otel-fastapi-style

Original：🇺🇸 English

Translated

FastAPI OpenTelemetry style: native FastAPIInstrumentor, centralized observability init, Python decorators, OTLP logs, and LLM cost metrics.

2installs

Sourcesuperloglabs/skills

Added on2026-05-11

NPX Install

npx skill4agent add superloglabs/skills otel-fastapi-style

SKILL.md Content

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OTel FastAPI Style

Use native FastAPI instrumentation. Do not replace request handling with manual middleware just to create spans.

python

from fastapi import FastAPI
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor

def init_observability(app: FastAPI) -> bool:
    ...
    FastAPIInstrumentor.instrument_app(app)
    return True

Keep

FastAPIInstrumentor.instrument_app(app)

with the rest of the observability setup so the bootstrap is easy to reason about. If OTLP credentials are absent, it is still okay to instrument the app with no-op providers, but keep that choice explicit in

init_observability(app)

.

Entrypoint

Initialize before serving user traffic.

python

app = FastAPI(title="Mugline API")
init_observability(app)

Bounded Work

Use module-scope OTel objects and decorators for helpers that auto-instrumented HTTP spans cannot see.

python

tracer = trace.get_tracer("mugline.api")
meter = metrics.get_meter("mugline.api")

@tracer.start_as_current_span("mug.recommend")
async def recommend_mug(*, tenant_id: str, preference: str) -> dict[str, str]:
    span = trace.get_current_span()
    span.set_attribute("tenant.id", tenant_id)
    ...

Logs

For OTLP-forwarded stdlib logs, configure all of these:

```
LoggerProvider
```
```
set_logger_provider(logger_provider)
```
```
OTLPLogExporter
```
```
LoggingHandler
```
```
LoggingInstrumentor().instrument(...)
```

LLM Calls

LLM routes need token coverage:

```
llm.tokens.input
```
```
llm.tokens.output
```

Tag explicit token counters with tenant, provider, model, use case, call site, and outcome only when provider instrumentation cannot capture token usage. Do not add app-side LLM cost metrics or pricing tables; Superlog estimates cost centrally from provider/model/token data.

otel-fastapi-style

NPX Install

Tags

SKILL.md Content

OTel FastAPI Style

Entrypoint

Bounded Work

Logs

LLM Calls