Building a Blue/Green Deployment Pipeline

name: blue-green-deploy

on:
  push:
    branches:
      - main

env:
  IMAGE_NAME: my-small-business-app
  REGISTRY: ghcr.io/YOUR_ORG
  COMMIT_SHA: ${{ github.sha }}

jobs:
  build-test-deploy:
    runs-on: ubuntu-latest

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

      - name: Run tests
        run: npm ci && npm test

      - name: Log in to container registry
        run: echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login "${{ env.REGISTRY }}" --username "${{ secrets.REGISTRY_USERNAME }}" --password-stdin

      - name: Build image
        run: docker build -t "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ env.COMMIT_SHA }}" .

      - name: Push image
        run: docker push "${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ env.COMMIT_SHA }}"

      - name: Deploy inactive stack
        uses: appleboy/ssh-action@v1.2.0
        with:
          host: ${{ secrets.DEPLOY_HOST }}
          username: ${{ secrets.DEPLOY_USER }}
          key: ${{ secrets.DEPLOY_SSH_KEY }}
          script: |
            export IMAGE_TAG="${{ env.COMMIT_SHA }}"
            ./deploy-inactive-stack.sh "${IMAGE_TAG}"
            ./wait-for-health.sh "http://app-inactive.internal:3000/health"

      - name: Run smoke tests
        run: |
          npm ci
          TARGET_URL="${{ secrets.INACTIVE_STACK_URL }}" npx playwright test tests/smoke

      - name: Switch proxy target
        uses: appleboy/ssh-action@v1.2.0
        with:
          host: ${{ secrets.DEPLOY_HOST }}
          username: ${{ secrets.DEPLOY_USER }}
          key: ${{ secrets.DEPLOY_SSH_KEY }}
          script: |
            ./switch-proxy-target.sh
            ./confirm-public-health.sh "https://www.example.com/health"