Approve documentation review

A Github Action to auto approve pull requests that contain only document reviews.

The Cloud Platform team have a document reviewal process that requires us to create a PR and have it reviewed by a colleague. This is cumbersome and unnecessary. An example of the PR in question looks like the following:

https://github.com/ministryofjustice/cloud-platform-user-guide/commit/de39ec0fd5f0bf97cc3e1054666e7709d56680e7

As you can see this is a fairly futile effort and time could be spent elsewhere. This GitHub action checks to see if the only changes contain the words last_review_on and whether the PR owner is from the team defined in the env var TEAM_NAME. If the criteria is met the PR is approved automatically.

To run this GitHub action you must create a GitHub personal access token and store it in a GitHub secret in the repository in question. An example of the Action would look like:

name: Auto-approve a pull request

on:
  pull_request

env:
  PR_OWNER: ${{ github.event.pull_request.user.login }}
  GITHUB_OAUTH_TOKEN: ${{ secrets.DOCUMENT_REVIEW_GITHUB }}
  TEAM_NAME: "MyTeamName"

jobs:
  check-diff:
    runs-on: ${{ matrix.os }}

    strategy:
      matrix:
        os: [ubuntu-latest]

    steps:
      - name: Checkout PR code
        uses: actions/checkout@v2
      - run: |
          git fetch --no-tags --prune --depth=1 origin +refs/heads/*:refs/remotes/origin/*
      - name: Run git diff against repository
        run: |
          git diff origin/main HEAD > changes
      - name: Auto-approval check
        id: approve_pr_check
        uses: ministryofjustice/cloud-platform-doc-checker@VERSION
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Approving PR
        uses: hmarr/auto-approve-action@v2

        if: steps.approve_pr_check.outputs.review_pr == 'true'
        with:
          github-token: "${{ secrets.GITHUB_TOKEN  }}"

GITHUB_TOKEN is provided automatically by github actions. You do not need to do anything extra to make it available. Just use the content above, exactly as shown.

NB: You do have to duplicate the conditional as shown. Although the github documentation states that you can put the conditional at the job level, that doesn't work, in this case.

How to contribute

Either fork or branch off of the repository and make your changes. All GitHub Actions must pass.

PR the changes back to main.

How to release

GoReleaser has been setup so it's a simple matter of creating a new tag and pushing it to the repository. A GitHub Action will create a release for you.

git tag -a v1.0.0 -m "Release 1.0.0"
git push --tags