TypeError from asyncio package when implementing Subscriptions

[deojonathan]

I'm trying to implement graphql subscriptions within our app, and I've been testing it using Ariadne's GraphQL playground.

subscription {
  testSubscription
}

Whenever I try to execute the statement above, I always receive this response:

{
  "error": "Could not connect to websocket endpoint ws://localhost:8000/graphql. Please check if the endpoint url is correct."
}

I also noticed these logs emitted by the running (local) uvicorn server:

uvicorn logs

lims_api           | INFO:     ('172.24.0.1', 55324) - "WebSocket /graphql" [accepted]
lims_api           | INFO:uvicorn.error:('172.24.0.1', 55324) - "WebSocket /graphql" [accepted]
lims_api           | INFO:     172.24.0.1:55318 - "POST /graphql HTTP/1.1" 200 OK
lims_api           | INFO:     172.24.0.1:55320 - "POST /graphql HTTP/1.1" 200 OK
lims_api           | INFO:     172.24.0.1:55322 - "POST /graphql HTTP/1.1" 200 OK
lims_api           | INFO:     172.24.0.1:55326 - "POST /graphql HTTP/1.1" 200 OK
lims_api           | INFO:     172.24.0.1:55310 - "POST /graphql HTTP/1.1" 200 OK
lims_api           | ERROR:    opening handshake failed
lims_api           | Traceback (most recent call last):
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/server.py", line 163, in handler
lims_api           |     await self.handshake(
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/server.py", line 597, in handshake
lims_api           |     raise self.connection_closed_exc()  # pragma: no cover
lims_api           | websockets.exceptions.ConnectionClosedError: no close frame received or sent
lims_api           | ERROR:uvicorn.error:opening handshake failed
lims_api           | Traceback (most recent call last):
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/server.py", line 163, in handler
lims_api           |     await self.handshake(
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/server.py", line 597, in handshake
lims_api           |     raise self.connection_closed_exc()  # pragma: no cover
lims_api           | websockets.exceptions.ConnectionClosedError: no close frame received or sent
lims_api           | INFO:     connection closed
lims_api           | INFO:uvicorn.error:connection closed
lims_api           | ERROR:    Exception in ASGI application
lims_api           | Traceback (most recent call last):
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 184, in run_asgi
lims_api           |     result = await self.app(self.scope, self.asgi_receive, self.asgi_send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
lims_api           |     return await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/applications.py", line 124, in __call__
lims_api           |     await self.middleware_stack(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/errors.py", line 149, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/cors.py", line 76, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/gzip.py", line 26, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/sessions.py", line 86, in __call__
lims_api           |     await self.app(scope, receive, send_wrapper)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/exceptions.py", line 51, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 680, in __call__
lims_api           |     await route.handle(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 334, in handle
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 81, in app
lims_api           |     await func(session)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/ariadne/asgi.py", line 291, in websocket_server
lims_api           |     message = await websocket.receive_json()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/websockets.py", line 132, in receive_json
lims_api           |     message = await self.receive()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/websockets.py", line 45, in receive
lims_api           |     message = await self._receive()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 285, in asgi_receive
lims_api           |     data = await self.recv()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/protocol.py", line 536, in recv
lims_api           |     await asyncio.wait(
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 411, in wait
lims_api           |     fs = {ensure_future(f, loop=loop) for f in fs}
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 411, in <setcomp>
lims_api           |     fs = {ensure_future(f, loop=loop) for f in fs}
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 677, in ensure_future
lims_api           |     raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
lims_api           | TypeError: An asyncio.Future, a coroutine or an awaitable is required
lims_api           | ERROR:uvicorn.error:Exception in ASGI application
lims_api           | Traceback (most recent call last):
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 184, in run_asgi
lims_api           |     result = await self.app(self.scope, self.asgi_receive, self.asgi_send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
lims_api           |     return await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/applications.py", line 124, in __call__
lims_api           |     await self.middleware_stack(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/errors.py", line 149, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/cors.py", line 76, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/gzip.py", line 26, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/sessions.py", line 86, in __call__
lims_api           |     await self.app(scope, receive, send_wrapper)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/middleware/exceptions.py", line 51, in __call__
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 680, in __call__
lims_api           |     await route.handle(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 334, in handle
lims_api           |     await self.app(scope, receive, send)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/routing.py", line 81, in app
lims_api           |     await func(session)
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/ariadne/asgi.py", line 291, in websocket_server
lims_api           |     message = await websocket.receive_json()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/websockets.py", line 132, in receive_json
lims_api           |     message = await self.receive()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/starlette/websockets.py", line 45, in receive
lims_api           |     message = await self._receive()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/uvicorn/protocols/websockets/websockets_impl.py", line 285, in asgi_receive
lims_api           |     data = await self.recv()
lims_api           |   File "/opt/venv/lib/python3.9/site-packages/websockets/legacy/protocol.py", line 536, in recv
lims_api           |     await asyncio.wait(
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 411, in wait
lims_api           |     fs = {ensure_future(f, loop=loop) for f in fs}
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 411, in <setcomp>
lims_api           |     fs = {ensure_future(f, loop=loop) for f in fs}
lims_api           |   File "/usr/local/lib/python3.9/asyncio/tasks.py", line 677, in ensure_future
lims_api           |     raise TypeError('An asyncio.Future, a coroutine or an awaitable is '
lims_api           | TypeError: An asyncio.Future, a coroutine or an awaitable is required

Setup

We're using the Starlette framework, the code snippets below show how I'm setting it up currently.

graphql.py

from ariadne.asgi import GraphQL
from ariadne import make_executable_schema

schema = make_executable_schema(type_defs, *bindables, directives=directives)
endpoint = GraphQL(schema=schema, debug=True)

server.py

app = Starlette(
    debug=settings.DEBUG, on_startup=[connectdb], on_shutdown=[disconnectdb]
)

# Separate routes for websocket and http.
app.add_route('/graphql', route=graphql.endpoint, name='graphql')
app.add_websocket_route('/graphql', route=graphql.endpoint)

resolvers.py

subscription = SubscriptionType()

@subscription.source("testSubscription")
async def counter_generator(obj, info):
    for i in range(5):
        await asyncio.sleep(1)
        yield i

@subscription.field("testSubscription")
def counter_resolver(count, info):
    return str(count + 1)

pyproject.toml

ariadne = "^0.15.1"
gino = "^0.8.5"
uvicorn = {version = "^0.17.6", extras = ["standard"]}
starlette = "^0.20.2"

Any ideas on what may cause this TypeError issue? 🙏