How do you access the dead letter sub-queue on an Azure subscription?

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When I use the following:

var deadLetterPath = SubscriptionClient.FormatDeadLetterPath(topicPath,subName);
var client = SubscriptionClient.CreateFromConnectionString(connectionString, deadLetterPath, subName);

I get an InvalidOperationException

Cannot directly create a client on a sub-queue. Create a client on the main queue and use that to create receivers on the appropriate sub-queue

Some parts of the azure documentation say to use SubscriptionClient.CreateReceiver to access a sub-queue but that method doesn't exist.

Does this approach work for you ?

MessagingFactory factory = MessagingFactory.CreateFromConnectionString(cnxString);
var deadLetterPath = SubscriptionClient.FormatDeadLetterPath(topicPath,subName);
var dlqReceiver = factory.CreateMessageReceiver(deadLetterPath, ReceiveMode.ReceiveAndDelete);

I haven't test it out here (in a meeting), but give it a try

cheers

Amazon SQS dead-letter queues, Does this approach work for you ? MessagingFactory factory = MessagingFactory​.CreateFromConnectionString(cnxString); var deadLetterPath  Cannot directly create a client on a sub-queue. Create a client on the main queue and use that to create receivers on the appropriate sub-queue. Some parts of the azure documentation say to use SubscriptionClient.CreateReceiver to access a sub-queue but that method doesn't exist.

Working with dead-letter queues, Think of a topic as a top-level queue with multiple subscriptions that live and topics each, have a sub-queue called the “Dead Letter Queue” (DLQ). Service Bus or other Microsoft Azure service offerings, please reach out! To receive messages, you create one or more subscriptions to the topic. Similar to queues, messages are received from a subscription using a SubscriptionClient object instead of a QueueClient object. Create the subscription client, passing the name of the topic, the name of the subscription, and (optionally) the receive mode as parameters.

If you are using Microsoft.Azure.ServiceBus instead of Microsoft.ServiceBus, it is slightly different.

var deadQueuePath = EntityNameHelper.FormatDeadLetterPath(your_queue_name);
var deadQueueReceiver = new MessageReceiver(connectionString, deadQueuePath);

As per EntityNameHelper class in Microsoft.Azure.ServiceBus namespace, for topics, use the subscription path instead of your_queue_name.

The name of the queue, or path of the subscription.

/// <summary>
/// Formats the dead letter path for either a queue, or a subscription.
/// </summary>
/// <param name="entityPath">The name of the queue, or path of the subscription.</param>
/// <returns>The path as a string of the dead letter entity.</returns>
public static string FormatDeadLetterPath(string entityPath)
{
    return EntityNameHelper.FormatSubQueuePath(entityPath, EntityNameHelper.DeadLetterQueueName);
}

Use the Azure portal to create a Service Bus queue, Microsoft Azure Service Bus (ASB) is Microsoft's premier enterprise-level Secondary sub-queue, called a dead-letter queue(DLQ). is enabled for a subscription, any errors that occur while a subscription's SQL filter rule  Browse other questions tagged azure azure-storage message-queue dead-letter message-bus or ask your own question. Blog Podcast: TFW You Accidentally Delete Your Database

Those who want to do it in python.

Receive the messages from the dead letter queue:

from azure.servicebus import ServiceBusClient
import json
connectionString = "Your Connection String to Service Bus"
serviceBusClient = ServiceBusClient.from_connection_string(connectionString)
queueName = "Your Queue Name created in the Service Bus"
queueClient = serviceBusClient.get_queue(queueName)
with queueClient.get_deadletter_receiver(prefetch=5) as queueReceiver:
    messages = queueReceiver.fetch_next(timeout=100)
    for message in messages:
        # message.body is a generator object. Use next() to get the body.
        body = next(message.body)
        message.complete()

Hope it helps to someone.

How do you access the dead letter sub-queue on an Azure , DownLoad Project:AzureTopic&Subscription Azure service bus Queue and topic subscription provide addition sub-queue called dead-letter  Deferred messages remain in the main queue along with all other active messages (unlike dead-letter messages that live in a subqueue), but they can no longer be received using the regular Receive/ReceiveAsync functions. Deferred messages can be discovered via message browsing if an application loses track of them.

Working With the Azure Service Bus Dead Letter Queue, Could you clarify - do we have one dead-letter queue for a topic or a It is required for docs.microsoft.com ➟ GitHub issue linking. that that message would go to the DLQ for just that Subscriptions. "Azure Service Bus queues and topic subscriptions provide a secondary sub-queue, called a dead-letter  Also, dead-letter queues must reside in the same region as the other queues that use the dead-letter queue. For example, if you create a queue in the US East (Ohio) region and you want to use a dead-letter queue with that queue, the second queue must also be in the US East (Ohio) region.

Dead- letter message processing - Azure Service Bus, Describes dead-letter queues in Azure Service Bus. Service Bus queues and topic subscriptions provide a secondary subqueue, called a dead-letter You can access the dead-letter queue by using the following syntax: So, Microsoft's reasoning for not auto-deleting messages from the dead letter queue is probably: If you're enabling dead lettering, you explicitly want expired message not to be thrown away but stored somewhere else (the dead letter queue) so that you can review them.

Azure Service Bus Dead-Letter Queues, Messages that are deadlettered will remain on the deadletter sub queue. for receiving messages form queues and subscriptions can be used for receiving  Each MsmqQueue object represents an existing private, public, or system queue. This cmdlet gets queues that are local to the computer where you run the cmdlet. If you do not specify parameters, this cmdlet gets all public, private, and system queues of the host computer.

Comments
  • That did it. I little frustrating the MessageReceiver and SubscriptionClient don't have a common interface. I had to wrap them in my own interface so I could share the processing logic.
  • @kareem. MessageReciever inherits/implements: MessageClientEntity, IMessageReceiver, IMessageBrowser. SubscriptionClient inherits/implements: MessageClientEntity, IMessageSessionEntity, IMessageClientEntity, IMessageReceiver, IMessageBrowser. So you probably dont need to wrap them in your own interface. You could use the IMessageReciever interface im guessing.
  • nevermind a lot of that is internal. Then you need to do it with reflection.
  • Should anyone need this to read the dead letter on a queue and not a topic: Replace the 2nd line with var deadLetterPath = QueueClient.FormatDeadLetterPath(queueName)
  • I like how it's work. Just add +"/$DeadLetterQueue" to the subscription name
  • Do NOT string-hack it. Use the proper FormatDeadLetterPath methods.
  • @granadaCoder what do you mean ? This sample use the FormatDeadLetterPath method
  • Sorry. Comment should be "@Marat", not you the OP.