nmdc-log-service: prevent logging the same connection-state message repeatedly

main.go

@@ -51,7 +51,11 @@ func LogMessage(hub, message string) {
 	}
 }
 
-func HubWorker(addr, nick, password string) {
+type HubWorker struct {
+	LastConnectionStateMessage string
+}
+
+func (this *HubWorker) MainLoop(addr, nick, password string) {
 
 	opts := libnmdc.HubConnectionOptions{
 		Address:       libnmdc.HubAddress(addr),
@@ -71,11 +75,16 @@ func HubWorker(addr, nick, password string) {
 		switch event.EventType {
 		case libnmdc.EVENT_CONNECTION_STATE_CHANGED:
 			if LogConnectionState {
+				str := "* " + event.StateChange.Format()
 				if len(event.Message) > 0 {
-					LogMessage(addr, "* "+event.StateChange.Format()+" ("+event.Message+")")
-				} else {
-					LogMessage(addr, "* "+event.StateChange.Format())
+					str += " (" + event.Message + ")"
 				}
+
+				// Prevent logging the same message repeatedly
+				if str != this.LastConnectionStateMessage {
+					LogMessage(addr, str)
+				}
+				this.LastConnectionStateMessage = str
 			}
 
 		case libnmdc.EVENT_PUBLIC:
@@ -135,7 +144,8 @@ func main() {
 		os.MkdirAll(GetDirectoryNameForHub(hubaddr), 0755)
 
 		// Launch logger
-		go HubWorker(hubaddr, *nick, *password)
+		hw := HubWorker{}
+		go hw.MainLoop(hubaddr, *nick, *password)
 
 		launch_ct++
 	}