Can’t patch loop of type <class 'uvloop.Loop'> when starting FastAPI app with nest_asyncio

[Eronwin]

Description
When running our FastAPI application in development mode, the startup fails with:

ValueError: Can't patch loop of type <class 'uvloop.Loop'>

This is raised by nest_asyncio.apply() inside our plugin loader, because uvicorn defaults to uvloop, which nest_asyncio cannot patch.

Reproduction Steps

1. Clone the repo and enter the backend directory:

cd agent-based-platform-backend/backend

2. Activate virtual environment and install dependencies.
3. Start the server in dev mode:

fastapi dev main.py

4. Observe the error in the reloader subprocess:

File ".../plugin/tools.py", line 93, in parse_plugin_config
  nest_asyncio.apply()
File ".../nest_asyncio.py", line 19, in apply
  _patch_loop(loop)
File ".../nest_asyncio.py", line 193, in _patch_loop
  raise ValueError('Can't patch loop of type %s' % type(loop))
ValueError: Can't patch loop of type <class 'uvloop.Loop'>

Additional Context
This issue is analogous to NVIDIA’s NeMo-Guardrails GitHub issue #112, where maintainers suggest using DISABLE_NEST_ASYNCIO=True or --loop asyncio.

[wu-clan]

This issue has been attempted to be resolved in #610 . Please pull the latest code and try again.

[Eronwin]

This issue has been attempted to be resolved in #610 . Please pull the latest code and try again.

LGTM 😄