Python package workflow (DifferentiableUniverseInitiative/jax_cosmo)

The Python package workflow from DifferentiableUniverseInitiative/jax_cosmo, explained and optimized by Latchkey.

What it does

This is the Python package workflow from the DifferentiableUniverseInitiative/jax_cosmo 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

# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions

name: Python package

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  build:

    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: [3.8, 3.9]

    steps:
    - uses: actions/checkout@v2

    - uses: conda-incubator/setup-miniconda@v2
      with:
        python-version: ${{ matrix.python-version }}
        channels: conda-forge,defaults
        channel-priority: strict
        show-channel-urls: true
        auto-update-conda: true

    - name: Install dependencies
      shell: bash -l {0}
      run: |
        conda config --set always_yes yes
        conda install pytest pip 
        conda install -c conda-forge pyccl
        pip install .
  
    - name: Test with pytest
      shell: bash -l {0}
      run: |
        pytest

The same workflow, on Latchkey

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

# This workflow will install Python dependencies, run tests and lint with a variety of Python versions
# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
 
name: Python package
 
on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
 
    runs-on: latchkey-small
    strategy:
      matrix:
        python-version: [3.8, 3.9]
 
    steps:
    - uses: actions/checkout@v2
 
    - uses: conda-incubator/setup-miniconda@v2
      with:
        python-version: ${{ matrix.python-version }}
        channels: conda-forge,defaults
        channel-priority: strict
        show-channel-urls: true
        auto-update-conda: true
 
    - name: Install dependencies
      shell: bash -l {0}
      run: |
        conda config --set always_yes yes
        conda install pytest pip 
        conda install -c conda-forge pyccl
        pip install .
  
    - name: Test with pytest
      shell: bash -l {0}
      run: |
        pytest
 

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