Client

Module Name: client.py

Description: This module contains the relevant classes for the persistmq functionality. It provides a convinient interface for moving from pure paho-mqtt. The Client spawns a process which runs in parallel and caches the queued data, if there are communication problems

Usage: Import the PersistClient class and create an instance: from persistmq.client import PersistClient my_client = PersistClient(client_id="testclient", cache_path=Path("/tmp/mymqttcache")) my_client.connect_async(mqtt_host="localhost") my_persist_client.publish("dt/blah", "Test Message") my_persist_client.stop()

Classes: - PersistClient: The class for convinient usage of the PersistMqWorker - PersistMqWorker: Worker class (do not use directly)

Depends on: - paho.mqtt

Author: Michael Oberhofer

Version: 0.0.1

Date: August 31, 2024

PersistClient

Bases: object

__init__(client_id, cache_type='sq3', cache_path=Path('./cache'), **kwargs)

Create an instance of PersistClient

Parameters:

Name	Type	Description	Default
client_id	str	id for underlying mqtt-client	required
cache_type	str	method of caching ["sq3", "pickle"]. Defaults to "sq3".	'sq3'
cache_path	Path	path for cache file(s). Defaults to Path("./cache").	Path('./cache')
**kwargs		additional arguments for paho-client	{}

connect_async(mqtt_host, mqtt_port=1883, **kwargs)

Start the worker process with connection to broker (uses paho mqtt connect_async method)

Parameters:

Name	Type	Description	Default
mqtt_host	str	hostname, ip of broker	required
mqtt_port	int	port of broker. Defaults to 1883.	1883
kwargs	optional	additional parameter for paho mqtt connect_async	{}

publish(topic, payload, qos=2)

Add a message to be published

Parameters:

Name	Type	Description	Default
topic	str	topic to be published	required
payload	Union[str, bytes, bytearray, int, float, None]	payload to be published	required
qos	int	Quality of Service. Defaults to 2.	2

stop()

Gently stop the worker and cache remaining data from queue

PersistMqWorker

__init__(mqtt_client, mqtt_host, mqtt_port, message_q, command_q, cache_path, **kwargs)

Worker class for actual processing the messages

Parameters:

Name	Type	Description	Default
mqtt_client	Client	paho-mqtt client instance to be used for actual publishing	required
mqtt_host	str	hostname/ip of the mqtt broker to connect	required
mqtt_port	int	port of the mqtt broker to connect	required
message_q	Queue	queue for messages	required
command_q	Queue	queue for worker commands	required
cache_path	Path	cache path for either files or database	required