Rename loop_once int the mqtt module to run_async. Also make the event loop run in a thread.

modules/mqtt_server/mqtt_server.cpp

@@ -40,13 +40,19 @@ void MQTTServer::listener_cb(struct evconnlistener *listener, evutil_socket_t fd
 	server->session_manager->accept_connection(bev);
 }
 
-void MQTTServer::loop_once() {
-	event_base_dispatch(evloop);
+void MQTTServer::run_async() {
+    if (_thread) {
+        printf("MQTTServer::run_async Error! A thread is already runnig!\n");
+        return;
+    }
+
+    _thread = new std::thread([this]() { event_base_dispatch(this->evloop); });
 }
 
 MQTTServer::MQTTServer() {
 	bind_address = "0";
 	port = 1883;
+	_thread = nullptr;
 
 	session_manager = new SessionManager();
 
@@ -55,11 +61,20 @@ MQTTServer::MQTTServer() {
 }
 
 MQTTServer::~MQTTServer() {
-    if (event_base_loopexit(evloop, NULL)) {
-        std::cerr << "failed to exit event loop\n";
+    //this first, as evloop runs in _thread
+	if (evloop && event_base_loopexit(evloop, NULL)) {
+		std::cout << "failed to exit event loop\n";
 	}
 
+	if (_thread) {
+		_thread->join();
+		delete _thread;
+	}
+
+	if (listener)
 		evconnlistener_free(listener);
+
+	if (evloop)
 		event_base_free(evloop);
 
 	delete session_manager;

modules/mqtt_server/mqtt_server.h

@@ -4,6 +4,7 @@
 #include <cstdio>
 #include <string>
 #include <vector>
+#include <thread>
 
 #include "./mqtt_broker/src/broker_session.h"
 #include "./mqtt_broker/src/session_manager.h"
@@ -31,11 +32,13 @@ public:
 	void on_error() { printf("on_error\n"); }
 
 	void initialize();
-	void loop_once();
+	void run_async();
 
 	MQTTServer();
 	~MQTTServer();
 
+	std::thread *_thread;
+
 	SessionManager *session_manager;
 	std::string bind_address;
 	uint16_t port;