api/rpc: accept grpc.ServerOption's for keepalive policy

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

etcdserver/api/v3rpc/grpc.go

@@ -39,7 +39,7 @@ func init() {
 	grpclog.SetLoggerV2(grpclog.NewLoggerV2(os.Stderr, os.Stderr, os.Stderr))
 }
 
-func Server(s *etcdserver.EtcdServer, tls *tls.Config) *grpc.Server {
+func Server(s *etcdserver.EtcdServer, tls *tls.Config, gopts ...grpc.ServerOption) *grpc.Server {
 	var opts []grpc.ServerOption
 	opts = append(opts, grpc.CustomCodec(&codec{}))
 	if tls != nil {
@@ -50,7 +50,7 @@ func Server(s *etcdserver.EtcdServer, tls *tls.Config) *grpc.Server {
 	opts = append(opts, grpc.MaxRecvMsgSize(int(s.Cfg.MaxRequestBytes+grpcOverheadBytes)))
 	opts = append(opts, grpc.MaxSendMsgSize(maxSendBytes))
 	opts = append(opts, grpc.MaxConcurrentStreams(maxStreams))
-	grpcServer := grpc.NewServer(opts...)
+	grpcServer := grpc.NewServer(append(opts, gopts...)...)
 
 	pb.RegisterKVServer(grpcServer, NewQuotaKVServer(s))
 	pb.RegisterWatchServer(grpcServer, NewWatchServer(s))