gitlab.freedesktop.org now has a bugbot for automatic issue/merge request processing

As of today, gitlab.freedesktop.org provides easy hooks to invoke the gitlab-triage tool for your project. gitlab-triage allows for the automation of recurring tasks, for example something like

If the label FOO is set, close the issue and add a comment containing ".... blah ..."

Many project have recurring tasks like this, e.g. the wayland project gets a lot of issues that are compositor (not protocol) issues. Being able to just set a label and have things happen is much more convenient than having to type out the same explanations over and over again.

The goal for us was to provide automated handling for these with as little friction as possible. And of course each project must be able to decide what actions should be taken. Usually gitlab-triage is run as part of project-specific scheduled pipelines but since we already have webhook-based spam-fighting tools we figured we could make this even easier.

So, bugbot was born. Any project registered with bugbot can use labels prefixed with "bugbot::" to have gitlab-triage invoked against the project's policies file. These labels thus serve as mini-commands for bugbot, though each project decides what happens for any particular label. bugbot effectively works like this:

sleep 30
for label in {issue|merge_request}.current_labels:
  if label.startswith("bugbot::"):
     wget https://gitlab.freedesktop.org/foo/bar/-/raw/{main|master}/.triage-policies.yml
     run-gitlab-triage --as-user @bugbot --use-file .triage-policies.yml
     break

And this is triggered on every issue/merge request update for any registered project which means that all you need to do is set the label and you're done. The things of note here:

• bugbot delays by 30 seconds, giving you time to unset an accidentally applied label before it takes effect
• bugbot doesn't care about the label beyond the (hard-coded) "bugbot::" prefix
• bugbot always runs your project's triage policies, from your main or master branch (whichever succeeds first)
• The actions are performed as the bugbot user, not your user

The full documentation of what you can do in a policies file is available at the gitlab-triage documentation but let's look at a simple example that shouldn't even need explanation:

resource_rules:
  issues:
    rules:
      - name: convert bugbot label to other label
        conditions:
          labels:
            - "bugbot::foo"
        actions:
          labels:
            - "foo"
          remove_labels:
            - "bugbot::foo"
          comment: |
            Nice label you have there. Would be a shame 
            if someone removed it
          status: "close"
  merge_requests:
    rules:
      []

And the effect of this file can be seen in this issue here.

Registering a project

Bugbot is part of the damspam project and registering a project can be done with a single command. Note: this can only be done by someone with the Maintainer role or above.

Create a personal access token with API access and save the token value as $XDG_CONFIG_HOME/bugbot/user.token Then run the following commands with your project's full path (e.g. mesa/mesa, pipewire/wireplumber, xorg/lib/libX11):

$ pip install git+https://gitlab.freedesktop.org/freedesktop/damspam
$ bugbot request-webhook foo/bar

After this you may remove the token file and the package

$ pip uninstall damspam
$ rm $XDG_CONFIG_HOME/bugbot/user.token

The bugbot command will file an issue in the freedesktop/fdo-bots repository. This issue will be automatically processed and should be done by the time you finish the above commands, see this issue for an example. Note: the issue processing requires a git push to an internal repo - if you script this for multiple repos please put a sleep(30) in to avoid conflicts.

Adding triage policies

Once registered, the .triage-policies.yml file must be added to the root directory of your project. What bugbot commands you want to respond to (and the actions to take) is up to you, though there are two things of note: you should always remove the bugbot label you are reacting to to avoid duplicate processing and gitlab-triage does not create new labels. So any label in your actions must be manually created in the project first. Beyond that - the sky's your limit.

Remember you can test your policies file with

 $ gitlab-triage --dry-run --token $GITLAB_TOKEN \
   --source-id foo/bar  --resource-reference 1234

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As usual, many thanks to Benjamin Tissoires for reviews and the magic of integrating this into infrastructure.