Merge pull request #10032 from gyuho/init-metrics-3.2

etcdserver/api/v3rpc: display all registered gRPC metrics at start (v3.2)

etcdserver/api/v3rpc/grpc.go

@@ -23,6 +23,8 @@ 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"
@@ -67,5 +69,9 @@ func Server(s *etcdserver.EtcdServer, tls *tls.Config, gopts ...grpc.ServerOptio
 			grpclog.SetLoggerV2(grpclog.NewLoggerV2(ioutil.Discard, os.Stderr, os.Stderr))
 		}
 	})
+
+	// to display all registered metrics with zero values
+	grpc_prometheus.Register(grpcServer)
+
 	return grpcServer
 }