What happens to a queued message from a Azure Log App + Azure Queue?

Question

Does the Azure Queue step (within the Logic App) auto-dequeue messages?

Here's some context:

I have a logic app which is setup to insert a string into an azure queue. Upon being enqueued, a function app is invoked via a queue trigger. By the time my function app processes this message, the queue is now empty. Or does the queue trigger processed by my function app (which doesnt explicitly dequeue/delete any queued message) does the auto-dequeing?

I noticed that when i test the queue by manually inserting a message into the queue (via Azure Storage Explorer), the message does disappear on its own. So this makes me think the queue trigger somehow auto-removes the message (i.e. dequeues it)?

Thanks.

Solution

I do not understand the question:

Does the Azure Queue step (within the Logic App) auto-dequeue messages?

Queueing a message doesn't dequeue a message. That is done by the azure function that is triggered by that same queue. Once the message is processed successfully the function runtime will mark the message as being completed so it won't show up again. If it fails it is retried up to a certain amount of retries.

So:

Or does the queue trigger processed by my function app (which doesnt explicitly dequeue/delete any queued message) does the auto-dequeing?

Yes!

See this GitHub issue for reference. Too bad it isn't explicitly mentioned at the docs