diff --git a/vendor/go.etcd.io/etcd/etcdserver/api/v3rpc/util.go b/vendor/go.etcd.io/etcd/etcdserver/api/v3rpc/util.go
new file mode 100644
index 0000000..281ddc7
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/api/v3rpc/util.go
@@ -0,0 +1,136 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package v3rpc
+
+import (
+	"context"
+	"strings"
+
+	"go.etcd.io/etcd/auth"
+	"go.etcd.io/etcd/etcdserver"
+	"go.etcd.io/etcd/etcdserver/api/membership"
+	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
+	pb "go.etcd.io/etcd/etcdserver/etcdserverpb"
+	"go.etcd.io/etcd/lease"
+	"go.etcd.io/etcd/mvcc"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+var toGRPCErrorMap = map[error]error{
+	membership.ErrIDRemoved:               rpctypes.ErrGRPCMemberNotFound,
+	membership.ErrIDNotFound:              rpctypes.ErrGRPCMemberNotFound,
+	membership.ErrIDExists:                rpctypes.ErrGRPCMemberExist,
+	membership.ErrPeerURLexists:           rpctypes.ErrGRPCPeerURLExist,
+	membership.ErrMemberNotLearner:        rpctypes.ErrGRPCMemberNotLearner,
+	membership.ErrTooManyLearners:         rpctypes.ErrGRPCTooManyLearners,
+	etcdserver.ErrNotEnoughStartedMembers: rpctypes.ErrMemberNotEnoughStarted,
+	etcdserver.ErrLearnerNotReady:         rpctypes.ErrGRPCLearnerNotReady,
+
+	mvcc.ErrCompacted:             rpctypes.ErrGRPCCompacted,
+	mvcc.ErrFutureRev:             rpctypes.ErrGRPCFutureRev,
+	etcdserver.ErrRequestTooLarge: rpctypes.ErrGRPCRequestTooLarge,
+	etcdserver.ErrNoSpace:         rpctypes.ErrGRPCNoSpace,
+	etcdserver.ErrTooManyRequests: rpctypes.ErrTooManyRequests,
+
+	etcdserver.ErrNoLeader:                   rpctypes.ErrGRPCNoLeader,
+	etcdserver.ErrNotLeader:                  rpctypes.ErrGRPCNotLeader,
+	etcdserver.ErrLeaderChanged:              rpctypes.ErrGRPCLeaderChanged,
+	etcdserver.ErrStopped:                    rpctypes.ErrGRPCStopped,
+	etcdserver.ErrTimeout:                    rpctypes.ErrGRPCTimeout,
+	etcdserver.ErrTimeoutDueToLeaderFail:     rpctypes.ErrGRPCTimeoutDueToLeaderFail,
+	etcdserver.ErrTimeoutDueToConnectionLost: rpctypes.ErrGRPCTimeoutDueToConnectionLost,
+	etcdserver.ErrUnhealthy:                  rpctypes.ErrGRPCUnhealthy,
+	etcdserver.ErrKeyNotFound:                rpctypes.ErrGRPCKeyNotFound,
+	etcdserver.ErrCorrupt:                    rpctypes.ErrGRPCCorrupt,
+	etcdserver.ErrBadLeaderTransferee:        rpctypes.ErrGRPCBadLeaderTransferee,
+
+	lease.ErrLeaseNotFound:    rpctypes.ErrGRPCLeaseNotFound,
+	lease.ErrLeaseExists:      rpctypes.ErrGRPCLeaseExist,
+	lease.ErrLeaseTTLTooLarge: rpctypes.ErrGRPCLeaseTTLTooLarge,
+
+	auth.ErrRootUserNotExist:     rpctypes.ErrGRPCRootUserNotExist,
+	auth.ErrRootRoleNotExist:     rpctypes.ErrGRPCRootRoleNotExist,
+	auth.ErrUserAlreadyExist:     rpctypes.ErrGRPCUserAlreadyExist,
+	auth.ErrUserEmpty:            rpctypes.ErrGRPCUserEmpty,
+	auth.ErrUserNotFound:         rpctypes.ErrGRPCUserNotFound,
+	auth.ErrRoleAlreadyExist:     rpctypes.ErrGRPCRoleAlreadyExist,
+	auth.ErrRoleNotFound:         rpctypes.ErrGRPCRoleNotFound,
+	auth.ErrRoleEmpty:            rpctypes.ErrGRPCRoleEmpty,
+	auth.ErrAuthFailed:           rpctypes.ErrGRPCAuthFailed,
+	auth.ErrPermissionDenied:     rpctypes.ErrGRPCPermissionDenied,
+	auth.ErrRoleNotGranted:       rpctypes.ErrGRPCRoleNotGranted,
+	auth.ErrPermissionNotGranted: rpctypes.ErrGRPCPermissionNotGranted,
+	auth.ErrAuthNotEnabled:       rpctypes.ErrGRPCAuthNotEnabled,
+	auth.ErrInvalidAuthToken:     rpctypes.ErrGRPCInvalidAuthToken,
+	auth.ErrInvalidAuthMgmt:      rpctypes.ErrGRPCInvalidAuthMgmt,
+}
+
+func togRPCError(err error) error {
+	// let gRPC server convert to codes.Canceled, codes.DeadlineExceeded
+	if err == context.Canceled || err == context.DeadlineExceeded {
+		return err
+	}
+	grpcErr, ok := toGRPCErrorMap[err]
+	if !ok {
+		return status.Error(codes.Unknown, err.Error())
+	}
+	return grpcErr
+}
+
+func isClientCtxErr(ctxErr error, err error) bool {
+	if ctxErr != nil {
+		return true
+	}
+
+	ev, ok := status.FromError(err)
+	if !ok {
+		return false
+	}
+
+	switch ev.Code() {
+	case codes.Canceled, codes.DeadlineExceeded:
+		// client-side context cancel or deadline exceeded
+		// "rpc error: code = Canceled desc = context canceled"
+		// "rpc error: code = DeadlineExceeded desc = context deadline exceeded"
+		return true
+	case codes.Unavailable:
+		msg := ev.Message()
+		// client-side context cancel or deadline exceeded with TLS ("http2.errClientDisconnected")
+		// "rpc error: code = Unavailable desc = client disconnected"
+		if msg == "client disconnected" {
+			return true
+		}
+		// "grpc/transport.ClientTransport.CloseStream" on canceled streams
+		// "rpc error: code = Unavailable desc = stream error: stream ID 21; CANCEL")
+		if strings.HasPrefix(msg, "stream error: ") && strings.HasSuffix(msg, "; CANCEL") {
+			return true
+		}
+	}
+	return false
+}
+
+// in v3.4, learner is allowed to serve serializable read and endpoint status
+func isRPCSupportedForLearner(req interface{}) bool {
+	switch r := req.(type) {
+	case *pb.StatusRequest:
+		return true
+	case *pb.RangeRequest:
+		return r.Serializable
+	default:
+		return false
+	}
+}