you want to test with isn’t hosted on a Gerrit or GitHub, contact the infrastructure team in the #opendev channel on the Freenode IRC network to discuss options.

In all cases, before starting this process, be sure you have discussed this with the team responsible for the project you want to test. You should get their approval to report test results on changes or pull-requests.

Hosted on an External Gerrit

If the project you wish to test is hosted on a Gerrit system (other than OpenDev’s Gerrit), you may need to connect Zuul to it first, if it isn’t already. To do so, propose a change to system-config which adds the connection information for the new server, then work with the infra team in #opendev to set up an account.

Once this is complete, propose a change to add the project(s) to OpenDev’s Zuul. Add them to project-config/zuul/main.yaml under the connection name established above.

The project should not be configured to load any configuration objects (i.e., it should have an include: [] stanza associated with it).

Hosted on GitHub

If the project you wish to test is hosted on GitHub, ask the team managing the project to install the “OpenStack Zuul” App into the project (or organization if multiple projects are involved).

Visit the OpenDev Zuul App page on GitHub and click the Install button to install the app.

Once this is complete, propose a change to add the project(s) to OpenDev’s Zuul. Add them to project-config/zuul/main.yaml under the github: connection.

The project should not be configured to load any configuration objects (i.e., it should have an include: [] stanza associated with it).

Add to Pipelines

Once Zuul is configured to know about the project, it can be added to pipelines just like any other project in Zuul. However, external projects should only be added to the third-party-check pipeline. Because we are not loading any in-tree configuration from these projects, this needs to be done in the project-config repo. Define the jobs you wish to run either in your own repos, or in openstack-zuul-jobs. Then create project definitions for the new projects in project-config/zuul.d/projects.yaml which adds those jobs to the new project on the third-party-check pipeline.