GitHub

The GitHub driver supports sources, triggers, and reporters. It can interact with the public GitHub service as well as site-local installations of GitHub enterprise.

Configure GitHub

There are two options currently available. GitHub’s project owner can either manually setup web-hook or install a GitHub Application. In the first case, the project’s owner needs to know the zuul endpoint and the webhook secrets.

Web-Hook

To configure a project’s webhook events:

Set Payload URL to http://<zuul-hostname>:<port>/api/connection/<connection-name>/payload.
Set Content Type to application/json.

Select Events you are interested in. See below for the supported events.

You will also need to have a GitHub user created for your zuul:

Zuul public key needs to be added to the GitHub account
A api_token needs to be created too, see this article

Then in the zuul.conf, set webhook_token and api_token.

Application

To create a GitHub application:

Go to your organization settings page to create the application, e.g.: https://github.com/organizations/my-org/settings/apps/new
Set GitHub App name to “my-org-zuul”
Set Setup URL to your setup documentation, when user install the application they are redirected to this url
Set Webhook URL to http://<zuul-hostname>:<port>/api/connection/<connection-name>/payload.
Create a Webhook secret
Set permissions:
- Repository administration: Read
- Checks: Read & Write
- Repository contents: Read & Write (write to let zuul merge change)
- Issues: Read & Write
- Pull requests: Read & Write
- Commit statuses: Read & Write
Set events subscription:
- Check run
- Commit comment
- Create
- Push
- Release
- Issue comment
- Issues
- Label
- Pull request
- Pull request review
- Pull request review comment
- Status
Set Where can this GitHub App be installed to “Any account”
Create the App
Generate a Private key in the app settings page

Then in the zuul.conf, set webhook_token, app_id and app_key. After restarting zuul-scheduler, verify in the ‘Advanced’ tab that the Ping payload works (green tick and 200 response)

Users can now install the application using its public page, e.g.: https://github.com/apps/my-org-zuul

Note

GitHub Pull Requests that modify GitHub Actions workflow configuration files cannot be merged by application credentials (this is any Pull Request that edits the .github/workflows directory and its contents). These Pull Requests must be merged by a normal user account. This means that Zuul will be limited to posting test results and cannot merge these PRs automatically when they pass testing.

GitHub Actions are still in Beta and this behavior may change.

Connection Configuration

There are two forms of operation. Either the Zuul installation can be configured as a Github App or it can be configured as a Webhook.

If the Github App approach is taken, the config settings app_id and app_key are required. If the Webhook approach is taken, the api_token setting is required.

The supported options in zuul.conf connections are:

<github connection>

<github connection>.driver (required)

github: The connection must set driver=github for GitHub connections.

<github connection>.app_id: App ID if you are using a GitHub App. Can be found under the Public Link on the right hand side labeled ID.

<github connection>.app_key: Path to a file containing the secret key Zuul will use to create tokens for the API interactions. In Github this is known as Private key and must be collected when generated.

<github connection>.api_token: API token for accessing GitHub if Zuul is configured with Webhooks. See Creating an access token for command-line use.

<github connection>.webhook_token: Required token for validating the webhook event payloads. In the GitHub App Configuration page, this is called Webhook secret. See Securing your webhooks.

<github connection>.sshkey Default: ~/.ssh/id_rsa: Path to SSH key to use when cloning github repositories if Zuul is configured with Webhooks.

<github connection>.server Default: github.com: Hostname of the github install (such as a GitHub Enterprise).

<github connection>.canonical_hostname: The canonical hostname associated with the git repos on the GitHub server. Defaults to the value of <github connection>.server. This is used to identify projects from this connection by name and in preparing repos on the filesystem for use by jobs. Note that Zuul will still only communicate with the GitHub server identified by server; this option is useful if users customarily use a different hostname to clone or pull git repos so that when Zuul places them in the job’s working directory, they appear under this directory name.

<github connection>.verify_ssl Default: true: Enable or disable ssl verification for GitHub Enterprise. This is useful for a connection to a test installation.

