Python application workflow

D

CI health grade

53/100

Health score

1

Job per trigger

4

Fixes in the optimized version

What it does

This is the Python application workflow GitHub offers by default. It sets up Python, installs dependencies, lints with flake8, and runs tests with pytest.

Notably it does not cache pip downloads and sets no job timeout or concurrency, all of which Latchkey adds below.

The workflow

name: Python application

on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]

permissions:
  contents: read

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up Python 3.10
        uses: actions/setup-python@v5
        with:
          python-version: "3.10"
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install flake8 pytest
          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
      - name: Lint with flake8
        run: |
          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
      - name: Test with pytest
        run: pytest

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

name: Python application

on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]

permissions:
  contents: read

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

jobs:
  build:
    runs-on: ubuntu-latest
    timeout-minutes: 30
    runs-on: latchkey-small
    steps:
      - uses: actions/checkout@v4
      - name: Set up Python 3.10
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: "3.10"
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install flake8 pytest
          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
      - name: Lint with flake8
        run: |
          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
      - name: Test with pytest
        run: pytest

What changed

1. Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. Each Linux x64 job moves to the Latchkey size matching its vCPU count, latchkey-small for a standard 2 vCPU runner; macOS, Windows and arm64 jobs stay as written.
2. Cancel superseded runs when a branch or PR gets a newer push.
3. Cache dependency installs on the setup step so they are served from cache.
4. 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:

• Dependency installs

This workflow runs 1 job per trigger. It runs on a standard GitHub-hosted Linux x64 runner, which in a private repository bills $0.006 a minute against $0.0025 on latchkey-small, 58% lower; in a public repository like this one it is free. Estimate the monthly difference with your own run counts.

Actions used in this workflow

• actions/checkout
• actions/setup-python

Frequently asked questions

References

• Python documentation
• pip documentation
• GitHub Actions documentation