Jaeger — Sending Traces from Python¶

uv add opentelemetry-api opentelemetry-sdk
uv add opentelemetry-exporter-otlp-proto-grpc      # OTLP gRPC -> :4317
uv add opentelemetry-exporter-otlp-proto-http      # OTLP HTTP -> :4318 (pick one, or install both)

# Instrumentation for the libraries in use
uv add opentelemetry-instrumentation-fastapi opentelemetry-instrumentation-requests

# app/telemetry.py
import os

from opentelemetry import trace
from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import OTLPSpanExporter
from opentelemetry.sdk.resources import Resource
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor


def setup_tracing(service_name: str) -> TracerProvider:
    resource = Resource.create({
        "service.name": service_name,
        "service.version": os.getenv("APP_VERSION", "dev"),
        "deployment.environment.name": os.getenv("APP_ENV", "local"),
    })
    provider = TracerProvider(resource=resource)
    # Endpoint and TLS come from OTEL_EXPORTER_OTLP_* env vars when not passed here
    provider.add_span_processor(BatchSpanProcessor(OTLPSpanExporter()))
    trace.set_tracer_provider(provider)
    return provider

# app/main.py
from contextlib import asynccontextmanager

import requests
from fastapi import FastAPI, HTTPException
from opentelemetry import trace
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
from opentelemetry.instrumentation.requests import RequestsInstrumentor

from app.telemetry import setup_tracing

provider = setup_tracing("orders-api")
RequestsInstrumentor().instrument()          # outgoing calls: client spans + traceparent header


@asynccontextmanager
async def lifespan(app: FastAPI):
    yield
    provider.shutdown()                      # flush buffered spans on shutdown


app = FastAPI(lifespan=lifespan)
FastAPIInstrumentor.instrument_app(
    app,
    excluded_urls="health",                  # no spans for health probes
    exclude_spans=["receive", "send"],       # drop the internal ASGI "http send/receive" spans
)                                            # incoming requests: server spans
tracer = trace.get_tracer(__name__)


@app.get("/health")
def health() -> dict[str, str]:
    return {"status": "ok"}


@app.get("/orders/{order_id}")
def get_order(order_id: str) -> dict:
    with tracer.start_as_current_span("load_order") as span:
        span.set_attribute("order.id", order_id)
        if order_id == "missing":
            raise HTTPException(status_code=404, detail="order not found")
    price = requests.get("http://pricing:8001/price", params={"order_id": order_id}, timeout=5)
    return {"id": order_id, "price": price.json()["amount"]}

OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 \
OTEL_EXPORTER_OTLP_INSECURE=true \
uv run uvicorn app.main:app --port 8000

orders-api   GET /orders/{order_id}            (server span, FastAPI)
orders-api   ├─ load_order                     (manual span)
orders-api   └─ GET                            (client span, requests)
pricing      └─ GET /price                     (server span, if pricing is instrumented)

uv add opentelemetry-distro opentelemetry-exporter-otlp
uv run opentelemetry-bootstrap -a requirements      # lists instrumentation packages to add

OTEL_SERVICE_NAME=orders-api \
OTEL_TRACES_EXPORTER=otlp \
OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 \
OTEL_EXPORTER_OTLP_PROTOCOL=grpc \
OTEL_PYTHON_EXCLUDED_URLS=health \
uv run opentelemetry-instrument uvicorn app.main:app --port 8000

# 1. Is Jaeger up?
curl -sf http://localhost:16686/api/v3/services

# 2. Send one span by hand over OTLP HTTP (no SDK involved)
NOW=$(date +%s)
curl -s -X POST http://localhost:4318/v1/traces \
  -H 'Content-Type: application/json' \
  -d '{"resourceSpans":[{"resource":{"attributes":[{"key":"service.name","value":{"stringValue":"curl-smoke"}}]},
       "scopeSpans":[{"spans":[{"traceId":"5b8efff798038103d269b633813fc60c","spanId":"eee19b7ec3c1b174",
       "name":"smoke","kind":1,"startTimeUnixNano":"'"${NOW}"'000000000","endTimeUnixNano":"'"${NOW}"'500000000"}]}]}]}'

# 3. Read it back
curl -s http://localhost:16686/api/v3/traces/5b8efff798038103d269b633813fc60c