nemo_gym.telemetry.contrib

Gym’s boundary onto nemo-lens’s propagation and framework-instrumentation helpers.

nemo_gym.telemetry is the only package that imports nemo.lens. Everything outside it reaches telemetry through this package, so a reader never has to work out whether a given nemo.lens import is reachable when the extra is not installed. The invariant is enforced by tests/unit_tests/telemetry/test_call_sites.py.

_fallbacks covers the primitives used at instrumentation sites. This module covers the two helpers that are not primitives: W3C context injection at Gym’s HTTP egress, and FastAPI auto-instrumentation at each server’s startup. Both are called only on paths that already established telemetry is active, so neither needs a no-op twin — but both are defensive anyway, because telemetry must never be the reason a server fails to start or a request fails to send.

Module Contents

Functions

Name	Description
`inject_trace_context`	Write the current span’s W3C `traceparent` into headers.
`instrument_fastapi_app`	Apply OpenTelemetry FastAPI auto-instrumentation to app.

Data

logger

API

nemo_gym.telemetry.contrib.inject_trace_context(
    headers: dict
) -> None

Write the current span’s W3C traceparent into headers.

The egress half of cross-process propagation. A no-op when there is no recording span, because the propagator has no context to write.

Call only behind a span-group gate: the import below is function-local so a disabled site never reaches it.

nemo_gym.telemetry.contrib.instrument_fastapi_app(
    app: typing.Any
) -> bool

Apply OpenTelemetry FastAPI auto-instrumentation to app.

The ingress half of cross-process propagation: it extracts an inbound traceparent and parents this server’s SERVER span to the caller’s span.

service_name is deliberately not passed. nemo.lens.contrib.fastapi’s helper accepts it and never uses it at the pinned commit; the name comes from OTEL_SERVICE_NAME, which init_telemetry resolves.

Returns: bool

True when instrumentation was applied. False when the optional instrumentation

nemo_gym.telemetry.contrib.logger = logging.getLogger(__name__)