[service] add level for trace configuration

[codeboten]

This allows users to configure a Noop TracerProvider if needed. Note that this configuration option breaks the zpages extension, which relies on a SDK implementation.

Fixes #10890

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.60%. Comparing base (d2ed276) to head (0c53567).
Report is 35 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10892   +/-   ##
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  Coverage   91.60%   91.60%           
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  Files         404      404           
  Lines       18990    18990           
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  Hits        17395    17395           
  Misses       1235     1235           
  Partials      360      360           

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[iblancasa]

Please, can you elaborate a little bit more on this?

Note that this configuration option breaks the zpages extension, which relies on a SDK implementation.

[codeboten]

Please, can you elaborate a little bit more on this?

Note that this configuration option breaks the zpages extension, which relies on a SDK implementation.

The zPages extension registers itself as a span processor to be able to record telemetry about all the spans emitted by the collector. This relies on the code here:

opentelemetry-collector/extension/zpagesextension/zpagesextension.go

Lines 52 to 58 in d2ed276

	if ok {
	sdktracer.RegisterSpanProcessor(zpe.zpagesSpanProcessor)
	zPagesMux.Handle(path.Join("/debug", tracezPath), zpages.NewTracezHandler(zpe.zpagesSpanProcessor))
	zpe.telemetry.Logger.Info("Registered zPages span processor on tracer provider")
	} else {
	zpe.telemetry.Logger.Warn("zPages span processor registration is not available")
	}

That code has always worked with the default configuration because there was no way to disable the tracer provider until the introduction of the feature gate this change is replacing. With a no-op tracer provider, the zpages will be unable to register itself and log the following message: zPages span processor registration is not available

[iblancasa]

Thanks a lot!

[TylerHelmuth]

For the sake of consistency with MetricsConfig I understand why we're using Level here, but my mind just wants a boolean enabled option instead. I don't feel strongly enough to block this work.

[songy23]

Some nits, LGTM otherwise

[songy23]

Should it be documented somewhere that level:none breaks zpage?

[codeboten]

I can add a note in the zpages documentation, note that the zpages extension already logs a warning if this happens