diff --git a/vendor/github.com/coreos/etcd/clientv3/naming/grpc.go b/vendor/github.com/coreos/etcd/clientv3/naming/grpc.go
new file mode 100644
index 0000000..3c0e8e6
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/clientv3/naming/grpc.go
@@ -0,0 +1,131 @@
+// 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 naming
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	etcd "github.com/coreos/etcd/clientv3"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/naming"
+	"google.golang.org/grpc/status"
+)
+
+var ErrWatcherClosed = fmt.Errorf("naming: watch closed")
+
+// GRPCResolver creates a grpc.Watcher for a target to track its resolution changes.
+type GRPCResolver struct {
+	// Client is an initialized etcd client.
+	Client *etcd.Client
+}
+
+func (gr *GRPCResolver) Update(ctx context.Context, target string, nm naming.Update, opts ...etcd.OpOption) (err error) {
+	switch nm.Op {
+	case naming.Add:
+		var v []byte
+		if v, err = json.Marshal(nm); err != nil {
+			return status.Error(codes.InvalidArgument, err.Error())
+		}
+		_, err = gr.Client.KV.Put(ctx, target+"/"+nm.Addr, string(v), opts...)
+	case naming.Delete:
+		_, err = gr.Client.Delete(ctx, target+"/"+nm.Addr, opts...)
+	default:
+		return status.Error(codes.InvalidArgument, "naming: bad naming op")
+	}
+	return err
+}
+
+func (gr *GRPCResolver) Resolve(target string) (naming.Watcher, error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	w := &gRPCWatcher{c: gr.Client, target: target + "/", ctx: ctx, cancel: cancel}
+	return w, nil
+}
+
+type gRPCWatcher struct {
+	c      *etcd.Client
+	target string
+	ctx    context.Context
+	cancel context.CancelFunc
+	wch    etcd.WatchChan
+	err    error
+}
+
+// Next gets the next set of updates from the etcd resolver.
+// Calls to Next should be serialized; concurrent calls are not safe since
+// there is no way to reconcile the update ordering.
+func (gw *gRPCWatcher) Next() ([]*naming.Update, error) {
+	if gw.wch == nil {
+		// first Next() returns all addresses
+		return gw.firstNext()
+	}
+	if gw.err != nil {
+		return nil, gw.err
+	}
+
+	// process new events on target/*
+	wr, ok := <-gw.wch
+	if !ok {
+		gw.err = status.Error(codes.Unavailable, ErrWatcherClosed.Error())
+		return nil, gw.err
+	}
+	if gw.err = wr.Err(); gw.err != nil {
+		return nil, gw.err
+	}
+
+	updates := make([]*naming.Update, 0, len(wr.Events))
+	for _, e := range wr.Events {
+		var jupdate naming.Update
+		var err error
+		switch e.Type {
+		case etcd.EventTypePut:
+			err = json.Unmarshal(e.Kv.Value, &jupdate)
+			jupdate.Op = naming.Add
+		case etcd.EventTypeDelete:
+			err = json.Unmarshal(e.PrevKv.Value, &jupdate)
+			jupdate.Op = naming.Delete
+		}
+		if err == nil {
+			updates = append(updates, &jupdate)
+		}
+	}
+	return updates, nil
+}
+
+func (gw *gRPCWatcher) firstNext() ([]*naming.Update, error) {
+	// Use serialized request so resolution still works if the target etcd
+	// server is partitioned away from the quorum.
+	resp, err := gw.c.Get(gw.ctx, gw.target, etcd.WithPrefix(), etcd.WithSerializable())
+	if gw.err = err; err != nil {
+		return nil, err
+	}
+
+	updates := make([]*naming.Update, 0, len(resp.Kvs))
+	for _, kv := range resp.Kvs {
+		var jupdate naming.Update
+		if err := json.Unmarshal(kv.Value, &jupdate); err != nil {
+			continue
+		}
+		updates = append(updates, &jupdate)
+	}
+
+	opts := []etcd.OpOption{etcd.WithRev(resp.Header.Revision + 1), etcd.WithPrefix(), etcd.WithPrevKV()}
+	gw.wch = gw.c.Watch(gw.ctx, gw.target, opts...)
+	return updates, nil
+}
+
+func (gw *gRPCWatcher) Close() { gw.cancel() }