GitHub Actions Cheat Sheet

name: Workflow Name
 
on: [push, pull_request]
 
jobs:
 job-name:
  runs-on: ubuntu-latest
 
  steps:
   - uses: actions/checkout@v5
   - run: echo "Hello World"

# Push to branches
on:
 push:
  branches: [ main, develop ]
  tags: [ 'v*' ]
  paths:
   - 'src/**'
   - '!docs/**'
 
# Pull requests
on:
 pull_request:
  types: [opened, synchronize, reopened]
  branches: [ main ]
 
# Schedule (cron)
on:
 schedule:
  - cron: '0 0 * * *' # Daily at midnight UTC
  - cron: '0 */6 * * *' # Every 6 hours
 
# Manual trigger
on:
 workflow_dispatch:
  inputs:
   environment:
    description: 'Deploy environment'
    required: true
    type: choice
    options: [staging, production]
 
# Multiple events
on: [push, pull_request, workflow_dispatch]
 
# Workflow call (reusable)
on:
 workflow_call:
  inputs:
   config-path:
    required: true
    type: string

# GitHub-hosted
runs-on: ubuntu-latest    # Ubuntu (most common)
runs-on: windows-latest    # Windows
runs-on: macos-latest    # macOS
runs-on: ubuntu-22.04    # Specific version
 
# Matrix
runs-on: ${{ matrix.os }}
 
# Self-hosted
runs-on: self-hosted
runs-on: [self-hosted, linux, x64]

# Workflow level
env:
 NODE_ENV: production
 
jobs:
 build:
  # Job level
  env:
   API_URL: https://api.example.com
 
  steps:
   # Step level
   - run: npm build
    env:
     BUILD_ENV: staging
 
   # Use variables
   - run: echo "API is $API_URL"
   - run: echo "Node env is ${{ env.NODE_ENV }}"

# Use secrets
- run: npm run deploy
 env:
  API_KEY: ${{ secrets.API_KEY }}
  DATABASE_URL: ${{ secrets.DATABASE_URL }}
 
# GitHub token (auto-provided)
- run: gh api /user
 env:
  GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

strategy:
 matrix:
  os: [ubuntu-latest, windows-latest, macos-latest]
  node-version: [18, 20, 22]
  # Creates 9 jobs (3 × 3)
 
 fail-fast: true # Stop all if one fails
 max-parallel: 2 # Run max 2 jobs simultaneously
 
steps:
 - uses: actions/setup-node@v6
  with:
   node-version: ${{ matrix.node-version }}

- uses: actions/checkout@v5
 with:
  fetch-depth: 0 # Full history
  submodules: true # Include submodules

# Node.js
- uses: actions/setup-node@v6
 with:
  node-version: '20'
  cache: 'npm'
 
# Python
- uses: actions/setup-python@v5
 with:
  python-version: '3.12'
  cache: 'pip'
 
# Go
- uses: actions/setup-go@v5
 with:
  go-version: '1.21'
 
# Java
- uses: actions/setup-java@v4
 with:
  distribution: 'temurin'
  java-version: '21'

# Automatic (Node.js)
- uses: actions/setup-node@v6
 with:
  node-version: '20'
  cache: 'npm'
 
# Manual
- uses: actions/cache@v4
 with:
  path: |
   ~/.npm
   node_modules
  key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
  restore-keys: |
   ${{ runner.os }}-node-

# Upload
- uses: actions/upload-artifact@v4
 with:
  name: build-files
  path: dist/
  retention-days: 7
 
# Download
- uses: actions/download-artifact@v4
 with:
  name: build-files
  path: dist/

jobs:
 build:
  runs-on: ubuntu-latest
  steps:
   - run: npm build
 
 test:
  needs: build # Wait for build
  runs-on: ubuntu-latest
  steps:
   - run: npm test
 
 deploy:
  needs: [build, test] # Wait for both
  runs-on: ubuntu-latest
  steps:
   - run: npm run deploy

# Job level
jobs:
 deploy:
  if: github.ref == 'refs/heads/main'
  runs-on: ubuntu-latest
 
# Step level
steps:
 - name: Deploy to production
  if: github.event_name == 'push' && github.ref == 'refs/heads/main'
  run: npm run deploy
 
 # Common conditions
 - if: success() # Previous steps succeeded
 - if: failure() # Previous steps failed
 - if: always()  # Always run
 - if: cancelled() # Workflow cancelled
 
