process_discovery: expose threadlocal_attribute_keys

[szegedi]

Summary

Adds an optional threadlocal_attribute_keys: Option<Vec<String>> field to the NAPI TracerMetadata and forwards it to libdatadog's tracer_metadata::TracerMetadata. When set, libdatadog's to_otel_process_ctx injects into the OTel process context:

threadlocal.schema_version    = "tlsdesc_v1_dev"
threadlocal.attribute_key_map = ["datadog.local_root_span_id",
                                  ...threadlocal_attribute_keys]

— giving an out-of-process reader the name table for the uint8 key indices that OTEP-4947 thread-context records carry on the wire. The implicit datadog.local_root_span_id key is prepended by libdatadog itself; callers only supply their additional keys (entry 0 in this list = wire key index 1).

Motivation

A Node.js OTEP-4947 thread-context writer (currently in development in DataDog/pprof-nodejs#347, to be integrated into dd-trace-js) needs to publish its attribute key list as part of the OTel process context so that an out-of-process eBPF reader can decode the on-wire key_index bytes back to attribute names. This change is the dd-trace-js-facing piece of that plumbing.

Implementation notes

• The field is gated behind libdatadog's otel-thread-ctx Cargo feature, which arrived after v29.0.0. The libdd-library-config dep is bumped from v29.0.0 → v35.0.0 (matching the version already pinned by the crashtracker crate in this workspace) and the feature is enabled.
• Existing 8-arg constructor calls keep working because the new field is optional.
• The test exercises both the absent and present forms.

Test plan

• yarn build-debug succeeds with the bumped dependency
• node test/process-discovery.js passes (both the existing positional call and the new threadlocal-keys variant)
• yarn lint test/process-discovery.js clean
• CI verifies the same on all supported Node versions / platforms

🤖 Generated with Claude Code

[github-actions]

Overall package size

Self size: 28.01 MB
Deduped: 28.01 MB
No deduping: 28.01 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------|

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}