What is the correct way to include MQTT topics in Message class

Question

I have developed an Azure IoT Edge module in Python which subscribes to MQTT messages from a device, this device is read only, means I can't login or change anything in the device except to receive messages using MQTT. I am sending the MQTT message received from the device to an output using send-message-to-output send_message_to_output(message, output_name) which in turn uploads it to Azure IoT Hub.

The message class takes MQTT Payload :

message = Message(MQTT_Payload) // Using message class

I tried sending MQTT topic in custom_properties of the message, it works. I can see the topic in Azure cloud shell using following command:

az iot hub monitor-events -n Intel-Hub1 --content-type application/json --properties app

Please note that I am not using MQTT to send message from IoT Edge to IoT Hub.

Question:

Am I doing the right thing? If not, what is the correct way to include MQTT Topic in "message" such that other Azure services like Azure TSItime-series-insights-overview can use the message easily? Appreciate if you can point me to relevant documentation or an example.
Is there any other approach?

Answer 1

I tried a simple method to constructed the message like this {"topic": {value}}. Following is the message on Azure Cloud Shell. I think Azure TSI seems to accept this payload format.

{
    "event": {
        "origin": "IntelGateway",
        "module": "PyModule",
        "interface": "",
        "component": "",
        "properties": {
            "application": {}
        },
        "payload": {
            "N/304511aed4fa/solarcharger/256/Dc/0/Voltage": 46.5099983215332
        }
    }
}

Please let me know if there is a better way of sending mqtt topic and value?