[FABG-726] monitorBlockHeight ticker chan not closed

This change adds a monitorBlockHeightDone channel to signal
completion of the goroutine.

Change-Id: I29f4f4db2c168268adff43884783ecd3b7360483
Signed-off-by: Troy Ronda <[email protected]>

pkg/fab/events/client/dispatcher/dispatcher.go

@@ -36,7 +36,7 @@ type Dispatcher struct {
 	connectionRegistration *ConnectionReg
 	connectionProvider     api.ConnectionProvider
 	discoveryService       fab.DiscoveryService
-	ticker                 *time.Ticker
+	monitorBlockHeightDone chan struct{}
 	peer                   fab.Peer
 	lock                   sync.RWMutex
 }
@@ -82,8 +82,9 @@ func (ed *Dispatcher) HandleStopEvent(e esdispatcher.Event) {
 	// Remove all registrations and close the associated event channels
 	// so that the client is notified that the registration has been removed
 	ed.clearConnectionRegistration()
-	if ed.ticker != nil {
-		ed.ticker.Stop()
+	if ed.monitorBlockHeightDone != nil {
+		close(ed.monitorBlockHeightDone)
+		ed.monitorBlockHeightDone = nil
 	}
 
 	ed.Dispatcher.HandleStopEvent(e)
@@ -146,7 +147,7 @@ func (ed *Dispatcher) HandleDisconnectEvent(e esdispatcher.Event) {
 		return
 	}
 
-	logger.Debug("Closing connection...")
+	logger.Debug("Closing connection due to disconnect event...")
 
 	ed.connection.Close()
 	ed.connection = nil
@@ -183,8 +184,8 @@ func (ed *Dispatcher) HandleConnectedEvent(e esdispatcher.Event) {
 	}
 
 	if ed.reconnectBlockHeightLagThreshold > 0 {
-		ed.ticker = time.NewTicker(ed.blockHeightMonitorPeriod)
-		go ed.monitorBlockHeight()
+		ed.monitorBlockHeightDone = make(chan struct{})
+		go ed.monitorBlockHeight(ed.monitorBlockHeightDone)
 	}
 }
 
@@ -210,8 +211,9 @@ func (ed *Dispatcher) HandleDisconnectedEvent(e esdispatcher.Event) {
 		logger.Warnf("Disconnected from event server: %s", evt.Err)
 	}
 
-	if ed.ticker != nil {
-		ed.ticker.Stop()
+	if ed.monitorBlockHeightDone != nil {
+		close(ed.monitorBlockHeightDone)
+		ed.monitorBlockHeightDone = nil
 	}
 }
 
@@ -283,19 +285,24 @@ func getMaxBlockHeight(peers []fab.Peer) uint64 {
 	return maxHeight
 }
 
-func (ed *Dispatcher) monitorBlockHeight() {
+func (ed *Dispatcher) monitorBlockHeight(done chan struct{}) {
 	logger.Debugf("Starting block height monitor on channel [%s]. Lag threshold: %d", ed.chConfig.ID(), ed.reconnectBlockHeightLagThreshold)
 
+	ticker := time.NewTicker(ed.blockHeightMonitorPeriod)
+	defer ticker.Stop()
+
 	for {
-		if _, ok := <-ed.ticker.C; !ok {
+		select {
+		case <-ticker.C:
+			if !ed.checkBlockHeight() {
+				// Disconnected
+				logger.Debugf("Client on channel [%s] has disconnected - stopping block height monitor", ed.chConfig.ID())
+				return
+			}
+		case <-done:
 			logger.Debugf("Stopping block height monitor on channel [%s]", ed.chConfig.ID())
 			return
 		}
-		if !ed.checkBlockHeight() {
-			// Disconnected
-			logger.Debugf("Client on channel [%s] has disconnected - stopping block height monitor", ed.chConfig.ID())
-			return
-		}
 	}
 }