Using Singleton attribute with ServiceBusTrigger in WebJobs SDK

Question

I am using the Microsoft.Azure.WebJobs and Microsoft.Azure.WebJobs.ServiceBus packages for capturing ServiceBus topic events.

Functions Code is as below -

public class Functions
{
    [Singleton]
    public static void Event4Processor(
      [ServiceBusTrigger("MyTopic", "MySubscription", AccessRights.Listen)] BrokeredMessage message,
      TextWriter log)
    {
        log.WriteLine(message);
    }
}

However, I am getting this error

{
  "Type": "FunctionCompleted",
  "EndTime": "2015-09-28T13:53:36.6540039+00:00",
  "Failure": {
    "ExceptionType": "System.ArgumentNullException",
    "ExceptionDetails": "System.ArgumentNullException: Value cannot be null.\r\nParameter name: bindingData\r\n   at Microsoft.Azure.WebJobs.Host.Bindings.BindingDataPathHelper.ConvertParameters(IReadOnlyDictionary`2 bindingData)\r\n   at Microsoft.Azure.WebJobs.Host.SingletonManager.GetBoundScope(String scope, IReadOnlyDictionary`2 bindingData)\r\n   at Microsoft.Azure.WebJobs.Host.Triggers.TriggeredFunctionBinding`1.<BindCoreAsync>d__7.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Azure.WebJobs.Host.Triggers.TriggeredFunctionBinding`1.<BindAsync>d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<ExecuteWithLogMessageAsync>d__c.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.<TryExecuteAsync>d__1.MoveNext()"
  },
  "ParameterLogs": {},
  "FunctionInstanceId": "a1dcf0a9-113f-4c7e-b136-fb8d8b7ee4aa",
  "Function": {
    "Id": "WebJobServiceBus.Functions.Event4Processor",
    "FullName": "WebJobServiceBus.Functions.Event4Processor",
    "ShortName": "Functions.Event4Processor",
    "Parameters": [
      {
        "NamespaceName": "my-ns",
        "TopicName": "myevents",
        "SubscriptionName": "mysubscription",
        "Name": "message",
        "DisplayHints": {
          "Description": "dequeue from 'mytopic/Subscriptions/mysubscription'",
          "Prompt": "Enter the queue message body"
        }
      },
      {
        "Type": "ParameterDescriptor",
        "Name": "log"
      }
    ]
  },
  "Reason": "AutomaticTrigger",
  "ReasonDetails": "New ServiceBus message detected on 'MyTopic/Subscriptions/MySubscription'.",
  "StartTime": "2015-09-28T13:53:35.6639049+00:00",
  "HostInstanceId": "ad1f5b26-ddec-4326-9cfb-df585065e773",
  "HostDisplayName": "WebJobServiceBus",
  "SharedQueueName": "azure-webjobs-host-ef6959df3bc9431680c944c6ca5b1eff",
  "InstanceQueueName": "azure-webjobs-host-ad1f5b26ddec43269cfbdf585065e773",
  "Heartbeat": {
    "SharedContainerName": "azure-webjobs-hosts",
    "SharedDirectoryName": "heartbeats/ef6959df3bc9431680c944c6ca5b1eff",
    "InstanceBlobName": "ad1f5b26ddec43269cfbdf585065e773",
    "ExpirationInSeconds": 45
  }
}

If I remove the Singleton attribute, everything works!

I've tried options like -

[Singleton(@"{CorrelationId}")]

However, Its not helping.

What's the problem(and fix)?

Answer 1

I believe I see a bug that we can fix tomorrow. For the time being, you should be able to work around this by binding to your own POCO Type rather than BrokeredMessage. Can you try that for now?

I'll respond back to this thread with a link to an updated package with the fix when ready.

Thanks.