我试图创建一个简单的停靠组合，将启动2个容器之一的应用程序，如下所示：

from fastapi import APIRouter

router = APIRouter()

@router.get("/")
async def root():
    return {"message": "This is a Test"}

from fastapi import FastAPI
import uvicorn as uvicorn

from routers import test

app = FastAPI()
app.include_router(test.router)

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

另一个用于NGINX，配置为：

worker_processes 1;

events {
  worker_connections 1024;
}

http {
    server {
        listen       80;

        location / {
            proxy_pass http://0.0.0.0:8000;
        }
    }
}

我的docker-compose如下所示：

version: "3.7"
services:
    web:
        build: nginx
        ports:
          - "80:80"
        depends_on:
          - app
        container_name: tensor_nginx

    app:
        build: app
        ports:
          - "8000:8000"
        container_name: test

当我启动时，一切都很好，我可以通过www.example.com连接到FastAPI创建的Swagger，端点返回代码中定义的字符串。0.0.0.0:8000/docs and the endpoint returns the string defined in the code.
但是如果我尝试使用nginx端口连接，它会说连接失败。

[error] 30#30: *5 connect() failed (111: Connection refused) while connecting to upstream, client: 172.31.0.1, server: , request: "GET / HTTP/1.1", upstream: "http://0.0.0.0:8000/", host: "127.0.0.1"

我在配置中遗漏了什么？