How to implement graceful shutdown in Node.js?

const http = require('http');

const server = http.createServer(app);
let connections = new Set();

server.on('connection', (conn) => {
  connections.add(conn);
  conn.on('close', () => connections.delete(conn));
});

function shutdown(signal) {
  console.log(`${signal} received. Shutting down gracefully...`);

  // Stop accepting new connections
  server.close(() => {
    console.log('HTTP server closed');

    // Close database connections
    mongoose.connection.close(false, () => {
      console.log('MongoDB connection closed');
      process.exit(0);
    });
  });

  // Force close after timeout
  setTimeout(() => {
    console.error('Forcing shutdown...');
    process.exit(1);
  }, 10000);

  // Close existing connections
  connections.forEach(conn => conn.end());
  setTimeout(() => {
    connections.forEach(conn => conn.destroy());
  }, 5000);
}

process.on('SIGTERM', () => shutdown('SIGTERM'));
process.on('SIGINT', () => shutdown('SIGINT'));

const express = require('express');
const app = express();

// Health check endpoint
let isShuttingDown = false;

app.use((req, res, next) => {
  if (isShuttingDown) {
    res.set('Connection', 'close');
    return res.status(503).send('Server is shutting down');
  }
  next();
});

function gracefulShutdown() {
  isShuttingDown = true;

  server.close(async () => {
    await db.disconnect();
    await redis.quit();
    await messageQueue.close();
    process.exit(0);
  });
}