How can i reload the change of DL Models on Fastapi?

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Example Code

no code example

Description

When i change the files of models the models files does not seem to be reloaded and the old ones seems to be used , so how can i make the change in models appear automatically also i dont want to reload the whole app using reload=True is there a way to do this ?

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.70.0

Python Version

3.7

Additional Context

No response

[insomnes]

You can create asyncio task on startup (and cancel it on shutdown) which checks files hashsum and sleeps for some time, if hashsum has been changed you reload your model into memory.

import asyncio
from hashlib import md5
from fastapi import FastAPI

FILE_PATH = "test.txt"


class MemLoader:
    def __init__(self, file_path: str):
        self.file_path = file_path
        self.file_content, self.file_hash = self.load_file()

    def load_file(self):
        with open(self.file_path) as file:
            file_content = file.read()

        file_hash = md5(file_content.encode("UTF-8")).digest()

        return file_content, file_hash

    def check_file_changed(self):
        file_content, file_hash = self.load_file()
        if file_hash != self.file_hash:
            print("FILE CHANGED RELOAD")
            self.file_content = file_content
            self.file_hash = file_hash

    def get_content(self):
        return self.file_content


app = FastAPI()


async def check_file_changed(mem_loader: MemLoader):
    loop = asyncio.get_running_loop()
    print("STARTING FILE CHECK")
    while True:
        await asyncio.sleep(15)
        await loop.run_in_executor(
            executor=None, func=mem_loader.check_file_changed
        )


@app.on_event("startup")
async def load_mem_loader():
    print("LOADING MEM LOADER")
    app.mem_loader = MemLoader(FILE_PATH)
    app.mem_loader_task = asyncio.create_task(
        check_file_changed(app.mem_loader)
    )


@app.on_event("shutdown")
async def cancel_mem_loader():
    app.mem_loader_task.cancel()
    print("CHECK TASK CANCELED")



@app.get("/content")
async def get_content():
    return app.mem_loader.get_content()

[HGamalElDiin]

@insomnes thanks for your help really, i did that and woks fine now