A production Node.js application should shut down cleanly when it receives termination signals.

A graceful shutdown should:

1. Stop accepting new connections.
2. Notify or disconnect active clients according to application requirements.
3. Close the Socket.IO server.
4. Close the HTTP server.
5. Close Redis connections.
6. Exit the process after cleanup.

This is especially important in Docker and Kubernetes deployments where applications receive termination signals during restarts and deployments.

The exact shutdown behavior should be designed according to your deployment platform and connection-draining requirements.

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

  io.disconnectSockets(true);

  await new Promise((resolve, reject) => {
    httpServer.close((error) => {
      if (error) reject(error);
      else resolve();
    });
  });

  await Promise.all([
    pubClient.quit(),
    subClient.quit()
  ]);

  process.exit(0);
}

process.on('SIGTERM', () => {
  shutdown('SIGTERM').catch(console.error);
});

process.on('SIGINT', () => {
  shutdown('SIGINT').catch(console.error);
});