:title: GitHub Driver .. _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://:/api/connection//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 ........... .. NOTE Duplicate content here and in howtos/github_setup.rst. Keep them in sync. 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://:/api/connection//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: .. attr:: .. attr:: driver :required: .. value:: github The connection must set ``driver=github`` for GitHub connections. .. attr:: 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**. .. attr:: 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. .. attr:: api_token API token for accessing GitHub if Zuul is configured with Webhooks. See `Creating an access token for command-line use `_. .. attr:: 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 `_. .. attr:: sshkey :default: ~/.ssh/id_rsa Path to SSH key to use when cloning github repositories if Zuul is configured with Webhooks. .. attr:: server :default: github.com Hostname of the github install (such as a GitHub Enterprise). .. attr:: canonical_hostname The canonical hostname associated with the git repos on the GitHub server. Defaults to the value of :attr:`.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. .. attr:: verify_ssl :default: true Enable or disable ssl verification for GitHub Enterprise. This is useful for a connection to a test installation. .. attr:: 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. .. attr:: repo_cache To configure Zuul to use a GitHub Enterprise `repository cache `_ set this value to the hostname of the cache (e.g., ``europe-ci.github.example.com``). Zuul will fetch commits as well as determine the global repo state of repositories used in jobs from this host. This setting is incompatible with :attr:`.sshkey`. Because the repository cache may be several minutes behind the canonical site, enabling this setting automatically sets the default :attr:`.repo_retry_timeout` to 600 seconds. That setting may still be overidden to specify a different value. .. attr:: repo_retry_timeout This setting is only used if :attr:`.repo_cache` is set. It specifies the amount of time in seconds that Zuul mergers and executors should spend attempting to fetch git commits which are not available from the GitHub repository cache host. When :attr:`.repo_cache` is set, this value defaults to 600 seconds, but it can be overridden. Zuul retries git fetches every 30 seconds, and this value will be rounded up to the next highest multiple of 30 seconds. 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. .. attr:: pipeline.trigger. The dictionary passed to the GitHub pipeline ``trigger`` attribute supports the following attributes: .. attr:: event :required: The event from github. Supported events are: .. value:: pull_request .. value:: pull_request_review .. value:: push .. value:: check_run .. attr:: action A :value:`pipeline.trigger..event.pull_request` event will have associated action(s) to trigger from. The supported actions are: .. value:: opened Pull request opened. .. value:: changed Pull request synchronized. .. value:: closed Pull request closed. .. value:: reopened Pull request reopened. .. value:: comment Comment added to pull request. .. value:: labeled Label added to pull request. .. value:: unlabeled Label removed from pull request. .. value:: status Status set on commit. The syntax is ``user:status:value``. This also can be a regular expression. A :value:`pipeline.trigger..event.pull_request_review` event will have associated action(s) to trigger from. The supported actions are: .. value:: submitted Pull request review added. .. value:: dismissed Pull request review removed. A :value:`pipeline.trigger..event.check_run` event will have associated action(s) to trigger from. The supported actions are: .. value:: requested A check run is requested. .. value:: completed A check run completed. .. attr:: 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. .. attr:: 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. .. attr:: 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. .. attr:: 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``. .. attr:: 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``. .. attr: check 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). .. attr:: 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. .. attr:: pipeline.. To report to GitHub, the dictionaries passed to any of the pipeline :ref:`reporter` attributes support the following attributes: .. attr:: status :type: str :default: None Report status via the Github `status API `__. Set to one of * ``pending`` * ``success`` * ``failure`` This is usually mutually exclusive with a value set in :attr:`pipeline...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. .. TODO support role markup in :default: so we can xref :attr:`web.status_url` below .. attr:: 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. .. attr:: check :type: string Report status via the Github `checks API `__. Set to one of * ``cancelled`` * ``failure`` * ``in_progress`` * ``neutral`` * ``skipped`` * ``success`` This is usually mutually exclusive with a value set in :attr:`pipeline...status`, since this reports similar results via a different API. .. attr:: 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. .. attr:: 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. .. attr:: review-body Text that will be submitted as the body of the review. Required if review is set to `comment` or `request-changes`. .. attr:: merge :default: false Boolean value that determines if the reporter should merge the pull reqeust. Only used for Pull Request based items. .. attr:: 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. .. attr:: 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. .. _Github App: https://developer.github.com/apps/ Requirements Configuration -------------------------- As described in :attr:`pipeline.require` and :attr:`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. .. attr:: pipeline.require. The dictionary passed to the GitHub pipeline `require` attribute supports the following attributes: .. attr:: 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. .. attr:: username If present, a code review from this username matches. It is treated as a regular expression. .. attr:: email If present, a code review with this email address matches. It is treated as a regular expression. .. attr:: 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``. .. attr:: newer-than If present, the code review must be newer than this amount of time to match. Same format as "older-than". .. attr:: type If present, the code review must match this type (or types). .. TODO: what types are valid? .. attr:: permission If present, the author of the code review must have this permission (or permissions) to match. The available values are ``read``, ``write``, and ``admin``. .. attr:: open A boolean value (``true`` or ``false``) that indicates whether the change must be open or closed in order to be enqueued. .. attr:: merged A boolean value (``true`` or ``false``) that indicates whether the change must be merged or not in order to be enqueued. .. attr:: 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. .. TODO: this could probably be expanded upon -- under what circumstances might this happen with github .. attr:: draft A boolean value (``true`` or ``false``) that indicates whether or not the change must be marked as a draft in GitHub in order to be enqueued. .. attr:: 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 :attr:`pipeline...status` or a :attr:`pipeline...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. .. attr:: label A string value indicating that the pull request must have the indicated label (or labels). .. attr:: pipeline.reject. The `reject` attribute is the mirror of the `require` attribute and is used to specify pull requests which should not be enqueued into a pipeline. It accepts a dictionary under the connection name and with the following attributes: .. attr:: review This requires that a certain kind of code review be absent for the pull request (it could be removed by the event in question). It takes several sub-parameters, all of which are optional and are combined together so that there must not be a code review matching all specified requirements. .. attr:: username If present, a code review from this username matches. It is treated as a regular expression. .. attr:: email If present, a code review with this email address matches. It is treated as a regular expression. .. attr:: 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``. .. attr:: newer-than If present, the code review must be newer than this amount of time to match. Same format as "older-than". .. attr:: type If present, the code review must match this type (or types). .. TODO: what types are valid? .. attr:: permission If present, the author of the code review must have this permission (or permissions) to match. The available values are ``read``, ``write``, and ``admin``. .. attr:: open A boolean value (``true`` or ``false``) that indicates whether the change must be open or closed in order to be rejected. .. attr:: merged A boolean value (``true`` or ``false``) that indicates whether the change must be merged or not in order to be rejected. .. attr:: 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 rejected. .. TODO: this could probably be expanded upon -- under what circumstances might this happen with github .. attr:: draft A boolean value (``true`` or ``false``) that indicates whether or not the change must be marked as a draft in GitHub in order to be rejected. .. attr:: 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 :attr:`pipeline...status` or a :attr:`pipeline...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. .. attr:: label A string value indicating that the pull request must not have the indicated label (or labels). 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 ```/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: .. literalinclude:: /examples/pipelines/github-reference-pipelines.yaml :language: yaml Github Checks API ----------------- Github provides two distinct methods for reporting results; a "checks" and a "status" API. The `checks API`_ provides some additional features compared to the `status API`_ like file comments and custom actions (e.g. cancel a running build). Either can be chosen when configuring Zuul to report for your Github project. However, there are some considerations to take into account when choosing the API. Design decisions ................ The Github checks API defines the concepts of `Check Suites`_ and `Check Runs`_. *Check suites* are a collection of *check runs* for a specific commit and summarize a final status A priori the check suite appears to be a good mapping for a pipeline execution in Zuul, where a check run maps to a single job execution that is part of the pipeline run. Unfortunately, there are a few problematic restrictions mapping between Github and Zuul concepts. Github check suites are opaque and the current status, duration and the overall conclusion are all calculated and set automatically whenever an included check run is updated. Most importantly, there can only be one check suite per commit SHA, per app. Thus there is no facility for for Zuul to create multiple check suite results for a change, e.g. one check suite for each pipeline such as check and gate. The Github check suite thus does not map well to Zuul's concept of multiple pipelines for a single change. Since a check suite is unique and global for the change, it can not be used to flag the status of arbitrary pipelines. This makes the check suite API insufficient for recording details that Zuul needs such as "the check pipeline has passed but the gate pipeline has failed". Another issue is that Zuul only reports on the results of the whole pipeline, not individual jobs. Reporting each Zuul job as a separate check is