Add graceful shutdown to example

_examples/advanced-generic-openapi31/main.go

@@ -3,13 +3,47 @@
 package main
 
 import (
+	"context"
+	"errors"
 	"log"
 	"net/http"
+	"os"
+	"os/signal"
+	"time"
 )
 
 func main() {
+	var srv http.Server
+
+	idleConnsClosed := make(chan struct{})
+	go func() {
+		sigint := make(chan os.Signal, 1)
+		signal.Notify(sigint, os.Interrupt)
+		<-sigint
+
+		log.Println("Shutting down...")
+
+		// We received an interrupt signal, shut down with up to 10 seconds of waiting for current requests to finish.
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+
+		if err := srv.Shutdown(ctx); err != nil {
+			// Error from closing listeners, or context timeout:
+			log.Printf("HTTP server Shutdown: %v", err)
+		}
+		log.Println("Shutdown complete")
+
+		close(idleConnsClosed)
+	}()
+
+	srv.Handler = NewRouter()
+	srv.Addr = "localhost:8012"
+
 	log.Println("http://localhost:8012/docs")
-	if err := http.ListenAndServe("localhost:8012", NewRouter()); err != nil {
-		log.Fatal(err)
+	if err := srv.ListenAndServe(); !errors.Is(err, http.ErrServerClosed) {
+		// Error starting or closing listener:
+		log.Fatalf("HTTP server ListenAndServe: %v", err)
 	}
+
+	<-idleConnsClosed
 }