Posting events to Azure Event Hubs using Policy defined on Event Hub Namespace

Question

I have created an Event Hub Namespace and 2 event hubs. I defined a Shared Access Policy (SAP) on the Event Hub Namespace. However, when I use the connection string defined on the namespace, I am able to send events to only one of the hubs even though I create the client using the correct event hub name

function void SendEvent(connectionString, eventHubName){
        await using(var producerClient = new EventHubProducerClient(connectionString, eventHubName)) {
            // Create a batch of events 
            using EventDataBatch eventBatch = await producerClient.CreateBatchAsync();
            
            var payload = GetEventModel(entity, entityName);
            // Add events to the batch. An event is a represented by a collection of bytes and metadata. 
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes(payload.ToString())));
            
            // Use the producer client to send the batch of events to the event hub
            await producerClient.SendAsync(eventBatch);
            
            System.Diagnostics.Debug.WriteLine($"Event for {entity} sent to Hub {eventHubName}");
    }
}

The above code is called for sending events to Hub1 and Hub2. When I use the connection string from the SAP defined on the Namespace, I can only send events to Hub1 or Hub2 whichever happens to be called first. I am specifying the eventHubName as Hub1 or Hub2 as appropriate.

I call the function SendEvent in my calling code.

The only way I can send to both hubs is to define SAP on each hub and use that connection string when creating the EventHubProducer

Am I missing something or is this by design?

How do you test for sending events to Hub1 and Hub2? do you mean in the first time you are using the code await using(var producerClient = new EventHubProducerClient(connectionString, Hub1)) {xx} for sending to Hub1, then in the next step, you copy the same code, just changing Hub1 to Hub2? — Ivan Yang
Would you mind sharing your connection string, with any shared key information redacted? I'm curious if you're using the Event Hub-level connection string rather than the namespace-level. — Jesse Squire
@JesseSquire I double checked the connection string. I can confirm it is not the connection string issue. The Hub level CS does not have the hub name in it. — rams

Ivan Yang Ivan Yang · Accepted Answer · 2020-08-27T05:51:36

I did a quick test at my side, and it can work well at my side.

Please try the code below, and let me know if it does not meet your need:

class Program
{
    //the namespace level sas
    private const string connectionString = "Endpoint=sb://yyeventhubns.servicebus.windows.net/;SharedAccessKeyName=mysas;SharedAccessKey=xxxx";

    //I try to send data to the following 2 eventhub instances.
    private const string hub1 = "yyeventhub1";
    private const string hub2 = "yyeventhub2";

    static async Task Main()
    {
        SendEvent(connectionString, hub1);
        SendEvent(connectionString, hub2);

        Console.WriteLine("**completed**");
        Console.ReadLine();
    }

    private static async void SendEvent(string connectionString, string eventHubName)
    {
        // Create a producer client that you can use to send events to an event hub
        await using (var producerClient = new EventHubProducerClient(connectionString, eventHubName))
        {
            // Create a batch of events 
            using EventDataBatch eventBatch = await producerClient.CreateBatchAsync();

            // Add events to the batch. An event is a represented by a collection of bytes and metadata. 
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("First event: "+eventHubName)));
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Second event: "+eventHubName)));
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Third event: "+eventHubName)));
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Fourth event: " + eventHubName)));
            eventBatch.TryAdd(new EventData(Encoding.UTF8.GetBytes("Fifth event: " + eventHubName)));

            // Use the producer client to send the batch of events to the event hub
            await producerClient.SendAsync(eventBatch);
            Console.WriteLine("A batch of 3 events has been published to: "+ eventHubName);
        }
    }

}

After running the code, I can see the data are sent to both of the 2 eventhub instances. Here is the screenshot:

Posting events to Azure Event Hubs using Policy defined on Event Hub Namespace

1 Answers