131 lines
4.5 KiB
Python
131 lines
4.5 KiB
Python
import asyncio
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import aiomqtt
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import json
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from command import Command, CommandResponse
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import inspect
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from paho.mqtt.properties import Properties
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from dataclasses import asdict
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BAUD = 115200
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INTERVAL = 5
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class MQTTHandler:
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def __init__(
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self,
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mqtt_client: aiomqtt.Client,
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handler_id: str,
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):
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self.handler_id = handler_id
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self.mqtt_client = mqtt_client
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self.topic_base = f"asset/{handler_id}"
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self.command_topic = f"{self.topic_base}/command"
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self.property_topic = f"{self.topic_base}/property"
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def get_available_commands(self):
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commands = {}
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for base in self.__class__.__mro__:
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for name, attr in vars(base).items():
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if isinstance(attr, Command):
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commands[name] = attr
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return commands
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async def publish_commands(self):
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for name, command in self.get_available_commands().items():
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await self.mqtt_client.publish(
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f"{self.command_topic}/{command.name}/schema",
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str(command.schema),
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qos=1,
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retain=True,
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)
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for k, v in command.additional_properties.items():
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await self.mqtt_client.publish(
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f"{self.command_topic}/{command.name}/{k}",
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str(v),
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qos=1,
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retain=True,
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)
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async def execute_command(
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self, command_name: str, payload: str, properties: Properties = None
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):
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async def respond(success: bool, message: str = None):
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if (
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properties is not None
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and hasattr(properties, "ResponseTopic")
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and properties.ResponseTopic is not None
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):
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correlation = (
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properties.CorrelationData.decode("utf-8")
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if hasattr(properties, "CorrelationData")
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else None
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)
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await self.mqtt_client.publish(
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properties.ResponseTopic,
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json.dumps(
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asdict(CommandResponse(success, str(message), correlation))
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),
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qos=1,
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retain=False,
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)
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try:
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command = self.get_available_commands()[command_name]
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argument = json.loads(payload)
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result = await command(argument)
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await respond(True, result)
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except json.decoder.JSONDecodeError as e:
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await respond(False, f"Failed to parse payload as JSON: {e}")
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except ValueError as e:
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await respond(False, f"Command payload does not match expected schema: {e}")
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except Exception as e:
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print(f"Failed to execute command {command_name} with unknown cause: ", e)
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await respond(False, "Unexpected error")
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async def mqtt_command_writer_task(self):
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async for message in self.mqtt_client.messages:
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topic = str(message.topic)
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payload = message.payload.decode("utf-8")
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if topic.startswith(self.command_topic):
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command_name = topic.removeprefix(f"{self.command_topic}/")
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await self.execute_command(command_name, payload, message.properties)
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async def run(self):
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while True:
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try:
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async with self.mqtt_client as client:
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await client.subscribe(f"{self.command_topic}/+")
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await self.publish_commands()
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tasks = [self.mqtt_command_writer_task()]
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# Inspect instance methods
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for attr_name in dir(self):
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attr = getattr(self, attr_name)
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if callable(attr) and getattr(attr, "_is_task", False):
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if not inspect.iscoroutinefunction(attr):
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raise TypeError(
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f"@task can only decorate async methods: {attr_name}"
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)
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tasks.append(attr()) # call it, returns coroutine
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await asyncio.gather(*tasks)
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except aiomqtt.MqttError as e:
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print(
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f"[{self.handler_id}] MQTT connection error: {e}. Reconnecting in {INTERVAL}s..."
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)
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await asyncio.sleep(INTERVAL)
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def task(func):
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"""Decorator to mark async methods for automatic gathering."""
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func._is_task = True
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return func
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