GODT-2014: bridge quit if gRPC client ends stream (v3)

internal/frontend/grpc/service.go

@@ -55,12 +55,13 @@ const (
 type Service struct { // nolint:structcheck
 	UnimplementedBridgeServer
 
-	grpcServer        *grpc.Server //  the gGRPC server
-	listener          net.Listener
-	eventStreamCh     chan *StreamEvent
-	eventStreamDoneCh chan struct{}
-	eventQueue        []*StreamEvent
-	eventQueueMutex   sync.Mutex
+	grpcServer         *grpc.Server //  the gGRPC server
+	listener           net.Listener
+	eventStreamCh      chan *StreamEvent
+	eventStreamChMutex sync.RWMutex
+	eventStreamDoneCh  chan struct{}
+	eventQueue         []*StreamEvent
+	eventQueueMutex    sync.Mutex
 
 	panicHandler   *crash.Handler
 	restarter      *restarter.Restarter

internal/frontend/grpc/service_methods.go

@@ -96,12 +96,15 @@ func (s *Service) GuiReady(ctx context.Context, _ *emptypb.Empty) (*emptypb.Empt
 // Quit implement the Quit gRPC service call.
 func (s *Service) Quit(ctx context.Context, empty *emptypb.Empty) (*emptypb.Empty, error) {
 	s.log.Debug("Quit")
+	return &emptypb.Empty{}, s.quit()
+}
 
+func (s *Service) quit() error {
 	// Windows is notably slow at Quitting. We do it in a goroutine to speed things up a bit.
 	go func() {
 		var err error
-		if s.eventStreamCh != nil {
-			if _, err = s.StopEventStream(ctx, empty); err != nil {
+		if s.isStreamingEvents() {
+			if err = s.stopEventStream(); err != nil {
 				s.log.WithError(err).Error("Quit failed.")
 			}
 		}
@@ -110,7 +113,7 @@ func (s *Service) Quit(ctx context.Context, empty *emptypb.Empty) (*emptypb.Empt
 		s.grpcServer.GracefulStop()
 	}()
 
-	return &emptypb.Empty{}, nil
+	return nil
 }
 
 // Restart implement the Restart gRPC service call.

internal/frontend/grpc/service_stream.go

@@ -29,19 +29,19 @@ import (
 func (s *Service) RunEventStream(request *EventStreamRequest, server Bridge_RunEventStreamServer) error {
 	s.log.Debug("Starting Event stream")
 
-	if s.eventStreamCh != nil {
+	if s.isStreamingEvents() {
 		return status.Errorf(codes.AlreadyExists, "the service is already streaming") // TO-DO GODT-1667 decide if we want to kill the existing stream.
 	}
 
 	s.bridge.SetCurrentPlatform(request.ClientPlatform)
 
-	s.eventStreamCh = make(chan *StreamEvent)
+	s.createEventStreamChannel()
 	s.eventStreamDoneCh = make(chan struct{})
 
 	// TO-DO GODT-1667 We should have a safer we to close this channel? What if an event occur while we are closing?
 	defer func() {
 		close(s.eventStreamCh)
-		s.eventStreamCh = nil
+		s.deleteEventStreamChannel()
 		close(s.eventStreamDoneCh)
 		s.eventStreamDoneCh = nil
 	}()
@@ -70,24 +70,34 @@ func (s *Service) RunEventStream(request *EventStreamRequest, server Bridge_RunE
 				s.log.Debug("Stop Event stream")
 				return err
 			}
+		case <-server.Context().Done():
+			s.log.Debug("Client closed the stream, exiting")
+			return s.quit()
 		}
 	}
 }
 
 // StopEventStream stops the event stream.
 func (s *Service) StopEventStream(_ context.Context, _ *emptypb.Empty) (*emptypb.Empty, error) {
+	return &emptypb.Empty{}, s.stopEventStream()
+}
+
+func (s *Service) stopEventStream() error {
+	s.eventStreamChMutex.RLock()
+	defer s.eventStreamChMutex.RUnlock()
+
 	if s.eventStreamCh == nil {
-		return nil, status.Errorf(codes.NotFound, "The service is not streaming")
+		return status.Errorf(codes.NotFound, "The service is not streaming")
 	}
 
 	s.eventStreamDoneCh <- struct{}{}
 
-	return &emptypb.Empty{}, nil
+	return nil
 }
 
 // SendEvent sends an event to the via the gRPC event stream.
 func (s *Service) SendEvent(event *StreamEvent) error {
-	if s.eventStreamCh == nil { // nobody is connected to the event stream, we queue events
+	if !s.isStreamingEvents() { // nobody is connected to the event stream, we queue events
 		s.queueEvent(event)
 		return nil
 	}
@@ -173,3 +183,24 @@ func (s *Service) queueEvent(event *StreamEvent) {
 		s.eventQueue = append(s.eventQueue, event)
 	}
 }
+
+func (s *Service) isStreamingEvents() bool {
+	s.eventStreamChMutex.RLock()
+	defer s.eventStreamChMutex.RUnlock()
+
+	return s.eventStreamCh != nil
+}
+
+func (s *Service) createEventStreamChannel() {
+	s.eventStreamChMutex.Lock()
+	defer s.eventStreamChMutex.Unlock()
+
+	s.eventStreamCh = make(chan *StreamEvent)
+}
+
+func (s *Service) deleteEventStreamChannel() {
+	s.eventStreamChMutex.Lock()
+	defer s.eventStreamChMutex.Unlock()
+
+	s.eventStreamCh = nil
+}