Concurrency Limit Span being created as an Orphan Span

[VishalSharma-123]

Environment Details

• Helidon Version: 4.3.x
• Helidon SE or Helidon MP
• JDK version: 21
• OS: Linux

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Problem Description

While testing out the new feature implemented in #9968 on a k8s based environment, I noticed that the "limit-span" that is being created, is created as an orphan span and not part of the trace tree of the actual request. Even though we have HTTP headers (x-b3-traceid, x-b3-parentspanid, x-b3-spanid, x-b3-sampled), it is not registered as the current span in the context. So, the Span.current().ifPresent() returns empty.

Due to this, the following line is never executed and the parent is not set for the limit-span.
Span.current().ifPresent(cs -> cs.context().asParent(spanBuilder))

I verified the same by adding debug statements in LimitSpan.java and Http1Connection.java

Following is the snippet of the trace tree. In the trace tree, the limit-span is not showing up as the child of the "forward-psr-ric-sampleapp" span

All the limit spans are created as an orphan span and have their separate traceIDs, recording a single span.

[tjquinno]

To be clear, if the incoming request has headers that propagate a span, that span should be the parent for the span created to represent the time the request is queued.

Once the request is released from the queue, that queueing time span will end and then the Helidon server-side request handling span will begin. So those two spans will be siblings, sharing the same parent span which is the propagated span derived from the incoming headers.

Neither the queueing span nor the request processing span will be a child of the other.