FastAPI integration fails if docs are disabled

[MattiasOlla]

I have a FastAPI application where the docs are disabled:

from fastapi import FastAPI
import rollbar
from rollbar.contrib.fastapi import add_to as rollbar_add_to

rollbar.init(
    ...,
    environment='test',
    handler="async",
    include_request_body=True,
)

app = FastAPI(docs_url=None, redoc_url=None)

rollbar_add_to(app)

Which gives me the error ERROR:rollbar.contrib.fastapi.routing:RollbarLoggingRoute must to be added to a bare router (before adding routes). See docs for more details.

I dug a bit, and the issue seems to be in this section

pyrollbar/rollbar/contrib/fastapi/utils.py

Lines 69 to 82 in 77cbffa

	def has_bare_routing(app_or_router):
	expected_app_routes = 4
	expected_router_routes = 0
	if (
	isinstance(app_or_router, FastAPI)
	and expected_app_routes != len(app_or_router.routes)
	) or (
	isinstance(app_or_router, APIRouter)
	and expected_router_routes != len(app_or_router.routes)
	):
	return False
	return True

where the number of expected routes for a bare app is hardwired to 4 (meaning it expects /openapi.json, /docs, /docs/oauth2-redirect, and /redoc), but my app only has one of those (/openapi.json).

Depending on the FastAPI setup, there might be anywhere between 0 and 4 available routes for a "bare" app. I might create a PR for this later, but my suggestion would be checking that there are no available routes other than the ones in the fields openapi_url, docs_url, redoc_url, and swagger_ui_oauth2_redirect_url on the FastAPI object https://github.com/tiangolo/fastapi/blob/3efb4f7edff99fdc12802a85ae9d140ec4772497/fastapi/applications.py#L107-L121

[antonio-cinnamon]

This is also happening to me.