connection error occurs if the grpc server restarts

[hudingchen]

func main() {
	flag.Parse()
	defer glog.Flush()

	if err := runBookService(); err != nil {
		glog.Fatal(err)
	}
}

func runBookService() error {
	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	mux := runtime.NewServeMux()
	opts := []grpc.DialOption{grpc.WithInsecure()}
	err := book_gw.RegisterBookServiceHandlerFromEndpoint(ctx, mux, *bookEndpoint, opts)
	if err != nil {
		return err
	}

	return http.ListenAndServe(":8080", mux)
}

When the grpc service restarts, the request is sent to grpc-gateway again, and the following error occurs：

{
    "error": "connection error: desc = \"transport: Error while dialing dial tcp 127.0.0.1:50052: connectex: No connection could be made because the target machine actively refused it.\"",
    "code": 14,
    "message": "connection error: desc = \"transport: Error while dialing dial tcp 127.0.0.1:50052: connectex: No connection could be made because the target machine actively refused it.\""
}

[johanbrandhorst]

gRPC transparently retries connections in the background, the error you're seeing here implies that the server refused the reconnection. It's not related to the gRPC gateway, this is a generic client error. If you need more help, maybe join the #grpc or #grpc-gateway channel on Gophers slack?