When tracing endpoint that have a path parameter, especially when the path parameter is a unique id for a resource, the number of operations when viewing traces becomes very large. Using the path templates sets a finite limit of possible operation names.

Inside your Fast API Example ( example/fastapi/requirements.txt ) , you have:

fastapi
jaeger-client
opentracing_instrumentation
requests
-e git://github.com/acidjunk/starlette-opentracing.git#egg=Starlette-OpenTracing
tornado==5.1.1  # pin to last release for 5, implicit install of 6 gives errors
uvicorn

This was made 9 months ago, and didn't was released Python 3.9, however, I think that Tornado version is not a problem now with python 3.9

I tried this example, and my requirements.txt are:

fastapi==0.63.0
uvicorn==0.13.3
requests==2.25.1

jaeger-client==4.3.0
opentracing-instrumentation==3.3.1
Starlette-OpenTracing==0.1.0

With Python 3.8 I got this error:

Traceback (most recent call last):  File "app.py", line 11, in <module>    from opentracing_instrumentation.client_hooks import install_all_patches  File "/usr/local/lib/python3.8/site-packages/opentracing_instrumentation/__init__.py", line 21, in <module>    from .request_context import get_current_span  # noqa  File "/usr/local/lib/python3.8/site-packages/opentracing_instrumentation/request_context.py", line 26, in <module>    from opentracing.scope_managers.tornado import TornadoScopeManager  File "/usr/local/lib/python3.8/site-packages/opentracing/scope_managers/tornado.py", line 24, in <module>    import tornado.stack_contextModuleNotFoundError: No module named 'tornado.stack_context'

However with Python 3.9.1 works perfectly :)

I think you can update your requirements in your example.

I am trying to send traces to tempo and it is not working. The traces do work on jaeger.

my opentracing config looks like this Config( config={ "sampler": {"type": "const", "param": 1}, "logging": False, "local_agent": {"reporting_host": "localhost"}, }, scope_manager=ContextVarsScopeManager(), service_name="Test App", )

The current middleware subclasses BaseHTTPMiddleware which per encode/starlette#919 and tiangolo/fastapi#2086 will cause all background tasks to run before the response is sent.