#
# This file is part of Scalable COncurrent Operations in Python (SCOOP).
#
# SCOOP is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as
# published by the Free Software Foundation, either version 3 of
# the License, or (at your option) any later version.
#
# SCOOP is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with SCOOP. If not, see <http://www.gnu.org/licenses/>.
#
from __future__ import print_function
import os
from collections import namedtuple
from functools import partial, reduce
import itertools
import scoop
from scoop._types import Future, NotStartedProperly, CallbackType
from scoop.reduction import reduction
from scoop import _control as control
# Constants stated by PEP 3148 (http://www.python.org/dev/peps/pep-3148/#module-functions)
FIRST_COMPLETED = 'FIRST_COMPLETED'
FIRST_EXCEPTION = 'FIRST_EXCEPTION'
ALL_COMPLETED = 'ALL_COMPLETED'
_AS_COMPLETED = '_AS_COMPLETED'
# This is the greenlet for running the controller logic.
_controller = None
callbackGroupID = itertools.count()
def _startup(rootFuture, *args, **kargs):
"""Initializes the SCOOP environment.
:param rootFuture: Any callable object (function or class object with *__call__*
method); this object will be called once and allows the use of parallel
calls inside this object.
:param args: A tuple of positional arguments that will be passed to the
callable object.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the callable object.
:returns: The result of the root Future.
Be sure to launch your root Future using this method."""
import greenlet
global _controller
_controller = greenlet.greenlet(control.runController)
try:
result = _controller.switch(rootFuture, *args, **kargs)
except scoop._comm.Shutdown:
result = None
control.execQueue.shutdown()
if scoop.DEBUG:
from scoop import _debug
_debug.writeWorkerDebug(control.debug_stats,
control.QueueLength)
return result
def _mapFuture(callable, *iterables, **kargs):
"""Similar to the built-in map function, but each of its
iteration will spawn a separate independent parallel Future that will run
either locally or remotely as `callable(*args, **kargs)`.
:param callable: Any callable object (function or class object with *__call__*
method); this object will be called to execute each Future.
:param iterables: A tuple of iterable objects; each will be zipped
to form an iterable of arguments tuples that will be passed to the
callable object as a separate Future.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the callable object.
:returns: A list of Future objects, each corresponding to an iteration of
map.
On return, the Futures are pending execution locally, but may also be
transfered remotely depending on global load. Execution may be carried on
with any further computations. To retrieve the map results, you need to
either wait for or join with the spawned Futures. See functions waitAny,
waitAll, or joinAll. Alternatively, You may also use functions mapWait or
mapJoin that will wait or join before returning."""
childrenList = []
for args in zip(*iterables):
childrenList.append(submit(callable, *args, **kargs))
return childrenList
[docs]def map(func, *iterables, **kargs):
"""Equivalent to
`map(func, \*iterables, ...)
<http://docs.python.org/library/functions.html#map>`_
but *func* is executed asynchronously
and several calls to func may be made concurrently. The returned iterator
raises a TimeoutError if *__next__()* is called and the result isn't
available after timeout seconds from the original call to *map()* [To be
done in future version of SCOOP]. If timeout is not specified or None then
there is no limit to the wait time. If a call raises an exception then that
exception will be raised when its value is retrieved from the iterator.
:param func: Any picklable callable object (function or class object with
*__call__* method); this object will be called to execute the Futures.
The callable must return a value.
:param iterables: Iterable objects; each will be zipped to form an iterable
of arguments tuples that will be passed to the callable object as a
separate Future.
:param timeout: The maximum number of seconds to wait [To be done in future
version of SCOOP]. If None, then there is no limit on the wait time.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the callable object.
:returns: A generator of map results, each corresponding to one map
iteration."""
# Remove 'timeout' from kargs to be compliant with the futures API
kargs.pop('timeout', None)
for future in _waitAll(*_mapFuture(func, *iterables, **kargs)):
yield future.resultValue
[docs]def mapScan(mapFunc, reductionOp, *iterables, **kargs):
"""Exectues the :meth:`~scoop.futures.map` function and then applies a
reduction function to its result while keeping intermediate reduction
values.
:param mapFunc: Any picklable callable object (function or class object with
*__call__* method); this object will be called to execute the Futures.
The callable must return a value.
