Ingest Telemetry from IoT Hub to Azure Digital Twin using Python Error

Question

Hello, I would like to send the telemetry data from the IOT hub to Azure digital twins using Python instead of C#( I don't have experience with C#), but I can't get it.

I have followed the complete example from Microsoft (https://learn.microsoft.com/en-us/azure/digital-twins/how-to-ingest-iot-hub-data) without success.

This is my code for Simulated Device. I checked and it successfully send the message to IoT Hub:

from azure.iot.device import IoTHubDeviceClient
import json
import random
import time

CONNECTION_STRING = "

Answer 1

Hi @Anh Dinh , as Sander said, you need to check if your Event Grid function is configured to receive data from Event Hub. If you look into the section Connect the IoT hub to the Azure function, it provides the Azure CLI command needed to link the IoT Hub with the Azure function. Please note that you would need to publish the function on the Azure function app before you get execute the following command.

az iot hub device-identity create --device-id thermostat67 --hub-name <your-IoT-hub-name> --resource-group <your-resource-group>

I would also recommend modifying the simulation code to ensure that the data sent is in utf-8 format. You can achieve this using the Message class from azure.iot.device package. Please refer the following sinppet

from azure.iot.device import IoTHubDeviceClient, Message

MSG_TXT = '{{"temperature": {temperature},"humidity": {humidity}}}'
while true:
    temperature = TEMPERATURE + (random.random() * 15)
    humidity = HUMIDITY + (random.random() * 20)
    msg_txt_formatted = MSG_TXT.format(temperature=temperature, humidity=humidity)
    message = Message(msg_txt_formatted, content_encoding="utf-8", content_type="application/json")
    client.send_message(message)

Within your Event Grid function inspect the data obtained by doing the following

def main(event: func.EventGridEvent):
    result = json.dumps({
        'id': event.id,
        'data': event.get_json(),
        'topic': event.topic,
        'subject': event.subject,
        'event_type': event.event_type,
    })

    logging.info('Python EventGrid trigger processed an event: %s', result)

Hope this helps. Please let us know if you have any addtioinal questions or need further assistance.

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Answer 2

Hello @Anh Dinh,

It seems you are receiving IoT messages using EventGrid.

Is 'logging.info(event.data)' executed? Does the message data look like what you expected?

Without sending the data toward ADT, do you see the Azure Function (when running in your VS Code) being executed using IoT Hub messages?

Without sending the data toward ADT, do you see the Azure Function (when running in the cloud) being executed using IoT Hub messages?

Notice you create a new DigitalTwinsClient EVERYTIME a call is made to the function. Functions are stateless. You could try to make the DigitalTwinsClient creation static, outside the function This works well in C#.

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