[pkg/ottl] Accept string (32 byte hex) {span,trace,profile} IDs

[andrewvc]

Description

Currently {TraceID,SpanID,ProfileID} only support byte IDs, however in #43429 it was brought up that it is difficult to take a string representation of an ID and directly use that to set a trace ID. This would be for a hexadecimal string representation comprising 32 bytes. This change allows the {TraceID,SpanID,ProfileID} functions to also work on string inputs.

In short, the following now works:

statements:
  - set(span.trace_id, TraceID("a389023abaa839283293ed323892389d"))

Link to tracking issue

Fixes #43429

Testing

In addition to the included go tests the following config

test-str-trace.yml

was used to manually test by invoking make otelcontribcol && ./bin/otelcontribcol_darwin_arm64 --config test-str-trace.yml in one window and telemetrygen traces --otlp-insecure --traces 1 in another. The output is as shown:

CLI Output

Span #0
    Trace ID       : a389023abaa839283293ed323892389d
    Parent ID      : e5c516b0c8942eab
    ID             : 1914136d5f9ca838
    Name           : okey-dokey-0
    Kind           : Server
    Start time     : 2025-10-29 18:59:03.312829 +0000 UTC
    End time       : 2025-10-29 18:59:03.312952 +0000 UTC
    Status code    : Unset
    Status message :
Attributes:
     -> network.peer.address: Str(1.2.3.4)
     -> peer.service: Str(telemetrygen-client)
Span #1
    Trace ID       : a389023abaa839283293ed323892389d
    Parent ID      :
    ID             : e5c516b0c8942eab
    Name           : lets-go
    Kind           : Client
    Start time     : 2025-10-29 18:59:03.312829 +0000 UTC
    End time       : 2025-10-29 18:59:03.312952 +0000 UTC
    Status code    : Unset
    Status message :
Attributes:
     -> network.peer.address: Str(1.2.3.4)
     -> peer.service: Str(telemetrygen-server)

Documentation

I don't currently see documentation for these functions, but I'm new here, maybe I'm missing something? Glad to update it

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: andrewvc / name: Andrew Cholakian (9ba8c4e)

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[andrewvc]

I've added a fix for the linter issues, but it looks like perhaps an approval is required to run CI again?

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[atoulme]

please take a look at the conflict and mark ready to review again.

[edmocosta]

Thank you @andrewvc and I'm sorry for the long delay to review.
To keep it consistent, we also need to change the SpanID and ProfileID functions. If you agree, I'd be fine reviewing/including them on this same PR (changes are small enough), otherwise we can open separate PRs for that. Thanks!

[andrewvc]

Benchmarks against main here: https://gist.github.com/andrewvc/4b9c73446cc1f9592177d3b980864c3a

[andrewvc]

This is a benchmark, no need to handle the possible error here IMHO

[edmocosta]

Adding require.NoError(b, err) would do the work and make any possible failure clearer than panicking while executing the function. It's ok for this specific one, but considering how easy it's for handling that, I wouldn't ignore it :)

[andrewvc]

It's not a huge deal for me, so I've added it. I don't love adding unneeded code in benchmarks, but in this case it makes no difference

[edmocosta]

Great work @andrewvc! thank you!
I've left a few final nits, otherwise LGTM!

[edmocosta]

Adding require.NoError(b, err) would do the work and make any possible failure clearer than panicking while executing the function. It's ok for this specific one, but considering how easy it's for handling that, I wouldn't ignore it :)

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