[FAB-3421] SDK Go - Disconnect and RegisterBlockEvent

Change-Id: Ia00750a2b49fea01347da7b055ce97d5f22a80d9
Signed-off-by: Sandra Vrtikapa <[email protected]>

fabric-client/events/eventhub.go

@@ -46,13 +46,13 @@ type EventHub interface {
 	SetPeerAddr(peerURL string, certificate string, serverHostOverride string)
 	IsConnected() bool
 	Connect() error
+	Disconnect()
 	RegisterChaincodeEvent(ccid string, eventname string, callback func(*ChaincodeEvent)) *ChainCodeCBE
 	UnregisterChaincodeEvent(cbe *ChainCodeCBE)
 	RegisterTxEvent(txID string, callback func(string, error))
 	UnregisterTxEvent(txID string)
 	RegisterBlockEvent(callback func(*common.Block))
 	UnregisterBlockEvent(callback func(*common.Block))
-	Disconnect()
 }
 
 // The EventHubExt interface allows extensions of the SDK to add functionality to EventHub overloads.
@@ -156,13 +156,13 @@ func (eventHub *eventHub) SetInterests(block bool) {
 
 // Disconnect disconnects from peer event source
 func (eventHub *eventHub) Disconnect() {
+	eventHub.mtx.Lock()
+	defer eventHub.mtx.Unlock()
+
 	if !eventHub.connected {
 		return
 	}
 
-	eventHub.mtx.Lock()
-	defer eventHub.mtx.Unlock()
-
 	// Unregister interests with server and stop the stream
 	eventHub.client.UnregisterAsync(eventHub.interestedEvents)
 	eventHub.client.Stop()
@@ -251,6 +251,9 @@ func (eventHub *eventHub) IsConnected() bool {
  */
 func (eventHub *eventHub) Connect() error {
 
+	eventHub.mtx.Lock()
+	defer eventHub.mtx.Unlock()
+
 	if eventHub.connected {
 		logger.Debugf("Nothing to do - EventHub already connected")
 		return nil
@@ -260,9 +263,6 @@ func (eventHub *eventHub) Connect() error {
 		return fmt.Errorf("eventHub.peerAddr is empty")
 	}
 
-	eventHub.mtx.Lock()
-	defer eventHub.mtx.Unlock()
-
 	if eventHub.client == nil {
 		eventsClient, _ := eventHub.eventsClientFactory.newEventsClient(eventHub.peerAddr, eventHub.peerTLSCertificate, eventHub.peerTLSServerHostOverride, 5, eventHub)
 		eventHub.client = eventsClient
@@ -316,13 +316,13 @@ func (eventHub *eventHub) Recv(msg *pb.Event) (bool, error) {
 
 // Disconnected implements consumer.EventAdapter interface for receiving events
 func (eventHub *eventHub) Disconnected(err error) {
+	eventHub.mtx.Lock()
+	defer eventHub.mtx.Unlock()
+
 	if !eventHub.connected {
 		return
 	}
 
-	eventHub.mtx.Lock()
-	defer eventHub.mtx.Unlock()
-
 	eventHub.client.Stop()
 	eventHub.connected = false
 }