Graceful shutdown handling in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is graceful shutdown in an Express server?

Graceful shutdown means stopping the server without abruptly cutting off active connections. It waits for ongoing requests to finish before closing.

beginner

Which Node.js event is commonly used to trigger graceful shutdown?

The 'SIGINT' signal is often used. It signals the app to start cleanup before exiting, like when you press Ctrl+C in the terminal.

intermediate

Why should you close the HTTP server during graceful shutdown?

Closing the HTTP server stops it from accepting new requests but lets existing requests finish, preventing sudden disconnections.

intermediate

How can you handle cleanup tasks like closing database connections during shutdown?

You add cleanup code inside the shutdown handler to close resources like database connections or file streams before exiting.

beginner

What happens if you don't implement graceful shutdown in an Express app?

The server may drop active requests abruptly, causing errors for users and possible data loss or corruption.

Which method stops an Express server from accepting new requests during shutdown?

A app.close()

B server.stop()

C server.close()

D app.shutdown()

The server.close() method stops the server from accepting new connections but allows existing ones to finish.

What Node.js signal is typically used to initiate graceful shutdown?

A SIGINT

B SIGKILL

C SIGSTOP

D SIGCONT

SIGINT is sent when you press Ctrl+C and is commonly used to start graceful shutdown.

Why is it important to wait for ongoing requests to finish during shutdown?

A To block new users from connecting

B To speed up server restart

C To free memory immediately

D To avoid losing data or causing errors for users

Waiting ensures users' requests complete successfully without abrupt errors.

Where should you place code to close database connections during shutdown?

A Inside the shutdown handler function

B In the main app setup

C In the request handler

D In the server.listen callback

Cleanup code belongs in the shutdown handler to run before the app exits.

What happens if you call process.exit() immediately without cleanup?

A The app waits for requests to finish

B The app exits abruptly, possibly causing errors

C The server restarts automatically

D The app logs out users safely

Immediate exit stops everything without cleanup, risking errors and data loss.

Explain how to implement graceful shutdown in an Express server.

Think about stopping new requests, finishing current ones, and cleaning resources.

Why is graceful shutdown important in web servers like Express?

Consider what happens if the server stops suddenly.