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Commit 394cd707 authored by Jesse Noller's avatar Jesse Noller
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Merged revisions 76433 via svnmerge from 

svn+ssh://pythondev@svn.python.org/python/trunk

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  r76433 | jesse.noller | 2009-11-21 09:01:56 -0500 (Sat, 21 Nov 2009) | 1 line

  issue5738: The distribution example was confusing, and out of date. It's too large to include inline in the docs as well. It belongs in an addons module outside the stdlib. Removing.
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Doc/includes/mp_distributing.py deleted 100644 → 0
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#
# Module to allow spawning of processes on foreign host
#
# Depends on `multiprocessing` package -- tested with `processing-0.60`
#
# Copyright (c) 2006-2008, R Oudkerk
# All rights reserved.
#
__all__ = ['Cluster', 'Host', 'get_logger', 'current_process']
#
# Imports
#
import sys
import os
import tarfile
import shutil
import subprocess
import logging
import itertools
import queue
try:
import pickle as pickle
except ImportError:
import pickle
from multiprocessing import Process, current_process, cpu_count
from multiprocessing import util, managers, connection, forking, pool
#
# Logging
#
def get_logger():
return _logger
_logger = logging.getLogger('distributing')
_logger.propagate = 0
_formatter = logging.Formatter(util.DEFAULT_LOGGING_FORMAT)
_handler = logging.StreamHandler()
_handler.setFormatter(_formatter)
_logger.addHandler(_handler)
info = _logger.info
debug = _logger.debug
#
# Get number of cpus
#
try:
slot_count = cpu_count()
except NotImplemented:
slot_count = 1
#
# Manager type which spawns subprocesses
#
class HostManager(managers.SyncManager):
'''
Manager type used for spawning processes on a (presumably) foreign host
'''
def __init__(self, address, authkey):
managers.SyncManager.__init__(self, address, authkey)
self._name = 'Host-unknown'
def Process(self, group=None, target=None, name=None, args=(), kwargs={}):
if hasattr(sys.modules['__main__'], '__file__'):
main_path = os.path.basename(sys.modules['__main__'].__file__)
else:
main_path = None
data = pickle.dumps((target, args, kwargs))
p = self._RemoteProcess(data, main_path)
if name is None:
temp = self._name.split('Host-')[-1] + '/Process-%s'
name = temp % ':'.join(map(str, p.get_identity()))
p.set_name(name)
return p
@classmethod
def from_address(cls, address, authkey):
manager = cls(address, authkey)
managers.transact(address, authkey, 'dummy')
manager._state.value = managers.State.STARTED
manager._name = 'Host-%s:%s' % manager.address
manager.shutdown = util.Finalize(
manager, HostManager._finalize_host,
args=(manager._address, manager._authkey, manager._name),
exitpriority=-10
)
return manager
@staticmethod
def _finalize_host(address, authkey, name):
managers.transact(address, authkey, 'shutdown')
def __repr__(self):
return '<Host(%s)>' % self._name
#
# Process subclass representing a process on (possibly) a remote machine
#
class RemoteProcess(Process):
'''
Represents a process started on a remote host
'''
def __init__(self, data, main_path):
assert not main_path or os.path.basename(main_path) == main_path
Process.__init__(self)
self._data = data
self._main_path = main_path
def _bootstrap(self):
forking.prepare({'main_path': self._main_path})
self._target, self._args, self._kwargs = pickle.loads(self._data)
return Process._bootstrap(self)
def get_identity(self):
return self._identity
HostManager.register('_RemoteProcess', RemoteProcess)
#
# A Pool class that uses a cluster
#
class DistributedPool(pool.Pool):
def __init__(self, cluster, processes=None, initializer=None, initargs=()):
self._cluster = cluster
self.Process = cluster.Process
pool.Pool.__init__(self, processes or len(cluster),
initializer, initargs)
def _setup_queues(self):
self._inqueue = self._cluster._SettableQueue()
self._outqueue = self._cluster._SettableQueue()
self._quick_put = self._inqueue.put
self._quick_get = self._outqueue.get
@staticmethod
def _help_stuff_finish(inqueue, task_handler, size):
inqueue.set_contents([None] * size)
#
# Manager type which starts host managers on other machines
#
def LocalProcess(**kwds):
p = Process(**kwds)
p.set_name('localhost/' + p.name)
return p
class Cluster(managers.SyncManager):
'''
Represents collection of slots running on various hosts.
`Cluster` is a subclass of `SyncManager` so it allows creation of
various types of shared objects.
'''
def __init__(self, hostlist, modules):
managers.SyncManager.__init__(self, address=('localhost', 0))
self._hostlist = hostlist
self._modules = modules
if __name__ not in modules:
modules.append(__name__)
files = [sys.modules[name].__file__ for name in modules]
for i, file in enumerate(files):
if file.endswith('.pyc') or file.endswith('.pyo'):
files[i] = file[:-4] + '.py'
self._files = [os.path.abspath(file) for file in files]
def start(self):
managers.SyncManager.start(self)
l = connection.Listener(family='AF_INET', authkey=self._authkey)
for i, host in enumerate(self._hostlist):
host._start_manager(i, self._authkey, l.address, self._files)
for host in self._hostlist:
