Implement EventHandler command mirroring (EH -> EH communication)

lib/tfw/networking/server/zmq_websocket_handler.py

@@ -21,12 +21,23 @@ class ZMQWebSocketHandler(WebSocketHandler):
         log.debug('WebSocket connection initiated')
         self._event_handler_connector.register_callback(self.zmq_callback)
 
-    @staticmethod
-    def zmq_callback(msg_parts):
+    @classmethod
+    def zmq_callback(cls, msg_parts):
+        keyhandlers = {'mirror': cls.mirror}
+
         key, data = deserialize_all(*msg_parts)
         log.debug('Received on pull socket: {}'.format(data))
-        for instance in ZMQWebSocketHandler.instances:
-            instance.write_message(data)
+        if key not in keyhandlers:
+            for instance in cls.instances:
+                instance.write_message(data)
+        else:
+            try: keyhandlers[key](data['data'])
+            except KeyError: log.error('Invalid mirror message format! Ignoring.')
+
+    @classmethod
+    def mirror(cls, data):
+        key = data['key']
+        cls._event_handler_connector.send_message({'data': data}, key)
 
     def on_message(self, message):
         log.debug('Received on WebSocket: {}'.format(message))