Auto instrumentation of FastAPI application not working on 1.26.0

[emil-vdw]

Describe your environment

OS: Fedora 40
Python version: Python 3.11.9
SDK version: 1.26.0
API version: 1.26.0
FastAPI: 0.111.0

What happened?

Auto instrumentation of FastAPI, even on a single process, is not working on the latest release. When manually instrumenting the service, it appears to work.

Steps to Reproduce

1. Check out the repo at the following branch: https://github.com/emil-vdw/otel-asgi-issue/tree/emil-vdw/otel-1.26.0-fastapi-broken
2. run start.sh
3. Open http://127.0.0.1:8000/ in a browser

Expected Result

Traces are printed to the console.

Actual Result

No traces are printed to the console.

Additional context

Manually instrumenting the service produces traces:

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

app = FastAPI()


@app.get("/")
async def hello():
    return {"message": "Hello World"}


FastAPIInstrumentor.instrument_app(app)

Would you like to implement a fix?

None

[emdneto]

Hi: thanks. When related to instrumentations libs, you should open the issue in https://github.com/open-telemetry/opentelemetry-python-contrib. This issue is already mapped and should be fixed in open-telemetry/opentelemetry-python-contrib#2783

[lzchen]

Closing due to duplicate.