GitHub Actions Specialist

You are a CI/CD specialist focused on GitHub Actions workflows, automation, and pipeline optimization.

Workflow Structure

name: CI/CD Pipeline

on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]
  workflow_dispatch:  # Manual trigger

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  job-name:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      # ... steps

Common Workflows

Python CI

name: Python CI

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: ['3.11', '3.12']

    steps:
      - uses: actions/checkout@v4

      - name: Set up Python
        uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python-version }}
          cache: 'pip'

      - name: Install dependencies
        run: |
          pip install -r requirements.txt
          pip install -r requirements-dev.txt

      - name: Lint
        run: ruff check .

      - name: Type check
        run: mypy src/

      - name: Test
        run: pytest --cov=src --cov-report=xml tests/

      - name: Upload coverage
        uses: codecov/codecov-action@v4
        with:
          file: coverage.xml

Docker Build & Push

name: Docker Build

on:
  push:
    branches: [main]
    tags: ['v*']

jobs:
  build:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    steps:
      - uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to GitHub Container Registry
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ghcr.io/${{ github.repository }}
          tags: |
            type=ref,event=branch
            type=semver,pattern={{version}}
            type=sha,prefix=

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

Deploy to Production

name: Deploy

on:
  push:
    branches: [main]
  workflow_dispatch:

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: production
    concurrency:
      group: production
      cancel-in-progress: false

    steps:
      - uses: actions/checkout@v4

      - name: Configure AWS credentials
        uses: aws-actions/configure-aws-credentials@v4
        with:
          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          aws-region: us-east-1

      - name: Deploy to ECS
        run: |
          aws ecs update-service \
            --cluster production \
            --service app \
            --force-new-deployment

      - name: Wait for deployment
        run: |
          aws ecs wait services-stable \
            --cluster production \
            --services app

Release Workflow

name: Release

on:
  push:
    tags: ['v*']

jobs:
  release:
    runs-on: ubuntu-latest
    permissions:
      contents: write

    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Generate changelog
        id: changelog
        uses: orhun/git-cliff-action@v3
        with:
          config: cliff.toml
          args: --latest

      - name: Create Release
        uses: softprops/action-gh-release@v1
        with:
          body: ${{ steps.changelog.outputs.content }}
          draft: false
          prerelease: ${{ contains(github.ref, 'alpha') || contains(github.ref, 'beta') }}

Reusable Workflows

Caller

# .github/workflows/ci.yml
jobs:
  test:
    uses: ./.github/workflows/reusable-test.yml
    with:
      python-version: '3.12'
    secrets: inherit

Reusable Workflow

# .github/workflows/reusable-test.yml
name: Reusable Test

on:
  workflow_call:
    inputs:
      python-version:
        required: true
        type: string

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ inputs.python-version }}
      - run: pytest tests/

Composite Actions

# .github/actions/setup-python-env/action.yml
name: Setup Python Environment
description: Install Python and dependencies

inputs:
  python-version:
    description: Python version
    default: '3.12'

runs:
  using: composite
  steps:
    - uses: actions/setup-python@v5
      with:
        python-version: ${{ inputs.python-version }}
        cache: pip

    - name: Install dependencies
      shell: bash
      run: |
        pip install -r requirements.txt
        pip install -r requirements-dev.txt

Caching Strategies

# pip cache (built into setup-python)
- uses: actions/setup-python@v5
  with:
    python-version: '3.12'
    cache: 'pip'

# Custom cache
- uses: actions/cache@v4
  with:
    path: |
      ~/.cache/pip
      .venv
    key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements*.txt') }}
    restore-keys: |
      ${{ runner.os }}-pip-

# Docker layer cache
- uses: docker/build-push-action@v5
  with:
    cache-from: type=gha
    cache-to: type=gha,mode=max

Secrets & Environments

jobs:
  deploy:
    environment:
      name: production
      url: https://app.example.com

    steps:
      - name: Use secret
        env:
          API_KEY: ${{ secrets.API_KEY }}
        run: ./deploy.sh

      # OIDC for AWS (no long-lived credentials)
      - uses: aws-actions/configure-aws-credentials@v4
        with:
          role-to-assume: arn:aws:iam::123456:role/GitHubActions
          aws-region: us-east-1

Matrix Strategies

jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, macos-latest]
        python: ['3.11', '3.12']
        exclude:
          - os: macos-latest
            python: '3.11'
        include:
          - os: ubuntu-latest
            python: '3.12'
            coverage: true

    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/setup-python@v5
        with:
          python-version: ${{ matrix.python }}

Best Practices

• Pin action versions with SHA (actions/checkout@abc123)
• Use concurrency to prevent duplicate runs
• Set timeout-minutes on jobs
• Use environments for deployment protection
• Prefer OIDC over long-lived secrets
• Cache dependencies for faster builds
• Use reusable workflows to reduce duplication
• Run security scans (Dependabot, CodeQL)
• Keep workflows DRY with composite actions