add watch-remote functionality which is using channels (async)

possible risk v.keystore is updated async (currenlt no mutex are used)

remote/remote.go

@@ -40,6 +40,29 @@ func (rc remoteConfigProvider) Watch(rp viper.RemoteProvider) (io.Reader, error)
 
 	return bytes.NewReader(resp), nil
 }
+func (rc remoteConfigProvider) WatchChannel(rp viper.RemoteProvider) (<-chan *viper.RemoteResponse, chan bool) {
+	cm, err := getConfigManager(rp)
+	if err != nil {
+		return nil, nil
+	}
+	quit := make(chan bool)
+	respChan := make(chan *viper.RemoteResponse, 0)
+	watchchan := cm.Watch(rp.Path(), quit)
+	// Todo Add quit channel
+	go func(w <-chan *crypt.Response) {
+		for {
+			resp := <-w
+			respChan <- &viper.RemoteResponse{
+				Error: resp.Error,
+				Value: resp.Value,
+			}
+		}
+
+	 }(watchchan)
+	return respChan ,quit
+
+}
+
 
 func getConfigManager(rp viper.RemoteProvider) (crypt.ConfigManager, error) {
 

viper.go

@@ -38,6 +38,11 @@ import (
 	"github.com/spf13/pflag"
 )
 
+// Response represents a response from a backend store.
+type RemoteResponse struct {
+	Value []byte
+	Error error
+}
 var v *Viper
 
 func init() {
@@ -47,6 +52,7 @@ func init() {
 type remoteConfigFactory interface {
 	Get(rp RemoteProvider) (io.Reader, error)
 	Watch(rp RemoteProvider) (io.Reader, error)
+	WatchChannel(rp RemoteProvider)(<-chan *RemoteResponse, chan bool)
 }
 
 // RemoteConfig is optional, see the remote package
@@ -1255,6 +1261,10 @@ func (v *Viper) WatchRemoteConfig() error {
 	return v.watchKeyValueConfig()
 }
 
+func (v *Viper) WatchRemoteConfigOnChannel() error {
+	return v.watchKeyValueConfigOnChannel()
+}
+
 // Unmarshall a Reader into a map.
 // Should probably be an unexported function.
 func unmarshalReader(in io.Reader, c map[string]interface{}) error {
@@ -1298,6 +1308,23 @@ func (v *Viper) getRemoteConfig(provider RemoteProvider) (map[string]interface{}
 	return v.kvstore, err
 }
 
+// Retrieve the first found remote configuration.
+func (v *Viper) watchKeyValueConfigOnChannel() error {
+	for _, rp := range v.remoteProviders {
+		respc, _ := RemoteConfig.WatchChannel(rp)
+		//Todo: Add quit channel
+		go func(rc <-chan *RemoteResponse) {
+			for {
+				b := <-rc
+				reader := bytes.NewReader(b.Value)
+				v.unmarshalReader(reader, v.kvstore)
+			}
+		}(respc)
+		return nil
+	}
+	return RemoteConfigError("No Files Found")
+}
+
 // Retrieve the first found remote configuration.
 func (v *Viper) watchKeyValueConfig() error {
 	for _, rp := range v.remoteProviders {