Documentation for pulsar 0.4.6. For development docs, go here.
Event driven concurrent framework for python. Tested in Windows and Linux, it requires python 2.6, 2.7, 3.2, 3.3 or pypy. With pulsar you can write asynchronous servers performing one or several activities in different threads and/or processes.
|Keywords:||server, asynchronous, concurrency, actor, thread, process, socket, task queue|
An example of a web server written with pulsar application framework which responds with “Hello World!” for every request:
from pulsar.apps import wsgi def hello(environ, start_response): '''Pulsar HTTP "Hello World!" application''' data = b'Hello World!\n' status = '200 OK' response_headers = [ ('Content-type','text/plain'), ('Content-Length', str(len(data))) ] start_response(status, response_headers) return [data] if __name__ == '__main__': wsgi.WSGIServer(callable=hello).start()
Pulsar’s goal is to provide an easy way to build scalable network programs. In the “Hello world!” web server example above, many client connections can be handled concurrently. Pulsar tells the operating system (through epoll or select) that it should be notified when a new connection is made, and then it goes to sleep.
Pulsar uses the multiprocessing module from the standard python library and it can be configured to run in multi-processing mode, multi-threading mode or a combination of the two.
Pulsar is a stand alone python library and it can be installed via pip:
pip install pulsar
easy_install or downloading the tarball from pypi.
Pulsar design allows for a host of different applications to be implemented in an elegant and efficient way. Out of the box it is shipped with the the following
Check out the examples directory for various working applications created using pulsar alone. It includes:
Pulsar internals are based on actors primitive. Actors are the atoms of pulsar’s concurrent computation, they do not share state between them, communication is achieved via asynchronous inter-process message passing, implemented using the standard python socket library.
Two special classes of actors are the Arbiter, used as a singleton, and the Monitor, a manager of several actors performing similar functions. The Arbiter runs the main eventloop and it controls the life of all actors. Monitors manage group of actors performing similar functions, You can think of them as a pool of actors.
More information about design and philosophy in the documentation.
Pulsar checks if some additional libraries are available, either during installation or at runtime, and uses them to add new functionalities.
For options and help type:
python runtests.py -h
For full coverage run tests with the following flags:
python runtests.py --concurrency thread --profile --benchmark --http-py-parser --verbosity 2
Pulsar project started as a fork of gunicorn (from where the arbiter idea) and has been developed using ideas from nodejs (api design), twisted (the deferred implementation), tornado web server (the event-loop implementation), celery (the task queue application) and many other open-source efforts.
Development of pulsar happens at Github. We very much welcome your contribution of course. To do so, simply follow these guidelines: