Automated Branch Pull Requests

This action will open a pull request to master branch (or otherwise specified) whenever a branch with some prefix is pushed to. The idea is that you can set up some workflow that pushes content to branches of the repostory, and you would then want this push reviewed for merge to master.

Here is an example of what to put in your .github/workflows/pull-request.yml file to trigger the action.

name: Pull Request on Branch Push
on:
  push:
    branches-ignore:
      - staging
      - launchpad
      - production
jobs:
  auto-pull-request:
    name: PullRequestAction
    runs-on: ubuntu-latest
    steps:
      - name: pull-request-action
        uses: vsoch/[email protected]
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          BRANCH_PREFIX: "update/"
          PULL_REQUEST_BRANCH: "master"

Environment Variable Inputs

Unlike standard actions, this action just uses variables from the environment.

Name	Description	Required	Default
BRANCH_PREFIX	the prefix to filter to. If the branch doesn't start with the prefix, it will be ignored	false	""
PULL_REQUEST_BRANCH	open pull request against this branch	false	master
PULL_REQUEST_FROM_BRANCH	if a branch isn't found in your GitHub payload, use this branch	false
PULL_REQUEST_BODY	the body for the pull request	false
PULL_REQUEST_TITLE	the title for the pull request	false
PULL_REQUEST_DRAFT	should this be a draft PR?	false	unset
MAINTAINER_CANT_MODIFY	Do not allow the maintainer to modify the PR	false	unset
PULL_REQUEST_ASSIGNEES	A list (string with spaces) of users to assign	false	unset
PULL_REQUEST_REVIEWERS	A list (string with spaces) of users to assign review	false	unset
PULL_REQUEST_TEAM_REVIEWERS	A list (string with spaces) of teams to assign review	false	unset
PASS_ON_ERROR	Instead of failing on an error response, pass	unset
PASS_IF_EXISTS	Instead of failing if the pull request already exists, pass	unset

For PULL_REQUEST_DRAFT, PASS_ON_ERROR, PASS_IF_EXISTS, and MAINTAINER_CANT_MODIFY, these are treated as environment booleans. If they are defined in the environment, they trigger the "true" condition. E.g.,:

• Define MAINTAINER_CANT_MODIFY if you don't want the maintainer to be able to modify the pull request.
• Define PULL_REQUEST_DRAFT if you want the PR to be a draft.
• Define PASS_ON_ERROR if you want the PR to not exit given any non 200/201 response.
• Define PASS_IF_EXISTS if you want the PR to not exit given the pull request is already open.

For PULL_REQUEST_ASSIGNEES, PULL_REQUEST_REVIEWERS, and PULL_REQUEST_TEAM_REVIEWERS you can provide a string of one or more GitHub usernames (or team names) to assign to the issue. Note that only users with push access can add assigness to an issue or PR, they are ignored otherwise.

The GITHUB_TOKEN secret is required to interact and authenticate with the GitHub API to open the pull request. The example is deployed here with an example opened (and merged) pull request here if needed.

Outputs

The action sets a few useful output and environment variables. An output can be referenced later as ${{ steps.<stepname>.outputs.<output-name> }}. An environment variable of course can be referenced as you usually would.

Name	Description	Environment
pull_request_number	If the pull request is opened, this is the number for it.	PULL_REQUEST_NUMBER
pull_request_url	If the pull request is opened, the html url for it.	PULL_REQUEST_URL
pull_request_return_code	Return code for the pull request	PULL_REQUEST_RETURN_CODE
assignees_return_code	Return code for the assignees request	ASSIGNEES_RETURN_CODE
reviewers_return_code	Return code for the reviewers request	REVIEWERS_RETURN_CODE

See the examples/outputs-example.yml for how this works. In this example, we can reference ${{ steps.pull_request.outputs.pull_request_url }} in either another environment variable declaration, or within a run statement to access our variable pull_request_url that was generated in a step with id pull_request. The screenshot below shows the example in action to interact with outputs in several ways.

Examples

Example workflows are provided in examples, and please contribute any examples that you might have to help other users! We will walk through a basic example here for a niche case. Let's say that we are opening a pull request on the release event. This would mean that the payload's branch variable would be null. We would need to define PULL_REQUEST_FROM. How would we do that? We can set environment variables for next steps. Here is an example:

name: Pull Request on Branch Push
on: [release]
jobs:
  pull-request-on-release:
    name: PullRequestAction
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Code
        uses: actions/checkout@v2
      - name: Derive from branch name
        run: |
            # do custom parsing of your code / date to derive a branch from
            PR_BRANCH_FROM=release-v$(cat VERSION)
            ::set-env name=PULL_REQUEST_FROM_BRANCH::${PR_BRANCH_FROM}
      - name: pull-request-action
        uses: vsoch/[email protected]
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PULL_REQUEST_BRANCH: "master"

The above workflow is triggered on a release, so the branch will be null in the GItHub payload. Since we want the release PR to come from a special branch, we derive it in the second step, and then set the PULL_REQUEST_FROM_BRANCH variable in the environment for the next step. In the Pull Request Action step, the pull request will be opened from PULL_REQUEST_FROM_BRANCH against PULL_REQUEST_BRANCH, which is master. If we do not set this variable, the job will exit in an error, as it is not clear what action to take.

Example use Case: Update Registry

As an example, I created this action to be intended for an organizational static registry for container builds. Specifically, you have modular repositories building container recipes, and then opening pull requests to the registry to update it.

• the container collection content should be generated from a separate GitHub repository, including the folder structure (manifests, tags, collection README) that are expected.
• the container collection metadata is pushed to a new branch on the registry repository, with namespace matching the GitHub repository, meaning that each GitHub repository always has a unique branch for its content.
• pushing this branch that starts with the prefix (update/) triggers the GitHub actions to open the pull request.

If the branch is already open for PR, it updates it. Take a look at this example for the pull request opened when we updated the previous GitHub syntax to the new yaml syntax. Although this doesn't describe the workflow above, it works equivalently in terms of the triggers.