<github connection>.rate_limit_logging Default: true: Enable or disable GitHub rate limit logging. If rate limiting is disabled in GitHub Enterprise this can save some network round trip times.

Trigger Configuration

GitHub webhook events can be configured as triggers.

A connection name with the GitHub driver can take multiple events with the following options.

pipeline.trigger.<github source>

The dictionary passed to the GitHub pipeline trigger attribute supports the following attributes:

pipeline.trigger.<github source>.event (required)

The event from github. Supported events are:

pull_request

pull_request_review

push

check_run

pipeline.trigger.<github source>.action

A pull_request event will have associated action(s) to trigger from. The supported actions are:

opened: Pull request opened.

changed: Pull request synchronized.

closed: Pull request closed.

reopened: Pull request reopened.

comment: Comment added to pull request.

labeled: Label added to pull request.

unlabeled: Label removed from pull request.

status: Status set on commit. The syntax is user:status:value. This also can be a regular expression.

A pull_request_review event will have associated action(s) to trigger from. The supported actions are:

submitted: Pull request review added.

dismissed: Pull request review removed.

A check_run event will have associated action(s) to trigger from. The supported actions are:

requested: A check run is requested.

completed: A check run completed.

pipeline.trigger.<github source>.branch: The branch associated with the event. Example: master. This field is treated as a regular expression, and multiple branches may be listed. Used for pull_request and pull_request_review events.

pipeline.trigger.<github source>.comment: This is only used for pull_request comment actions. It accepts a list of regexes that are searched for in the comment string. If any of these regexes matches a portion of the comment string the trigger is matched. comment: retrigger will match when comments containing ‘retrigger’ somewhere in the comment text are added to a pull request.

pipeline.trigger.<github source>.label: This is only used for labeled and unlabeled pull_request actions. It accepts a list of strings each of which matches the label name in the event literally. label: recheck will match a labeled action when pull request is labeled with a recheck label. label: 'do not test' will match a unlabeled action when a label with name do not test is removed from the pull request.

pipeline.trigger.<github source>.state: This is only used for pull_request_review events. It accepts a list of strings each of which is matched to the review state, which can be one of approved, comment, or request_changes.

pipeline.trigger.<github source>.status: This is used for pull-request and status actions. It accepts a list of strings each of which matches the user setting the status, the status context, and the status itself in the format of user:context:status. For example, zuul_github_ci_bot:check_pipeline:success.

pipeline.trigger.<github source>.ref: This is only used for push events. This field is treated as a regular expression and multiple refs may be listed. GitHub always sends full ref name, eg. refs/tags/bar and this string is matched against the regular expression.

Reporter Configuration

Zuul reports back to GitHub via GitHub API. Available reports include a PR comment containing the build results, a commit status on start, success and failure, an issue label addition/removal on the PR, and a merge of the PR itself. Status name, description, and context is taken from the pipeline.

pipeline.<reporter>.<github source>

To report to GitHub, the dictionaries passed to any of the pipeline reporter attributes support the following attributes:

pipeline.<reporter>.<github source>.status Default: None Type: str

Report status via the Github status API. Set to one of

pending
success
failure

This is usually mutually exclusive with a value set in pipeline.<reporter>.<github source>.check, since this reports similar results via a different API. This API is older and results do not show up on the “checks” tab in the Github UI. It is recommended to use check unless you have a specific reason to use the status API.

pipeline.<reporter>.<github source>.status-url Default: link to the build status page Type: string

URL to set in the Github status.

