Python 如何使uvicorn运行异步构造的应用程序?
给定Python 如何使uvicorn运行异步构造的应用程序?,python,async-await,python-asyncio,uvicorn,asgi,Python,Async Await,Python Asyncio,Uvicorn,Asgi,给定main.py: import asyncio async def new_app(): # Await some things. async def app(scope, receive, send): ... return app app = asyncio.run(new_app()) 其次是: uvicorn main.app 给出: RuntimeError: asyncio.run() cannot be called from
main.py
:
import asyncio
async def new_app():
# Await some things.
async def app(scope, receive, send):
...
return app
app = asyncio.run(new_app())
其次是:
uvicorn main.app
给出:
RuntimeError: asyncio.run() cannot be called from a running event loop
这是因为在导入我的应用程序之前,
uvicorn
已经启动了一个事件循环。如何在uvicorn
下异步构造应用程序?您无需使用asyncio.run
。您的类或函数应该只实现接口。像这样,最简单的方法是可行的:
# main.py
def app(scope):
async def asgi(receive, send):
await send(
{
"type": "http.response.start",
"status": 200,
"headers": [[b"content-type", b"text/plain"]],
}
)
await send({"type": "http.response.body", "body": b"Hello, world!"})
return asgi
您可以在uvicorn:uvicorn main:app
下启动它
参数main:app
将由uvicorn
解析导入,并在其eventloop中以这种方式导入:
app = self.config.loaded_app
scope: LifespanScope = {
"type": "lifespan",
"asgi": {"version": self.config.asgi_version, "spec_version": "2.0"},
}
await app(scope, self.receive, self.send)
如果要制作可执行模块,可以执行以下操作:
import uvicorn
# app definition
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)