From 2e3fbc4f8f3789057f412ef7df071d9ee73307fc Mon Sep 17 00:00:00 2001
From: yangzhouhan <yangzhouhan@gmail.com>
Date: Fri, 7 Aug 2015 17:12:15 -0700
Subject: [PATCH] change the name resolver interface

---
 clientconn.go                                   | 12 ------------
 etcdnaming/etcdnaming.go => naming/etcd/etcd.go | 14 ++++++++++++--
 naming/naming.go                                | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 14 deletions(-)
 rename etcdnaming/etcdnaming.go => naming/etcd/etcd.go (92%)
 create mode 100644 naming/naming.go

diff --git a/clientconn.go b/clientconn.go
index 8a45185b..52d47a57 100644
--- a/clientconn.go
+++ b/clientconn.go
@@ -71,18 +71,6 @@ type dialOptions struct {
 // DialOption configures how we set up the connection.
 type DialOption func(*dialOptions)
 
-// NameResolver dose name resolution and watches for the resolution changes.
-type NameResolver interface {
-	// Get gets a snapshot of the current name resolution results for target.
-	Get(target string) map[string]string
-	// Watch watches for the name resolution changes on target. It blocks until Stop() is invoked. The watch results are obtained via GetUpdate().
-	Watch(target string)
-	// GetUpdate returns a name resolution change when watch is triggered. It blocks until it observes a change. The caller needs to call it again to get the next change.
-	GetUpdate() (string, string)
-	// Stop shuts down the NameResolver.
-	Stop()
-}
-
 // WithCodec returns a DialOption which sets a codec for message marshaling and unmarshaling.
 func WithCodec(c Codec) DialOption {
 	return func(o *dialOptions) {
diff --git a/etcdnaming/etcdnaming.go b/naming/etcd/etcd.go
similarity index 92%
rename from etcdnaming/etcdnaming.go
rename to naming/etcd/etcd.go
index 59e01c13..838c2377 100644
--- a/etcdnaming/etcdnaming.go
+++ b/naming/etcd/etcd.go
@@ -1,4 +1,4 @@
-package etcdnaming
+package etcd
 
 import (
 	"fmt"
@@ -6,6 +6,7 @@ import (
 
 	etcdcl "github.com/coreos/etcd/client"
 	"golang.org/x/net/context"
+	"google.golang.org/grpc/naming"
 )
 
 type kv struct {
@@ -73,7 +74,7 @@ type etcdNR struct {
 }
 
 // NewETCDNR creates an etcd NameResolver
-func NewETCDNR(cfg etcdcl.Config) *etcdNR {
+func NewETCDNR(cfg etcdcl.Config) naming.Resolver {
 	c, err := etcdcl.New(cfg)
 	if err != nil {
 		panic(err)
@@ -106,6 +107,10 @@ func (nr *etcdNR) Get(target string) map[string]string {
 	}
 	res := make(map[string]string)
 	getNode(resp.Node, res)
+
+	for k,v := range res {
+		fmt.Println("key is :",k,"value is :",v)}
+
 	return res
 }
 
@@ -132,6 +137,9 @@ func (nr *etcdNR) GetUpdate() (string, string) {
 	select {
 	case i := <-nr.recv.get():
 		nr.recv.load()
+		if i == nil {
+		return "",""
+	}
 		// returns key and the corresponding value of the updated kv
 		return i.key, i.value
 	}
@@ -141,3 +149,5 @@ func (nr *etcdNR) Stop() {
 	nr.recv.stop()
 	nr.cancel()
 }
+
+
diff --git a/naming/naming.go b/naming/naming.go
new file mode 100644
index 00000000..bba0f52a
--- /dev/null
+++ b/naming/naming.go
@@ -0,0 +1,14 @@
+package naming;
+
+// Resolver dose name resolution and watches for the resolution changes.
+type Resolver interface {
+	// Get gets a snapshot of the current name resolution results for target.
+	Get(target string) map[string]string
+	// Watch watches for the name resolution changes on target. It blocks until Stop() is invoked. The watch results are obtained via GetUpdate().
+	Watch(target string)
+	// GetUpdate returns a name resolution change when watch is triggered. It blocks until it observes a change. The caller needs to call it again to get the next change.
+	GetUpdate() (string, string)
+	// Stop shuts down the NameResolver.
+	Stop()
+}
+