Linux tests workflow (python-lsp/python-lsp-server)

The Linux tests workflow from python-lsp/python-lsp-server, explained and optimized by Latchkey.

What it does

This is the Linux tests workflow from the python-lsp/python-lsp-server 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: Linux tests

on:
  push:
    branches:
      - develop

  pull_request:
    branches:
      - '*'

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

jobs:
  build:
    name: Linux Py${{ matrix.PYTHON_VERSION }}
    runs-on: ubuntu-latest
    env:
      CI: 'true'
      OS: 'linux'
      PYTHON_VERSION: ${{ matrix.PYTHON_VERSION }}
    strategy:
      fail-fast: false
      matrix:
        PYTHON_VERSION: ['3.14', '3.13', '3.12', '3.11', '3.10', '3.9']
    timeout-minutes: 10
    steps:
      - uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-${{ matrix.PYTHON_VERSION }}-pip-${{ hashFiles('pyproject.toml') }}
          restore-keys: ${{ runner.os }}-${{ matrix.PYTHON_VERSION }}-pip-
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.PYTHON_VERSION }}
          architecture: 'x64'
      - name: Create Jedi environment for testing
        run: |
          python3 -m venv /tmp/pyenv
          /tmp/pyenv/bin/python -m pip install loghub
      - run: python -m pip install --upgrade pip setuptools
      - run: pip install -e .[all,test]
      - name: Show test environment
        run: pip list
      - run: pytest --color=yes -v test/
      # Enable this if SSH debugging is required
      # - name: Setup tmate session
      #   uses: mxschmitt/action-tmate@v3
      #   if: ${{ failure() }}

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: Linux tests
 
on:
  push:
    branches:
      - develop
 
  pull_request:
    branches:
      - '*'
 
concurrency:
  group: test-linux-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    name: Linux Py${{ matrix.PYTHON_VERSION }}
    runs-on: latchkey-small
    env:
      CI: 'true'
      OS: 'linux'
      PYTHON_VERSION: ${{ matrix.PYTHON_VERSION }}
    strategy:
      fail-fast: false
      matrix:
        PYTHON_VERSION: ['3.14', '3.13', '3.12', '3.11', '3.10', '3.9']
    timeout-minutes: 10
    steps:
      - uses: actions/cache@v4
        with:
          path: ~/.cache/pip
          key: ${{ runner.os }}-${{ matrix.PYTHON_VERSION }}-pip-${{ hashFiles('pyproject.toml') }}
          restore-keys: ${{ runner.os }}-${{ matrix.PYTHON_VERSION }}-pip-
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ matrix.PYTHON_VERSION }}
          architecture: 'x64'
      - name: Create Jedi environment for testing
        run: |
          python3 -m venv /tmp/pyenv
          /tmp/pyenv/bin/python -m pip install loghub
      - run: python -m pip install --upgrade pip setuptools
      - run: pip install -e .[all,test]
      - name: Show test environment
        run: pip list
      - run: pytest --color=yes -v test/
      # Enable this if SSH debugging is required
      # - name: Setup tmate session
      #   uses: mxschmitt/action-tmate@v3
      #   if: ${{ failure() }}
 

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.
• Cache dependency installs on the setup step so they are served from cache.

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 (6 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