在Flask中创建一个异步任务 [英] Making an asynchronous task in Flask

问题描述

我在 Flask 中写了一个应用程序，除了 WSGI 是同步和阻塞外，我有一个任务，特别是调用第三方API，这个任务可能需要几分钟才能完成。我想打这个电话（实际上是一系列的电话），让它运行。而控制返回到Flask。

我的看法如下所示：

  @ app.route（'/ render /< id>'，methods = ['POST']）
 def render_script（id = None）：
 ... 
 data = json .loads（request.data）
 text_list = data.get（'text_list'）
 final_file = audio_class.render_audio（data = text_list）
＃do stuff 
 return Response（
 mimetype ='application / json'，
 status = 200 
）
  

<现在，我想要做的是有行

  final_file = audio_class.render_audio（）
 
 code> 

在方法返回时运行并提供一个回调函数，而Flask可以继续处理请求。这是我需要Flask异步运行的唯一任务，并且我想就如何最好地实现这一点提供一些建议。我已经看过 Twisted 和 Klein ，但是我不确定它们是否过量，也许线程就足够了。

任何建议都将非常感谢。

编辑

或者也许 Celery 是一个不错的选择吗？

解决方案

我会使用 Celery 为您处理异步任务。你需要安装一个代理作为你的任务队列（推荐使用RabbitMQ和Redis）。

app.py


 从瓶子导入瓶子
从芹菜导入Celery 
 
 broker_url = 'amqp：// guest @ localhost'＃RabbitMQ任务队列的代理URL 
 $ b $ app = Flask（__ name__）
 celery = celery（app.name，broker = broker_url）
 celery.config_from_object（'celeryconfig'）＃celeryconfig.py中的celery配置
 $ b @ celery.task（bind = True）
 def some_long_task（self，x，y）：
 $做一些长期任务
 ... 
 
 @ app.route（'/ render /< id>'，methods = ['POST']）
 def render_script（id = None）：
 ... 
 data = json.loads（request.data）
 text_list = data.get（'text_list'）
 final_file = audio_class。 render_audio（data = text_list）
 some_long_task.delay（x，y）＃调用你的异步任务，并传递任何必要的变量iables 
返回响应（
 mimetype ='application / json'，
 status = 200 
）
  

运行你的Flask应用程序，并启动另一个进程来运行你的芹菜工作器。

  $ celery worker -A app.celery --loglevel = debug 
  

我也会参考Miguel Gringberg的<一个href =http://blog.miguelgrinberg.com/post/using-celery-with-flask>写了一个更深入的指南使用芹菜与烧瓶。

I am writing an application in Flask, which works really well except that WSGI is synchronous and blocking. I have one task in particular which calls out to a third party API and that task can take several minutes to complete. I would like to make that call (it's actually a series of calls) and let it run. while control is returned to Flask.

My view looks like:

@app.route('/render/<id>', methods=['POST'])
def render_script(id=None):
    ...
    data = json.loads(request.data)
    text_list = data.get('text_list')
    final_file = audio_class.render_audio(data=text_list)
    # do stuff
    return Response(
        mimetype='application/json',
        status=200
    )

Now, what I want to do is have the line

final_file = audio_class.render_audio()

run and provide a callback to be executed when the method returns, whilst Flask can continue to process requests. This is the only task which I need Flask to run asynchronously, and I would like some advice on how best to implement this. I have looked at Twisted and Klein, but I'm not sure they are overkill, as maybe Threading would suffice.

Any advice would be much appreciated.

EDIT

Or Maybe Celery is a good choice for this?

解决方案

I would use Celery to handle the asynchronous task for you. You'll need to install a broker to serve as your task queue (RabbitMQ and Redis are recommended).

app.py:

from flask import Flask
from celery import Celery

broker_url = 'amqp://guest@localhost'          # Broker URL for RabbitMQ task queue

app = Flask(__name__)    
celery = Celery(app.name, broker=broker_url)
celery.config_from_object('celeryconfig')      # Your celery configurations in a celeryconfig.py

@celery.task(bind=True)
def some_long_task(self, x, y):
    # Do some long task
    ...

@app.route('/render/<id>', methods=['POST'])
def render_script(id=None):
    ...
    data = json.loads(request.data)
    text_list = data.get('text_list')
    final_file = audio_class.render_audio(data=text_list)
    some_long_task.delay(x, y)                 # Call your async task and pass whatever necessary variables
    return Response(
        mimetype='application/json',
        status=200
    )

Run your Flask app, and start another process to run your celery worker.

$ celery worker -A app.celery --loglevel=debug

I would also refer to Miguel Gringberg's write up for a more in depth guide to using Celery with Flask.

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