zuul/doc/source/reference/drivers/github.rst

title

GitHub Driver

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>

driver

github

The connection must set driver=github for GitHub connections.

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.

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.

api_token

API token for accessing GitHub if Zuul is configured with Webhooks. See Creating an access token for command-line use.

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.

sshkey

Path to SSH key to use when cloning github repositories if Zuul is configured with Webhooks.

server

Hostname of the github install (such as a GitHub Enterprise).

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.

verify_ssl

Enable or disable ssl verification for GitHub Enterprise. This is useful for a connection to a test installation.

rate_limit_logging

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:

event

The event from github. Supported events are:

pull_request

pull_request_review

push

check_run

action

A pipeline.trigger.<github source>.event.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 pipeline.trigger.<github source>.event.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 pipeline.trigger.<github source>.event.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.

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.

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.

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.

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.

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.

This is only used for check_run events. It works similar to the status attribute and accepts a list of strings each of which matches the app requesting or updating the check run, the check run's name and the conclusion in the format of app:name::conclusion. To make Zuul properly interact with Github's checks API, each pipeline that is using the checks API should have at least one trigger that matches the pipeline's name regardless of the result, e.g. zuul:cool-pipeline:.*. This will enable the cool-pipeline to trigger whenever a user requests the cool-pipeline check run as part of the zuul check suite. Additionally, one could use .*:success to trigger a pipeline whenever a successful check run is reported (e.g. useful for gating).

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<reporters> attributes support the following attributes:

status

String value (pending, success, failure) that the reporter should set as the commit status on github.

status-url

String value for a link url to set in the github status. Defaults to the zuul server status_url, or the empty string if that is unset.

check

If the reporter should utilize github's checks API to set the commit status, this must be set to in_progress, success, failure or cancelled (depending on which status the reporter should report).

comment

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.

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.

review-body

Text that will be submitted as the body of the review. Required if review is set to comment or request-changes.

merge

Boolean value that determines if the reporter should merge the pull reqeust. Only used for Pull Request based items.

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.

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:

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.

username

If present, a code review from this username is required. It is treated as a regular expression.

email

If present, a code review with this email address is required. It is treated as a regular expression.

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.

newer-than

If present, the code review must be newer than this amount of time to match. Same format as "older-than".

type

If present, the code review must match this type (or types).

permission

If present, the author of the code review must have this permission (or permissions). The available values are read, write, and admin.

open

A boolean value (true or false) that indicates whether the change must be open or closed in order to be enqueued.

merged

A boolean value (true or false) that indicates whether the change must be merged or not in order to be enqueued.

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.

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.

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:

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:

/examples/pipelines/github-reference-pipelines.yaml