GitHub Actions Setup

You are a DevOps engineer setting up CI/CD pipelines. The user wants to create and configure GitHub Actions workflow files for automated testing, building, and deployment.

What to check first

• Verify the .github/workflows/ directory exists in the repository root—create it if missing
• Check the repository has write permissions and the user has admin or maintainer access to enable Actions
• Review the target branch protection rules to ensure workflows can run on pull requests

Steps

1. Create the .github/workflows/ directory structure at the repository root (not nested inside src/ or other subdirectories)
2. Create a workflow file with .yml or .yaml extension—e.g., .github/workflows/ci.yml
3. Define the name field to label the workflow in the Actions UI
4. Set on: trigger events (e.g., push, pull_request, schedule) with specific branches using branches: key
5. Define jobs: with a unique job identifier and runs-on: specifying the runner (e.g., ubuntu-latest, macos-latest)
6. Add steps: with uses: for pre-built actions and run: for shell commands, including actions/checkout@v4 as the first step
7. Use env: at workflow or step level to inject environment variables
8. Commit the workflow file to the default branch—GitHub automatically enables it

Code

name: CI Pipeline

on:
  push:
    branches:
      - main
      - develop
  pull_request:
    branches:
      - main

env:
  NODE_VERSION: '18'

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [16.x, 18.x, 20.x]

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Setup Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

      - name: Run linter
        run: npm run lint

      - name: Run tests
        run: npm test -- --coverage

      - name: Upload coverage
        uses: codecov/codecov-action@v3
        with:
          files: ./coverage/lcov.info
          fail_ci_if_error: false

  build:
    runs-on: ubuntu-latest
    needs: test

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

Note: this example was truncated in the source. See the GitHub repo for the latest full version.

Common Pitfalls

• Treating this skill as a one-shot solution — most workflows need iteration and verification
• Skipping the verification steps — you don't know it worked until you measure
• Applying this skill without understanding the underlying problem — read the related docs first

When NOT to Use This Skill

• When a simpler manual approach would take less than 10 minutes
• On critical production systems without testing in staging first
• When you don't have permission or authorization to make these changes

How to Verify It Worked

• Run the verification steps documented above
• Compare the output against your expected baseline
• Check logs for any warnings or errors — silent failures are the worst kind

Production Considerations

• Test in staging before deploying to production
• Have a rollback plan — every change should be reversible
• Monitor the affected systems for at least 24 hours after the change