automating-with-github-actions

name	Automating with GitHub Actions
description	The agent implements GitHub Actions CI/CD workflows with builds, tests, and deployments. Use when setting up continuous integration, automating deployments, creating reusable actions, or implementing security scanning.

Automating with GitHub Actions

Quick Start

# .github/workflows/ci.yml
name: CI

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: npm
      - run: npm ci
      - run: npm test
      - run: npm run build

Features

Feature	Description	Guide
Workflows	Event-driven automation pipelines	Trigger on push, PR, schedule, or manual dispatch
Jobs	Parallel or sequential task execution	Use needs for dependencies, matrix for variations
Actions	Reusable workflow components	Use marketplace actions or create custom composite
Environments	Deployment targets with protection	Configure approvals, secrets, and URLs
Artifacts	Build output persistence	Upload/download between jobs, retention policies
Caching	Dependency caching for speed	Cache npm, pip, gradle directories

Common Patterns

Matrix Build

jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
        node: [18, 20, 22]
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}
      - run: npm ci && npm test

Deployment with Environments

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment:
      name: production
      url: https://example.com
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm run build
      - name: Deploy
        run: ./deploy.sh
        env:
          DEPLOY_TOKEN: ${{ secrets.DEPLOY_TOKEN }}

Docker Build and Push

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: docker/setup-buildx-action@v3
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
      - uses: docker/build-push-action@v5
        with:
          push: true
          tags: ghcr.io/${{ github.repository }}:${{ github.sha }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

Best Practices

Do	Avoid
Use concurrency groups to cancel stale runs	Hardcoding secrets in workflows
Cache dependencies for faster builds	Skipping security scanning
Use matrix strategies for cross-platform	Using deprecated action versions
Implement environment protection rules	Running unnecessary jobs on PRs
Set timeouts on long-running jobs	Ignoring workflow permissions
Use reusable workflows for common patterns	Self-hosted runners without security review
Upload test artifacts on failure	Skipping concurrency controls