how do i integrate my data from azure functions to azure digital twins so that the data is reflected in the digital twins model?

Ho Kin Haw 25

Hi,

I am having difficulty trying to get my sensor data reading to be reflected in my Azure Digital Twins model. I have already connected by sensor to Azure IoT explorer and published my Azure function but I'm not sure how to reflect the sensor data into my Digital Twins model. Could someone kindly assist me with this?

AshokPeddakotla-MSFT 27,966 Reputation points

2024-01-09T10:00:08.8866667+00:00

Ho Kin Haw Welcome to Microsoft Q&A Forum, Thank you for posting your query here!

Did you check the documentation Ingest IoT Hub telemetry into Azure Digital Twins already?

Also, The simplest way to ingest IoT data from Azure Digital Twins into Azure Data Explorer is to use the data history feature. This feature allows you to set up a connection between your Azure Digital Twins instance and an Azure Data Explorer cluster, and graph updates (including twin property updates, twin lifecycle events, and relationship lifecycle events) are automatically historized to the cluster. This is a good choice if you're using device telemetry data to bring your digital twins to life. For more information about this feature, see Data history (with Azure Data Explorer).

Do let me know if that helps or have any further queries.
Ho Kin Haw 25 Reputation points

2024-01-09T14:09:31.3533333+00:00

Hello Ashok,

Yes, I tried following the documentation. Currently, I have my own Azure Function as well as IoT Hub and they are both connected already. I have registered my device - BME280 sensor with the IoT Hub and I am able to send telemetry data to the IoT Hub. My issue now is getting the sensor data to be updated in the Azure Digital Twins Model
LeelaRajeshSayana-MSFT 13,546 Reputation points

2024-01-18T01:51:00.9333333+00:00

Hi @Ho Kin Haw Greetings! I am following up to see if you got a chance to review the below response. Please let us know if you have any additional questions or need further assistance.

If the response helped, please do click Accept Answer and Yes for the answer provided. Doing so would help other community members with similar issue identify the solution. I highly appreciate your contribution to the community.

1 answer

Sander van de Velde 29,271 Reputation points MVP

2024-01-09T18:53:04.7+00:00

Hello @Ho Kin Haw,

welcome to this moderated Azure community forum.

I expect you created an Azure Digital Twins environment already and have a twin setup in the graph.

To manipulate the digital twin properties in the graph, you need to execute specific code in an Azure Function (that has enough rights to manipulate twins).

Take a look at this blog post with more details. Sample Azure Function code is available on GitHub.

So, the flow is:

device -> iothub -> Azure Function -> Azure Digital Twins environment

Notice you need to update the properties of the twin. Azure Digital Twins also offers ingesting telemetry but this is a pass-through solution, generating ADT events but not changing the properties.

Azure IoT Explorer is a tool to check for incoming messages on the IoT Hub and offers limited abilities to manipulate IoT Hub device registrations. This tool also has no role within the flow seen above.

Also, notice that Azure Data Explorer is not part of this flow.

Azure Data Explorer offers a historical view of ADT twin changes when connected as a database.

In that case, the flow is:

device -> iothub -> Azure Function -> Azure Digital Twins environment -> Azure Data Explorer table with historical events.

If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.
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1 person found this answer helpful.
Ho Kin Haw 25 Reputation points

2024-01-10T10:28:54.45+00:00

Hi Sander,

Yes, I have setup my IoT Hub and Azure functions and have assigned the Digital Twins Data Owner Role in the function app. Under 'events' for my IoT Hub and azure functions, it does reflect that it is receiving published events. I have also created an azure digital twin instance and created a twin. However, when I run my sensor and click on 'Run Query' in digital twins explorer, the parameters are not updating still. I'm not sure if I'm missing any code to send the telemetry to azure digital twins or there is something wrong with my code.

Here is my code for the azure function:

using System; using Azure; using System.Net.Http; using Azure.Core.Pipeline; using Azure.DigitalTwins.Core; using Azure.Identity; using Microsoft.Azure.WebJobs; using Microsoft.Azure.WebJobs.Extensions.EventGrid; using Microsoft.Extensions.Logging; using Newtonsoft.Json; using Newtonsoft.Json.Linq; using Azure.Messaging.EventGrid; namespace IotHubtoTwins { public class IoTHubtoTwins { private static readonly string adtInstanceUrl = Environment.GetEnvironmentVariable("ADT_SERVICE_URL"); private static readonly HttpClient httpClient = new HttpClient(); [FunctionName("IoTHubtoTwins")] #pragma warning disable AZF0001 // Suppress async void error public async void Run([EventGridTrigger] EventGridEvent eventGridEvent, ILogger log) #pragma warning restore AZF0001 // Suppress async void error { if (adtInstanceUrl == null) log.LogError("Application setting \"ADT_SERVICE_URL\" not set"); try { // Authenticate with Digital Twins var cred = new DefaultAzureCredential(); var client = new DigitalTwinsClient(new Uri(adtInstanceUrl), cred); log.LogInformation($"ADT service client connection created."); if (eventGridEvent != null && eventGridEvent.Data != null) { log.LogInformation(eventGridEvent.Data.ToString()); // Deserialize event data JObject deviceMessage = (JObject)JsonConvert.DeserializeObject(eventGridEvent.Data.ToString()); string deviceId = (string)deviceMessage["systemProperties"]["iothub-connection-device-id"]; var temperature = deviceMessage["body"]["Temperature"]; var humidity = deviceMessage["body"]["Humidity"]; log.LogInformation($"Device:{deviceId} Temperature is:{temperature} and Humidity is:{humidity}"); // Update twin with temperature and humidity var updateTwinData = new JsonPatchDocument(); updateTwinData.AppendReplace("/Temperature", temperature.Value<double>()); updateTwinData.AppendReplace("/Humidity", humidity.Value<double>()); await client.UpdateDigitalTwinAsync(deviceId, updateTwinData); } } catch (Exception ex) { log.LogError($"Error in ingest function: {ex.Message}"); } } } }

This is my code for my DTDL model:

{ "@context": "dtmi:dtdl:context;2", "@id": "dtmi:ingestfunction:DryCabinet;1", "@type": "Interface", "displayName": "Dry Cabinet", "contents": [ { "@type": "Property", "name": "temperature", "displayName": "Temperature", "schema": "double", }, { "@type": "Property", "name": "humidity", "displayName": "Humidity", "schema": "double", } ] }

Sander van de Velde 29,271 Reputation points MVP

2024-01-10T12:41:23.3433333+00:00

Hello @Ho Kin Haw,

I have seen that properties were not updated because they were still empty/null/nil.

Do the properties of your twin have a default value to start with?

Can you give the properties of your twin a value?

Ho Kin Haw 25 Reputation points

2024-01-11T04:48:37.8+00:00

Hello Sander, Sorry, which part are you referring to when you mention that properties were not updated because they were still empty/null/nil? The properties of my twin do not have a default value to start with but I can give it a random value

Sander van de Velde 29,271 Reputation points MVP

2024-01-11T18:00:16.5166667+00:00

Hello @Ho Kin Haw, yes, just fill in some default values for the properties (eg. temperature = 37, humidity = 42) of your twin in the Azure Digital Twins explorer. You need to refresh the explorer a couple of times to see the properties are (perhaps rerunning a query is good enough). Good luck!
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