Deploying Node.js

import express from 'express';

const app = express();
let ready = true;
let inFlight = 0;

app.use((req, res, next) => {
  inFlight++;
  res.on('finish', () => inFlight--);
  next();
});
app.get('/health', (req, res) => res.json({ status: 'ok', uptime: process.uptime() > 0 }));
app.get('/ready', (req, res) => (ready ? res.json({ ready }) : res.status(503).json({ ready })));
app.get('/slow-report', async (req, res) => {
  await new Promise((r) => setTimeout(r, 200));
  res.json({ report: 'done' });
});

const server = app.listen(0, async () => {
  const base = `http://localhost:${server.address().port}`;
  console.log(await (await fetch(`${base}/health`)).text());

  const pending = fetch(`${base}/slow-report`).then((r) => r.json());
  await new Promise((r) => setTimeout(r, 50));
  process.emit('SIGTERM');

  console.log((await fetch(`${base}/ready`)).status);
  console.log('In-flight request finished:', JSON.stringify(await pending));
});

process.on('SIGTERM', () => {
  console.log(`SIGTERM: ${inFlight} request(s) in progress, draining`);
  ready = false;
  setTimeout(() => {
    server.close(() => console.log('Server closed cleanly'));
    server.closeIdleConnections();
  }, 300);
});

# Dockerfile
FROM node:22-slim
ENV NODE_ENV=production
WORKDIR /app
COPY package.json package-lock.json ./
RUN npm ci --omit=dev
COPY --chown=node:node src ./src
USER node
EXPOSE 3000
HEALTHCHECK CMD node -e "fetch('http://localhost:3000/health').then(r => process.exit(r.ok ? 0 : 1)).catch(() => process.exit(1))"
CMD ["node", "src/server.js"]

# .github/workflows/deploy.yml
name: test-and-deploy
on:
  push:
    branches: [main]
jobs:
  build:
    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 test
      - run: npm audit --audit-level=high
      - run: curl -fsS -X POST "${{ secrets.DEPLOY_HOOK_URL }}"