How would you implement graceful shutdown for an HTTP server handling long-lived connections?

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Accepted Answer

func main() {
    srv := &http.Server{Addr: ":8080", Handler: buildHandler()}

// Start server in a goroutine
    go func() {
        if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
            log.Fatalf("server error: %v", err)
        }
    }()

// Wait for termination signal
    ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGTERM, syscall.SIGINT)
    defer stop()
    <-ctx.Done()

log.Println("shutdown signal received")

// Mark health check as unhealthy (let LB drain traffic)
    atomic.StoreInt32(&healthy, 0)
    time.Sleep(5 * time.Second) // wait for LB to remove from rotation

// Shutdown with deadline
    shutdownCtx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()

if err := srv.Shutdown(shutdownCtx); err != nil {
        log.Printf("shutdown error: %v", err)
    }

// Flush queues, close DB connections
    db.Close()
    messageQueue.Flush()

log.Println("server stopped cleanly")
}

// Health endpoint
var healthy int32 = 1

func healthHandler(w http.ResponseWriter, r *http.Request) {
    if atomic.LoadInt32(&healthy) == 0 {
        w.WriteHeader(http.StatusServiceUnavailable)
        return
    }
    w.WriteHeader(http.StatusOK)
} server.Shutdown() stops accepting new connections and waits for active requests to complete Set a shutdown deadline (30s) to force-close stuck connections after the timeout Mark health endpoint unhealthy before shutdown — gives load balancer time to drain Drain message queue consumers before exit to avoid duplicate processing on restart Use preStop hook in Kubernetes to add the delay before SIGTERM is sent

How would you implement graceful shutdown for an HTTP server handling long-lived connections?

Listen for SIGTERM/SIGINT, call server.Shutdown() with a deadline context, drain in-flight requests, and signal health checks as unhealthy before stopping to let the load balancer route away.

How would you implement graceful shutdown for an HTTP server handling long-lived connections?

Listen for SIGTERM/SIGINT, call server.Shutdown() with a deadline context, drain in-flight requests, and signal health checks as unhealthy before stopping to let the load balancer route away.

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