Fabric gossip component - Discovery module

Change-Id: I6e596752871efa4c6ff372ba629e44815fa97ac6
Signed-off-by: Yacov Manevich <yacovm@il.ibm.com>

gossip/discovery/consts.go

@@ -0,0 +1,21 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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 discovery
+
+import "fmt"
+
+var INVALID_MSG_TYPE = fmt.Errorf("Invalid message type")

gossip/discovery/discovery.go

@@ -75,4 +75,8 @@ type DiscoveryService interface {
 
 	// GetMembership returns the alive members in the view
 	GetMembership() []NetworkMember
+
+	// InitiateSync makes the instance ask a given number of peers
+	// for their membership information
+	InitiateSync(peerNum int)
 }