name: ci-cd
description: CI/CD pipeline patterns with GitHub Actions. Use when writing or
reviewing workflow files, deployment pipelines, or branch protection rules.

CI/CD Pipeline Rules

1. GitHub Actions Workflow Structure

Directory Layout

.github/
├── workflows/
│   ├── ci.yml              # Build + test on PR
│   ├── cd-dev.yml          # Deploy to dev
│   ├── cd-staging.yml      # Deploy to staging
│   └── cd-prod.yml         # Deploy to production
└── actions/
    └── gradle-setup/       # Reusable composite action
        └── action.yml

Naming Convention

2. CI Workflow Template

Kotlin/Spring Boot

name: CI

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

permissions:
  contents: read
  checks: write

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: '21'

      - uses: gradle/actions/setup-gradle@v4

      - name: Build and test
        run: ./gradlew build

      - name: Publish test results
        uses: EnricoMi/publish-unit-test-result-action@v2
        if: always()
        with:
          files: '**/build/test-results/**/*.xml'

3. CD Workflow Template

Build and Push Container Image

name: CD - Dev

on:
  push:
    branches: [develop]

permissions:
  contents: read
  id-token: write

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: dev
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: '21'

      - uses: gradle/actions/setup-gradle@v4

      - name: Build JAR
        run: ./gradlew bootJar -x test

      - name: Build and push Docker image
        uses: docker/build-push-action@v6
        with:
          context: .
          push: true
          tags: |
            ${{ vars.REGISTRY }}/${{ vars.IMAGE_NAME }}:${{ github.sha }}

      - name: Deploy to Kubernetes
        run: |
          kubectl set image deployment/${{ vars.APP_NAME }} \
            app=${{ vars.REGISTRY }}/${{ vars.IMAGE_NAME }}:${{ github.sha }} \
            -n ${{ vars.NAMESPACE }}

4. Environment and Secret Management

GitHub Environments

Secret Naming Convention

DB_URL              # Database connection URL
DB_USERNAME         # Database username
DB_PASSWORD         # Database password
REGISTRY_USERNAME   # Container registry username
REGISTRY_PASSWORD   # Container registry password
KUBECONFIG          # Kubernetes config (base64 encoded)

Secret Management Rules

• Use GitHub Environments to scope secrets per deployment target
• Never echo or print secrets in workflow steps
• Use ${{ secrets.NAME }} — never hardcode values
• Rotate secrets periodically and after team member changes
• Use OIDC (id-token: write) over long-lived credentials when possible

5. Caching Strategy

Gradle Cache

- uses: gradle/actions/setup-gradle@v4
  # Gradle action handles caching automatically

Docker Layer Cache

- uses: docker/build-push-action@v6
  with:
    context: .
    push: true
    cache-from: type=gha
    cache-to: type=gha,mode=max

Caching Rules

• Always cache dependency downloads (Gradle, npm, pip)
• Use GitHub Actions cache or setup actions that handle caching
• Set appropriate cache keys to avoid stale caches
• Monitor cache hit rates — low hit rate means wasted storage

6. Deployment Safety

Production Deployment Checklist

• [ ] All CI checks passed on the commit being deployed
• [ ] Staging deployment verified (manual or automated smoke test)
• [ ] Required reviewers approved the deployment
• [ ] Database migrations tested against production-like data
• [ ] Rollback plan documented and tested

Rollback Strategy

# Quick rollback via kubectl
- name: Rollback on failure
  if: failure()
  run: |
    kubectl rollout undo deployment/${{ vars.APP_NAME }} \
      -n ${{ vars.NAMESPACE }}

Progressive Deployment

7. Workflow Best Practices

Do

• Pin action versions with full SHA or major version (@v4)
• Use permissions to limit GITHUB_TOKEN scope
• Separate CI (test) and CD (deploy) workflows
• Use environment for deployment protection rules
• Run tests in parallel when possible (strategy.matrix)
• Fail fast — stop remaining jobs on first failure

Do Not

• Use pull_request_target without careful security review
• Store secrets in workflow files or repository code
• Skip tests in CD pipeline ("it passed in CI")
• Deploy directly from feature branches to production
• Use latest tags for production container images
• Run sudo or install packages without pinned versions

8. Branch Protection Rules

Recommended Settings for Main Branch