app.py

import uvicorn
from fastapi import FastAPI
import asyncio

import ray
from ray import serve

@ray.remote
def my_task():
    print("in a training job")


def create_app():
    app = FastAPI()

    @app.get("/")
    async def func():
        ray.put(1)
        await my_task.remote()
        return "done!"
    
    return app

@serve.deployment(route_prefix=None)
class DirectIngressApp:
    async def __init__(self, port:int):
        self.app = create_app()

        config = uvicorn.Config(
            self.app,
            port=port,
            access_log=True,
        )
        server = uvicorn.Server(config=config)
        self.serving_task = asyncio.get_event_loop().create_task(server.serve())

    # That's it, don't implement call method and don't call it explicitly

serve.start()
DirectIngressApp.deploy(port=9999)

while True:
    import time
    time.sleep(10)