Azure Function 应该记录或抛出错误异常？

Question

I have Azure Function (Http trigger) that can fail. I also have Application Insights configured for it.

In case of error (Which is better):

1. Catch exception, wrap with more info and rethrow it. (Sends 500 response) OR
2. Catch exception, log it, wrap it, rethrow it to caller. (Sends 500 response) OR
3. Catch exception, log it (Don't throw it), Manual send 500 response.

Application Insight is able log exceptions. I don't really see point in logging error and throwing exception at the same time.

What are the guidelines? What is good practise?

Answer 1

Based on the Azure functions best practices

Use structured error handling

Capturing and publishing errors is critical to monitoring the health of your application. The top-most level of any function code should include a try/catch block. In the catch block, you can capture and publish errors.

Answer 2

From my experience which is building an HTTP triggered azure function with Python, I noticed that: When handling exceptions and then manually return something to the client you do have control over the function returned value but the framework marks the function's job as 'Succeeded', which then makes it more difficult to be tracked & monitored in the Application Insights.

For your question, I ended up with a catch clause that mixes 1 & 3 ie a hybrid approach where I try to identify the origin of the exception, then for exceptions from my code I'm wrapping it and return 500, and for other exceptions that originated from code that I'm using I re-throw them and let the azure function framework return a 500 and to mark the function's job as 'Failed'.