[hw-5] concurrency, graceful shutdown, concurrent tests

cart/cmd/server/main.go

@@ -1,7 +1,14 @@
 package main
 
 import (
+	"context"
+	"net/http"
 	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/rs/zerolog/log"
 
 	"route256/cart/internal/app"
 )
@@ -9,10 +16,27 @@ import (
 func main() {
 	srv, err := app.NewApp(os.Getenv("CONFIG_FILE"))
 	if err != nil {
-		panic(err)
+		log.Fatal().Err(err).Msg("failed creating app")
 	}
 
-	if err := srv.ListenAndServe(); err != nil {
-		panic(err)
+	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer stop()
+
+	go func() {
+		if err := srv.ListenAndServe(ctx); err != nil && err != http.ErrServerClosed {
+			log.Fatal().Err(err).Msg("serving error")
+		}
+	}()
+
+	<-ctx.Done()
+	log.Info().Msg("shutdown signal received")
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if err := srv.Shutdown(shutdownCtx); err != nil {
+		log.Error().Err(err).Msg("graceful shutdown failed")
+	} else {
+		log.Info().Msg("server stopped gracefully")
 	}
 }