From 38aed6f0f612ed6ea38b7857887208a250cc79b2 Mon Sep 17 00:00:00 2001
From: Vasiliy Tolstov <v.tolstov@unistack.org>
Date: Sat, 4 Apr 2020 00:37:18 +0300
Subject: [PATCH] api/handler/rpc: not log error on client disconnect (#1482)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
---
 api/handler/rpc/stream.go | 97 ++++++++++++++++++++++++---------------
 1 file changed, 59 insertions(+), 38 deletions(-)

diff --git a/api/handler/rpc/stream.go b/api/handler/rpc/stream.go
index a4741769..d54f933e 100644
--- a/api/handler/rpc/stream.go
+++ b/api/handler/rpc/stream.go
@@ -135,27 +135,38 @@ func serveWebsocket(ctx context.Context, w http.ResponseWriter, r *http.Request,
 
 	// receive from stream and send to client
 	for {
-		// read backend response body
-		buf, err := rsp.Read()
-		if err != nil {
-			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
-				logger.Error(err)
-			}
+		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)
+				}
+				return
+			}
 
-		// write the response
-		if err := wsutil.WriteServerMessage(rw, op, buf); err != nil {
-			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
-				logger.Error(err)
+			// write the response
+			if err := wsutil.WriteServerMessage(rw, op, buf); err != nil {
+				if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+					logger.Error(err)
+				}
+				return
 			}
-			return
-		}
-		if err = rw.Flush(); err != nil {
-			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
-				logger.Error(err)
+			if err = rw.Flush(); err != nil {
+				if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
+					logger.Error(err)
+				}
+				return
 			}
-			return
 		}
 	}
 }
@@ -166,30 +177,40 @@ func writeLoop(rw io.ReadWriter, stream client.Stream) {
 	defer stream.Close()
 
 	for {
-		buf, op, err := wsutil.ReadClientData(rw)
-		if err != nil {
-			if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
-				logger.Error(err)
-			}
+		select {
+		case <-stream.Context().Done():
 			return
-		}
-		switch op {
 		default:
-			// not relevant
-			continue
-		case ws.OpText, ws.OpBinary:
-			break
-		}
-		// send to backend
-		// 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)
+			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
+				continue
+			case ws.OpText, ws.OpBinary:
+				break
+			}
+			// send to backend
+			// 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)
+				}
+				return
 			}
-			return
 		}
 	}
 }