[OpenTelemetry] Add traceparent and tracestate

[stankiewicz]

Add traceparent and tracestate as part of context propagation
https://www.w3.org/TR/trace-context/

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[stankiewicz]

R: @kennknowles

[gemini-code-assist]

Summary of Changes

Hello @stankiewicz, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request integrates OpenTelemetry's traceparent and tracestate fields into the Beam Fn API's ElementMetadata protobuf definition. This foundational change enables robust distributed tracing and context propagation within the Beam execution model, aligning with the W3C Trace Context specification for improved observability.

Highlights

• OpenTelemetry Integration: Introduces traceparent and tracestate fields into the ElementMetadata protobuf message, facilitating OpenTelemetry context propagation.
• Distributed Tracing Support: Enhances the beam_fn_api.proto to support W3C Trace Context, allowing for better observability and distributed tracing across Beam's execution graph.

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[stankiewicz]

R: @sjvanrossum

[stankiewicz]

R: @kennknowles

[kennknowles]

LGTM but maybe someone broke HEAD...

[scwhittle]

Can some comments be added on what they are and/or link to doc? I'm guessing parent is some id? but what is trace state? Should it be an enum? Should either of these be bytes?

[stankiewicz]

thanks for the feedback. It've linked to the doc and added the comment and example

[stankiewicz]

Run Python PreCommit 3.12

[stankiewicz]

Run Python_ML PreCommit 3.13

[stankiewicz]

Run Java_PVR_Prism_Loopback PreCommit

[stankiewicz]

I will try to make it green like before.

[kennknowles]

OK this is just too silly. That test needs to be modified or something if it is so unreliable. LGTM and I'll merge.

[kennknowles]

Actually, nit: can you make the commit description nice. Like "[OpenTelemetry] Add traceparent and tracestate to extended element metadata proto"