Defaults to a link to the build status or results page. This should probably be left blank unless there is a specific reason to override it.

pipeline.<reporter>.<github source>.check Type: string

Report status via the Github checks API. Set to one of

in_progress
success
failure
cancelled

This is usually mutually exclusive with a value set in pipeline.<reporter>.<github source>.status, since this reports similar results via a different API.

pipeline.<reporter>.<github source>.comment Default: true: Boolean value that determines if the reporter should add a comment to the pipeline status to the github pull request. Only used for Pull Request based items.

pipeline.<reporter>.<github source>.review: One of approve, comment, or request-changes that causes the reporter to submit a review with the specified status on Pull Request based items. Has no effect on other items.

pipeline.<reporter>.<github source>.review-body: Text that will be submitted as the body of the review. Required if review is set to comment or request-changes.

pipeline.<reporter>.<github source>.merge Default: false: Boolean value that determines if the reporter should merge the pull reqeust. Only used for Pull Request based items.

pipeline.<reporter>.<github source>.label: List of strings each representing an exact label name which should be added to the pull request by reporter. Only used for Pull Request based items.

pipeline.<reporter>.<github source>.unlabel: List of strings each representing an exact label name which should be removed from the pull request by reporter. Only used for Pull Request based items.

Requirements Configuration

As described in pipeline.require and pipeline.reject, pipelines may specify that items meet certain conditions in order to be enqueued into the pipeline. These conditions vary according to the source of the project in question. To supply requirements for changes from a GitHub source named my-github, create a configuration such as the following:

pipeline:
  require:
    my-github:
      review:
        - type: approved

This indicates that changes originating from the GitHub connection named my-github must have an approved code review in order to be enqueued into the pipeline.

pipeline.require.<github source>

The dictionary passed to the GitHub pipeline require attribute supports the following attributes:

pipeline.require.<github source>.review

This requires that a certain kind of code review be present for the pull request (it could be added by the event in question). It takes several sub-parameters, all of which are optional and are combined together so that there must be a code review matching all specified requirements.

pipeline.require.<github source>.review.username: If present, a code review from this username is required. It is treated as a regular expression.

pipeline.require.<github source>.review.email: If present, a code review with this email address is required. It is treated as a regular expression.

pipeline.require.<github source>.review.older-than: If present, the code review must be older than this amount of time to match. Provide a time interval as a number with a suffix of “w” (weeks), “d” (days), “h” (hours), “m” (minutes), “s” (seconds). Example 48h or 2d.

pipeline.require.<github source>.review.newer-than: If present, the code review must be newer than this amount of time to match. Same format as “older-than”.

pipeline.require.<github source>.review.type: If present, the code review must match this type (or types).

pipeline.require.<github source>.review.permission: If present, the author of the code review must have this permission (or permissions). The available values are read, write, and admin.

pipeline.require.<github source>.open: A boolean value (true or false) that indicates whether the change must be open or closed in order to be enqueued.

pipeline.require.<github source>.merged: A boolean value (true or false) that indicates whether the change must be merged or not in order to be enqueued.

pipeline.require.<github source>.current-patchset: A boolean value (true or false) that indicates whether the item must be associated with the latest commit in the pull request in order to be enqueued.

pipeline.require.<github source>.status

A string value that corresponds with the status of the pull request. The syntax is user:status:value. This can also be a regular expression.

Zuul does not differentiate between a status reported via status API or via checks API (which is also how Github behaves in terms of branch protection and status checks). Thus, the status could be reported by a pipeline.<reporter>.<github source>.status or a pipeline.<reporter>.<github source>.check.

When a status is reported via the status API, Github will add a [bot] to the name of the app that reported the status, resulting in something like user[bot]:status:value. For a status reported via the checks API, the app’s slug will be used as is.

pipeline.require.<github source>.label: A string value indicating that the pull request must have the indicated label (or labels).

pipeline.reject.<github source>

The reject attribute is the mirror of the require attribute. It also accepts a dictionary under the connection name. This dictionary supports the following attributes:

pipeline.reject.<github source>.review: This takes a list of code reviews. If a code review matches the provided criteria the pull request can not be entered into the pipeline. It follows the same syntax as pipeline.require.<github source>.review

Reference pipelines configuration

Branch protection rules

The rules prevent Pull requests to be merged on defined branches if they are not met. For instance a branch might require that specific status are marked as success before allowing the merge of the Pull request.

