diff --git a/vendor/go.etcd.io/etcd/etcdserver/api/v2store/watcher.go b/vendor/go.etcd.io/etcd/etcdserver/api/v2store/watcher.go
new file mode 100644
index 0000000..4b1e846
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/etcdserver/api/v2store/watcher.go
@@ -0,0 +1,95 @@
+// Copyright 2015 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 v2store
+
+type Watcher interface {
+	EventChan() chan *Event
+	StartIndex() uint64 // The EtcdIndex at which the Watcher was created
+	Remove()
+}
+
+type watcher struct {
+	eventChan  chan *Event
+	stream     bool
+	recursive  bool
+	sinceIndex uint64
+	startIndex uint64
+	hub        *watcherHub
+	removed    bool
+	remove     func()
+}
+
+func (w *watcher) EventChan() chan *Event {
+	return w.eventChan
+}
+
+func (w *watcher) StartIndex() uint64 {
+	return w.startIndex
+}
+
+// notify function notifies the watcher. If the watcher interests in the given path,
+// the function will return true.
+func (w *watcher) notify(e *Event, originalPath bool, deleted bool) bool {
+	// watcher is interested the path in three cases and under one condition
+	// the condition is that the event happens after the watcher's sinceIndex
+
+	// 1. the path at which the event happens is the path the watcher is watching at.
+	// For example if the watcher is watching at "/foo" and the event happens at "/foo",
+	// the watcher must be interested in that event.
+
+	// 2. the watcher is a recursive watcher, it interests in the event happens after
+	// its watching path. For example if watcher A watches at "/foo" and it is a recursive
+	// one, it will interest in the event happens at "/foo/bar".
+
+	// 3. when we delete a directory, we need to force notify all the watchers who watches
+	// at the file we need to delete.
+	// For example a watcher is watching at "/foo/bar". And we deletes "/foo". The watcher
+	// should get notified even if "/foo" is not the path it is watching.
+	if (w.recursive || originalPath || deleted) && e.Index() >= w.sinceIndex {
+		// We cannot block here if the eventChan capacity is full, otherwise
+		// etcd will hang. eventChan capacity is full when the rate of
+		// notifications are higher than our send rate.
+		// If this happens, we close the channel.
+		select {
+		case w.eventChan <- e:
+		default:
+			// We have missed a notification. Remove the watcher.
+			// Removing the watcher also closes the eventChan.
+			w.remove()
+		}
+		return true
+	}
+	return false
+}
+
+// Remove removes the watcher from watcherHub
+// The actual remove function is guaranteed to only be executed once
+func (w *watcher) Remove() {
+	w.hub.mutex.Lock()
+	defer w.hub.mutex.Unlock()
+
+	close(w.eventChan)
+	if w.remove != nil {
+		w.remove()
+	}
+}
+
+// nopWatcher is a watcher that receives nothing, always blocking.
+type nopWatcher struct{}
+
+func NewNopWatcher() Watcher                 { return &nopWatcher{} }
+func (w *nopWatcher) EventChan() chan *Event { return nil }
+func (w *nopWatcher) StartIndex() uint64     { return 0 }
+func (w *nopWatcher) Remove()                {}