v3rpc: replace grpc metrics w/ go-grpc-prometheus

And disable histogram

etcdserver/api/v3rpc/interceptor.go

@@ -25,6 +25,7 @@ import (
 	"github.com/coreos/etcd/pkg/types"
 	"github.com/coreos/etcd/raft"
 
+	prometheus "github.com/grpc-ecosystem/go-grpc-prometheus"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"
@@ -53,7 +54,8 @@ func newUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
 				}
 			}
 		}
-		return metricsUnaryInterceptor(ctx, req, info, handler)
+
+		return prometheus.UnaryServerInterceptor(ctx, req, info, handler)
 	}
 }
 
@@ -88,38 +90,11 @@ func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor
 
 			}
 		}
-		return metricsStreamInterceptor(srv, ss, info, handler)
+
+		return prometheus.StreamServerInterceptor(srv, ss, info, handler)
 	}
 }
 
-func metricsUnaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
-	service, method := splitMethodName(info.FullMethod)
-	receivedCounter.WithLabelValues(service, method).Inc()
-
-	start := time.Now()
-	resp, err = handler(ctx, req)
-	if err != nil {
-		failedCounter.WithLabelValues(service, method, grpc.Code(err).String()).Inc()
-	}
-	handlingDuration.WithLabelValues(service, method).Observe(time.Since(start).Seconds())
-
-	return resp, err
-}
-
-func metricsStreamInterceptor(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
-	service, method := splitMethodName(info.FullMethod)
-	receivedCounter.WithLabelValues(service, method).Inc()
-
-	streamsGauage.WithLabelValues(service, method).Inc()
-	err := handler(srv, ss)
-	streamsGauage.WithLabelValues(service, method).Dec()
-	if err != nil {
-		failedCounter.WithLabelValues(service, method, grpc.Code(err).String()).Inc()
-	}
-
-	return err
-}
-
 func splitMethodName(fullMethodName string) (string, string) {
 	fullMethodName = strings.TrimPrefix(fullMethodName, "/") // remove leading slash
 	if i := strings.Index(fullMethodName, "/"); i >= 0 {

etcdserver/api/v3rpc/metrics.go

@@ -17,39 +17,6 @@ package v3rpc
 import "github.com/prometheus/client_golang/prometheus"
 
 var (
-	receivedCounter = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: "etcd",
-			Subsystem: "grpc",
-			Name:      "requests_total",
-			Help:      "Counter of received requests.",
-		}, []string{"grpc_service", "grpc_method"})
-
-	failedCounter = prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Namespace: "etcd",
-			Subsystem: "grpc",
-			Name:      "requests_failed_total",
-			Help:      "Counter of failed requests.",
-		}, []string{"grpc_service", "grpc_method", "grpc_code"})
-
-	streamsGauage = prometheus.NewGaugeVec(
-		prometheus.GaugeOpts{
-			Namespace: "etcd",
-			Subsystem: "grpc",
-			Name:      "active_streams",
-			Help:      "Number of active streams.",
-		}, []string{"grpc_service", "grpc_method"})
-
-	handlingDuration = prometheus.NewHistogramVec(
-		prometheus.HistogramOpts{
-			Namespace: "etcd",
-			Subsystem: "grpc",
-			Name:      "unary_requests_duration_seconds",
-			Help:      "Bucketed histogram of processing time (s) of handled unary (non-stream) requests.",
-			Buckets:   prometheus.ExponentialBuckets(0.0005, 2, 13),
-		}, []string{"grpc_service", "grpc_method"})
-
 	sentBytes = prometheus.NewCounter(prometheus.CounterOpts{
 		Namespace: "etcd",
 		Subsystem: "network",
@@ -66,11 +33,6 @@ var (
 )
 
 func init() {
-	prometheus.MustRegister(receivedCounter)
-	prometheus.MustRegister(failedCounter)
-	prometheus.MustRegister(streamsGauage)
-	prometheus.MustRegister(handlingDuration)
-
 	prometheus.MustRegister(sentBytes)
 	prometheus.MustRegister(receivedBytes)
 }