Python workflow (django-commons/django-unicorn)

The Python workflow from django-commons/django-unicorn, explained and optimized by Latchkey.

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Source: django-commons/django-unicorn.github/workflows/python.ymlLicense MITView source

What it does

This is the Python workflow from the django-commons/django-unicorn 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: Python

on:
  push:
  workflow_dispatch:

env:
  LINT_PYTHON_VERSION: 3.11

jobs:
  lint:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 1

      - name: Install uv
        uses: astral-sh/setup-uv@v5
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"

      - name: Set up Python ${{ env.LINT_PYTHON_VERSION }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ env.LINT_PYTHON_VERSION }}

      - name: Install dependencies
        run: |
          uv sync --dev

      - name: ruff check
        run: uv run ruff check .

      # - name: mypy check
      #   run: uv run mypy django_unicorn

  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ["3.10", "3.11", "3.12"]
        django-version: ["5.2", "6.0"]
        exclude:
          - python-version: "3.10"
            django-version: "6.0"
          - python-version: "3.11"
            django-version: "6.0"

    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 1

      - name: Install uv
        uses: astral-sh/setup-uv@v5
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"

      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}

      - name: Install dependencies
        run: |
          uv sync --all-extras --dev
          uv pip install django==${{ matrix.django-version }}

      - name: Fast tests
        run: uv run pytest -m 'not slow and not playwright'

      - name: Slow tests
        run: uv run pytest -m 'slow'

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
 
on:
  push:
  workflow_dispatch:
 
env:
  LINT_PYTHON_VERSION: 3.11
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  lint:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 1
 
      - name: Install uv
        uses: astral-sh/setup-uv@v5
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"
 
      - name: Set up Python ${{ env.LINT_PYTHON_VERSION }}
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ env.LINT_PYTHON_VERSION }}
 
      - name: Install dependencies
        run: |
          uv sync --dev
 
      - name: ruff check
        run: uv run ruff check .
 
      # - name: mypy check
      #   run: uv run mypy django_unicorn
 
  test:
    timeout-minutes: 30
    runs-on: latchkey-small
    strategy:
      matrix:
        python-version: ["3.10", "3.11", "3.12"]
        django-version: ["5.2", "6.0"]
        exclude:
          - python-version: "3.10"
            django-version: "6.0"
          - python-version: "3.11"
            django-version: "6.0"
 
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 1
 
      - name: Install uv
        uses: astral-sh/setup-uv@v5
        with:
          enable-cache: true
          cache-dependency-glob: "uv.lock"
 
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
 
      - name: Install dependencies
        run: |
          uv sync --all-extras --dev
          uv pip install django==${{ matrix.django-version }}
 
      - name: Fast tests
        run: uv run pytest -m 'not slow and not playwright'
 
      - name: Slow tests
        run: uv run pytest -m 'slow'

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.
Cache dependency installs on the setup step so they are served from cache.
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
End-to-end and browser tests

This workflow runs 2 jobs (7 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 astral-sh/setup-uv actions/setup-python