Can we turn messages from Dead Letter queue to Active message? - azure

Question

I have dot net code which read loan-numbers from Azure service queue and calls my API for each loan-number.
This is my code which calls the api
private async Task ProcessMessagesAsync(Message message, CancellationToken token)
{
try
{
string loanNumber = Encoding.UTF8.GetString(message.Body);
_logger.LogInformation($"Received message: SequenceNumber:{message.SystemProperties.SequenceNumber} LoanNumber:{loanNumber}");
//API CALL HERE
await _apiClient.getResult(loanNumber);
await _queueClient.CompleteAsync(message.SystemProperties.LockToken);
}
catch (Exception ex)
{
//sending failed messages to Dead Letter queue
await _queueClient.AbandonAsync(message.SystemProperties.LockToken);
}
}
Failed loan-numbers are successfully sent to Dead Letter queue. When the server is down or bad request from API response.
I want to call the api after certain duration on the loan-numbers which are in Dead Letter Queue.
Is there any way to convert the messages in Dead Letter queue to active messages after some interval??
I am new to azure. Please help me to resolve the issue.
Thanks in advance.

Answer 1

Is there any way to convert the messages in Dead Letter queue to
active messages after some interval??
Automatically, no. However what you could do is read the messages from dead letter queue and then post them as new message in your main queue.
As far as automating the whole process, one possible solution would be to run a timer triggered Azure Function that reads messages from a dead letter queue periodically and post them in your main queue.

Answer 2

#akhil, it's worth noting that these messages will automatically be re-queued on the main queue until their DeliveryCount exceeds the MaxDeliveryCount of your main queue. The default value for MaxDeliveryCount is 10 so any failed requests to the API be retried ten times by this handler before being moved to the DLQ.
If you wanted to be a bit 'smarter' about this you could delay the retries using the Scheduled​Enqueue​Time​Utc property on the message in your catch block.
As #Gaurav Mantri has said, the framework offers nothing to process dead-letter messages 'for free'; you'll have to code a handler yourself as you would for a normal queue.

Answer 3

No, there is no way to convert the DLQ message to active message.
you need to process the DLQ and fix the reason as to why it ended in DLQ and then re transmit it back to your queue.
A sample from Github can be useful here.
https://github.com/Azure/azure-service-bus/tree/master/samples/DotNet/Microsoft.ServiceBus.Messaging/DeadletterQueue
(This sample shows how to move messages to the Dead-letter queue, how to retrieve messages from it, and resubmit corrected message back into the main queue.)

Answer 4

This could be an old answer but we can use ServiceBusExplorer from Microsoft. It can pull the messages from dead letter queue and then those can be requeued using
Let me know if you have any further questions.