Sending to Service Bus Event Hubs from a WCF Message Inspector

Question

I've got a working web service and test client and i can intercept the messages between them. but when i add the code to send to my event hub the client shows a fault:

An unhandled exception of type 'System.ServiceModel.FaultException`1' occurred in mscorlib.dll

Additional information: The argument Endpoints is null or empty.

Parameter name: Endpoints

The more detailed exception:

System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]:    The argument Endpoints is null or empty.
Parameter name: Endpoints (Fault Detail is equal to An ExceptionDetail,  likely created by IncludeExceptionDetailInFaults=true, whose value is:
System.ArgumentException: The argument Endpoints is null or empty.
Parameter name: Endpoints
at Microsoft.ServiceBus.ServiceBusConnectionStringBuilder.Validate()
at Microsoft.ServiceBus.ServiceBusConnectionStringBuilder.ToString()
at  Microsoft.ServiceBus.Messaging.Configuration.KeyValueConfigurationManager.
Initialize(String connection, Nullable`1 transportType)
at Microsoft.ServiceBus.Messaging.Configuration.KeyValueConfigurationManager.
.ctor(Nullable`1 transportType)
at Microsoft.ServiceBus.Messaging.EventHubClient.Create(String path)
at WCFInterceptor.MessageInspector.AfterReceiveRequest(Message& request,  ICli
entChannel channel, InstanceContext instanceContext)
at  System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.AfterReceiveReques
tCore(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(Me
ssageRpc& rpc)
at System.ServiceModel.Dispatc...).

And heres the code i add:

try
        {
            NamespaceManager namespaceManager = NamespaceManager.CreateFromConnectionString(GetServiceBusConnectionString());
            Manage.CreateEventHub(hubName, 16, namespaceManager);
        }
        catch (Exception e)
        {
            Console.WriteLine("SetupEHError" + e);
        }
        EventHubClient client = EventHubClient.Create(hubName);
        Console.WriteLine("eventhubclient iniciado");
        EventData messageData = new EventData(Encoding.UTF8.GetBytes(serializedString));

        try
        {
            client.Send(messageData);
            Console.WriteLine("MessageData enviada");
        }
        catch (Exception e)
        {

            Console.WriteLine("ErrorMessage:" + e);
        }

Here is the CreateEventHub Method:

public static void CreateEventHub(string eventHubName, int        numberOfPartitions, NamespaceManager manager)
    {
        try
        {
            // Create the Event Hub
            Console.WriteLine("Creating Event Hub...");
            EventHubDescription ehd = new EventHubDescription(eventHubName);
            ehd.PartitionCount = numberOfPartitions;
            manager.CreateEventHubIfNotExistsAsync(ehd).Wait();
            Console.WriteLine("Created");
        }
        catch (AggregateException agexp)
        {
            Console.WriteLine(agexp.Flatten());
        }
    }

The WebService Console App prints up to

Creating Event Hub
Created

So i was thinking i might need to add Endpoints for the MessageInspector in the WebService to be able to send data to a Service Bus Event Hub. if so, how is the configuration?

Thanks in Advance

Answer 1

Background:

ServiceBus SDK has 2 major interfaces:

1. NamespaceManager: for all Management operations (aka Control Plane) like Create Delete Topics/EHubs etc
2. EntityClients (TopicClient, EventHubClient etc) : for runtime operations (aka Data Plane) - to Send/Recv from Topics/EventHubs.

Both these interfaces will need their own connection strings for connecting to ServiceBus. For ex: The connection string specified to NamespaceManager will need ManageClaims and for EntityClients will just need Send/Recv claims.

You created EventHubClient with just EventHub Name and didn't pass connection string there. In this case, the above error is thrown from our ServiceBus client sdk - when the connection string is not passed via app.config. To fix this, change this line (as you are using ConnectionString directly for NamespaceManager and not using any app.config):

EventHubClient client = EventHubClient.Create(hubName);

Change it to:

----edit-----
    var eHubConnStr = GetServiceBusConnectionString();
    eHubConnStr.EntityPath = eventHubName;
    // Evaluate here, if you have to populate the Security related properties from the ConnectionString
    // eHubConnStr.SasKey and SasKeyName to Send only or Recv only
----edit-----
    EventHubClient client = EventHubClient.CreateFromConnectionString(eHubConnStr); // this connection string should be the EventHub Send conn str.

HTH! Sree

Answer 2

Actually all i needed to do was editing the app config of my web service server with the connection string. seems like the Create method of the eventhubclient takes the eventhub name and then goes to the appconfig for the key, thus so it wasn't finding it.