wait_msg() is not working properly with Subscribe

[kkumar326]

Publishing is working fine on same MQTT connection while subscribe is not working.
I traced back the error to this function:

wait_msg()

res = self.sock.read(1) is receiving: b'' on sending data on subscribed topic.

[dpgeorge]

To help fix this issue you will need to please provide more detailed information about your set-up. Ideally provide a minimal test case that reproduces the issue, along with the version of the library you used and the version and port of MicroPython.

[kkumar326]

Library is umqtt.simple and umqtt version is the latest one taken directly from micropython-lib.

Micropython version:

MicroPython v1.9.2-8-gbf8f45cf on 2017-08-23; ESP module with ESP8266

Broker that I'm using is

Mosquitto v3.1.1

Code that I'm running is like this:

from umqtt.simple import MQTTClient

def switch_message(topic, msg):
	print("Remote Switch Func called")
	time.sleep(5)

c = MQTTClient(client_id = 'client-id', server='iot.xxxxx.com', port=1883, user = "username", password = "password")
c.set_callback(switch_message)
c.connect()
print("MQTT connected")

c.subscribe("client/{}/{}/switch".format("sub_p1", "sub_p2"), qos=1)
while True:
	c.check_msg()
	time.sleep(1)

Publishing is working fine on this exactly same connection and topic, but subscription is returning OSError -1. When I tried to print self.sock.read(1), it just showed b"" after publishing on that topic.

Full Error:

Traceback (most recent call last):
  File "main.py", line 18, in <module>
  File "umqtt/simple.py", line 202, in check_msg
  File "umqtt/simple.py", line 171, in wait_msg
OSError: -1

I'm also running paho mqtt subscriber on my web server which is subscribed to this topic and it is receiving everything fine.

[kkumar326]

Please use this working code to test:

from umqtt.simple import MQTTClient

def switch_message(topic, msg):
	print("Remote Switch Func called")
	time.sleep(5)

c = MQTTClient(client_id = 'client-id-test', server='iot.airize.com', port=1883, user = "test_airize", password = "password")
c.set_callback(switch_message)
c.connect()
print("MQTT connected")

c.subscribe("client/{}/{}/switch".format("sub_p1", "sub_p2"), qos=1)
while True:
	c.check_msg()
	time.sleep(1)

[kkumar326]

It's working fine. I made a mistake in acl file. I'm really sorry for this unnecessary issue.

[dpgeorge]

No problem. Good that you managed to solve it yourself.