How do I delay the execution of an Azure function after it fails?

Question

I am using an Azure Function (written in C#) that is triggered when there is a new message on the storage queue. The function is calling an external web-service to process the message, and when the external service is responding, everything is OK.

The problem is when the external web-site is down, and the web-client gives an exception (without a try/catch block around it). What happens then is that the function is retried (by azure) 5 times, with less than a second between each attempt. As you can imagine, the web service will probably still be down for all 5 attempts which will make azure move the message to the "poison"-queue.

Is it possible to configure the the amount of time it waits before retrying, or do i need to set up another azure function that runs once a minute to check the poison-queue for messages that then needs to be recreated in the normal queue?

Answer 1

We don't currently expose a way for you to configure the visibility timeout for failed messages. It is currently hardcoded to TimeSpan.Zero as you've noticed. I agree with you that we should allow this to be customized. I've logged an issue in our public repo with more details here.