*: initialize gRPC server metrics with zero values

etcdmain/grpc_proxy.go

@@ -318,6 +318,10 @@ func newGRPCProxyServer(client *clientv3.Client) *grpc.Server {
 	pb.RegisterAuthServer(server, authp)
 	v3electionpb.RegisterElectionServer(server, electionp)
 	v3lockpb.RegisterLockServer(server, lockp)
+
+	// set zero values for metrics registered for this grpc server
+	grpc_prometheus.Register(server)
+
 	return server
 }
 

etcdserver/api/v3rpc/grpc.go

@@ -22,6 +22,7 @@ import (
 	"github.com/coreos/etcd/etcdserver"
 	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 
+	"github.com/grpc-ecosystem/go-grpc-prometheus"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/grpclog"
@@ -66,5 +67,8 @@ func Server(s *etcdserver.EtcdServer, tls *tls.Config, gopts ...grpc.ServerOptio
 	hsrv.SetServingStatus("", healthpb.HealthCheckResponse_SERVING)
 	healthpb.RegisterHealthServer(grpcServer, hsrv)
 
+	// set zero values for metrics registered for this grpc server
+	grpc_prometheus.Register(grpcServer)
+
 	return grpcServer
 }