:param reductionOp: Any picklable callable object (function or class object
with *__call__* method); this object will be called to reduce the
Futures results. The callable must support two parameters and return a
single value.
:param iterables: Iterable objects; each will be zipped to form an iterable
of arguments tuples that will be passed to the callable object as a
separate Future.
:param timeout: The maximum number of seconds to wait [To be done in future
version of SCOOP]. If None, then there is no limit on the wait time.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the mapFunc callable object.
:returns: Every return value of the reduction function applied to every
mapped data sequentially ordered."""
kargs.pop('timeout', None)
launches = []
thisCallbackGroupID = next(callbackGroupID)
for args in zip(*iterables):
try:
child = Future(control.current.id, mapFunc, *args, **kargs)
except AttributeError:
raise NotStartedProperly("SCOOP was not started properly.\n"
"Be sure to start your program with the "
"'-m scoop' parameter. You can find further "
"information in the documentation.")
child = Future(control.current.id, mapFunc, *args, **kargs)
child.add_done_callback(partial(reduction, operation=reductionOp),
inCallbackType=CallbackType.universal,
inCallbackGroup=thisCallbackGroupID)
control.futureDict[control.current.id].children[child] = None
control.execQueue.append(child)
launches.append(child)
workerResults = {}
# Execute the task
for future in _waitAll(*launches):
workerResults.setdefault(future.executor, []).append(future.result())
# Cleanup phase
control.execQueue.socket.eraseBuffer(thisCallbackGroupID)
return workerResults
[docs]def mapReduce(mapFunc, reductionOp, *iterables, **kargs):
"""Exectues the :meth:`~scoop.futures.map` function and then applies a
reduction function to its result. The reduction function will cumulatively
merge the results of the map function in order to get a final single value.
:param mapFunc: Any picklable callable object (function or class object with
*__call__* method); this object will be called to execute the Futures.
The callable must return a value.
:param reductionOp: Any picklable callable object (function or class object
with *__call__* method); this object will be called to reduce the
Futures results. The callable must support two parameters and return a
single value.
:param iterables: Iterable objects; each will be zipped to form an iterable
of arguments tuples that will be passed to the callable object as a
separate Future.
:param timeout: The maximum number of seconds to wait [To be done in future
version of SCOOP]. If None, then there is no limit on the wait time.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the mapFunc callable object.
:returns: A single value."""
# TODO: make DRY with submit
launches = []
# Set a callback group ID for the Futures generated within this scope
thisCallbackGroupID = (control.current.id, next(callbackGroupID))
for args in zip(*iterables):
try:
child = Future(control.current.id, mapFunc, *args, **kargs)
except AttributeError:
raise NotStartedProperly("SCOOP was not started properly.\n"
"Be sure to start your program with the "
"'-m scoop' parameter. You can find further "
"information in the documentation.")
child = Future(control.current.id, mapFunc, *args, **kargs)
child.add_done_callback(partial(reduction, operation=reductionOp),
inCallbackType=CallbackType.universal,
inCallbackGroup=thisCallbackGroupID)
control.futureDict[control.current.id].children[child] = None
control.execQueue.append(child)
launches.append(child)
workerResults = {}
# Execute the task
for future in sorted(_waitAll(*launches), key=lambda x: x.executor[1]):
workerResults[(future.executor[0], future.executor[2])] = future.result()
# Cleanup phase
control.execQueue.socket.eraseBuffer(thisCallbackGroupID)
return reduce(reductionOp, workerResults.values())
[docs]def submit(func, *args, **kargs):
"""Submit an independent parallel :class:`~scoop._types.Future` that will
either run locally or remotely as `func(*args, **kargs)`.
:param func: Any picklable callable object (function or class object with
*__call__* method); this object will be called to execute the Future.
The callable must return a value.
:param args: A tuple of positional arguments that will be passed to the
callable object.
:param kargs: A dictionary of additional keyword arguments that will be
passed to the callable object.
:returns: A future object for retrieving the Future result.
On return, the Future can be pending execution locally but may also be
transfered remotely depending on load or on remote distributed workers. You
may carry on with any further computations while the Future completes.
