My Azure Function in Python v2 doesn't show any signs of running, but it probably is

Question

I have a simple function app in Python v2. The plan is to process millions of images, but right I just want to make the scaffolding right, i.e. no image processing, just dummy data. So I have two functions:

• process with an HTTP trigger @app.route, this inserts 3 random image URLs to the Azure Queue Storage,
• process_image with a Queue trigger @app.queue_trigger, that processes one image URL from above (currently only logs the event).

I trigger the first one with curl request and as expected, I can see the invocation in the Azure portal in the function's invocation section and I can see the items in the Storage Explorer's queue.

But unexpectedly, I do not see any invocations for the second function, even though after a few seconds the items disappear from the images queue and end up in the images-poison queue. So this means that something did run with the queue items 5 times. I see the following warning in the application insights checking traces and exceptions:

Message has reached MaxDequeueCount of 5. Moving message to queue 'case-images-deduplication-poison'.

Can anyone help with what's going on? Here's the gist of the code.

Answer 1

@Rok Carl ,

Please make sure that the message encoding is set to Base64
https://stackoverflow.com/questions/71439701/error-message-has-reached-maxdequeuecount-of-5-moving-message-to-queue-webjo

https://stackoverflow.com/questions/71305020/azure-queue-trigger-reaches-maxdequeuecount-immediately

Also please make sure you have try catch block in the Queue trigger function to capture the exceptions which can be seen in the logs