Zuul provides the attribute tenant.untrusted-projects.exclude-unprotected-branches. This attribute is by default set to false but we recommend to set it to true for the whole tenant. By doing so Zuul will benefit from:

exluding in-repo development branches used to open Pull requests. This will prevent Zuul to fetch and read useless branches data to find Zuul configuration files.

reading protection rules configuration from the Github API for a given branch to define whether a Pull request must enter the gate pipeline. As of now Zuul only takes in account “Require status checks to pass before merging” and the checked status checkboxes.

With the use of the reference pipelines below, the Zuul project recommends to set the minimum following settings:

attribute tenant.untrusted-projects.exclude-unprotected-branches to true in the tenant (main.yaml) configuration file.

on each Github repository, activate the branch protections rules and configure the name of the protected branches. Furthermore set “Require status checks to pass before merging” and check the status labels checkboxes (at least `<tenant>/check`) that must be marked as success in order for Zuul to make the Pull request enter the gate pipeline to be merged.

Reference pipelines

Here is an example of standard pipelines you may want to define:

- pipeline:
    name: check
    description: |
      Newly uploaded patchsets enter this pipeline to receive an
      initial check status.
    manager: independent
    trigger:
      github:
        # Run this pipeline on new/changed pull requests
        - event: pull_request
          action:
            - opened
            - changed
            - reopened
        # Run in response to a pull request comment "recheck"
        - event: pull_request
          action: comment
          comment: (?i)^\s*recheck\s*$
        # When using the checks API to report results, failed runs
        # will have a "re-run" button which emits this event.
        - event: check_run
          action: rerequested
          check: .*/check:.*
    start:
      github:
        check: 'in_progress'
        comment: false
        # It is recommended to use the checks API for consistency with
        # other common CI tools that integrate with Github.  Results
        # will appear on the "checks" tab of PR and changes.  There is
        # generally no need to have Zuul leave comments when using the
        # checks API.
        #
        # The older status API appears inline with the PR and can be
        # enabled by uncommenting the "status:" in the various
        # sections below.  You should choose one or the other
        # depending on project preferences.
        #
        #status: 'pending'
        #comment: false
    success:
      github:
        check: 'success'
        comment: false
        #status: 'success'
    failure:
      github:
        check: 'failure'
        comment: false
        #status: 'failure'
    dequeue:
      github:
        check: cancelled
        comment: false

- pipeline:
    name: gate
    description: |
      Changes that have been approved by core developers are enqueued
      in order in this pipeline, and if they pass tests, will be
      merged.
    manager: dependent
    precedence: high
    supercedes: check
    require:
      github:
        review:
          # Require an approval from user with write access (e.g. core-reviewer)
          - permission: write
            type: approved
        # Require label
        label: gate
        open: True
        current-patchset: True
    trigger:
      github:
        - event: pull_request_review
          action: submitted
          state: approved
        - event: pull_request
          action: comment
          comment: (?i)^\s*regate\s*$
        - event: pull_request_review
          action: submitted
          state: approved
        - event: pull_request_review
          action: dismissed
          state: request_changes
        - event: pull_request
          action: status
          status: ".*:success"
        - event: pull_request
          action: labeled
          label:
            - gate
    start:
      github:
        check: 'in_progress'
        comment: false
        #status: 'pending'
    success:
      github:
        check: 'success'
        comment: false
        #status: 'success'
        merge: true
    failure:
      github:
        check: 'failure'
        #status: 'failure'
        comment: false
    dequeue:
      github:
        check: cancelled
        comment: false
    window-floor: 20
    window-increase-factor: 2

- pipeline:
    name: post
    post-review: true
    description: This pipeline runs jobs that operate after each change is merged.
    manager: independent
    precedence: low
    trigger:
      github:
        - event: push
          ref: ^refs/heads/.*$

- pipeline:
    name: tag
    description: This pipeline runs jobs in response to any tag event.
    manager: independent
    precedence: high
    post-review: True
    trigger:
      github:
        - event: push
          ref: ^refs/tags/.*$