Python Checks workflow (calebstewart/pwncat)

The Python Checks workflow from calebstewart/pwncat, explained and optimized by Latchkey.

What it does

This is the Python Checks workflow from the calebstewart/pwncat 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 Checks
on:
  workflow_dispatch:

jobs:
  testing:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        python-versions: [3.8,3.9]

    services:
      centos:
        image: calebjstewart/pwncat-testing:centos
        ports:
          - 4444:4444
      ubuntu:
        image: calebjstewart/pwncat-testing:ubuntu
        ports:
          - 4445:4444

    steps:
      - uses: actions/checkout@v2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v2
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install pwncat
        run: |
          python -m pip install --upgrade pip
          pip install flake8 pytest
          pip install -r requirements.txt
          python setup.py install --user
#       - name: Lint with flake8
#         run: |
#           flake8
      - name: Test with pytest
        env:
          CENTOS_HOST: "127.0.0.1"
          CENTOS_BIND_PORT: "4444"
          UBUNTU_HOST: "127.0.0.1"
          UBUNTU_BIND_PORT: "4445"
        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 Checks
on:
  workflow_dispatch:
 
jobs:
  testing:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    strategy:
      matrix:
        python-versions: [3.8,3.9]
 
    services:
      centos:
        image: calebjstewart/pwncat-testing:centos
        ports:
          - 4444:4444
      ubuntu:
        image: calebjstewart/pwncat-testing:ubuntu
        ports:
          - 4445:4444
 
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v2
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Install pwncat
        run: |
          python -m pip install --upgrade pip
          pip install flake8 pytest
          pip install -r requirements.txt
          python setup.py install --user
#       - name: Lint with flake8
#         run: |
#           flake8
      - name: Test with pytest
        env:
          CENTOS_HOST: "127.0.0.1"
          CENTOS_BIND_PORT: "4444"
          UBUNTU_HOST: "127.0.0.1"
          UBUNTU_BIND_PORT: "4445"
        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.
• 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.

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