Cooperative

Write non-blocking computationally expensive code to go along with non-blocking io, without having to think about everything in callbacks.

batch_accumulate will iterate over a generator in batches, yielding to other iterators passed into twisted.internet.task.cooperate

Example

#!/usr/bin/env python
# _*_ coding: utf-8 _*_
from operator import add

import sys
from twisted.internet import defer
from twisted.internet.task import react
from twisted.python import log

from cooperative import batch_accumulate


def expensive(number):
    log.msg("starting {}".format(number))
    for value in range(100000):
        if 25000 == value:
            log.msg("1/4 for {}".format(number))
        if 50000 == value:
            log.msg("1/2 for {}".format(number))
        if 75000 == value:
            log.msg("3/4 for {}".format(number))
        yield number * value / 3.0


@defer.inlineCallbacks
def do_some_expensive_things(number):
    """
    Perform one expensive computation cooperatively with any
     other iterator passed into twisted's cooperate, then
     use it's result to pass into the second computation.

    :param number:
    :return:
    """
    result = yield batch_accumulate(1000, expensive(number))
    total = reduce(add, result, 0)
    log.msg("first for {}: {}".format(number, total))

    result = yield batch_accumulate(1000, expensive(int(total/1e9)))
    total = reduce(add, result, 0)
    log.msg("second for {}: {}".format(number, total))
    defer.returnValue(total)


def main(reactor):
    d1 = do_some_expensive_things(54.0)
    d2 = do_some_expensive_things(42)
    d3 = do_some_expensive_things(10)
    d4 = do_some_expensive_things(34)

    # Enqueue events to simulate handling external events
    d5 = defer.Deferred().addCallback(log.msg)
    reactor.callLater(0.3, d5.callback, "########## simulated request 1 ############")

    d6 = defer.Deferred().addCallback(log.msg)
    reactor.callLater(0.5, d6.callback, "########## sim request 2 ############")

    d7 = defer.Deferred().addCallback(log.msg)
    reactor.callLater(1.0, d7.callback, "########## simulated request 3 ############")

    return defer.gatherResults([d1, d2, d3, d4, d5, d6, d7]).addCallback(log.msg)

if __name__ == "__main__":
    log.startLogging(sys.stdout)
    react(main, [])

Documentation

Read the docs: http://cooperative.readthedocs.org/en/latest/

Contributing:

Submit any issues or questions here: https://github.com/johnwlockwood/cooperative/issues.

Make pull requests to development branch of

https://github.com/johnwlockwood/cooperative.

Documentation is written in reStructuredText and currently uses the

Sphinx style for field lists http://sphinx-doc.org/domains.html#info-field-lists

Check out closed pull requests to see the flow of development, as almost every change to master is done via a pull request on GitHub. Code Reviews are welcome, even on merged Pull Requests. Feel free to ask questions about the code.