use signal.NotifyContext when shutting down

cmd/gonic/gonic.go

@@ -298,7 +298,9 @@ func main() {
 		mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
 	}
 
-	errgrp, ctx := errgroup.WithContext(context.Background())
+	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
+	defer cancel()
+	errgrp, ctx := errgroup.WithContext(ctx)
 
 	errgrp.Go(func() error {
 		defer logJob("http")()
@@ -315,7 +317,10 @@ func main() {
 		if *confTLSCert != "" && *confTLSKey != "" {
 			return server.ListenAndServeTLS(*confTLSCert, *confTLSKey)
 		}
-		return server.ListenAndServe()
+		if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+			return err
+		}
+		return nil
 	})
 
 	errgrp.Go(func() error {
@@ -439,20 +444,7 @@ func main() {
 		return nil
 	})
 
-	errShutdown := errors.New("shutdown")
-
-	errgrp.Go(func() error {
-		sigChan := make(chan os.Signal, 1)
-		signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
-		select {
-		case <-ctx.Done():
-			return nil
-		case <-sigChan:
-			return errShutdown
-		}
-	})
-
-	if err := errgrp.Wait(); err != nil && !errors.Is(err, errShutdown) {
+	if err := errgrp.Wait(); err != nil {
 		log.Panic(err)
 	}