# Tai Sakuma <tai.sakuma@gmail.com>
from __future__ import print_function
import logging
import multiprocessing
import threading
from operator import itemgetter
from ..progressbar import NullProgressMonitor
from .TaskPackage import TaskPackage
from .Worker import Worker
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# https://docs.python.org/3/howto/logging-cookbook.html#logging-to-a-single-file-from-multiple-processes
def logger_thread(queue):
while True:
record = queue.get()
if record is None:
break
logger = logging.getLogger(record.name)
logger.handle(record)
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[docs]class MultiprocessingDropbox(object):
[docs] def __init__(self, nprocesses=16, progressMonitor=None):
if nprocesses <= 0:
raise ValueError("nprocesses must be at least one: {} is given".format(nprocesses))
self.progressMonitor = NullProgressMonitor() if progressMonitor is None else progressMonitor
self.n_max_workers = nprocesses
self.workers = [ ]
self.task_queue = multiprocessing.JoinableQueue()
self.result_queue = multiprocessing.Queue()
self.logging_queue = multiprocessing.Queue()
self.lock = multiprocessing.Lock()
self.n_ongoing_tasks = 0
self.task_idx = -1 # so it starts from 0
def __repr__(self):
return '{}(progressMonitor={!r}, n_max_workers={!r}, n_ongoing_tasks={!r}, task_idx={!r})'.format(
self.__class__.__name__,
self.progressMonitor,
self.n_max_workers,
self.n_ongoing_tasks,
self.task_idx
)
def open(self):
if len(self.workers) >= self.n_max_workers:
# workers already created
return
# start logging listener
self.loggingListener = threading.Thread(
target=logger_thread, args=(self.logging_queue,)
)
self.loggingListener.start()
# start workers
for i in range(self.n_max_workers):
worker = Worker(
task_queue=self.task_queue,
result_queue=self.result_queue,
logging_queue=self.logging_queue,
progressReporter=self.progressMonitor.createReporter(),
lock=self.lock
)
worker.start()
self.workers.append(worker)
def put(self, package):
self.task_idx += 1
self.task_queue.put((self.task_idx, package))
self.n_ongoing_tasks += 1
def put_multiple(self, packages):
for package in packages:
self.put(package)
def receive(self):
messages = [ ] # a list of (task_idx, result)
while self.n_ongoing_tasks >= 1:
if self.result_queue.empty(): continue
message = self.result_queue.get()
messages.append(message)
self.n_ongoing_tasks -= 1
# sort in the order of task_idx
messages = sorted(messages, key=itemgetter(0))
results = [result for task_idx, result in messages]
return results
def terminate(self):
for worker in self.workers:
worker.terminate()
# wait until all workers are terminated.
while any([w.is_alive() for w in self.workers]):
pass
self.workers = [ ]
def close(self):
# end workers
if self.workers:
for i in range(len(self.workers)):
self.task_queue.put(None)
self.task_queue.join()
self.workers = [ ]
# end logging listener
self.logging_queue.put(None)
self.loggingListener.join()
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