[PHASE-9] Fix graceful shutdown

cmd/server/main.go

@@ -8,7 +8,6 @@ import (
 	"os"
 	"os/signal"
 	"syscall"
-	"time"
 
 	"hash-of-wisdom/internal/config"
 	"hash-of-wisdom/internal/lib/sl"
@@ -18,8 +17,6 @@ import (
 	"hash-of-wisdom/internal/service"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"github.com/prometheus/client_golang/prometheus/collectors"
-	"github.com/prometheus/client_golang/prometheus"
 	_ "net/http/pprof"
 )
 
@@ -66,9 +63,7 @@ func main() {
 		},
 	}
 
-	// Register Go runtime metrics
-	prometheus.MustRegister(collectors.NewGoCollector())
-	prometheus.MustRegister(collectors.NewProcessCollector(collectors.ProcessCollectorOpts{}))
+	// Go runtime metrics are automatically registered by default registry
 
 	// Start metrics and pprof HTTP server
 	go func() {
@@ -79,31 +74,31 @@ func main() {
 		}
 	}()
 
+	// Create context that cancels on interrupt signals
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+
 	// Create server
 	srv := server.NewTCPServer(wisdomService, serverConfig,
 		server.WithLogger(logger))
 
 	// Start server
-	ctx := context.Background()
 	if err := srv.Start(ctx); err != nil {
 		logger.Error("failed to start server", sl.Err(err))
 		os.Exit(1)
 	}
 
-	// Wait for interrupt
-	sigChan := make(chan os.Signal, 1)
-	signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
-
 	logger.Info("server ready - press ctrl+c to stop")
-	<-sigChan
+
+	// Wait for context cancellation (signal received)
+	<-ctx.Done()
 
 	// Graceful shutdown
 	logger.Info("shutting down server")
 	if err := srv.Stop(); err != nil {
 		logger.Error("error during shutdown", sl.Err(err))
+	} else {
+		logger.Info("server stopped gracefully")
 	}
 
-	// Give connections time to close
-	time.Sleep(100 * time.Millisecond)
-	logger.Info("server stopped")
 }