CI/CD

name: Build and deploy

on:
  push:
    branches: [main]
  pull_request:            # run tests on PRs, but do not deploy

# Cancel an in-progress run when a newer commit is pushed to the same branch.
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

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

      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm            # cache dependencies between runs

      # `npm ci` respects the lockfile exactly. `npm install` may resolve
      # different versions, which defeats the point of testing.
      - run: npm ci
      - run: npm run lint
      - run: npm test

  build-and-push:
    needs: test                 # only if tests passed
    if: github.ref == 'refs/heads/main'    # not on pull requests
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - uses: docker/build-push-action@v6
        with:
          push: true
          # Tag with the commit SHA: immutable, traceable, never ambiguous.
          tags: ghcr.io/${{ github.repository }}:${{ github.sha }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

  deploy:
    needs: build-and-push
    runs-on: ubuntu-latest
    environment: production     # attach required reviewers here for delivery
    steps:
      - uses: actions/checkout@v4

      - name: Deploy to Kubernetes
        run: |
          kubectl set image deploy/web \
            web=ghcr.io/${{ github.repository }}:${{ github.sha }}
          # Waits for the rollout and FAILS the job if it does not succeed —
          # without this, the pipeline goes green on a broken deploy.
          kubectl rollout status deploy/web --timeout=5m

env:
  DATABASE_URL: ${{ secrets.DATABASE_URL }}