Filter all NEBTYPE_NOTIFICATION_START

Filter all notifications where contacts_notified == 0
Naemon calls the broker_notification_data method for each host and service check twice.
This produces a lot of SPAM and useless data - at least for Statusengine.
For now, we are going to filter all notification data we are not interested in

src/MessageHandler/MessageHandler.h

@@ -359,15 +359,19 @@ namespace statusengine {
         */
         void SendMessage(NagiosObject &obj) override {
             if (bulk) {
-                bulkMessages.push_back(new NagiosObject(&obj));
-                if (++(*globalBulkCounter) >= maxBulkSize) {
-                    mhlist.FlushBulkQueue();
+                if(!obj.isEmpty()){
+                    bulkMessages.push_back(new NagiosObject(&obj));
+                    if (++(*globalBulkCounter) >= maxBulkSize) {
+                        mhlist.FlushBulkQueue();
+                    }
                 }
             }
             else {
-                std::string msg = obj.ToString();
-                for (auto &handler : *handlers) {
-                    handler->SendMessage(queue, msg);
+                if(!obj.isEmpty()){
+                    std::string msg = obj.ToString();
+                    for (auto &handler : *handlers) {
+                        handler->SendMessage(queue, msg);
+                    }
                 }
             }
         }

src/NagiosObject.h

@@ -33,6 +33,15 @@ namespace statusengine {
             return std::string(json_object_to_json_string(data));
         }
 
+        /**
+         * Check if the JSON object is empty
+         * Objects can be empty, if the broker filters certain events
+         * @return true if the JSON object is empty, false otherwise
+         */
+        bool isEmpty() const {
+            return json_object_object_length(data) == 0;
+        }
+
         /**
          * Counter will be incremented
          * @return json_object*
@@ -504,6 +513,13 @@ namespace statusengine {
     class NagiosNotificationData : public NagiosObject {
     public:
         explicit NagiosNotificationData(const nebstruct_notification_data *notificationData) {
+            if(notificationData->type == 600 || notificationData->contacts_notified == 0){
+                // 600 = NEBTYPE_NOTIFICATION_START
+                // Naemon calls the broker_notification_data nearly for every service check. This produces a lot of traffic to the broker.
+                // Due to we dont need the NEBTYPE_NOTIFICATION_START data, and if no contacts where notified, we drop all this data hardcoded for now.
+                return;
+            }
+
             SetData("type", notificationData->type);
             SetData("flags", notificationData->flags);
             SetData("attr", notificationData->attr);