Opentelemetry baggage propagation fix

[romank0]

What was changed

Fixed OpenTelemetry baggage propagation in the inbound interceptor by explicitly attaching the extracted context before starting spans. Changed from passing context=extracted_ctx as a parameter to using context.attach(extracted_ctx) + context.detach(token).

Why?

The previous implementation used start_as_current_span(context=extracted_ctx) which only uses the provided context to determine the parent span for trace propagation. When building the new span context, OpenTelemetry always uses context.get_current() that is the active context from the stack, not the context= parameter. But the active context is not set from the unpacked values received in headers.

This meant that while trace parent-child relationships worked correctly, baggage values from the extracted context were not copied into the new span context, making them unavailable within Temporal activities/workflows.

By calling context.attach(extracted_ctx) first, we make the extracted context active on the context stack. This ensures that when the new span context is created, it copies all data (including baggage) from the extracted context, properly propagating baggage across service boundaries.

This aligns with the standard pattern used by other OpenTelemetry instrumentations (django, gRPC, etc.).

Checklist

1. Closes [Feature Request] Make sure OTel baggage propagates properly throughout activities #362

2. How was this tested:

   • Unit/intergration tests in this PR
   • Tested in real system basically the same way test_opentelemetry_baggage_propagation_basic test does this, namely:
     1. setting baggage
     2. invoking the workflow that executes an activity
     3. checking the baggage is available in the activity
   • Verified trace parent-child relationships still work correctly

3. Any docs updates needed?
   I don't think so.

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[tconley1428]

@VegetarianOrc we should evaluate how this intersects with your changes to protect detach elsewhere.

[VegetarianOrc]

The usage in the outbound interceptor which shouldn't be susceptible to the token mismatch. The activity inbound interceptor does potentially run on a different thread which I think theoretically could trigger the mismatch. IMO we should add the check just to be defensive.

if token and context is opentelemetry.context.get_current():
    opentelemetry.context.detach(token)

[tconley1428]

I don't think the exporter is needed for many(any?) of these tests since you aren't actually checking anything on outgoing spans. I could be wrong though, does the baggage not happen otherwise?

[romank0]

Indeed exporter is not needed, for baggage to work only tracer with a TracerProvider is required.

[tconley1428]

Two other things you'll have to do. First, poe lint is failing. Second, your commits have multiple email addresses associated:

You'll need to add the second email to your github account so that the CLA is signed for all the commits. Either that or modify the commits to the correct email in some way.