Skill v1.0.0

v1 → v2 (instance 1)
v1     (instance 2, still running)

Blue (v1)  ← traffic       →  Blue (v1)  idle (standby)
Green (v2) idle             →  Green (v2) ← traffic

v1: 95%  →  v1: 50%  →  v2: 100%
v2:  5%  →  v2: 50%

FROM node:22-alpine AS deps
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci --production=false
 
FROM node:22-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
RUN npm run build && npm prune --production
 
FROM node:22-alpine AS runner
WORKDIR /app
RUN addgroup -g 1001 -S appgroup && adduser -S appuser -u 1001
USER appuser
COPY --from=builder --chown=appuser:appgroup /app/node_modules ./node_modules
COPY --from=builder --chown=appuser:appgroup /app/dist ./dist
COPY --from=builder --chown=appuser:appgroup /app/package.json ./
ENV NODE_ENV=production
EXPOSE 3000
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD wget -qO- http://localhost:3000/health || exit 1
CMD ["node", "dist/server.js"]

FROM python:3.12-slim AS builder
WORKDIR /app
RUN pip install --no-cache-dir uv
COPY requirements.txt .
RUN uv pip install --system --no-cache -r requirements.txt
 
FROM python:3.12-slim AS runner
WORKDIR /app
RUN useradd -r -u 1001 appuser
USER appuser
COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
COPY . .
ENV PYTHONUNBUFFERED=1
EXPOSE 8000
HEALTHCHECK --interval=30s --timeout=3s \
  CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8000/health/')" || exit 1
CMD ["gunicorn", "config.wsgi:application", "--bind", "0.0.0.0:8000", "--workers", "4"]

✅ Use specific version tags (node:22-alpine, not node:latest)
✅ Multi-stage builds — minimize production image size
✅ Run as non-root user (uid 1001)
✅ COPY dependency files BEFORE source (layer caching)
✅ Add HEALTHCHECK instruction
✅ Use .dockerignore (exclude node_modules, .git, tests, .env)
 
❌ Running as root
❌ :latest tags
❌ Storing secrets in image layers (use env vars)
❌ One giant container with all services

name: CI/CD
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
 
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 22
          cache: npm
      - run: npm ci
      - run: npm run lint
      - run: npm run typecheck
      - run: npm test -- --coverage
      - uses: actions/upload-artifact@v4
        if: always()
        with:
          name: coverage
          path: coverage/
 
  build:
    needs: test
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    steps:
      - uses: actions/checkout@v4
      - uses: docker/setup-buildx-action@v3
      - 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 }}:${{ github.sha }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
 
  deploy:
    needs: build
    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'
    environment: production
    steps:
      - name: Deploy
        run: |
          # Railway: railway up
          # Vercel:  vercel --prod
          # K8s:     kubectl set image deployment/app app=ghcr.io/${{ github.repository }}:${{ github.sha }}
          echo "Deploying ${{ github.sha }}"

PR opened:
  lint → typecheck → unit tests → integration tests → preview deploy
 
Merged to main:
  lint → typecheck → unit tests → integration tests
  → build image → deploy staging → smoke tests → deploy production

// Simple — for liveness
app.get('/health', (req, res) => res.status(200).json({ status: 'ok' }))
// Detailed — for readiness / monitoring
app.get('/health/detailed', async (req, res) => {
  const checks = {
    database: await checkDatabase(),
    cache: await checkRedis(),
  }
  const allHealthy = Object.values(checks).every(c => c.status === 'ok')
  res.status(allHealthy ? 200 : 503).json({
    status: allHealthy ? 'ok' : 'degraded',
    timestamp: new Date().toISOString(),
    version: process.env.APP_VERSION,
    checks,
  })
})

livenessProbe:
  httpGet: { path: /health, port: 3000 }
  initialDelaySeconds: 10
  periodSeconds: 30
  failureThreshold: 3
 
readinessProbe:
  httpGet: { path: /health, port: 3000 }
  initialDelaySeconds: 5
  periodSeconds: 10
  failureThreshold: 2

import { z } from 'zod'
// Validate ALL required env vars at startup — fail fast
const envSchema = z.object({
  NODE_ENV: z.enum(['development', 'staging', 'production']),
  PORT: z.coerce.number().default(3000),
  DATABASE_URL: z.string().url(),
  JWT_SECRET: z.string().min(32),
  LOG_LEVEL: z.enum(['debug', 'info', 'warn', 'error']).default('info'),
})
export const env = envSchema.parse(process.env)

# Kubernetes
kubectl rollout undo deployment/app
 
# Vercel
vercel rollback
 
# Railway
railway up --commit <previous-sha>
 
# Database (if reversible)
npx prisma migrate resolve --rolled-back <migration-name>