CI/CD for Containers: Automating Builds, Tests, and Deployments with GitHub Actions & Kubernetes¶

name: CI/CD – Build, Test, Deploy

on:
  push:
    branches: [ main ]          # Run on pushes to main
  pull_request:
    branches: [ main ]          # And on PRs targeting main

env:
  IMAGE_NAME: ghcr.io/${{ github.repository }}   # GitHub Container Registry
  HELM_RELEASE: my-app
  KUBEVERSION: "1.28"        # Adjust to your cluster version

jobs:
  build-test:
    runs-on: ubuntu-latest
    steps:
      # -----------------------------------------------------------------
      # 1️⃣ Checkout source
      # -----------------------------------------------------------------
      - name: Checkout repository
        uses: actions/checkout@v4

      # -----------------------------------------------------------------
      # 2️⃣ Set up Docker Buildx (multi‑platform builds)
      # -----------------------------------------------------------------
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      # -----------------------------------------------------------------
      # 3️⃣ Log in to GitHub Container Registry
      # -----------------------------------------------------------------
      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # -----------------------------------------------------------------
      # 4️⃣ Build & push the image (cache layers for speed)
      # -----------------------------------------------------------------
      - name: Build and push Docker image
        id: docker_build
        uses: docker/build-push-action@v5
        with:
          context: .
          file: Dockerfile
          push: true
          tags: |
            ${{ env.IMAGE_NAME }}:latest
            ${{ env.IMAGE_NAME }}:${{ github.sha }}
          cache-from: type=registry,ref=${{ env.IMAGE_NAME }}:buildcache
          cache-to: type=registry,ref=${{ env.IMAGE_NAME }}:buildcache,mode=max

      # -----------------------------------------------------------------
      # 5️⃣ Run unit tests *inside* the built image
      # -----------------------------------------------------------------
      - name: Run unit tests
        run: |
          # Pull the just‑built image
          docker pull ${{ env.IMAGE_NAME }}:${{ github.sha }}
          # Run tests (example assumes a Python test suite)
          docker run --rm ${{ env.IMAGE_NAME }}:${{ github.sha }} pytest -q

      # -----------------------------------------------------------------
      # 6️⃣ Security scan (Trivy)
      # -----------------------------------------------------------------
      - name: Scan image for vulnerabilities
        uses: aquasecurity/trivy-action@latest
        with:
          image-ref: ${{ env.IMAGE_NAME }}:${{ github.sha }}
          format: 'sarif'
          output: 'trivy-results.sarif'
          exit-code: '1'  # Fail the job if any vulnerability > median severity is found
      - name: Upload Trivy SARIF (GitHub Security scans)
        uses: github/codeql-action/upload-sarif@v3
        with:
          sarif_file: trivy-results.sarif

  deploy:
    needs: build-test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
    permissions:
      contents: read
      id-token: write   # Needed for OIDC to talk to the cluster
    steps:
      # -----------------------------------------------------------------
      # 7️⃣ Checkout again (needed for helm chart files)
      # -----------------------------------------------------------------
      - name: Checkout repository (for helm chart)
        uses: actions/checkout@v4

      # -----------------------------------------------------------------
      # 8️⃣ Set up kubectl (cluster access via OIDC)
      # -----------------------------------------------------------------
      - name: Set up kubectl
        uses: azure/setup-kubectl@v3
        with:
          version: 'v1.28.0'

      # -----------------------------------------------------------------
      # 9️⃣ Authenticate to the cluster (example uses OIDC with GitHub)
      # -----------------------------------------------------------------
      - name: Authenticate to Kubernetes cluster
        env:
          KUBECONFIG: /tmp/kubeconfig
        run: |
          # Example for a cluster that trusts GitHub OIDC:
          # az aks get-credentials --resource-group MyRG --name MyCluster --overwrite-existing
          # Replace the above with your own method (e.g., kubeconfig from secret)
          echo "KUBECONFIG=/tmp/kubeconfig" >> $GITHUB_ENV

      # -----------------------------------------------------------------
      # 10️⃣ Deploy with Helm (only if image passes tests & security scan)
      # -----------------------------------------------------------------
      - name: Deploy to Kubernetes with Helm
        env:
          IMAGE_TAG: ${{ github.sha }}
        run: |
          # Add Helm repo (if not already added)
          helm repo add bitnami https://charts.bitnami.com/bitnami
          helm repo update

          # Upgrade the release – this performs a rolling update
          helm upgrade --install ${{ env.HELM_RELEASE }} ./helm/my-app \
            --namespace production \
            --create-namespace \
            --set image.repository=${{ env.IMAGE_NAME }} \
            --set image.tag=${{ env.IMAGE_TAG }} \
            --set resources.limits.cpu=200m \
                     resources.limits.memory=512Mi