added semaphore to lock mqtt client access on esp32

ADIS_ESP32_Eclipse/main/myMqtt.c

@@ -20,6 +20,7 @@ static const char *TAG = "MY_MQTT";
 
 // local cars
 char _brokerIp[] = "255.255.255.255";  // max length of ip
+SemaphoreHandle_t semaphoreMqtt = NULL;
 
 // declarations
 static void log_error_if_nonzero(const char *message, int error_code);
@@ -29,8 +30,16 @@ static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_
 esp_mqtt_client_handle_t client;
 
 bool MyMqtt_Init(void){
+	// initialize semaphore
+	semaphoreMqtt = xSemaphoreCreateRecursiveMutex();
+	if(semaphoreMqtt == NULL){
+		ESP_LOGE(TAG, "Failed to initialize semaphore for MyMqtt!");
+	}else{
+		vQueueAddToRegistry(semaphoreMqtt, "mymqtt_semphr");
+	}
+
+	// get mqtt broker IP from NVS
 	char brokerUri[50];
-	// get from NVS
 	Challenge_Nvs_GetBrokerIpFromNVS(_brokerIp, sizeof(_brokerIp));
 	McuUtility_strcpy((unsigned char*)brokerUri, sizeof(brokerUri), (unsigned char*)"mqtt://");
 	McuUtility_strcat((unsigned char*)brokerUri, sizeof(brokerUri), (unsigned char*)_brokerIp);
@@ -54,14 +63,35 @@ void MyMqtt_Deinit(void){
 	esp_mqtt_client_destroy(client);
 }
 
+/* HELPERS FOR SEMAPHORE */
+static bool MyMqtt_AquireMutex(void){
+	if(xSemaphoreTakeRecursive(semaphoreMqtt, pdMS_TO_TICKS(1000)) != pdTRUE){
+		/* timeout */
+		ESP_LOGW(TAG, "Timemout while aquiring myMqtt semaphore.");
+		return false;
+	}
+	return true;
+}
+
+static void MyMqtt_ReleaseMutex(void){
+	xSemaphoreGive(semaphoreMqtt);
+}
+
+
 void MyMqtt_Publish(const char *topic, const char *data){
-    int msg_id = esp_mqtt_client_publish(client, topic, data, 0, 2, 0);
-    ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id);
+	if(MyMqtt_AquireMutex()){
+		int msg_id = esp_mqtt_client_publish(client, topic, data, 0, 2, 0);
+		ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id);
+		MyMqtt_ReleaseMutex();
+	}
 }
 
 void MyMqtt_Subscribe(const char *topic){
-    int msg_id = esp_mqtt_client_subscribe(client, topic, 0);
-    ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d, success=%s", msg_id, msg_id==-1 ? "false" : "true");
+	if(MyMqtt_AquireMutex()){
+		int msg_id = esp_mqtt_client_subscribe(client, topic, 0);
+		ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d, success=%s", msg_id, msg_id==-1 ? "false" : "true");
+		MyMqtt_ReleaseMutex();
+	}
 }
 
 char* MyMqtt_GetBrokerIP(void){