Fipy, umqtt.simple library: check_msg() is blocking

[Mirox]

I'm using the umqtt.simple library to connect to the Azure IoT Hub and can successfully send messages to the topic, but when I call client.check_msg() to check if a message has been sent to the device, it's blocking my code when no message is sent instead of just returning if a message is in the queue or not.

So when it get stucked at client.check_msg() and then I send a message to the device the message is printed and the code is continued.

This is my code:

.
.
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client = MQTTClient(device_id, hostname, user=username, password=password, ssl=True, port=8883)

topic = "devices/{device_id}/messages/events/".format(device_id=device_id)
sub_topic = "devices/{device_id}/messages/devicebound/#".format(device_id=device_id)

client.set_callback(sub_cb)

client.connect()

client.subscribe(sub_topic)

print("subscribed")

time.sleep(1)

print("Start sending...")
cntr = 0

while (True):
    client.publish(topic, "message", qos=1)
    print("message sent\n")
    print("check messages\n")
    client.check_msg()      #At this point it get stucked when no message has been sent to the device
    cntr+=1
    time.sleep(20)

Hardware: Fipy, Pytrack, NB-IoT is used to connect to the Azure IoT Hub

[MarcosC]

@Mirox , how have you fix this? I have exactly the same issue and cannot fix it. The chec_msg() method get stucked. Thanks!

[randomrnti]

@MarcosC I've had the same issue. The only workaround for me was to use non-SSL that's the only one that appears to work non-blocking.

[Alan Zhang]

Someone found a workaround - check out this github here: https://github.com/pycom/pycom-micropython-sigfox/issues/424