What is graceful shutdown and how do you implement it in Node.js?

Question

Accepted Answer

**Graceful shutdown** — finish in-flight requests before closing the server.

```javascript
const http = require("http");

const server = http.createServer(app);

function gracefulShutdown(signal) {
    console.log(`${signal} received. Starting graceful shutdown...`);

server.close(() => {
        console.log("HTTP server closed");
        // Close database connections
        db.pool.end();
        // Close Redis
        redis.quit();
        process.exit(0);
    });

// Force shutdown after 30 seconds
    setTimeout(() => {
        console.error("Forced shutdown");
        process.exit(1);
    }, 30000);
}

process.on("SIGTERM", () => gracefulShutdown("SIGTERM"));
process.on("SIGINT", () => gracefulShutdown("SIGINT"));

server.listen(3000);
```

**Key steps:**
- 1. Stop accepting new connections.
- 2. Finish in-flight requests.
- 3. Close DB/Redis connections.
- 4. Exit process.
- 5. Force kill after timeout.

Node.js: What is graceful shutdown and how do you implement it in Node.js?