CODEWITHSUNDEEP
azure-functionsazure-iot-hub
Randy Minder
Randy Minder

Reputation: 48402

Access To ServiceBus.Messaging.EventData in an Azure Function?

I'd like to create an Azure Function that fires whenever a message is sent to an Azure IoT hub. In a C# app I wrote, I create a method that pulls messages off the hub. In that method I have access to the ServiceBus.Messaging.EventData object that contains all available information about a message. The method looks as follows:

   private static async Task ReceiveMessagesFromDeviceAsync(string partition, CancellationToken ct)
    {
        var eventHubReceiver = eventHubClient.GetDefaultConsumerGroup().CreateReceiver(partition, System.DateTime.UtcNow);

        while (true)
        {
            if (ct.IsCancellationRequested)
                break;

            EventData eventData = await eventHubReceiver.ReceiveAsync();
            if (eventData == null)
                continue;

            // Get the Device Id which is included in the SystemProperties dictionary
            string deviceId = eventData.SystemProperties["iothub-connection-device-id"].ToString();

            string data = Encoding.UTF8.GetString(eventData.GetBytes());
            Console.WriteLine("Message received - DeviceId: {0}; Partition: {1}; Data: '{2}'", deviceId, partition, data);
        }
    }

When I attempt to create a C# based Azure Function in the portal, the default method created looks as follows:

public static void Run(string myIoTHubMessage, TraceWriter log)
{
    log.Info($"C# IoT Hub trigger function processed a message: {myIoTHubMessage}");
}

I was wondering if there was someway I could get access to the entire message object, like I can in my C# app, as opposed to just the message itself ('myIotHubMessage')?

Note: I tried the following but Azure Functions didn't like the first using reference. It couldn't find the reference.

using Microsoft.ServiceBus.Messaging;
using System.Text;

public static void Run(EventData eventData, TraceWriter log)
{
    var data = Encoding.UTF8.GetString(eventData.GetBytes());

    log.Info($"C# IoT Hub trigger function processed a message: {data}");
}

Upvotes: 0

Views: 838

Answers (2)

Michael Xu
Michael Xu

Reputation: 4432

You can follow the next steps to create an Azure Function that fires whenever a message is sent to an Azure IoT hub.

  1. Create an IoT hub using the Azure portal, please refer to this article.
  2. Create Function Apps, and add a function for IoTHub, this function will be run whenever an IoT Hub delivers a new message for Event Hub-compatible endpoints. enter image description here
  3. Modify the code in your function as following, save and run the function.
#r "Microsoft.ServiceBus"
using System.Text;
using Microsoft.ServiceBus.Messaging;

public static void Run(EventData myIoTHubMessage, TraceWriter log)
{
    log.Info($"{Encoding.UTF8.GetString(myIoTHubMessage.GetBytes())}");
}

When you use a device client send messages to IoT Hub, the function app will fire, it will show in the logs. enter image description here

Upvotes: 1

Mikhail Shilkov
Mikhail Shilkov

Reputation: 35134

Yes, just replace string with EventData, add reference to the package and using for the namespace:

#r "Microsoft.ServiceBus"
using System.Text;
using Microsoft.ServiceBus.Messaging;

public static void Run(EventData myEventHubMessage, TraceWriter log)
{
    log.Info($"{Encoding.UTF8.GetString(myEventHubMessage.GetBytes())}");
}

Upvotes: 1

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