if host.hostname != 'localhost':
conn = l.accept()
i, address, cpus = conn.recv()
conn.close()
other_host = self._hostlist[i]
other_host.manager = HostManager.from_address(address,
self._authkey)
other_host.slots = other_host.slots or cpus
other_host.Process = other_host.manager.Process
else:
host.slots = host.slots or slot_count
host.Process = LocalProcess
self._slotlist = [
Slot(host) for host in self._hostlist for i in range(host.slots)
]
self._slot_iterator = itertools.cycle(self._slotlist)
self._base_shutdown = self.shutdown
del self.shutdown
def shutdown(self):
for host in self._hostlist:
if host.hostname != 'localhost':
host.manager.shutdown()
self._base_shutdown()
def Process(self, group=None, target=None, name=None, args=(), kwargs={}):
slot = next(self._slot_iterator)
return slot.Process(
group=group, target=target, name=name, args=args, kwargs=kwargs
)
def Pool(self, processes=None, initializer=None, initargs=()):
return DistributedPool(self, processes, initializer, initargs)
def __getitem__(self, i):
return self._slotlist[i]
def __len__(self):
return len(self._slotlist)
def __iter__(self):
return iter(self._slotlist)
#
# Queue subclass used by distributed pool
#
class SettableQueue(queue.Queue):
def empty(self):
return not self.queue
def full(self):
return self.maxsize > 0 and len(self.queue) == self.maxsize
def set_contents(self, contents):
# length of contents must be at least as large as the number of
# threads which have potentially called get()
self.not_empty.acquire()
try:
self.queue.clear()
self.queue.extend(contents)
self.not_empty.notifyAll()
finally:
self.not_empty.release()
Cluster.register('_SettableQueue', SettableQueue)
#
# Class representing a notional cpu in the cluster
#
class Slot(object):
def __init__(self, host):
self.host = host
self.Process = host.Process
#
# Host
#
class Host(object):
'''
Represents a host to use as a node in a cluster.
`hostname` gives the name of the host. If hostname is not
"localhost" then ssh is used to log in to the host. To log in as
a different user use a host name of the form
"username@somewhere.org"
`slots` is used to specify the number of slots for processes on
the host. This affects how often processes will be allocated to
this host. Normally this should be equal to the number of cpus on
that host.
'''
def __init__(self, hostname, slots=None):
self.hostname = hostname
self.slots = slots
def _start_manager(self, index, authkey, address, files):
if self.hostname != 'localhost':
tempdir = copy_to_remote_temporary_directory(self.hostname, files)
debug('startup files copied to %s:%s', self.hostname, tempdir)
p = subprocess.Popen(
['ssh', self.hostname, 'python', '-c',
'"import os; os.chdir(%r); '
'from distributing import main; main()"' % tempdir],
stdin=subprocess.PIPE
)
data = dict(
name='BoostrappingHost', index=index,
dist_log_level=_logger.getEffectiveLevel(),
dir=tempdir, authkey=str(authkey), parent_address=address
)
pickle.dump(data, p.stdin, pickle.HIGHEST_PROTOCOL)
p.stdin.close()
#
# Copy files to remote directory, returning name of directory
#
unzip_code = '''"
import tempfile, os, sys, tarfile
tempdir = tempfile.mkdtemp(prefix='distrib-')
os.chdir(tempdir)
tf = tarfile.open(fileobj=sys.stdin, mode='r|gz')
for ti in tf:
tf.extract(ti)
print tempdir
"'''
def copy_to_remote_temporary_directory(host, files):
p = subprocess.Popen(
['ssh', host, 'python', '-c', unzip_code],
stdout=subprocess.PIPE, stdin=subprocess.PIPE
)
tf = tarfile.open(fileobj=p.stdin, mode='w|gz')
for name in files:
tf.add(name, os.path.basename(name))
tf.close()
p.stdin.close()
return p.stdout.read().rstrip()
#
# Code which runs a host manager
#
def main():
# get data from parent over stdin
data = pickle.load(sys.stdin)
sys.stdin.close()
# set some stuff
_logger.setLevel(data['dist_log_level'])
forking.prepare(data)
# create server for a `HostManager` object
server = managers.Server(HostManager._registry, ('', 0), data['authkey'])
current_process()._server = server
# report server address and number of cpus back to parent
conn = connection.Client(data['parent_address'], authkey=data['authkey'])
conn.send((data['index'], server.address, slot_count))
conn.close()
# set name etc
current_process().set_name('Host-%s:%s' % server.address)
util._run_after_forkers()
# register a cleanup function
def cleanup(directory):
debug('removing directory %s', directory)
shutil.rmtree(directory)
debug('shutting down host manager')
util.Finalize(None, cleanup, args=[data['dir']], exitpriority=0)
# start host manager
debug('remote host manager starting in %s', data['dir'])
server.serve_forever()
Doc/library/multiprocessing.rst
View file @ 394cd707
......@@ -2228,10 +2228,3 @@ Some simple benchmarks comparing :mod:`multiprocessing` with :mod:`threading`:
.. literalinclude:: ../includes/mp_benchmarks.py
An example/demo of how to use the :class:`managers.SyncManager`, :class:`Process`
and others to build a system which can distribute processes and work via a
distributed queue to a "cluster" of machines on a network, accessible via SSH.
You will need to have private key authentication for all hosts configured for
this to work.
.. literalinclude:: ../includes/mp_distributing.py
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