problematic for a number of reasons. Zuul often runs the same job for the same change multiple times; for example in the check and gate pipeline. There is no facility for these runs to be reported differently in the single check suite for the Github change. When configuring branch protection in Github, only a *check run* can be selected as required status check. This is in conflict with managing jobs in pipelines with Zuul. For example, to implement branch protection on GitHub would mean listing each job as a dedicated check, leading to a check run list that is not kept in sync with the project's Zuul pipeline configuration. Additionally, you lose some of Zuul's features like non-voting jobs as Github branch protections has no concept of a non-voting job. Thus Zuul can integrate with the checks API, but only at a pipeline level. Each pipeline execution will map to a check-run result reported to Github. Behaviour in Zuul ................. Reporting ~~~~~~~~~ The Github reporter is able to report both a status :attr:`pipeline...status` or a check :attr:`pipeline...check`. While it's possible to configure a Github reporter to report both, it's recommended to use only one. Reporting both might result in duplicated status check entries in the Github PR (the section below the comments). Trigger ~~~~~~~ The Github driver is able to trigger on a reported check (:value:`pipeline.trigger..event.check_run`) similar to a reported status (:value:`pipeline.trigger..action.status`). Requirements ~~~~~~~~~~~~ While trigger and reporter differentiates between status and check, the Github driver does not differentiate between them when it comes to pipeline requirements. This is mainly because Github also doesn't differentiate between both in terms of branch protection and `status checks`_. Actions / Events ................ Github provides a set of default actions for check suites and check runs. Those actions are available as buttons in the Github UI. Clicking on those buttons will emit webhook events which will be handled by Zuul. These actions are only available on failed check runs / check suites. So far, a running or successful check suite / check run does not provide any action from Github side. Available actions are: Re-run all checks Github emits a webhook event with type ``check_suite`` and action ``rerequested`` that is meant to re-run all check-runs contained in this check suite. Github does not provide the list of check-runs in that case, so it's up to the Github app what should run. Re-run failed checks Github emits a webhook event with type ``check_run`` and action ``rerequested`` for each failed check run contained in this suite. Re-run Github emits a webhook event with type ``check_run`` and action ``rerequested`` for the specific check run. Zuul will handle all events except for the `Re-run all checks` event; it does not make sense in the Zuul model to trigger all pipelines to run simultaneously. These events are unable to be customized in Github. Github will always report "You have successfully requested ..." despite nothing listening to the event. Therefore, it might be a solution to handle the `Re-run all checks` event in Zuul similar to `Re-run failed checks` just to not do anything while Github makes the user believe an action was really triggered. File comments (annotations) ........................... Check runs can be used to post file comments directly in the files of the PR. Those are similar to user comments, but must provide some more information. Zuul jobs can already return file comments via ``zuul_return`` (see: :ref:`return_values`). We can simply use this return value, build the necessary annotations (how Github calls it) from it and attach them to the check run. Custom actions ~~~~~~~~~~~~~~ Check runs can provide some custom actions which will result in additional buttons being available in the Github UI for this specific check run. Clicking on such a button will emit a webhook event with type ``check_run`` and action ``requested_action`` and will additionally contain the id/name of the requested action which we can define when creating the action on the check run. We could use these custom actions to provide some "Re-run" action on a running check run (which might otherwise be stuck in case a check run update fails) or to abort a check run directly from the Github UI. Restrictions and Recommendations ................................ Although both the checks API and the status API can be activated for a Github reporter at the same time, it's not recommended to do so as this might result in multiple status checks to be reported to the PR for the same pipeline execution (which would result in duplicated entries in the status section below the comments of a PR). In case the update on a check run fails (e.g. request timeout when reporting success or failure to Github), the check run will stay in status "in_progess" and there will be no way to re-run the check run via the Github UI as the predefined actions are only available on failed check runs. Thus, it's recommended to configure a :value:`pipeline.trigger..action.comment` trigger on the pipeline to still be able to trigger re-run of the stuck check run via e.g. "recheck". The check suite will only list check runs that were reported by Zuul. If the requirements for a certain pipeline are not met and it is not run, the check run for this pipeline won't be listed in the check suite. However, this does not affect the required status checks. If the check run is enabled as required, Github will still show it in the list of required status checks - even if it didn't run yet - just not in the check suite. .. _checks API: https://docs.github.com/v3/checks/ .. _status API: https://docs.github.com/v3/repos/statuses/ .. _Check Suites: https://docs.github.com/v3/checks/suites/ .. _Check Runs: https://docs.github.com/v3/checks/runs/ .. _status checks: https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/about-status-checks#types-of-status-checks-on-github