異步任務隊列：celery

celery是一個異步任務隊列/基于分布式消息傳遞的作業隊列。它側重于實時操作，但對調度支持也很好。

celery用于生產系統每天處理數以百萬計的任務。

celery是用Python編寫的，但該協議可以在任何語言實現。它也可以與其他語言通過webhooks實現。

建議的消息代理RabbitMQ的，但提供有限支持Redis, Beanstalk, MongoDB, CouchDB, ，和數據庫（使用SQLAlchemy的或Django的 ORM） 。

Celery is...

• Simple

  Celery is easy to use and maintain, and does not need configuration files.

  It has an active, friendly community you can talk to for support, including a mailing-list and and an IRC channel.

  Here's one of the simplest applications you can make:

  from celery import Celery
  
  celery = Celery('hello', broker='amqp://guest@localhost//')
  
  @celery.task
  def hello():
      return 'hello world'

• Highly Available

  Workers and clients will automatically retry in the event of connection loss or failure, and some brokers support HA in way of Master/Master or Master/Slave replication.

• Fast

  A single Celery process can process millions of tasks a minute, with sub-millisecond round-trip latency (using RabbitMQ, py-librabbitmq, and optimized settings).

• Flexible

  Almost every part of Celery can be extended or used on its own, Custom pool implementations, serializers, compression schemes, logging, schedulers, consumers, producers, autoscalers, broker transports and much more.