etcdmain/grpc-proxy: add 'metrics-addr' option

Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>

etcdmain/grpc_proxy.go

@@ -42,6 +42,7 @@ import (
 
 var (
 	grpcProxyListenAddr        string
+	grpcProxyMetricsListenAddr string
 	grpcProxyEndpoints         []string
 	grpcProxyDNSCluster        string
 	grpcProxyInsecureDiscovery bool
@@ -91,6 +92,7 @@ func newGRPCProxyStartCommand() *cobra.Command {
 
 	cmd.Flags().StringVar(&grpcProxyListenAddr, "listen-addr", "127.0.0.1:23790", "listen address")
 	cmd.Flags().StringVar(&grpcProxyDNSCluster, "discovery-srv", "", "DNS domain used to bootstrap initial cluster")
+	cmd.Flags().StringVar(&grpcProxyMetricsListenAddr, "metrics-addr", "", "listen for /metrics requests on an additional interface")
 	cmd.Flags().BoolVar(&grpcProxyInsecureDiscovery, "insecure-discovery", false, "accept insecure SRV records")
 	cmd.Flags().StringSliceVar(&grpcProxyEndpoints, "endpoints", []string{"127.0.0.1:2379"}, "comma separated etcd cluster endpoints")
 	cmd.Flags().StringVar(&grpcProxyAdvertiseClientURL, "advertise-client-url", "127.0.0.1:23790", "advertise address to register (must be reachable by client)")