pombredanne / pulsar-django

django pulse application

Asynchronous Django

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Documentation:	https://github.com/quantmind/pulsar-django
Downloads:	http://pypi.python.org/pypi/pulsar-django
Source:	https://github.com/quantmind/pulsar-django
Keywords:	asynchronous, django, wsgi, websocket, redis

The pulse module is a django application for running a django web site with pulsar. Add it to the list of your INSTALLED_APPS:

INSTALLED_APPS = (
    ...,
    'pulse',
    ...
)

and run the site via the pulse command:

python manage.py pulse

Check the django chat example djchat for a django chat application served by a multiprocessing pulsar server.

By default, the pulse command creates a Wsgi middleware which runs the django application in a separate thread of execution from the main event loop. This is a standard programming pattern when using asyncio with blocking functions. To control the number of thread workers in the event loop executor (which is a pool of threads) one uses the thread-workers option. For example, the following command:

python manage.py pulse -w 4 --thread-workers 20

will run four process based actors, each with an executor with up to 20 threads.

Greenlets

It is possible to run django in fully asynchronous mode, i.e. without running the middleware in the event loop executor. Currently, this is available when using PostgreSql backend only, and it requires the greenlet library.

To run django using greenlet support:

python manage.py pulse -w 4 --greenlet

By default it will run the django middleware on a pool of 100 greenlets (and therefore approximately 100 separate database connections per actor). To adjust this number:

python manage.py pulse -w 4 --greenlet 200

Django Chat Example

This is a web chat application which illustrates how to run a django site with pulsar and how to include pulsar asynchronous request middleware into django.

To run:

python manage.py pulse

If running for the first time, issue the:

python manage.py syncdb

command and create the super user.

Message and data backend

By default, messages from connected (websocket) clients are synchronised via the pulsar data store which starts when the django site starts.

It is possible to specify a different data store via the data-store option. For example, it is possible to use redis as an alternative data store by issuing the following start up command:

python manage.py pulse --data-store redis://127.0.0.1:6379/3