Lint workflow (alerta/alerta)

The Lint workflow from alerta/alerta, explained and optimized by Latchkey.

What it does

This is the Lint workflow from the alerta/alerta repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

name: Lint

on:
  push:
  pull_request:
    branches: [ master ]

env:
  SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}

jobs:
  lint:
    runs-on: ubuntu-latest

    strategy:
      matrix:
        python-version: ['3.9', '3.11']

    steps:
      - uses: actions/checkout@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies
        id: install-deps
        run: |
          python -m pip install --upgrade pip
          pip install flake8 bandit pytest
          pip install -r requirements-dev.txt
      - name: Pre-commit hooks
        id: hooks
        run: |
          pre-commit run -a --show-diff-on-failure
      - name: Lint with flake8
        id: lint
        run: |
          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
          flake8 . --count --exit-zero --max-complexity=50 --max-line-length=127 --statistics
      - name: Security scan with bandit
        id: bandit
        run: |
          bandit -r alerta -c pyproject.toml -q

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: Lint
 
on:
  push:
  pull_request:
    branches: [ master ]
 
env:
  SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  lint:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    strategy:
      matrix:
        python-version: ['3.9', '3.11']
 
    steps:
      - uses: actions/checkout@v4
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v5
        with:
          cache: 'pip'
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies
        id: install-deps
        run: |
          python -m pip install --upgrade pip
          pip install flake8 bandit pytest
          pip install -r requirements-dev.txt
      - name: Pre-commit hooks
        id: hooks
        run: |
          pre-commit run -a --show-diff-on-failure
      - name: Lint with flake8
        id: lint
        run: |
          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
          flake8 . --count --exit-zero --max-complexity=50 --max-line-length=127 --statistics
      - name: Security scan with bandit
        id: bandit
        run: |
          bandit -r alerta -c pyproject.toml -q
 

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 (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