parametric: enable nodejs otel metrics

[mabdinur]

Motivation

Add OpenTelemetry metrics API support to Node.js parametric server for cross-language testing and fix type preservation issues that could cause incorrect int/double handling in OTLP exports.

Changes

Added OTel Metrics Endpoints to Node.js Parametric Server (server.js)

Implemented 13 endpoints matching the Python parametric server:

• Meter management: get_meter, force_flush
• Synchronous instruments: create_counter, counter_add, create_updowncounter, updowncounter_add, create_gauge, gauge_record, create_histogram, histogram_record
• Asynchronous instruments: create_asynchronous_counter, create_asynchronous_updowncounter, create_asynchronous_gauge

Fixed OpenTelemetry API Module Singleton Issue (package.json)

Added npm overrides to ensure single @opentelemetry/api instance, preventing MeterProvider registration failures:

"overrides": {
  "@opentelemetry/api": "$@opentelemetry/api"
}

Fixed Type Preservation (server.py)

Reordered Pydantic Union types from Union[float, int] → Union[int, float] in all metric value fields (10 models + 3 functions). This ensures:

• 42 stays as int → OTLP asInt (sfixed64)
• 42.0 stays as float → OTLP asDouble

Critical for correct OTLP protocol compliance.

Cleanup

Removed debug print statements.

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes
3. Mark it as ready for review
   • Test logic is modified? -> Get a review from RFC owner.
   • Framework is modified, or non obvious usage of it -> get a review from R&P team

🚀 Once your PR is reviewed and the CI green, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• If PR title starts with [<language>], double-check that only <language> is impacted by the change
• No system-tests internal is modified. Otherwise, I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added (or removed)?
  • Get a review from R&P team

[github-actions]

CODEOWNERS have been resolved as:

tests/parametric/test_otel_metrics.py                                   @DataDog/system-tests-core @DataDog/apm-sdk-capabilities
utils/build/docker/nodejs/parametric/package.json                       @DataDog/dd-trace-js @DataDog/system-tests-core
utils/build/docker/nodejs/parametric/server.js                          @DataDog/dd-trace-js @DataDog/system-tests-core
utils/build/docker/python/parametric/apm_test_client/server.py          @DataDog/apm-python @DataDog/asm-python @DataDog/system-tests-core
utils/parametric/_library_client.py                                     @DataDog/system-tests-core

[mabdinur]

float is used to convert strings into a number (float(9) == int(9) in python).