Result retrieval is made via the :meth:`~scoop._types.Future.result`
function on the Future."""
assert hasattr(func, "__call__"), ("The provided func parameter is not a "
"callable")
try:
child = Future(control.current.id, func, *args, **kargs)
except AttributeError:
raise NotStartedProperly("SCOOP was not started properly.\n"
"Be sure to start your program with the "
"'-m scoop' parameter. You can find further "
"information in the documentation.")
control.futureDict[control.current.id].children[child] = None
control.execQueue.append(child)
return child
def _waitAny(*children):
"""Waits on any child Future created by the calling Future.
:param children: A tuple of children Future objects spawned by the calling
Future.
:return: A generator function that iterates on futures that are done.
The generator produces results of the children in a non deterministic order
that depends on the particular parallel execution of the Futures. The
generator returns a tuple as soon as one becomes available."""
n = len(children)
# check for available results and index those unavailable
for index, future in enumerate(children):
if future.exceptionValue is not None:
raise future.exceptionValue
if future.resultValue is not None:
yield future
n -= 1
else:
future.index = index
future = control.current
while n > 0:
# wait for remaining results; switch to controller
future.stopWatch.halt()
childFuture = _controller.switch(future)
future.stopWatch.resume()
if childFuture.exceptionValue:
raise childFuture.exceptionValue
yield childFuture
n -= 1
def _waitAll(*children):
"""Wait on all child futures specified by a tuple of previously created
Future.
:param children: A tuple of children Future objects spawned by the calling
Future.
:return: A generator function that iterates on Future results.
The generator produces results in the order that they are specified by
the children argument. Because Futures are executed in a non deterministic
order, the generator may have to wait for the last result to become
available before it can produce an output. See waitAny for an alternative
option."""
for future in children:
for f in _waitAny(future):
yield f
[docs]def wait(fs, timeout=None, return_when=ALL_COMPLETED):
"""Wait for the futures in the given sequence to complete.
:param fs: The sequence of Futures (possibly created by another instance) to
wait upon.
:param timeout: The maximum number of seconds to wait [To be done in future
version of SCOOP]. If None, then there
is no limit on the wait time.
:param return_when: Indicates when this function should return. The options
are:
=============== ================================================
FIRST_COMPLETED Return when any future finishes or is cancelled.
FIRST_EXCEPTION Return when any future finishes by raising an
exception. If no future raises an exception then
it is equivalent to ALL_COMPLETED.
ALL_COMPLETED Return when all futures finish or are cancelled.
=============== ================================================
:return: A named 2-tuple of sets. The first set, named 'done', contains the
futures that completed (is finished or cancelled) before the wait
completed. The second set, named 'not_done', contains uncompleted
futures."""
DoneAndNotDoneFutures = namedtuple('DoneAndNotDoneFutures', 'done not_done')
if return_when == FIRST_COMPLETED:
for future in _waitAny(*fs):
break
elif return_when == ALL_COMPLETED:
for future in _waitAll(*fs):
pass
elif return_when == FIRST_EXCEPTION:
for future in _waitAny(*fs):
if future.exceptionValue is not None:
break
done = set(f for f in fs if f.done())
not_done = set(fs) - done
return DoneAndNotDoneFutures(done, not_done)
[docs]def as_completed(fs, timeout=None):
"""An iterator over the given futures that yields each as it completes.
:param fs: The sequence of Futures (possibly created by another instance) to
wait upon.
:param timeout: The maximum number of seconds to wait [To be done in future
version of SCOOP]. If None, then there
is no limit on the wait time.
:return: An iterator that yields the given Futures as they complete
(finished or cancelled).
"""
return _waitAny(*fs)
def _join(child):
"""This private function is for joining the current Future with one of its
child Future.
:param child: A child Future object spawned by the calling Future.
:return: The result of the child Future.
Only one Future can be specified. The function returns a single
corresponding result as soon as it becomes available."""
for future in _waitAny(child):
return future.resultValue
def _joinAll(*children):
"""This private function is for joining the current Future with all of the
children Futures specified in a tuple.
:param children: A tuple of children Future objects spawned by the calling
Future.
:return: A list of corresponding results for the children Futures.
This function will wait for the completion of all specified child Futures
before returning to the caller."""
return [_join(future) for future in _waitAll(*children)]
[docs]def shutdown(wait=True):
"""This function is here for compatibility with `futures` (PEP 3148).
:param wait: Unapplied parameter."""
pass
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