Auto-raise Github PRs on commit to master

We use submodules for some of our projects to allow for a single soure of truth. Keeping our main project up to date with these changes can be quite painful. This action runs on push to a repo's master branch, and updates the submodule in another repo automatically and raises a pull request

Example Usage

Add the following to .github/workflows/update-submodule.yml:

name: Update Submodule
on:
  push:
    branches:
      - master
jobs:
  build:
    name: Update Submodule
    runs-on: ubuntu-latest
    steps:
      - uses: nexmo/github-actions/submodule-auto-pr@master
        env:
          GH_ADMIN_TOKEN: ${{ secrets.GH_ADMIN_TOKEN }}
          PR_ACTIVE_BRANCH: master
          PR_BRANCH_NAME: automated-oas-update
          PR_SUBMODULE_PATH: _open_api/api_specs
          PR_TARGET_BRANCH: master
          PR_TARGET_ORG: nexmo
          PR_TARGET_REPO: nexmo-developer
          PR_TITLE: API Specification Update

Configuration

• GH_ADMIN_TOKEN - a custom GitHub token to use to make API requests. The default GITHUB_TOKEN provided is scoped to the current repo, and we want to change other repos
• PR_TARGET_ORG - the name of the organization that owns the repo that a PR will be created on
• PR_TARGET_REPO - the name of the repo that a PR will be created on
• PR_SUBMODULE_PATH - the path to the submodule that needs updating
• PR_BRANCH_NAME - the name of the branch to create when updating submodules
• PR_TITLE - the title to use for the PR. This will also be your commit message
• PR_TARGET_BRANCH - the branch that we want to merge our PR in to
• PR_ACTIVE_BRANCH - check if the push was to this branch before continuing (usually master)

How it works

In the repo that uses this action

• Someone commits to the default branch in a repo that uses this action

In PR_TARGET_REPO

• Create PR_BRANCH_NAME if it does not already exist
• Create a commit with the new submodule SHA
  • If PR_BRANCH_NAME is created, a new commit is added on top of the latest commit on the default branch
  • If PR_BRANCH_NAME only contains a single commit, a new commit will be force pushed with the new submodule commit
  • If there is more than 1 commit, the new submodule will be added as a new commit to the existing tree
• Create a PR named PR_TITLE if there is not currently a PR open for PR_BRANCH_NAME
• Assign the PR to the person that merged the commit to the default branch