DevOps & Cloud

# .github/workflows/ci.yml
name: CI

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

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

      # Dependency cache: avoids repeated downloads
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'

      - run: npm ci
      - run: npm run lint
      - run: npm run test -- --coverage

      # Upload coverage for visibility into tests
      - uses: codecov/codecov-action@v4
        with:
          token: ${{ secrets.CODECOV_TOKEN }}

  build:
    needs: test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4

      # Build and push the Docker image
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - uses: docker/build-push-action@v5
        with:
          push: true
          tags: ghcr.io/${{ github.repository }}:latest
          cache-from: type=gha   # Cache Docker layers between runs
          cache-to: type=gha,mode=max

# Multi-stage Dockerfile
# Stage 1: Build (everything needed to compile)
FROM node:20-alpine AS builder
WORKDIR /app

# Copy only package.json first for efficient caching
# This layer is reused when code changes but dependencies do not
COPY package*.json ./
RUN npm ci --only=production

COPY . .
RUN npm run build

# Stage 2: Runtime (only what is needed to run)
FROM node:20-alpine AS runner
WORKDIR /app

# Non-root user: basic hardening
RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# Copy only the build output
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
COPY --from=builder --chown=nextjs:nodejs /app/public ./public

USER nextjs
EXPOSE 3000
ENV PORT=3000 NODE_ENV=production

# Health check: exposes container health to the orchestrator
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s \
  CMD wget -qO- http://localhost:3000/api/health || exit 1

CMD ["node", "server.js"]

# Measure the final image size for your application