Bumping k8s dependencies to 1.13

vendor/google.golang.org/grpc/health/health.go

@@ -16,7 +16,7 @@
  *
  */
 
-//go:generate protoc --go_out=plugins=grpc:. grpc_health_v1/health.proto
+//go:generate ./regenerate.sh
 
 // Package health provides some utility functions to health-check a server. The implementation
 // is based on protobuf. Users need to write their own implementations if other IDLs are used.
@@ -36,12 +36,14 @@ type Server struct {
 	mu sync.Mutex
 	// statusMap stores the serving status of the services this Server monitors.
 	statusMap map[string]healthpb.HealthCheckResponse_ServingStatus
+	updates   map[string]map[healthpb.Health_WatchServer]chan healthpb.HealthCheckResponse_ServingStatus
 }
 
 // NewServer returns a new Server.
 func NewServer() *Server {
 	return &Server{
-		statusMap: make(map[string]healthpb.HealthCheckResponse_ServingStatus),
+		statusMap: map[string]healthpb.HealthCheckResponse_ServingStatus{"": healthpb.HealthCheckResponse_SERVING},
+		updates:   make(map[string]map[healthpb.Health_WatchServer]chan healthpb.HealthCheckResponse_ServingStatus),
 	}
 }
 
@@ -49,24 +51,67 @@ func NewServer() *Server {
 func (s *Server) Check(ctx context.Context, in *healthpb.HealthCheckRequest) (*healthpb.HealthCheckResponse, error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	if in.Service == "" {
-		// check the server overall health status.
+	if servingStatus, ok := s.statusMap[in.Service]; ok {
 		return &healthpb.HealthCheckResponse{
-			Status: healthpb.HealthCheckResponse_SERVING,
-		}, nil
-	}
-	if status, ok := s.statusMap[in.Service]; ok {
-		return &healthpb.HealthCheckResponse{
-			Status: status,
+			Status: servingStatus,
 		}, nil
 	}
 	return nil, status.Error(codes.NotFound, "unknown service")
 }
 
+// Watch implements `service Health`.
+func (s *Server) Watch(in *healthpb.HealthCheckRequest, stream healthpb.Health_WatchServer) error {
+	service := in.Service
+	// update channel is used for getting service status updates.
+	update := make(chan healthpb.HealthCheckResponse_ServingStatus, 1)
+	s.mu.Lock()
+	// Puts the initial status to the channel.
+	if servingStatus, ok := s.statusMap[service]; ok {
+		update <- servingStatus
+	} else {
+		update <- healthpb.HealthCheckResponse_SERVICE_UNKNOWN
+	}
+
+	// Registers the update channel to the correct place in the updates map.
+	if _, ok := s.updates[service]; !ok {
+		s.updates[service] = make(map[healthpb.Health_WatchServer]chan healthpb.HealthCheckResponse_ServingStatus)
+	}
+	s.updates[service][stream] = update
+	defer func() {
+		s.mu.Lock()
+		delete(s.updates[service], stream)
+		s.mu.Unlock()
+	}()
+	s.mu.Unlock()
+	for {
+		select {
+		// Status updated. Sends the up-to-date status to the client.
+		case servingStatus := <-update:
+			err := stream.Send(&healthpb.HealthCheckResponse{Status: servingStatus})
+			if err != nil {
+				return status.Error(codes.Canceled, "Stream has ended.")
+			}
+		// Context done. Removes the update channel from the updates map.
+		case <-stream.Context().Done():
+			return status.Error(codes.Canceled, "Stream has ended.")
+		}
+	}
+}
+
 // SetServingStatus is called when need to reset the serving status of a service
 // or insert a new service entry into the statusMap.
-func (s *Server) SetServingStatus(service string, status healthpb.HealthCheckResponse_ServingStatus) {
+func (s *Server) SetServingStatus(service string, servingStatus healthpb.HealthCheckResponse_ServingStatus) {
 	s.mu.Lock()
-	s.statusMap[service] = status
+	s.statusMap[service] = servingStatus
+	for _, update := range s.updates[service] {
+		// Clears previous updates, that are not sent to the client, from the channel.
+		// This can happen if the client is not reading and the server gets flow control limited.
+		select {
+		case <-update:
+		default:
+		}
+		// Puts the most recent update to the channel.
+		update <- servingStatus
+	}
 	s.mu.Unlock()
 }