fix(grpc): attach handlers before join (#355)

Author: tarrencev

cmd/signal/grpc/server/server.go

@@ -79,26 +79,6 @@ func (s *SFUServer) Signal(stream pb.SFU_SignalServer) error {
 				}
 			}
 
-			answer, err := peer.Join(payload.Join.Sid, offer)
-			if err != nil {
-				switch err {
-				case sfu.ErrTransportExists:
-					fallthrough
-				case sfu.ErrOfferIgnored:
-					err = stream.Send(&pb.SignalReply{
-						Payload: &pb.SignalReply_Error{
-							Error: fmt.Errorf("join error: %w", err).Error(),
-						},
-					})
-					if err != nil {
-						log.Errorf("grpc send error %v ", err)
-						return status.Errorf(codes.Internal, err.Error())
-					}
-				default:
-					return status.Errorf(codes.Unknown, err.Error())
-				}
-			}
-
 			// Notify user of new ice candidate
 			peer.OnIceCandidate = func(candidate *webrtc.ICECandidateInit, target int) {
 				bytes, err := json.Marshal(candidate)
@@ -156,6 +136,26 @@ func (s *SFUServer) Signal(stream pb.SFU_SignalServer) error {
 				}
 			}
 
+			answer, err := peer.Join(payload.Join.Sid, offer)
+			if err != nil {
+				switch err {
+				case sfu.ErrTransportExists:
+					fallthrough
+				case sfu.ErrOfferIgnored:
+					err = stream.Send(&pb.SignalReply{
+						Payload: &pb.SignalReply_Error{
+							Error: fmt.Errorf("join error: %w", err).Error(),
+						},
+					})
+					if err != nil {
+						log.Errorf("grpc send error %v ", err)
+						return status.Errorf(codes.Internal, err.Error())
+					}
+				default:
+					return status.Errorf(codes.Unknown, err.Error())
+				}
+			}
+
 			marshalled, err := json.Marshal(answer)
 			if err != nil {
 				return status.Errorf(codes.Internal, fmt.Sprintf("sdp marshal error: %v", err))

go.sum

@@ -516,6 +516,7 @@ golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a h1:DcqTD9SDLc+1P/r1EmRBwnVsrOwW+kk2vWf9n+1sGhs=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=