21_mqtt: mqtt automatic reconnection issue

[krambriw]

Hello, nice example!

I just have an issue that the mqtt automatic reconnection is not working. I think it is the while loop that prevents the disconnect callback so the mqtt client is never making a reconnection

I did set the .auto_reconnect = true and it works if I just comment out the while loop

So instead I believe that the sensor readings using the while loop and mqtt publishing maybe should be moved to a separate task - My initial tests seems to work but the last bit I cannot find out, the mqtt publishing from inside the task

So my code below looks something like this (simplified and using a temperatur sensor) and it builds correctly but it crashes when the mqtt publishing happens

1. program starts correctly, mqtt client connects, xtask is created, sensor temperature is read correctly
2. mqtt publishing -> crash
3. I guess something goes wrong with pointer/address in data
4. if I run the code without mqtt publishing, everything works fine, if I restart mqtt broker, the program reconnects perfectly
5. happy for any suggestion how to make mqtt publishing correct instead, maybe putting it into a separate function?

Best regards, Walter

bool mqtt_conn = false;


void read_temp(void *data)
{
    while(mqtt_conn)
    {
        float rt = ds18b20_get_temp();
        char temp_string[10];
        sprintf(temp_string, "%.1f", rt);
        printf("%s\n",temp_string);
        mqtt_publish(data, "/room/temperature", temp_string, strlen(temp_string), 0, 0);
        vTaskDelay(5000 / portTICK_RATE_MS);

    }
    vTaskDelete( NULL );
}


// MQTT connected callback
void mqtt_connected_callback(mqtt_client *client, mqtt_event_data_t *event_data)
{
    printf(" connected!\n");
    mqtt_conn = true;
    xTaskCreate(&read_temp, "read_temp_task", 10000, &client, 5, NULL);
}


// MQTT disconnected callback
void mqtt_disconnected_callback(mqtt_client *client, mqtt_event_data_t *event_data)
{
    printf("MQTT disconnected!\n");
    mqtt_conn = false;
}

[krambriw]

Just to let you know, the above code works now, with a small but so important change
Changed
xTaskCreate(&read_temp, "read_temp_task", 10000, &client, 5, NULL);
to
xTaskCreate(&read_temp, "read_temp_task", 10000, client, 5, NULL);
I tried to pass the complete mqtt client struct when I started experimenting but I failed for some stupid reason, started to play with pointers...but hey, now it works!!! The ESP32 reconnects now automatically after a broker restart