[英]calling sync functions from async function
I am in the process of trying to port a flask
app to quart
to utilise asyncio
.我在试图端口的过程
flask
应用quart
利用asyncio
。 I don't think my current approach is working, as my entire function chain is written without async in mind - consider the following:我认为我目前的方法行不通,因为我的整个函数链是在没有考虑异步的情况下编写的 - 考虑以下几点:
def long_running_task(task):
result = some_synchronous_function(task)
return result
@app.route('/<task>', methods=['GET'])
async def do_task(task):
ok = await long_running_task(task)
if ok:
return (ok.result)
else:
return ('Something went wrong')
If long_running_task
and its whole chain of function calls are not declared as async
, am I actually getting any benefit from my route being declared as async
?如果
long_running_task
及其整个函数调用链未声明为async
,我实际上是否从我的路由声明为async
获得任何好处?
To run a blocking synchronous function from asyncio, without blocking the main event loop, you can use loop.run_in_executor()
to run the blocking function in a ThreadPoolExecutor
or ProcessPoolExecutor
` (ie in its own thread or process).要从 asyncio 运行阻塞同步函数,而不阻塞主事件循环,您可以使用
loop.run_in_executor()
在ThreadPoolExecutor
或ProcessPoolExecutor
`(即在其自己的线程或进程中)运行阻塞函数。
From within the async function you want to call it from:从你想要调用它的异步函数中:
loop = asyncio.get_event_loop()
result = await loop.run_in_executor(None, long_running_task, task)
The first argument None
is to tell it to use the default executor for the loop.第一个参数
None
是告诉它使用循环的默认执行器。 Obviously do_task()
will still have to wait for result
to complete, but while it is waiting, other async tasks will be able to run in event-loop.显然
do_task()
仍然需要等待result
完成,但在等待期间,其他异步任务将能够在事件循环中运行。
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