Mypy workflow (jbuchermn/newm)

The Mypy workflow from jbuchermn/newm, explained and optimized by Latchkey.

What it does

This is the Mypy workflow from the jbuchermn/newm 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: Mypy

on: [push, pull_request]

jobs:
  build:
    runs-on: ubuntu-latest
    name: Mypy
    steps:
    - name: Checkout newm
      uses: actions/checkout@v3
      with:
        path: newm
    - name: Checkout pywm
      uses: actions/checkout@v3
      with:
        repository: jbuchermn/pywm
        path: pywm
    - name: Setup python 3.9
      uses: actions/setup-python@v1
      with:
        python-version: 3.9
    - name: Install dependencies
      run: |
        pip install mypy
        pip install -r newm/requirements.txt
        pip install -r pywm/requirements.txt
    - name: Run mypy
      working-directory: newm
      run: |
        MYPYPATH=$MYPYPATH:$GITHUB_WORKSPACE/pywm mypy newm

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: Mypy
 
on: [push, pull_request]
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
    runs-on: latchkey-small
    name: Mypy
    steps:
    - name: Checkout newm
      uses: actions/checkout@v3
      with:
        path: newm
    - name: Checkout pywm
      uses: actions/checkout@v3
      with:
        repository: jbuchermn/pywm
        path: pywm
    - name: Setup python 3.9
      uses: actions/setup-python@v1
      with:
        cache: 'pip'
        python-version: 3.9
    - name: Install dependencies
      run: |
        pip install mypy
        pip install -r newm/requirements.txt
        pip install -r pywm/requirements.txt
    - name: Run mypy
      working-directory: newm
      run: |
        MYPYPATH=$MYPYPATH:$GITHUB_WORKSPACE/pywm mypy newm
 

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• Cancel superseded runs when a branch or PR gets a newer push.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.

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. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow