Writing a patch

Create a local working branch

Start by creating a local git branch where you will commit your work:

git checkout origin/develop -b myfeature

This will create a local git branch called myfeature that is associated with the upstream develop branch for easy rebasing.

Beaker uses a number of Javascript libraries which are tracked using git submodules. You must run git submodule init followed by git submodule update to clone them.

For new features and any invasive bug fixes (e.g. those requiring database changes), the working branch should be based on origin/develop as shown.

For bug fixes that don’t require invasive changes, then the working branch should be based on the latest release branch. For example, if the latest release shown on the release download page is Beaker 26.5, then local branches to work on bug fixes should be created with a command like:

git checkout origin/release-26 -b bz123456_fix_this_bug

Including the bug number in the branch name isn’t required (since the branch name is never published to anyone else), but it’s a useful reference point when working on multiple patches in parallel.

Develop against a production database snapshot

If possible, load a large, realistic database dump into your local Beaker database before you start writing any code, rather than starting from an empty database. This will give you a more realistic picture of how your code will perform in real world conditions.

Beaker core developers can use a database dump from Red Hat’s production Beaker instance for their development, which will help to reveal potential problems in your patch when it has to run against tables containing tens or hundreds of millions of rows.

After you have loaded and migrated a database snapshot, perform the following steps to safeguard data and avoid interfering with production systems:

  1. Set all user passwords to NULL:

    UPDATE tg_user SET password = NULL;
  2. Set the power settings stored in the power table to NULL:

    UPDATE power SET power_address = NULL, power_user = NULL, power_passwd = NULL;
  3. In order to log in, set the password for a user. For example:

    UPDATE tg_user SET password = sha("admin") WHERE user_name = "admin";

Testing your patch

While working on your patch, you can run individual test cases as you add or update them. For example:

cd IntegrationTests/
./ -sv bkr.inttest.server.selenium.test_recipes:RecipeHTTPTest.test_anonymous_cannot_update_recipe

Once your code is ready, you can run all the tests for a particular page, command, or area of functionality to check for unintended side effects:

./ -v bkr.inttest.server.selenium.test_recipes

You can also run the complete test suite (but bear in mind that it takes over 2 hours to run, and Jenkins will do this for you once your patch is posted to Gerrit):


The script is a thin wrapper around nosetests which sets up PYTHONPATH for running from a git checkout.

Once you’ve verified the patch passes the test suite, commit it to your local branch:

git commit

You can also run the Beaker test suite in Beaker (assuming you have access to a working Beaker instance) using the /distribution/beaker/dogfood task. If your Beaker instance doesn’t already have a copy of this task, you can build it from Beaker’s source under the Tasks subdirectory. You can base your job on this sample dogfood job XML.

Building RPMs

You can use Misc/ to build Beaker RPMs for testing:

Misc/ -bb

or if you have Mock or Koji suitably configured, you can generate an SRPM and build from that:

Misc/ -bs

You may first need to install all the build dependencies using yum-builddep beaker.spec. The Misc/ script will build from the HEAD commit in git, so make sure you have committed your changes to your local branch.

If the patch changes an existing feature or adds a new one, then ideally the relevant documentation should be updated. Also note that linking the documented feature to the release notes, and/or using the ‘versionchanged/versionadded’ directive where appropriate is encouraged.

Submitting your patch

The Beaker project uses the Gerrit code review tool to manage patches. All patches are reviewed on Beaker’s Gerrit installation before being merged:

New users can sign in using any OpenID account (preferably your Fedora OpenID). Be sure to configure your e-mail addresses and SSH keys in Gerrit after creating your account. Your SSH key is needed to authenticate you when pushing patches using git. The e-mail address in your git commits must also match one of the e-mail addresses you have registered in Gerrit.

For convenience, you can add the Gerrit server as a git remote:

git remote add --fetch gerrit \

Once you’re happy with the change and the test you have written for it, push your local myfeature branch to Gerrit for review:

git push gerrit myfeature:refs/for/develop

The destination branch in Gerrit should match the branch used as a basis for the patch. As mentioned above, new features and invasive changes should target the develop branch, whereas minor fixes can target the current maintenance branch (for example release-26). For a bug fix targeting the Beaker 26 maintenance series, the appropriate command would be:

git review release-26

A new “change” in Gerrit will be created from your commit. Beaker developers can then review and merge it as appropriate. See the Gerrit documentation for more info.

