micropython / micropython/micropython-lib
MQTT connection and client.check_msg() problem
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- Python
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Description
I'm using Adafruit IO switches to turn my nodeMCU lights ON and OFF. The following code works but for a limited period of time. 5 minutes after the connection into Adafruit IO it seems the client tries to reconnect and if this happens I lose my switch funcionality at my adafruit dashboard. Either if I try to turn on or off the LED on my dashboard, the nodeMCU does not responds accordingly. Here is the code used (I'm using micropython, pycharm and a Lolin v3 nodemcu)
from machine import Pin
import sys
import os
import network
from umqtt.robust import MQTTClient
random_num = int.from_bytes(os.urandom(3), 'little')
mqtt_client_id = bytes('client_' + str(random_num), 'utf-8')
ADAFRUIT_LINK = b'io.adafruit.com'
ADAFRUIT_USERNAME = b'rodrigo1120'
ADAFRUIT_KEY = b'AAAAAAAAAAAAAAAAAAAAAAAAAAAA'
ADAFRUIT_FEEDNAME1 = b'gpio16'
ADAFRUIT_FEEDNAME2 = b'gpio2'
ssid = "WIFIUSERNAME"
password = "WIFIPASSWORD"
client = MQTTClient(client_id= mqtt_client_id,
server= ADAFRUIT_LINK,
user=ADAFRUIT_USERNAME,
password=ADAFRUIT_KEY)
mqtt_feedname1 = bytes('{:s}/feeds/{:s}'.format(ADAFRUIT_USERNAME, ADAFRUIT_FEEDNAME1), 'utf-8')
mqtt_feedname2 = bytes('{:s}/feeds/{:s}'.format(ADAFRUIT_USERNAME, ADAFRUIT_FEEDNAME2), 'utf-8')
def connect_to_ap():
wlan = network.WLAN(network.STA_IF)
wlan.active(True)
if not wlan.isconnected():
print('Connecting to {}'.format(ssid))
wlan.connect(ssid, password)
while not wlan.isconnected():
pass
print('Credentials: ', wlan.ifconfig())
try:
client.connect()
except Exception as e:
print('Could not connect to MQTT Server {}{}'.format(type(e).__name__, e))
def callback_routine(feed, msg):
print('Received Data from: feed={}, msg={}'.format(feed, msg))
if ADAFRUIT_FEEDNAME1 in feed:
action = str(msg, 'utf-8')
if action == 'ON':
pin16.value(0)
else:
pin16.value(1)
print('Action: {}'.format(action))
if ADAFRUIT_FEEDNAME2 in feed:
action = str(msg, 'utf-8')
if action == 'ON':
pin2.value(0)
else:
pin2.value(1)
print('Action: {}'.format(action))
pin16 = Pin(16, Pin.OUT)
pin2 = Pin(2, Pin.OUT)
pin16.value(1)
pin2.value(1)
def main():
connect_to_ap()
while True:
client.set_callback(callback_routine)
client.subscribe(mqtt_feedname1)
client.subscribe(mqtt_feedname2)
try:
client.wait_msg()
except KeyboardInterrupt:
print('Ctrl+C pressed, exiting')
client.disconnect()
sys.exit()
if __name__ == '__main__':
main()
Here is a picture of my serial monitor with this problem: (I took this picture 15 minutes after I stopped using the adafruit IO switches)

Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
The issue provides a MicroPython reproduction using umqtt.robust.MQTTClient, connect_to_ap(), and the main() wait_msg() loop, but names no repository file or test. Start by reproducing the reconnect after several minutes and inspect the MQTTClient reconnect and wait_msg behavior; done should identify a confirmed cause and an agreed change or documentation update.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- embedded-iot, networking
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100