New Span being created for each HTTP request in OpenTracingServerFilter

[achatterjee104]

Discussed in #230

^{Originally posted by achatterjee104 January 20, 2023}

Expectation

Scenario 1:

1. There are 2 REST services - service-A and service-B
2. A request comes to service-A and its OpenTracingServerFilter creates a new span, say [trace-id=1, span-id=1]
3. service-A invokes service-B, waits for its response and then returns the consolidated result
4. service-B will get the request with [trace-id=1, span-id=1] and it should created its new span [trace-id=1, span-id=2] (since trace-id is already present)
5. At the end, there will be 2 spans (span-id=1 & span-id=2) as child of trace-id=1

Scenario 2:

1. There is a REST service with 2 endpoints - /books & /authors
2. A request comes to /books and its OpenTracingServerFilter creates a new span, say [trace-id=1, span-id=1]
3. /books endpoint internally invokes /authors endpoint (via a REST call), waits for its response and then returns the consolidated result
4. during /authors endpoint call, the OpenTracingServerFilter will get the request with [trace-id=1, span-id=1] and it should created its new span [trace-id=1, span-id=2] (since trace-id is already present)
5. At the end, there will be 2 spans (span-id=1 & span-id=2) as child of trace-id=1

Ref: This guide says "Whenever a Micronaut server receives a request, it creates a new span"

From Source Code

From OpenTracingServerFilter,

Tracer.SpanBuilder spanBuilder = continued ? null : newSpan(request, initSpanContext(request))

it seems to be creating new span everytime, irrespective of presence of existing trace-id.

[n0tl3ss]

Hi @achatterjee104 can you give better explanation. What is now happening, and what should happened? My understanding that trace-id identifies whole trace with all spans on it. I don't see a problem with creating a new span.

[achatterjee104]

Hi @n0tl3ss I have not tested scenario 1, but in scenario 2, I could see 4th step is not being followed - it is creating new trace-id for /authors request instead of creating new span under the existing trace-id that was created for /books request.

I also could not see any place where this trace-id is actually created in the code. Can you please point me to that place, it will help me to track the flow more closely.

[n0tl3ss]

Hi @achatterjee104 I will have to follow the guide myself then I will see what is happening :) I will report back to you.