automatic-merging.md

Automatic PR merging

Prow github actions supports automatic PR merging through Github actions cron jobs.

name: "Merge on lgtm label"
on:
  schedule:
  - cron: "0 * * * *"

jobs:
  execute:
    runs-on: ubuntu-latest
    steps:
      - uses: jpmcb/prow-github-actions@v1
        with:
          jobs: 'lgtm'
          github-token: "${{ secrets.GITHUB_TOKEN }}"

          # this configuration is optional and will default to 'merge'
          # possible options are 'merge', 'rebase', or 'squash'
          merge-method: 'squash'

This Github workflow will check every hour for PRs with the lgtm label and will attempt to automatically merge them. If the hold label is present, it will block automatic merging.

The following workflow is meant to run on PR update / creation and integrates into the lgtm family of jobs.

name: "Run Jobs on PR"
on: pull_request

jobs:
  execute:
    runs-on: ubuntu-latest
    steps:
      - uses: jpmcb/prow-github-actions@v1
        with:
          jobs: 'lgtm'
          github-token: "${{ secrets.GITHUB_TOKEN }}"

This workflow will remove the lgtm label from a PR that gets updated. This prevents any un-reviewed code from being automatically merged by the lgtm-merger mechanism.

Refer to the lgtm command and the PR jobs for further reference.

Known limitations

This job pulls PRs from github in batches of 100. This may trigger a state where github rate limits Prow github actions. This may only happen with very large projects. Please open an issue if you see this consistently happen.