github-actions

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GitHub Actions

Automate software workflows directly in your GitHub repository with GitHub Actions.

When to Use This Skill

Use this skill when:

Setting up CI/CD pipelines for GitHub repositories
Automating build, test, and deployment workflows
Creating reusable workflow components
Configuring self-hosted runners
Managing workflow secrets and variables
Debugging failed workflow runs

Prerequisites

GitHub repository with write access
Understanding of YAML syntax
For self-hosted runners: server with Docker (optional)

Workflow File Structure

Workflows are defined in .github/workflows/ directory:

yaml

name: CI Pipeline

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

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

Common Triggers

Push and Pull Request

yaml

on:
  push:
    branches: [main]
    paths:
      - 'src/**'
      - 'package.json'
  pull_request:
    branches: [main]

Scheduled Runs

yaml

on:
  schedule:
    - cron: '0 2 * * *'  # Daily at 2 AM UTC

Manual Dispatch

yaml

on:
  workflow_dispatch:
    inputs:
      environment:
        description: 'Deployment environment'
        required: true
        default: 'staging'
        type: choice
        options:
          - staging
          - production

Job Configuration

Matrix Builds

yaml

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

Job Dependencies

yaml

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - run: npm run build
      
  test:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - run: npm test
      
  deploy:
    needs: [build, test]
    runs-on: ubuntu-latest
    steps:
      - run: ./deploy.sh

Environment Protection

yaml

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment:
      name: production
      url: https://example.com
    steps:
      - run: ./deploy.sh

Secrets and Variables

Using Secrets

yaml

steps:
  - name: Deploy
    env:
      AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
      AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
    run: aws s3 sync ./dist s3://my-bucket

Using Variables

yaml

steps:
  - name: Build
    env:
      API_URL: ${{ vars.API_URL }}
    run: npm run build

Caching Dependencies

yaml

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
    restore-keys: |
      ${{ runner.os }}-node-

Artifacts

Upload Artifacts

yaml

- uses: actions/upload-artifact@v4
  with:
    name: build-output
    path: dist/
    retention-days: 5

Download Artifacts

yaml

- uses: actions/download-artifact@v4
  with:
    name: build-output
    path: dist/

Docker Builds

yaml

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
      
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: user/app:latest

Reusable Workflows

Define Reusable Workflow

yaml

# .github/workflows/reusable-deploy.yml
name: Reusable Deploy

on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
    secrets:
      deploy_key:
        required: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: ${{ inputs.environment }}
    steps:
      - run: echo "Deploying to ${{ inputs.environment }}"

Call Reusable Workflow

yaml

jobs:
  deploy-staging:
    uses: ./.github/workflows/reusable-deploy.yml
    with:
      environment: staging
    secrets:
      deploy_key: ${{ secrets.STAGING_KEY }}

Self-Hosted Runners

Register Runner

bash

# Download runner
mkdir actions-runner && cd actions-runner
curl -o actions-runner-linux-x64.tar.gz -L https://github.com/actions/runner/releases/download/v2.311.0/actions-runner-linux-x64-2.311.0.tar.gz
tar xzf actions-runner-linux-x64.tar.gz

# Configure
./config.sh --url https://github.com/OWNER/REPO --token TOKEN

# Run
./run.sh

Use Self-Hosted Runner

yaml

jobs:
  build:
    runs-on: self-hosted
    steps:
      - uses: actions/checkout@v4

Debugging Workflows

Enable Debug Logging

Set repository secrets:

ACTIONS_RUNNER_DEBUG: true
ACTIONS_STEP_DEBUG: true

Debug Step

yaml

- name: Debug
  run: |
    echo "GitHub context: ${{ toJson(github) }}"
    echo "Job context: ${{ toJson(job) }}"

Common Issues

Issue: Workflow Not Triggering

Problem: Workflow doesn't run on push/PR Solution: Check branch filters, path filters, and ensure workflow file is on the default branch

Issue: Permission Denied

Problem: Actions can't push or create PRs Solution: Configure permissions in workflow or update repository settings

yaml

permissions:
  contents: write
  pull-requests: write

Issue: Cache Not Restoring

Problem: Cache misses despite existing cache Solution: Verify cache key matches exactly, check runner OS

Best Practices

Pin action versions to specific commits or tags
Use caching for dependencies to speed up builds
Minimize secrets exposure with environment scoping
Use matrix builds for cross-platform testing
Implement proper error handling with continue-on-error
Keep workflows DRY with reusable workflows and composite actions

Related Skills

gitlab-ci - GitLab CI/CD alternative
docker-management - Container builds
semantic-versioning - Automated releases

GitHub Actions

When to Use This Skill

Prerequisites

Workflow File Structure

Common Triggers

Push and Pull Request

Scheduled Runs

Manual Dispatch

Job Configuration

Matrix Builds

Job Dependencies

Environment Protection

Secrets and Variables

Using Secrets

Using Variables

Caching Dependencies

Artifacts

Upload Artifacts

Download Artifacts

Docker Builds

Reusable Workflows

Define Reusable Workflow

Call Reusable Workflow

Self-Hosted Runners

Register Runner

Use Self-Hosted Runner

Debugging Workflows

Enable Debug Logging

Debug Step

Common Issues

Issue: Workflow Not Triggering

Issue: Permission Denied

Issue: Cache Not Restoring

Best Practices

Related Skills

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