GitHub Actions workflow (BayesWitnesses/m2cgen)

The GitHub Actions workflow from BayesWitnesses/m2cgen, explained and optimized by Latchkey.

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Source: BayesWitnesses/m2cgen.github/workflows/main.ymlLicense MITView source

What it does

This is the GitHub Actions workflow from the BayesWitnesses/m2cgen repository, a real project running GitHub Actions. It is shown here with attribution under its MIT license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

workflow (.yml)

name: GitHub Actions

on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master

jobs:
  test:
    name: "Python ${{ matrix.python }}, Test: ${{ matrix.lang }}"
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python:
          - "3.7"
          - "3.8"
          - "3.9"
          - "3.10"
        lang:
          - "API"
          - "c_lang or python or java or go_lang or javascript or php or haskell or ruby or rust"
          - "c_sharp or visual_basic or f_sharp"
          - "r_lang"
          - "elixir"
          - "dart or powershell"
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
        with:
          fetch-depth: 5
      - name: Build Docker image
        run: docker build . --file Dockerfile -t m2cgen-docker --build-arg python=${{ matrix.python }}
      - name: Run tests
        run: |
          if [[ "${{ matrix.lang }}" == "API" ]]; then
            export TEST="API";
          else
            export TEST="E2E";
          fi
          docker run \
            --ulimit stack=-1 \
            -v "$GITHUB_WORKSPACE":"/m2cgen" \
            -e TEST \
            -e LANG="${{ matrix.lang }}" \
            -e GITHUB_ACTIONS \
            -e GITHUB_WORKFLOW \
            -e GITHUB_RUN_ID \
            -e GITHUB_SHA \
            -e GITHUB_REF \
            -e GITHUB_HEAD_REF \
            -e GITHUB_REPOSITORY \
            -e GITHUB_SERVER_URL \
            -e GITHUB_TOKEN=${{ secrets.GITHUB_TOKEN }} \
            m2cgen-docker \
            bash /m2cgen/.ci/test.sh
      - name: Generate artifact with code examples
        if: matrix.python == '3.10' && matrix.lang == 'API'
        uses: actions/upload-artifact@v3
        with:
          name: code_examples
          path: ${{ github.workspace }}/generated_code_examples/
          if-no-files-found: error
  all-successful:
    # https://github.community/t/is-it-possible-to-require-all-github-actions-tasks-to-pass-without-enumerating-them/117957/4?u=graingert
    runs-on: ubuntu-latest
    needs: test
    steps:
    - name: Note that all tests succeeded
      run: echo "🎉"

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

name: GitHub Actions
 
on:
  push:
    branches:
      - master
  pull_request:
    branches:
      - master
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  test:
    timeout-minutes: 30
    name: "Python ${{ matrix.python }}, Test: ${{ matrix.lang }}"
    runs-on: latchkey-small
    strategy:
      fail-fast: false
      matrix:
        python:
          - "3.7"
          - "3.8"
          - "3.9"
          - "3.10"
        lang:
          - "API"
          - "c_lang or python or java or go_lang or javascript or php or haskell or ruby or rust"
          - "c_sharp or visual_basic or f_sharp"
          - "r_lang"
          - "elixir"
          - "dart or powershell"
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
        with:
          fetch-depth: 5
      - name: Build Docker image
        run: docker build . --file Dockerfile -t m2cgen-docker --build-arg python=${{ matrix.python }}
      - name: Run tests
        run: |
          if [[ "${{ matrix.lang }}" == "API" ]]; then
            export TEST="API";
          else
            export TEST="E2E";
          fi
          docker run \
            --ulimit stack=-1 \
            -v "$GITHUB_WORKSPACE":"/m2cgen" \
            -e TEST \
            -e LANG="${{ matrix.lang }}" \
            -e GITHUB_ACTIONS \
            -e GITHUB_WORKFLOW \
            -e GITHUB_RUN_ID \
            -e GITHUB_SHA \
            -e GITHUB_REF \
            -e GITHUB_HEAD_REF \
            -e GITHUB_REPOSITORY \
            -e GITHUB_SERVER_URL \
            -e GITHUB_TOKEN=${{ secrets.GITHUB_TOKEN }} \
            m2cgen-docker \
            bash /m2cgen/.ci/test.sh
      - name: Generate artifact with code examples
        if: matrix.python == '3.10' && matrix.lang == 'API'
        uses: actions/upload-artifact@v3
        with:
          name: code_examples
          path: ${{ github.workspace }}/generated_code_examples/
          if-no-files-found: error
  all-successful:
    timeout-minutes: 30
    # https://github.community/t/is-it-possible-to-require-all-github-actions-tasks-to-pass-without-enumerating-them/117957/4?u=graingert
    runs-on: latchkey-small
    needs: test
    steps:
    - name: Note that all tests succeeded
      run: echo "🎉"

What changed

Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
Cancel superseded runs when a branch or PR gets a newer push.
Add a job timeout so a hung step cannot burn hours of runner time.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

Container pulls and builds
End-to-end and browser tests

This workflow runs 2 jobs (25 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow

actions/checkout actions/upload-artifact