If your patch fixes a bug, be sure to include a reference to the Bugzilla number as a footer line like “Bug: 123456” in the commit message (example).

To update the patch on an existing change, you can use git commit --amend. You must ensure that the correct Change-Id footer appears in your amended commit message. Refer to the Gerrit Change-Id documentation for more details.

To avoid forgetting the Change-Id footer and accidentally creating a new review instead of updating an existing one, it’s useful to install this hook which automatically adds an appropriate “Change-Id” entry to the commit message when a patch is first committed locally:

scp -p -P 29418 .git/hooks/

Reviewing a patch

For a change to make it through review and be merged into the development branch for the next Beaker release, it needs to first be marked in Gerrit as “+1 Verified” and have a “+2 Looks good to me, approved” code review (only the core Beaker developers can grant the latter).

The “+1 Verified” marker indicates one of the following:

  • If it’s a bug fix that is reproduceable and testable, the new test case has been verified to fail before the fix, and pass after the fix.
  • If it’s a bug fix that is not amenable to an automated test, the patch has been verified to fix the bug through some other means (such as trying it out manually).
  • If it’s a new feature, the feature has been verified to work as described.
  • If it’s a code change, the test suite has been verified to pass in full.
  • If it’s a docs change, the docs have been verified to build correctly and look right.
  • On some rare occasions (for example, fixing a typo in a comment or README), it may simply indicate that the patch has been determined not to run a risk of breaking the application or documentation.

The “+2 Approved” code review marker should only be granted when all the following criteria are met:

  • The patch is targetting the right branch (develop for new features and invasive bug fixes, latest release branch for non-invasive bug fixes)
  • All significant review comments have been addressed, with the aim of ensuring the Beaker code remains maintainable rather than degenerating over time.
  • Whenever practical, automated tests have been added to ensure the bug fix or new feature works as expected.
  • The code is commented appropriately (for example, explanations or issue tracker references are included for any obscure workarounds).
  • The documentation (including docstrings) has been updated appropriately
  • A release note has been added as described in the What’s New source for new features, bug fixes that may break existing workarounds, and any changes that require manual steps from system administrators when upgrading an existing installation.
  • The commit message is correctly formatted with a short summary line and any additional continuation lines separated from the summary by a blank line.
  • For changes driven by a Bugzilla entry, the correct “Bug: NNNNNN” reference is present in the commit message (as described above in “Submitting your patch”).
  • For functional and testing changes (that is, changes affecting code, not just documentation), another core developer has already granted “+1 Looks good to me, but someone else must approve” based on the above criteria (this criterion may occasionally be waived based on core developer availability).

Reviewers should also be looking for “missing updates”: changes which should have been made, but are not part of the current patch. For example, if a new attribute is added for Jobs, then the Job detail page should probably be updated to display that attribute as well. Another example would be that if a patch changes the repo layout, then the description of that layout in the README file should also be updated.

There’s no simple guideline to help identify “what’s missing” in cases that aren’t automatically detected through failing tests: it’s something that can only come from experience with Beaker and its code. To minimise such cases, it is often desirable to add a test case that ensures the two components are kept in sync, rather than relying on developers to remember to update both places (assuming the duplication can’t be eliminated entirely by changing the implementation). That way, the missing updates should be picked up automatically as a failure in the test suite, rather than requiring the patch creator or reviewer to notice that additional changes are needed.

Exceptions to the review process

Core developers are permitted to bypass the review process by setting the review on their own patches in at least the following circumstances:

  • when a previously approved patch needs to be rebased to get Gerrit to merge it, but no actual changes were needed as part of the rebase (Gerrit is configured to rebase automatically, but the web UI sometimes gets confused and hides the submit button even though the rebase would work automatically)
  • when minor fixes have been made to a previously approved documentation patch (documentation patch reviews are mainly aimed at overall structure and picking up omissions and technical errors. Fixing a typo or grammar error doesn’t require restarting the entire review process)
  • updating the git submodules for the documentation (this may be pushed directly to git, bypassing Gerrit entirely)
  • design proposal updates (design proposals should generally be discussed on the development mailing list rather than in a Gerrit review, although the latter can be useful for line-by-line commenting on specific details)
  • technical road map updates (the overall technical road map is only updated by, or at the direction of, the Beaker Development Lead, rather than using the regular change review process)
  • any changes to the beaker-administrivia repo (these scripts are just used to help with issue management and status tracking, and don’t directly impact the actual functional code, tests or documentation)

As other exceptional cases are identified, they will also be noted here.