uvicorn launching fastapi Streaming works fine when using reload and not when not using it

[Lizidong01]

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Example Code

# main.py
from fastapi import FastAPI, Request
from fastapi.responses import StreamingResponse
import time

app = FastAPI()

async def generate_data():
    for i in range(10):
        time.sleep(0.1)
        yield f"data {i}\n"
        
@app.post("/test")
async def agent_chain(request: Request):
    form_data = await request.form()
    res = generate_data()
    async def generate():
        async for i in res:
            print(f"stream data:{i}")
            yield i
        for i in form_data.get("data"):
            
            yield f"data {i}\n"
    return StreamingResponse(generate(), media_type="text/event-stream")

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=12334)


#request.py
import requests

data = {"data": "hello world"}

response = requests.post("http://localhost:12334/test", data=data, stream=True)
for chunk in response.iter_content(chunk_size=1024):
    if chunk:
        print(chunk)

Description

When I use fastapi to make a streaming interface, I encountered such a problem, not quite sure whether it is a problem with the code I wrote or a problem with fastapi, so I mentioned here to start the question.
When I use the following command, my code returns normally step-by-step in streaming fashion

uvicorn main:app  --port 12334 --reload

But when I use the following command, the streaming doesn't return properly and the returned response is returned as if it were non-streaming.

uvicorn main:app  --port 12334

My library version

fastapi                0.111.0
uvicorn                0.29.0

I want to know if I need to stream normally without adding --reload how should I implement it.

2024-05-10.16-23-08.mp4

Operating System

Linux, Windows

Operating System Details

No response

FastAPI Version

0.111.0

Pydantic Version

2.7.0b1

Python Version

3.10.14

Additional Context

No response

[Lizidong01]

You only need to await asyncio.sleep(0.05)