api/handler/rpc: not log error on client disconnect (#1482)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

stream.go

@@ -135,9 +135,19 @@ func serveWebsocket(ctx context.Context, w http.ResponseWriter, r *http.Request,
 
 	// receive from stream and send to client
 	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-stream.Context().Done():
+			return
+		default:
 			// read backend response body
 			buf, err := rsp.Read()
 			if err != nil {
+				// wants to avoid import  grpc/status.Status
+				if strings.Contains(err.Error(), "context canceled") {
+					return
+				}
 				if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 					logger.Error(err)
 				}
@@ -159,6 +169,7 @@ func serveWebsocket(ctx context.Context, w http.ResponseWriter, r *http.Request,
 			}
 		}
 	}
+}
 
 // writeLoop
 func writeLoop(rw io.ReadWriter, stream client.Stream) {
@@ -166,13 +177,23 @@ func writeLoop(rw io.ReadWriter, stream client.Stream) {
 	defer stream.Close()
 
 	for {
+		select {
+		case <-stream.Context().Done():
+			return
+		default:
 			buf, op, err := wsutil.ReadClientData(rw)
 			if err != nil {
+				wserr := err.(wsutil.ClosedError)
+				switch wserr.Code {
+				case ws.StatusNormalClosure, ws.StatusNoStatusRcvd:
+					return
+				default:
 					if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 						logger.Error(err)
 					}
 					return
 				}
+			}
 			switch op {
 			default:
 				// not relevant
@@ -184,7 +205,6 @@ func writeLoop(rw io.ReadWriter, stream client.Stream) {
 			// default to trying json
 			// if the extracted payload isn't empty lets use it
 			request := &raw.Frame{Data: buf}
-
 			if err := stream.Send(request); err != nil {
 				if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
 					logger.Error(err)
@@ -193,6 +213,7 @@ func writeLoop(rw io.ReadWriter, stream client.Stream) {
 			}
 		}
 	}
+}
 
 func isStream(r *http.Request, srv *api.Service) bool {
 	// check if it's a web socket