opentracing/specification

Add Span#isRoot

felixbarny opened this issue · 4 comments

felixbarny commented

I want to make sampling decisions independently of the tracer implementation. But obviously, I must only set the sampling priority on root spans to not end up with partial traces. Right now, only a Tracer implementation is able to do that. That makes it impossible for libraries like stagemonitor to provide a tracer independent sampling mechanism.

wu-sheng commented

I think your question is bigger than isRoot. It is actually about adding a new sampling mechanism. IMHO, isRoot is the check before using shouldSample, right? I prefer to provide to provide Tracer#newTraceListener . In that, you can decide to sample or not.

felixbarny commented

I like the idea of Tracer#newTraceListener. But there are alternatives for that, for example java-api-extensions. I wrote my own tracer wrapper and SpanEventListener for stagemonitor. In SpanEventListener#onStart(SpanWrapper spanWrapper) I can do my own sampling decisions.

So for now, this issue is really only about adding the Span#isRoot method

IMHO, isRoot is the check before using shouldSample, right?

correct

wu-sheng commented

In skywalking, also have similar sampling mechanism. But is it suitable for spec level? hard to say now.
@tedsuo @yurishkuro @bhs @pavolloffay opinion?

felixbarny commented

Any opinions? I currently have to use quite a bad hack for that I'd like to get rid of.