Please help with MQTT and OTA startup and shutdown

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1

Hi all

My current code looks like:

void mqttOnDisconnect()
{
  disconnected = true;
}

...
IotMqtt_Connect(...)
IotMqtt_TimedSubscribe(...)
OTA_AgentInit(...)
while(!disconnected)
{
  ...
}
OTA_AgentShutdown(...)

I pull the ethernet plug and get mqttOnDisconnect(KEEP_ALIVE_TIMEOUT) as expected.

Problem here is that by the time OTA_AgentShutdown() is called the MQTT connection is aleady closed and _IotMqtt_RemoveSubscriptionByTopicFilter() hangs on ASSERT (contextIndex = -1).

I then tried moving OTA_AgentShutdown() to mqttOnDisconnect(), but it looks as if OTA spins off a job that ends up calling _IotMqtt_RemoveSubscriptionByTopicFilter() after OTA_AgentShutdown() returns (leading to mqttOnDisconnect() returning leading to MQTT closing the connection).

So, when do I call OTA_AgentShutdown() or don’t I need to do that (i.e. does MQTT clean that up properly?)

Or do I need to wait for OTA to shutdown in mqttOnDisconnect? This feels… wrong somehow :slight_smile:

Thanks

W

2

Hello,

Can you please share the version/release you are using ?

3

Hi pvyawaha

Latest version of everything as far as I can tell.

MQTT V2.3.1
OTA 1.2.1
FreeRTOS 10.4.3

4

OK to close this thread gracefully. Thanks to all the people who made the patches which ended up fixing my problem.

For the record, after mqttOnDisconnect(KEEP_ALIVE_TIMEOUT) the latest code requires that I call IotMqtt_Disconnect() after calling OTA_AgentShutdown. IotMqtt_Disconnect now checks and doesn’t complain or break when called after a timeout, and frees all the resources that need to be free’ed.

Thanks

W