Hallo Pythonisten,
gegeben sei das unter https://paste.debian.net/1335477/ hinterlegte
Programm:
#!/usr/bin/python
"""
keks.
"""
import time
import uuid
import paho.mqtt.client as mqtt
class MQTTClient:
"""maintain connection to MQTT broker"""
def __init__(
self,
broker_host,
subscribe_topic,
broker_port=1883,
max_retries=20,
retry_delay=30,
keepalive=60,
):
self.broker_host = broker_host
self.broker_port = broker_port
self.subscribe_topic = subscribe_topic
self.max_retries = max_retries
self.retry_delay = retry_delay
self.keepalive = keepalive
# Initialize MQTT client
print("create mqtt.Client")
client_id = f"mqttkeks-{uuid.uuid4()}"
self.client = mqtt.Client(client_id=client_id)
print("mqtt.Client created")
self.client.on_connect = self.on_connect
self.client.on_disconnect = self.on_disconnect
def __del__(self):
self.disconnect()
def connect(self):
"""connect to broker and begin the mqtt loop"""
if not self.reconnect_with_retry():
print("Failed to connect to MQTT broker")
def disconnect(self):
"""disconnect"""
if self.client.is_connected():
self.client.loop_stop()
self.client.disconnect()
print("Disconnected from MQTT broker.")
def reconnect_with_retry(self):
retry_count = 0
while retry_count < self.max_retries:
try:
self.client.loop_stop(force=True)
self.client.disconnect()
self.client.connect(
self.broker_host,
self.broker_port,
self.keepalive
)
print("(Re)connected successfully to MQTT")
self.loop_start()
print("restarted MQTT loop")
return True
except (ConnectionRefusedError, OSError) as ex:
print(
"Failed to connect to MQTT broker: "
f"(Attempt {retry_count + 1}): {ex}"
)
retry_count += 1
if retry_count < self.max_retries:
print(
"Retrying connection in "
f"{self.retry_delay} seconds..."
)
time.sleep(self.retry_delay)
else:
print(
"Max retry attempts reached. "
"Could not connect to MQTT broker"
)
raise
def on_connect(self, client, userdata, flags, rc):
"""subscribe to topic and log successful connection"""
print(f"Connected to MQTT broker {rc=}")
if rc == 0:
try:
self.client.subscribe(self.subscribe_topic)
print(f"Subscribed to {self.subscribe_topic=}")
except Exception as ex:
print(
f"subscribe to {self.subscribe_topic=} failed."
f"{ex=}"
)
else:
print(
f"Connection failed with code {rc}."
)
def on_disconnect(self, client, userdata, rc):
"""Handle unexpected disconnection and try to reconnect."""
print(
f"Disconnected from MQTT broker with result code {rc}"
)
if rc != 0: # If disconnection is unexpected
print("Attempting to reconnect to MQTT broker...")
self.reconnect_with_retry()
def start(self):
"""Start MQTT client"""
self.connect()
def stop(self):
"""Stop MQTT client and disconnect"""
self.disconnect()
def loop_start(self):
"""Start MQTT network loop in a separate thread"""
self.client.loop_start()
if __name__ == "__main__":
mqttc = MQTTClient(
'mqtt.ka51.zugschlus.de',
'tele/rain/raw_json',
retry_delay=5,
)
try:
print("mqtt.start(")
mqttc.start()
print(")")
while True:
time.sleep(10) # Keeps the program alive
except KeyboardInterrupt:
print("\nKeyboardInterrupt received; exiting.")
finally:
print("mqtt.stop(")
mqttc.stop()
print(")")
# end
Beim Erstaufruf verhält es sich wie es soll:
create mqtt.Client
mqtt.Client created
mqtt.start(
(Re)connected successfully to MQTT
restarted MQTT loop
)
Connected to MQTT broker rc=0
Subscribed to self.subscribe_topic='tele/rain/raw_json'
Wenn ich nun den mqtt Broker neu starte, versucht es sofort zu
reconnecten, holt sich ein TCP RST ab, weil der Broker so schnell nicht
wieder da ist.
Disconnected from MQTT broker with result code 7
Attempting to reconnect to MQTT broker...
Failed to connect to MQTT broker: (Attempt 1): [Errno 111] Connection refused
Retrying connection in 30 seconds...
und nach 30 Sekunden reconnected er wieder:
(Re)connected successfully to MQTT
restarted MQTT loop
Aber es wird on_connect nicht aufgerufen, deswegen geht das subscribe
nicht raus.
Die Plattform ist Debian stable, python 3.11 und paho-mqtt 1.6.1.
Hat hier jemand mehr praktische Erfahrung mit der Paho-Bibliothek?
Grüße
Marc
--
-----------------------------------------------------------------------------
Marc Haber | "I don't trust Computers. They | Mailadresse im Header
Leimen, Germany | lose things." Winona Ryder | Fon: *49 6224 1600402
Nordisch by Nature | How to make an American Quilt | Fax: *49 6224 1600421
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