 # Check actor
 - if: github.actor != 'dependabot[bot]'
  run: npm test
 
 # Check event
 - if: github.event_name == 'pull_request'
  run: echo "This is a PR"

jobs:
 build:
  runs-on: ubuntu-latest
  outputs:
   version: ${{ steps.get-version.outputs.version }}
 
  steps:
   - id: get-version
    run: echo "version=1.2.3" >> $GITHUB_OUTPUT
 
 deploy:
  needs: build
  runs-on: ubuntu-latest
  steps:
   - run: echo "Deploying version ${{ needs.build.outputs.version }}"

concurrency:
 group: ${{ github.workflow }}-${{ github.ref }}
 cancel-in-progress: true # Cancel old runs on new push

permissions:
 contents: write   # Push to repo
 pull-requests: write # Comment on PRs
 issues: write    # Manage issues
 packages: write   # Publish packages
 deployments: write # Create deployments

jobs:
 build:
  runs-on: ubuntu-latest
  timeout-minutes: 10 # Job timeout
 
  steps:
   - run: npm test
    timeout-minutes: 5 # Step timeout

# Use container
jobs:
 build:
  runs-on: ubuntu-latest
  container:
   image: node:20-alpine
   env:
    NODE_ENV: production
 
# Build & push Docker image
- uses: docker/setup-buildx-action@v3
- uses: docker/login-action@v3
 with:
  username: ${{ secrets.DOCKER_USERNAME }}
  password: ${{ secrets.DOCKER_PASSWORD }}
 
- uses: docker/build-push-action@v5
 with:
  context: .
  push: true
  tags: user/app:latest
  cache-from: type=gha
  cache-to: type=gha,mode=max

# .github/workflows/reusable.yml
on:
 workflow_call:
  inputs:
   environment:
    required: true
    type: string
  outputs:
   result:
    value: ${{ jobs.deploy.outputs.result }}
 
jobs:
 deploy:
  runs-on: ubuntu-latest
  outputs:
   result: ${{ steps.deploy.outputs.status }}
  steps:
   - run: echo "Deploying to ${{ inputs.environment }}"

# .github/workflows/main.yml
jobs:
 call-workflow:
  uses: ./.github/workflows/reusable.yml
  with:
   environment: production

# GitHub context
${{ github.event_name }}   # push, pull_request, etc.
${{ github.ref }}       # refs/heads/main
${{ github.sha }}       # Commit SHA
${{ github.actor }}      # User who triggered
${{ github.repository }}   # owner/repo
${{ github.workspace }}    # /home/runner/work/repo/repo
 
# Runner context
${{ runner.os }}       # Linux, Windows, macOS
${{ runner.arch }}      # X64, ARM, ARM64
${{ runner.temp }}      # Temp directory
 
# Job context
${{ job.status }}       # success, failure, cancelled
 
# Steps context
${{ steps.step-id.outputs.value }}
${{ steps.step-id.conclusion }} # success, failure

name: Node.js CI
 
on: [push, pull_request]
 
jobs:
 test:
  runs-on: ubuntu-latest
 
  strategy:
   matrix:
    node-version: [18, 20, 22]
 
  steps:
   - uses: actions/checkout@v5
   - uses: actions/setup-node@v6
    with:
     node-version: ${{ matrix.node-version }}
     cache: 'npm'
   - run: npm ci
   - run: npm test
   - run: npm run lint

name: Release
 
on:
 push:
  tags: ['v*']
 
jobs:
 deploy:
  runs-on: ubuntu-latest
  steps:
   - uses: actions/checkout@v5
   - run: npm ci
   - run: npm run build
   - run: npm publish
    env:
     NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

- uses: actions/github-script@v7
 with:
  script: |
   github.rest.issues.createComment({
    issue_number: context.issue.number,
    owner: context.repo.owner,
    repo: context.repo.repo,
    body: 'Build successful!'
   })

- uses: actions/labeler@v5
 with:
  repo-token: ${{ secrets.GITHUB_TOKEN }}

# Debug step
- name: Debug
 run: |
  echo "Event: ${{ github.event_name }}"
  echo "Ref: ${{ github.ref }}"
  echo "SHA: ${{ github.sha }}"
  env
 
# Enable debug logs
# Set repository secrets:
# ACTIONS_RUNNER_DEBUG = true
# ACTIONS_STEP_DEBUG = true