是否可以在使用 Redis 后端的 Celery Worker 中使用 mqttasgi 发送 MQTT 消息

Question

我在 Django 中使用 mqttasgi 库接收大量消息，并使用 REDIS 队列处理它们，我想将此信息发布回另一个主题。这可能吗？如果是，我该怎么做？目前我只是将发布功能覆盖到我的消费者中，如下所示。

from mqttasgi.consumers import MqttConsumer
from mqtt_handler.tasks import processmqttmessage
import json

class MyMqttConsumer(MqttConsumer):

async def connect(self):
    await self.subscribe('application/5/device/+/event/up', 2)

async def receive(self, mqtt_message):
    print('Received a message at topic:', mqtt_message['topic'])
    print('With payload', mqtt_message['payload'])
    print('And QOS:', mqtt_message['qos'])
    print(type(mqtt_message['payload']))
    dictresult = json.loads(mqtt_message['payload'])
    print(type(dictresult))
    print(dictresult)
    jsonresult = json.dumps(dictresult)
    print(type(jsonresult))
    print(jsonresult)
    processmqttmessage.delay(jsonresult)
    print("test")
    pass

async def publish(self, topic, payload, qos=1, retain=False):
    await self.send({
        'type': 'mqtt.pub',
        'mqtt': {
            'topic': topic,
            'payload': payload,
            'qos': qos,
            'retain': retain,
        }
    })

async def disconnect(self):
    await self.unsubscribe('application/5/device/+/event/up')

我希望现在能够从我的任务进程内部发布 mqttmessage。

谢谢。

Pd：@Santiago Ivulich 也许你可以帮助我。

Answer 1

是的，这是可能的，没有必要覆盖基础消费者的发布。我会向 return 推荐需要发布回 MQTTAsgi 的结果，以维护单个 MQTT 连接。为此，您可以在通道层中使用一个组，以便将需要发送的内容发送回 mqttasgi。

from mqttasgi.consumers import MqttConsumer
from mqtt_handler.tasks import processmqttmessage
import json

class MyMqttConsumer(MqttConsumer):
    async def connect(self):
        await self.subscribe('application/5/device/+/event/up', 2)
        # Subscribe consumer to channel layer group.
        await self.channel_layer.group_add("my.group", self.channel_name)

    async def receive(self, mqtt_message):
        print('Received a message at topic:', mqtt_message['topic'])
        print('With payload', mqtt_message['payload'])
        print('And QOS:', mqtt_message['qos'])
        print(type(mqtt_message['payload']))
        dictresult = json.loads(mqtt_message['payload'])
        print(type(dictresult))
        print(dictresult)
        jsonresult = json.dumps(dictresult)
        print(type(jsonresult))
        print(jsonresult)
        processmqttmessage.delay(jsonresult)
        print("test")
        pass

    async def publish_results(self, event):
        data = event['text']
        self.publish('my/publish/topic', data, qos=2, retain=False)


    async def disconnect(self):
        await self.unsubscribe('application/5/device/+/event/up')

并且来自 celery 任务：

from channels.layers import get_channel_layer
from asgiref.sync import async_to_sync

def processmqttmessage():
    ...
    channel_layer = get_channel_layer()
    async_to_sync(channel_layer.group_send)("my.group", 
    {"type": "publish.results", "text":"Hi from outside of the consumer"})

如果多个消费者将同时运行您可以通过编程方式为组生成一个名称并将其作为参数传递给任务。

重要提示：确保您在 celery 和 mqttasgi 项目中使用相同的后端通道。

是否可以在使用 Redis 后端的 Celery Worker 中使用 mqttasgi 发送 MQTT 消息

Is it possible to send an MQTT message with mqttasgi inside a Celery Worker that use Redis Backend

python

python-3.x

django

mqtt

asgi