Legacy tests workflow (neuralgcm/neuralgcm)

The Legacy tests workflow from neuralgcm/neuralgcm, explained and optimized by Latchkey.

What it does

This is the Legacy tests workflow from the neuralgcm/neuralgcm repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

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

The workflow

name: Legacy tests

on:
  # Triggers the workflow on push or pull request events but only for the main branch
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:

jobs:
  build:
    name: "python ${{ matrix.python-version }} legacy"
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11"]
    steps:
    - name: Cancel previous
      uses: styfle/cancel-workflow-action@0.7.0
      with:
        access_token: ${{ github.token }}
      if: ${{github.ref != 'refs/head/main'}}
    - uses: actions/checkout@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        python-version: ${{ matrix.python-version }}
        cache: 'pip'
    - name: Install NeuralGCM legacy
      run: |
        pip install -e .[tests]
    - name: Run unit tests
      run: |
        pytest -v neuralgcm

The same workflow, on Latchkey

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

name: Legacy tests
 
on:
  # Triggers the workflow on push or pull request events but only for the main branch
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
  # Allows you to run this workflow manually from the Actions tab
  workflow_dispatch:
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
    name: "python ${{ matrix.python-version }} legacy"
    runs-on: latchkey-small
    strategy:
      fail-fast: false
      matrix:
        python-version: ["3.10", "3.11"]
    steps:
    - name: Cancel previous
      uses: styfle/cancel-workflow-action@0.7.0
      with:
        access_token: ${{ github.token }}
      if: ${{github.ref != 'refs/head/main'}}
    - uses: actions/checkout@v4
    - name: Set up Python ${{ matrix.python-version }}
      uses: actions/setup-python@v5
      with:
        python-version: ${{ matrix.python-version }}
        cache: 'pip'
    - name: Install NeuralGCM legacy
      run: |
        pip install -e .[tests]
    - name: Run unit tests
      run: |
        pytest -v neuralgcm
 

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.

1 third-party action is referenced by a movable tag. Pin it to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

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:

• Dependency installs

This workflow runs 1 job (2 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