Graceful shutdown handling in Express - Mini Project: Build & Apply

Graceful shutdown handling

📖 Scenario: You are building a simple Express server that needs to stop cleanly when the app is closed or restarted. This means it should finish any ongoing requests before shutting down.

🎯 Goal: Create an Express server that listens on port 3000 and implements graceful shutdown by closing the server and exiting the process when it receives a termination signal.

📋 What You'll Learn

Create an Express app with a basic route

Start the server listening on port 3000

Add a variable to hold the server instance

Implement a function to handle graceful shutdown

Listen for termination signals and call the shutdown function

💡 Why This Matters

🌍 Real World

Servers often need to stop without dropping active users or leaving resources open. Graceful shutdown helps keep apps reliable and user-friendly.

💼 Career

Understanding graceful shutdown is important for backend developers and DevOps engineers to maintain stable and maintainable server applications.

1

Create the Express app and basic route

Create an Express app by requiring express and calling it to create app. Then add a GET route on '/' that sends the text 'Server is running'.

Express

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

// Your code here

Need a hint?

Use require('express') to import Express and app.get to create a route.

2

Start the server and save the server instance

Start the server listening on port 3000 by calling app.listen(3000). Save the returned server instance in a variable called server.

Express

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

app.get('/', (req, res) => {
  res.send('Server is running');
});

// Your code here

Need a hint?

Save the result of app.listen(3000) to server.

3

Create a graceful shutdown function

Create a function called gracefulShutdown that calls server.close() with a callback. Inside the callback, call process.exit(0) to exit the process cleanly.

Express

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

app.get('/', (req, res) => {
  res.send('Server is running');
});

const server = app.listen(3000);

// Your code here

Need a hint?

Use server.close() with a callback that calls process.exit(0).

4

Listen for termination signals and call graceful shutdown

Use process.on to listen for the 'SIGINT' and 'SIGTERM' signals. For each, call the gracefulShutdown function.

Express

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

app.get('/', (req, res) => {
  res.send('Server is running');
});

const server = app.listen(3000);

function gracefulShutdown() {
  server.close(() => {
    process.exit(0);
  });
}

// Your code here

Need a hint?

Use process.on to listen for 'SIGINT' and 'SIGTERM' and call gracefulShutdown.