How to write data to aioredis with FastApi

Question

I'm new to Redis, and I want to use aioredis in fastapi (write data to redis then get data)

The code and error result is following:

code

import asyncio
from redis import asyncio as aioredis
from fastapi import FastAPI
import uvicorn

app = FastAPI()

HOST = "0.0.0.0"
REDIS_PORT = 6379


@app.on_event('startup')
async def register_redis():
    app.state.redis = await aioredis.from_url(
        f'redis://{HOST}',
        port=REDIS_PORT,
        encoding='utf-8'
    )
    print('INFO:     Resister redis successfully')


@app.get("/read-from-redis/{key}")
async def read_from_redis(key: str) -> dict:
    value = await app.state.redis.get(key)
    if value is not None:
        return {"key": key, "value": value}
    else:
        return {"message": "Key not found in Redis"}


async def write_to_redis(key: str, value: str) -> dict:
    await app.state.redis.set(key, value)
    return {"message": f"Value '{value}' written to Redis with key '{key}'"}


asyncio.run(write_to_redis(1, 10))

if __name__ == "__main__":
    uvicorn.run(app="io_redis:app", host=HOST, port=8000, reload=True)

Result

INFO:     Started server process [3888]
INFO:     Waiting for application startup.
INFO:     Resister redis successfully
INFO:     Application startup complete.
Traceback (most recent call last):
  File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\starlette\datastructures.py", line 695, in __getattr__
    return self._state[key]
KeyError: 'redis'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "d:\io_redis.py", line 44, in <module>
    await app.state.redis.set(key, value)
  File "C:\Users\AppData\Local\Programs\Python\Python38\lib\site-packages\starlette\datastructures.py", line 698, in __getattr__
    raise AttributeError(message.format(self.__class__.__name__, key))
AttributeError: 'State' object has no attribute 'redis'

register_redis() will setup app.state.redis when application startup.

Why the app.state cannot get redis when call write_to_redis()?