I am trying to use SSE as fastApi endpoint. And the event generator never exits and getting stuck.
Machine details:
- Ubuntu 20
- Python 3.8
Server:
import asyncio
import uvicorn
from fastapi import FastAPI, Request
from sse_starlette.sse import EventSourceResponse
from concurrent.futures import CancelledError
app = FastAPI()
@app.get("/")
async def get_events_stream(request: Request):
async def event_generator():
count = 0
print("starting the loop")
while True:
try:
print(f"Sleeping - {count}")
await asyncio.sleep(1)
print("Finished sleeping")
except CancelledError:
if not await request.is_disconnected():
print('Cancelled future error')
except Exception:
print('Exception!')
if await request.is_disconnected():
print("disconnected")
break
yield {'event': 'message', 'data': count}
count += 1
print("ended the loop - finished serving")
return EventSourceResponse(event_generator(), ping=1)
uvicorn.run(app=app, port=5555, loop="asyncio")
Client:
from sseclient import SSEClient
address = "http://127.0.0.1:5555/"
read_client = SSEClient(address)
for new_event in read_client:
print(f'event: {new_event.event}, {new_event.data}')
After closing the client the SSE connection never close, instead it is stuck in the asyncio.sleep() command.
output from the server:
INFO: Started server process [15989]
INFO: Waiting for application startup.
INFO: Application startup complete.
INFO: Uvicorn running on http://127.0.0.1:5555 (Press CTRL+C to quit)
INFO: 127.0.0.1:51114 - "GET / HTTP/1.1" 200 OK
starting the loop
Sleeping - 0
Finished sleeping
Sleeping - 1
Finished sleeping
Sleeping - 2
Finished sleeping
Sleeping - 3
Finished sleeping
Sleeping - 4 # The client stopped.
