celery/examples/eventlet

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Example using the Eventlet Pool
==================================

Introduction
============

This is a Celery application containing two example tasks.

First you need to install Eventlet, and also recommended is the `dnspython`
module (when this is installed all name lookups will be asynchronous)::

$ pip install eventlet
$ pip install dnspython

Before you run any of the example tasks you need to start celeryd::

$ cd examples/eventlet
$ celeryd -l info --concurrency=500 --pool=eventlet

As usual you need to have RabbitMQ running, see the Celery getting started
guide if you haven't installed it yet.

Tasks
=====

* `tasks.urlopen`

This task simply makes a request opening the URL and returns the size
of the response body::

$ cd examples/eventlet
$ python
>>> from tasks import urlopen
>>> urlopen.delay("http://www.google.com/").get()
9980

To open several URLs at once you can do:

$ cd examples/eventlet
$ python
>>> from tasks import urlopen
>>> from celery.task.sets import TaskSet
>>> result = TaskSet(urlopen.subtask((url, ))
... for url in LIST_OF_URLS).apply_async()
>>> for incoming_result in result.iter_native():
... print(incoming_result, )

* `webcrawler.crawl`

This is a simple recursive web crawler. It will only crawl
URLs for the current host name. Please see comments in the
`webcrawler.py` file.