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November 2024

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paho-mqtt verhält sich bei Reconnect anders
by Marc Haber Nov. 14, 2024

Nov. 14, 2024

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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less-like pager als python-modul?
by Marc Haber Nov. 13, 2024

Nov. 13, 2024

Hallo Pythonisten, ich suche einen less-artigen Pager, den ich leicht in ein python-Programm integrieren kann. Wichtig sind mir folgende Features, die bis auf das erste und das zweite in less implementiert sind: - Frei setzbarer Prompt in der Statuszeile - Zugriff auf das letzte Kommando das gegeben wurde - Vorwärts- und Rückwärtsscrollen - Horizontales Scrolling - Umbruch zu langer Zeilen einschaltbar - Vorwärts- und Rückwärtssuche, auch mit regexps - Markierung der auf die letzte regexp passenden Stellen Sowas wird es nicht geben, nehme ich an? 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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