Can tailsamplingprocessor be configured to take the "sampled" flag (from trace-flags) into account?

[jpkrohling]

Discussed in #32495

^{Originally posted by BatmanAoD April 17, 2024}
I have a service that is sending trace data to an OTEL collector, where it is sampled by the tailsamplingprocessor before being sent to Honeycomb. There is a client that does head-sampling, then sends its trace data directly to Honeycomb. I'd like to ensure that any calls that come from a client using head-sampling get sampled, i.e. that the sampled flag from the TraceContext's trace-flags is respected.

I can't tell if this is possible from the documentation of tailsamplingprocessor. @jpkrohling, in this comment, it sounds like you're saying that it's possible to use the sampled flag, but the README says:

This processor must be placed in pipelines after any processors that rely on context, e.g. k8sattributes. It reassembles spans into new batches, causing them to lose their original context.

Does this mean that the tailsamplingprocessor doesn't receive the original trace context, including the traceparent header?

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• processor/tailsampling: @jpkrohling

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This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

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[mikocot]

what is the blocker for this improvement? Is it conflicting with some existing changes or just needs additional cases to be taken into account?

[jpkrohling]

@mikocot, if you have a PR lined up, I'll review it.

[mikocot]

I don't, I'm not familiar with the code base, just wondering if that's something that is not implemented due to lack of resources, conflicting with some existing code, or it's not considered even the right approach.