Implement Graceful Shutdown

When the application receives a termination signal, it should stop accepting new connections and release resources cleanly.

The shutdown sequence should:

Stop accepting new HTTP connections.
Allow active requests to finish within a reasonable deadline.
Disconnect from MongoDB.
Exit the process.

This is particularly important in containerized environments and during automated deployments.

Production Shutdown Deadline

Add a shutdown timeout and account for keep-alive connections. Your application should complete cleanup within the hosting platform's termination grace period.

Graceful Shutdown

import http from 'node:http';
import app from './app.js';
import { connectDatabase, disconnectDatabase } from './config/database.js';

const server = http.createServer(app);

async function startServer() {
  await connectDatabase();

  server.listen(process.env.PORT || 3000);
}

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

  server.close(async (error) => {
    try {
      await disconnectDatabase();

      if (error) {
        console.error(error);
        process.exit(1);
      }

      process.exit(0);
    } catch (shutdownError) {
      console.error(shutdownError);
      process.exit(1);
    }
  });
}

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

startServer().catch((error) => {
  console.error(error);
  process.exit(1);
});

Creates an explicit HTTP server, closes it on termination, and disconnects from MongoDB before exiting.

Key Takeaways

Handle SIGTERM and SIGINT.
Stop accepting new connections during shutdown.
Close database connections before exiting.

Implement Graceful Shutdown

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