Hi,
Not claiming I am an expert, but we do have a similar setup (Mosquitto, mcu
as lwip mqtt client).
I am also using freertos as OS, maybe that confuses things a bit. After
establishing a connection (we use ppp over serial, with an LTE modem), it
is indeed simply calling connect, and await the callback (sent from mqtt.c,
line 702)
Here a copy/paste from what we use
LOCK_TCPIP_CORE();
_client = mqtt_client_new();
UNLOCK_TCPIP_CORE();
struct mqtt_connect_client_info_t clientInfo = { };
clientInfo.client_id = id.c_str();
etl_short_string will_topic;
fmt::format_to(std::back_inserter(will_topic), "t/{}/{}", id.c_str(),
iobox_status_topic);
clientInfo.will_topic = will_topic.c_str();
clientInfo.will_msg = "lost connection";
clientInfo.will_qos = 2;
clientInfo.keep_alive = 60;
LOCK_TCPIP_CORE();
err_t error = mqtt_client_connect(
_client,
&_ip_address,
item.get_mqtt_port(),
connect_callback,
this,
&clientInfo);
UNLOCK_TCPIP_CORE();
if (error == ERR_OK)
{
// If connect returned OK, we expect a callback (with accept)
_free_rtos.semaphore_take(_callback_semaphore, portMAX_DELAY);
// Set the callbacks for subscriptions once after successful connect
LOCK_TCPIP_CORE();
mqtt_set_inpub_callback(
_client,
subscription_topic_received_callback,
subsription_payload_received_callback, this);
UNLOCK_TCPIP_CORE();
return _connected;
}
in the callback I check for the connection state:
void mqtt_client::connect_callback(
mqtt_client_t *client,
void *arg,
mqtt_connection_status_t status)
{
auto me = reinterpret_cast<mqtt_client*>(arg);
me->_logger.write_debug_to<50>(logging_category_mqtt, "connect callback: {}",
status);
switch (status)
{
case MQTT_CONNECT_ACCEPTED:
if (me->_connected)
{
// If already connected and we receive an ACCEPT, the server restarted
// We want to reconnect and resubscribe
mqtt_disconnect(client);
mqtt_client_free(client);
// Wait a bit to be sure we no longer receive
// data for delete client
vTaskDelay(500);
}
else
{
me->_connected = true;
me->_free_rtos.semaphore_give(me->_callback_semaphore);
}
break;
case MQTT_CONNECT_DISCONNECTED:
case MQTT_CONNECT_TIMEOUT:
mqtt_disconnect(client);
mqtt_client_free(client);
me->_connected = false;
// Wait a bit to be sure we no longer receive
// data for delete client
vTaskDelay(500);
me->_free_rtos.semaphore_give(me->_reconnect_semaphore);
me->_free_rtos.semaphore_give(me->_callback_semaphore);
break;
default:
// Ignore for now
project_assert(false, error_code_mqtt_unknown_error_connection_lost);
break;
}
I never receive the state 'connecting'. Are you sure you have a working ppp
connection?
Op di 9 aug. 2022 om 07:17 schreef Ganesh Thambhahalli Satyen <
[email protected]>:
> Hi,
>
> A gentle reminder about these queries.
>
> Regards,
>
> Ganesh
>
>
>
>
>
> *From:* Ganesh Thambhahalli Satyen
> *Sent:* 01 August 2022 13:10
> *To:* '[email protected]' <[email protected]>; [email protected]
> *Cc:* Dhanashree Mohite <[email protected]>
> *Subject:* RE: Callbacks in MQTT
>
>
>
> Hi,
>
> As mentioned in the previous mail, we are trying to use the MQTT
> application present in LWIP along with a local Mosquitto broker. The
> callbacks provided in the detailed description here - lwIP: MQTT client
> (nongnu.org) <https://www.nongnu.org/lwip/2_0_x/group__mqtt.html> are
> being used.
>
>
>
> In mqtt_connection_cb, it can be seen that the connection state needs to
> be MQTT_CONNECT_ACCEPTED for the the mqtt_set_inpub_callback to be called
> which in turn will call the incoming_publish and incoming_data callbacks
> which are needed for the subscribe data.
>
>
>
> As per our observation, in the example_do_connect function, the connection
> state post mqtt_client_connect call is TCP_CONNECTING and not
> MQTT_CONNECT_ACCEPTED. Further, mqtt_connection_cb is not entered. This
> leads us to ask the following questions:
>
> 1. When is the mqtt_connection_cb called?
> 2. In mqtt_client_connect it can be observed that the connection state
> is manually set to TCP_CONNECTING. Thus, does it imply that the connection
> state needs to be manually set to another state?
> 3. What is the flow for the connection state to reach
> MQTT_CONNECT_ACCEPTED?
>
> Eagerly awaiting your response
>
> Regards,
>
> Ganesh
>
>
>
> *From:* Ganesh Thambhahalli Satyen
> *Sent:* 28 July 2022 13:47
> *To:* [email protected]
> *Cc:* Dhanashree Mohite <[email protected]>
> *Subject:* Callbacks in MQTT
>
>
>
> Hi,
>
> We are trying to use the MQTT application present in LWIP along with a
> local Mosquitto broker. As per the documentation, the connect callback is
> supposed to be called after the connection goes through. We are not able to
> replicate the same when we utilise the detailed description provided here
> - lwIP: MQTT client (nongnu.org)
> <https://www.nongnu.org/lwip/2_0_x/group__mqtt.html>. The client gets
> connected, but the callback is not entered. The conclusion that the
> callback is not entered is based on the flags we have added at the start
> and end of the callback. Is there any parameter change/ change in the
> order of calling which needs to be done?
>
> Eagerly awaiting your response
>
> Regards,
>
> Ganesh
>
>
> _______________________________________________
> lwip-users mailing list
> [email protected]
> https://lists.nongnu.org/mailman/listinfo/lwip-users
>
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