fix(instr-undici): respect requireParent flag when INVALID_SPAN_CONTEXT is used

[reberhardt7]

Which problem is this PR solving?

This PR mirrors this fix in the http instrumentation: open-telemetry/opentelemetry-js#4788

The http instrumentation (and many other instrumentation libraries) create spans with INVALID_SPAN_CONTEXT to create NonRecordingSpans when we enable requireParent and no parent is present: https://github.com/open-telemetry/opentelemetry-js/blob/main/experimental/packages/opentelemetry-instrumentation-http/src/http.ts#L769

That works fine; those spans are not exported. However, when we create child spans, those end up becoming real spans that are exported. E.g. if we have an http server, when a request comes in, we create a span with INVALID_SPAN_CONTEXT, and then if the http request handler makes an outbound request, the instrumentation sees that it has a parent span (even though it is invalid) and creates a real child span, initiating a new trace.

The opentelemetry sdk creates new traces for descendants of INVALID_SPAN_CONTEXT: https://github.com/open-telemetry/opentelemetry-js/blob/ecc88a38d85d5d6adf847306d96e7be77b7df8d6/packages/opentelemetry-sdk-trace-base/src/Tracer.ts#L91

Short description of the changes

This checks whether the parent span is recording, and does not create a real child span if the parent isn't recording.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: david-luna / name: David Luna (0702bcf)
• ✅ login: reberhardt7 / name: Ryan Eberhardt (0506cea)

[david-luna]

Hi @reberhardt7

1st of all thanks for contributing to OpenTelemetry :)

Could you please sign the CLA so we can proceed on moving your PR forward?

Thanks!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.29%. Comparing base (dfb2dff) to head (0702bcf).
Report is 165 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2273      +/-   ##
==========================================
- Coverage   90.97%   90.29%   -0.68%     
==========================================
  Files         146      147       +1     
  Lines        7492     7246     -246     
  Branches     1502     1504       +2     
==========================================
- Hits         6816     6543     -273     
- Misses        676      703      +27     

Files	Coverage Δ
plugins/node/instrumentation-undici/src/undici.ts	96.27% <100.00%> (ø)

... and 53 files with indirect coverage changes

[reberhardt7]

@david-luna I've signed the CLA now. Thank you :)

[reberhardt7]

@david-luna thanks for the review! Would you be the right person to take a look at this analogous instrumentation-http PR, or would that be someone else?

[david-luna]

@reberhardt7 I can give my review and notice the members of the SIG to get another approval