Python application workflow (Mause/duckdb_engine)

The Python application workflow from Mause/duckdb_engine, explained and optimized by Latchkey.

What it does

This is the Python application workflow from the Mause/duckdb_engine 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

name: Python application

on: [pull_request, workflow_dispatch]
permissions:
  checks: write

jobs:
  build_backend:
    runs-on: ubuntu-latest

    strategy:
      fail-fast: false
      matrix:
        python: [3.9, "3.10"]

    env:
      FORCE_COLOR: 1

    steps:
      - uses: actions/checkout@v5
      - name: Remove cached duckdb extensions
        run: rm -rf ~/.duckdb
      - uses: fjwillemsen/setup-nox2@v3.0.0
      - run: python -m pip install github-action-utils uv -U
      - name: List nox envs
        run: nox -l
      - run: nox --pythons '${{ matrix.python }}'
      - run: uvx poetry build
      - run: uvx poetry check --strict
      - name: Publish Unit Test Results
        uses: EnricoMi/publish-unit-test-result-action@v2
        if: always()
        with:
          files: results.xml
          comment_mode: off
          check_name:  "Test Results - ${{ join(matrix.*, ', ') }}"
      - uses: codecov/codecov-action@v5.5.1
        env:
          PYTHON: ${{matrix.python}}
          BLEEDING_EDGE: ${{matrix.bleeding_edge}}
        with:
          files: ./coverage.xml
          token: ${{ secrets.CODECOV_TOKEN }}
          env_vars: PYTHON # ,BLEEDING_EDGE  # set from matrix
          fail_ci_if_error: true
          verbose: true

The same workflow, on Latchkey

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

name: Python application
 
on: [pull_request, workflow_dispatch]
permissions:
  checks: write
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build_backend:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    strategy:
      fail-fast: false
      matrix:
        python: [3.9, "3.10"]
 
    env:
      FORCE_COLOR: 1
 
    steps:
      - uses: actions/checkout@v5
      - name: Remove cached duckdb extensions
        run: rm -rf ~/.duckdb
      - uses: fjwillemsen/setup-nox2@v3.0.0
      - run: python -m pip install github-action-utils uv -U
      - name: List nox envs
        run: nox -l
      - run: nox --pythons '${{ matrix.python }}'
      - run: uvx poetry build
      - run: uvx poetry check --strict
      - name: Publish Unit Test Results
        uses: EnricoMi/publish-unit-test-result-action@v2
        if: always()
        with:
          files: results.xml
          comment_mode: off
          check_name:  "Test Results - ${{ join(matrix.*, ', ') }}"
      - uses: codecov/codecov-action@v5.5.1
        env:
          PYTHON: ${{matrix.python}}
          BLEEDING_EDGE: ${{matrix.bleeding_edge}}
        with:
          files: ./coverage.xml
          token: ${{ secrets.CODECOV_TOKEN }}
          env_vars: PYTHON # ,BLEEDING_EDGE  # set from matrix
          fail_ci_if_error: true
          verbose: true
 

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.

3 third-party actions are referenced by a movable tag. Pin them 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