aclose() exception in Uvicorn when subscription running

[kdowney-cloudwallcapital]

After less than 30 seconds of subscribing the Tartiflette ASGI implementation blows up with an exception.

I see this both with Altair and with a simple Python graphql_client-based client, so pretty sure this is Tartiflette not the client. The platform is Ubuntu focal, Python 3.8.12, with:

• tartiflette==1.4.1
• tartiflette-asgi==0.11.0
• uvicorn==0.15.0
• websockets==9.1

Note same issue also observed with uvicorn 0.17.0-post1 and websockets 10.1, though the error recovery appears a bit more graceful with the newer versions.

This is quite critical for us as our backend is all based on Tartiflette, and I cannot switch to another GraphQL server implementation due to core library conflicts with another major library in our stack.

2022-01-26 20:48:51,050 [Thread-7] - uvicorn.error - ERROR - Exception in ASGI application
Traceback (most recent call last):
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 203, in run_asgi
    result = await self.app(self.scope, self.asgi_receive, self.asgi_send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
    return await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/applications.py", line 112, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/middleware/errors.py", line 146, in __call__
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette_exporter/middleware.py", line 101, in __call__
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/exceptions.py", line 58, in __call__
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/routing.py", line 656, in __call__
    await route.handle(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/routing.py", line 408, in handle
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_app.py", line 90, in __call__
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_middleware.py", line 14, in __call__
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/routing.py", line 656, in __call__
    await route.handle(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/routing.py", line 315, in handle
    await self.app(scope, receive, send)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/starlette/endpoints.py", line 76, in dispatch
    await self.on_disconnect(websocket, close_code)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_endpoints.py", line 116, in on_disconnect
    await self.protocol.on_disconnect(close_code)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_subscriptions/impl.py", line 25, in on_disconnect
    await super().on_disconnect(close_code)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_subscriptions/protocol.py", line 164, in on_disconnect
    await self._unsubscribe(opid)
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_subscriptions/protocol.py", line 101, in _unsubscribe
    await subscription.aclose()
  File "/workspaces/serenity.core/venv/lib/python3.8/site-packages/tartiflette_asgi/_subscriptions/protocol.py", line 36, in aclose
    await self._agen.aclose()
RuntimeError: aclose(): asynchronous generator is already running