IoT: connection drop after around 24 hours

[kilabyte]

Our raspi connection to google iot via mqtt fails to persist past the 24hour mark. I have the JWT refreshing about every 20 mins or so.

Running on a raspi 3 with mqtt and code is identical from the examples posted here just changed my device id and project id and other vars to match my instance.

[gguuss]

Thanks for reporting this issue, I'll see if I can figure out what's going on.

[kilabyte]

If i use the pubsub client library as also on your documentation this works flawlessly but then i get no information within the IoT console for things like last seen, heartbeat, config sent etc

[gguuss]

There are a lot of potential causes for a disconnect. If you go to the console and look up your device are you seeing any error details?

[kilabyte]

I get either "The connection was closed or broken by the client" or i get "The authorization token expired" Which either doesnt make sense. The raspi is also hardwired to my router and im refreshing the token every 20 minutes.

[kilabyte]

Or if i use the client library instead is there anyway to specify the device id so i can maintain status of each iot device?

[gguuss]

I'm able to reproduce the console error issue now. There's a chance the device is not correctly refreshing the JWT, but it looks like to me like it should work as the JWT is refreshed in the call to get_client.

There's a chance on the reconnect we need to call:

client.disconnect()
client.loop()

To cleanly disconnect after this line to avoid the error. But I believe I have tested this before and it worked, despite the console errors. If you're doing a lot of calculations between the calls to mqtt.loop() the client loses its connection and behavior after that could get inconsistent.

[kilabyte]

ok i can update and try that. what is the difference between client.loop(), client.stop_loop() and client.loop_start() ?

[gguuss]

client.loop is synchronous, client.loop_stop / client.loop_start are asynchronous helpers that create a background thread. The asynchronous methods run smoother in practice but can be difficult to test.

Don't mix client.loop() with client.loop_stop() and client.loop_start().

[gguuss]

Of note, adding the disconnect seems to be the right thing to do, I'm working on a PR to set it up.