Create a new linked Span from the current Context

[bogdandrutu]

Problem Statement

In a long-living operation (context), I want to start a new Trace that is linked to the long-living operation. An example can be a bidirectional grpc stream where every received message represents a new operation, or a long living consumer operation in a pub-sub solution where every received message is a new operation.

Right now, I had to do something like this (in a grpc case):

	// Since the receiverCtx is long lived do not use it to start the span, just link to it.
	_, span = rec.tracer.Start(context.Background(), spanName, trace.WithLinks(trace.Link{
		SpanContext: trace.SpanContextFromContext(receiverCtx),
	}))

	ctx = trace.ContextWithSpan(receiverCtx, span)

Proposed Solution

	// Since the receiverCtx is long lived do not use it to start the span, just link to it.
	ctx, span = rec.tracer.Start(receiverCtx, spanName, trace.WithParentAsLink(true))

OR:

	// Since the receiverCtx is long lived do not use it to start the span, just link to it.
	ctx, span = rec.tracer.Start(receiverCtx, spanName, trace.WithNoParent(true), trace.WithLinks(trace.Link{
		SpanContext: trace.SpanContextFromContext(receiverCtx),
	})

[Aneurysm9]

Does the existing trace.WithNewRoot() option enable the second proposed solution? I think trace.WithParentAsLink(true) is nicer/simpler, but perhaps combining WIthNewRoot and a simpler Link initializer might be more flexible.

[bogdandrutu]

Thanks for pointing me to a bug :D

#2071