bump go-grpc-prometheus since 1.2.0 actually exposes the metrics

v1.1.0 (which is what we currently use), does not expose metrics which
makes it impossible to migrate.

vendor/github.com/grpc-ecosystem/go-grpc-prometheus/server.go

@@ -6,69 +6,43 @@
 package grpc_prometheus
 
 import (
-	"golang.org/x/net/context"
+	prom "github.com/prometheus/client_golang/prometheus"
 	"google.golang.org/grpc"
 )
 
-// PreregisterServices takes a gRPC server and pre-initializes all counters to 0.
-// This allows for easier monitoring in Prometheus (no missing metrics), and should be called *after* all services have
-// been registered with the server.
+var (
+	// DefaultServerMetrics is the default instance of ServerMetrics. It is
+	// intended to be used in conjunction the default Prometheus metrics
+	// registry.
+	DefaultServerMetrics = NewServerMetrics()
+
+	// UnaryServerInterceptor is a gRPC server-side interceptor that provides Prometheus monitoring for Unary RPCs.
+	UnaryServerInterceptor = DefaultServerMetrics.UnaryServerInterceptor()
+
+	// StreamServerInterceptor is a gRPC server-side interceptor that provides Prometheus monitoring for Streaming RPCs.
+	StreamServerInterceptor = DefaultServerMetrics.StreamServerInterceptor()
+)
+
+func init() {
+	prom.MustRegister(DefaultServerMetrics.serverStartedCounter)
+	prom.MustRegister(DefaultServerMetrics.serverHandledCounter)
+	prom.MustRegister(DefaultServerMetrics.serverStreamMsgReceived)
+	prom.MustRegister(DefaultServerMetrics.serverStreamMsgSent)
+}
+
+// Register takes a gRPC server and pre-initializes all counters to 0. This
+// allows for easier monitoring in Prometheus (no missing metrics), and should
+// be called *after* all services have been registered with the server. This
+// function acts on the DefaultServerMetrics variable.
 func Register(server *grpc.Server) {
-	serviceInfo := server.GetServiceInfo()
-	for serviceName, info := range serviceInfo {
-		for _, mInfo := range info.Methods {
-			preRegisterMethod(serviceName, &mInfo)
-		}
-	}
+	DefaultServerMetrics.InitializeMetrics(server)
 }
 
-// UnaryServerInterceptor is a gRPC server-side interceptor that provides Prometheus monitoring for Unary RPCs.
-func UnaryServerInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
-	monitor := newServerReporter(Unary, info.FullMethod)
-	monitor.ReceivedMessage()
-	resp, err := handler(ctx, req)
-	monitor.Handled(grpc.Code(err))
-	if err == nil {
-		monitor.SentMessage()
-	}
-	return resp, err
-}
-
-// StreamServerInterceptor is a gRPC server-side interceptor that provides Prometheus monitoring for Streaming RPCs.
-func StreamServerInterceptor(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
-	monitor := newServerReporter(streamRpcType(info), info.FullMethod)
-	err := handler(srv, &monitoredServerStream{ss, monitor})
-	monitor.Handled(grpc.Code(err))
-	return err
-}
-
-func streamRpcType(info *grpc.StreamServerInfo) grpcType {
-	if info.IsClientStream && !info.IsServerStream {
-		return ClientStream
-	} else if !info.IsClientStream && info.IsServerStream {
-		return ServerStream
-	}
-	return BidiStream
-}
-
-// monitoredStream wraps grpc.ServerStream allowing each Sent/Recv of message to increment counters.
-type monitoredServerStream struct {
-	grpc.ServerStream
-	monitor *serverReporter
-}
-
-func (s *monitoredServerStream) SendMsg(m interface{}) error {
-	err := s.ServerStream.SendMsg(m)
-	if err == nil {
-		s.monitor.SentMessage()
-	}
-	return err
-}
-
-func (s *monitoredServerStream) RecvMsg(m interface{}) error {
-	err := s.ServerStream.RecvMsg(m)
-	if err == nil {
-		s.monitor.ReceivedMessage()
-	}
-	return err
+// EnableHandlingTimeHistogram turns on recording of handling time
+// of RPCs. Histogram metrics can be very expensive for Prometheus
+// to retain and query. This function acts on the DefaultServerMetrics
+// variable and the default Prometheus metrics registry.
+func EnableHandlingTimeHistogram(opts ...HistogramOption) {
+	DefaultServerMetrics.EnableHandlingTimeHistogram(opts...)
+	prom.Register(DefaultServerMetrics.serverHandledHistogram)
 }