From 205ffa5cb6b251eacb8e2fbd2e309839d2a727b4 Mon Sep 17 00:00:00 2001
From: Xiang Li <xiangli.cs@gmail.com>
Date: Thu, 28 Jan 2016 08:54:32 -0800
Subject: [PATCH] clientv3: initial watch API

---
 clientv3/watch.go | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 clientv3/watch.go

diff --git a/clientv3/watch.go b/clientv3/watch.go
new file mode 100644
index 000000000..87de6cc18
--- /dev/null
+++ b/clientv3/watch.go
@@ -0,0 +1,43 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// 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 clientv3
+
+import (
+	"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	storagepb "github.com/coreos/etcd/storage/storagepb"
+)
+
+type Watcher interface {
+	// Watch watches on a single key. The watched events will be returned
+	// through the returned channel.
+	// If the watch is slow or the required rev is compacted, the watch request
+	// might be canceled from the server-side and the chan will be closed.
+	Watch(cxt context.Context, key string, rev int64) <-chan WatchResponse
+
+	// Watch watches on a prefix. The watched events will be returned
+	// through the returned channel.
+	// If the watch is slow or the required rev is compacted, the watch request
+	// might be canceled from the server-side and the chan will be closed.
+	WatchPrefix(cxt context.Context, prefix string, rev int64) <-chan WatchResponse
+
+	// Close closes the watcher and cancels all watch requests.
+	Close() error
+}
+
+type WatchResponse struct {
+	Header pb.ResponseHeader
+	Events []*storagepb.Event
+}