Hi Lauren:
Message: 1
Date: Thu, 21 Oct 2010 23:47:56 +0200
From: Laurens Van Houtven <[email protected]>
Subject: [Twisted-Python] PyCon extreme Twisted talk!
To: Twisted general discussion <[email protected]>
Message-ID:
<[email protected]>
Content-Type: text/plain; charset="utf-8"
>Greetings fellow Twisted aficionados!
>So, Allen (dash) and I have decided that we were going to co-do the >Twisted
>Extreme talk at PyCon US 2011. Extreme talks are like talks, >except with less
>talking and more coding, so preferably something >actionable for an entire 45
>minutes! That most likely means many steps: >start small, and then do
>something more complex.
I am probably going to submit an extreme talk for PyCon 2011. I'll either
refine the "Prototyping Go's Select" talk. Or discuss about my work-in-progress
about join conditions. Twisted has a simple join in the form of a deferred list.
Inspired by the Ray Hettinger Monocle post-talk discussion and writing examples
with stackless.select(), I thought submitting another extreme talk that would
revisit the lost world of Stackless Python/Twisted integration. As we
discussed, why not a special reactor that incorporates the Stackless scheduler?
Right now, a lot my examples use Twisted for sleep(). Creating a Stackless
reactor would hopefully allow me to get rid of stuff like
This way I can get rid of stuff like:
l = task.LoopingCall(stackless.schedule)
l.start(.001)
stackless.tasklet(startTwisted)()
stackless.tasklet(santa)(reindeers, elves)
stackless.run()
and eventually
def tick(seconds):
tickCh = stackless.channel()
reactor.callLater(seconds, tickCh.send, None)
tickCh.receive()
what is particularly exciting is talk in the pypy-dev list about incorporating
Stackless with the JIT....
Cheers,
Andrew
P.S - I have provided an example of using Stackless and Twisted to solve the
Santa Claus Problem
#!/usr/bin/env python
"""
simpleSanta.py
Andrew Francis
October 21th, 2010
The purpose of simpleSanta is as follows:
1) Show a solution to the Santa Claus problem using the select
2) Point out improvements to the select statement
3) Give hints as to why a solution with Join conditions may be easier
for now, we leave out priority to reindeer
"""
import random
import time
import sys
from twisted.internet import reactor
from twisted.internet import defer
from twisted.internet import task
from twisted.python.failure import Failure
import stackless
# we can use ETIME and RTIME to control how long reindeers and elves wait
# before asking questions
RTIME = (10,12)
ETIME = (1,12)
def tick(seconds):
tickCh = stackless.channel()
reactor.callLater(seconds, tickCh.send, None)
tickCh.receive()
def startTwisted():
reactor.run()
def stopTwisted():
reactor.callLater(1, reactor.stop)
print "that's all folks"
def worker(ch, name, theRange):
myChannel = stackless.channel()
while True:
waitTime = random.randint(theRange[0], theRange[1])
tick(waitTime)
ch.send((name, myChannel))
answer = myChannel.receive()
"""
a way of telling the tasklets that Santa is done
"""
def acceptChannels(channels, status):
for name, channel in channels:
channel.send(status)
def deliveryToys(reindeer):
print "All the reindeer have arrived - delivering toys"
acceptChannels(reindeer, True)
def consultWithSanta(elves):
print "Santa consulting with elves"
acceptChannels(elves, True)
def santa(reindeer, elves):
reindeerChannels = [ch for name, ch, waitTime in reindeer]
elvesChannels = [ch for name, ch, waitTime in elves]
reindeerCases = [ch.receiveCase() for ch in reindeerChannels]
elvesCases = [ch.receiveCase() for ch in elvesChannels]
reindeerQueue = []
elvesQueue = []
cases = reindeerCases + elvesCases
while True:
ch, operation, value = stackless.select(cases)
print value
if ch in reindeerChannels:
reindeerQueue.append(value)
if len(reindeerQueue) == 9:
deliveryToys(reindeerQueue)
reindeerQueue = []
elif ch in elvesChannels:
elvesQueue.append(value)
if len(elvesQueue) == 3:
consultWithSanta(elvesQueue)
elvesQueue = []
else:
print "WHAT?"
stopTwisted()
print "Twisted is dead"
def makeWorkers(workers):
for name, ch, waitTime in workers:
stackless.tasklet(worker)(ch, name, waitTime)
return
if __name__ == "__main__":
random.seed()
reindeers = [(reindeer, stackless.channel(), RTIME) for reindeer in \
["DANCER", "PRANCER", "VIXEN", "COMET", "CUPID", "DONER", \
"DASHER", "BLITZEN", "RUDOLPH"]]
elves = [(elf, stackless.channel(), ETIME) for elf in \
['A','B','C','D','E','F','G','H','I','J']]
makeWorkers(reindeers)
makeWorkers(elves)
l = task.LoopingCall(stackless.schedule)
l.start(.001)
stackless.tasklet(startTwisted)()
stackless.tasklet(santa)(reindeers, elves)
stackless.run()
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