Go graceful shutdown pattern

Go HTTP servers need to handle shutdown gracefully, finishing in-flight requests before stopping.

Implement signal-based graceful shutdown:

package main

import (
	"context"
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"
)

func main() {
	mux := http.NewServeMux()
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		// Simulate work
		time.Sleep(2 * time.Second)
		w.Write([]byte("OK"))
	})

	srv := &http.Server{
		Addr:         ":8080",
		Handler:      mux,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	// Start server in goroutine
	go func() {
		log.Printf("Server starting on %s", srv.Addr)
		if err := srv.ListenAndServe(); err != http.ErrServerClosed {
			log.Fatalf("Server error: %v", err)
		}
	}()

	// Wait for interrupt signal
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit
	log.Println("Shutting down...")

	// Give in-flight requests time to complete
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	if err := srv.Shutdown(ctx); err != nil {
		log.Fatalf("Forced shutdown: %v", err)
	}

	log.Println("Server stopped gracefully")
}

For multiple services (DB, cache, workers):

// Shutdown in reverse order of startup
log.Println("Stopping HTTP server...")
srv.Shutdown(ctx)

log.Println("Closing worker pool...")
workerPool.Stop()

log.Println("Closing database...")
db.Close()

log.Println("Closing cache...")
cache.Close()

Without graceful shutdown, in-flight requests get terminated mid-response, database transactions are left incomplete, and resources leak.

Go services that need clean shutdown