Receiving method arguments and return value on span

[YonatanHunger]

Is it possible to add to a span the arguments that have entered the method and the return value?
if not, what type of extension should I use to wrap the user methods?
tnx.

[mateuszrzeszutek]

Hey @YonatanHunger ,
Are you using the @WithSpan annotation? If so, you can use the @SpanAttribute annotation on the method params to capture them as span attributes.
There's no annotation that can capture the return value though - for now you can do that by calling Span.current().setAttribute("return", returnVal); just before returning from the method.

[YonatanHunger]

Hi @mateuszrzeszutek thank you for the answer, I am trying to do it in automatic instrumentation.

[YonatanHunger]

I think my question will be more clear when I explain that I am trying to capture all HTTP spans. I have seen this and I want to know how can I see all these attributes?

[mateuszrzeszutek]

The request & response header capturing is configurable, you need to provide the list of headers that you want to add as span attributes - please refer to the docs here.
Once enabled, you should be able to observe these attributes in the observability backend that you're using.

About the method params/return value: do I understand it correctly that you want to add some custom attributes to the HTTP server spans? If so, you can probably start by using the Span.current() method from opentelemetry-api.