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58 | import threading
import time
from Queue import Queue, Empty
def make_work(callback, tasks, limit):
"""
Run up to "limit" threads, do tasks and yield results.
Arguments:
callback - the function that will process single task
tasks - the sequence or iterator or queue of tasks
limit - the maximum number of threads
"""
# If tasks is not a Queue convert them into Queue
if not isinstance(tasks, Queue):
new_tasks = Queue()
[new_tasks.put(x) for x in tasks]
tasks = new_tasks
# Here results of task processing will be saved
results = Queue()
def _worker(tasks, results):
while True:
try:
results.put(callback(tasks.get(False)))
except Empty:
return
# Prepare and run up to "limit" threads
threads = []
for x in xrange(limit):
thread = threading.Thread(target=_worker, args=[tasks, results])
thread.start()
threads.append(thread)
# While tasks exist we can except some results in results queue
while not tasks.empty():
yield results.get()
# When tasks queue becomes empty wait for terminating of all threads
for thread in threads:
thread.join()
# Let's see if some results were placed into results queue
while not results.empty():
yield results.get()
if __name__ == '__main__':
tasks = range(100)
def worker(arg):
print '%s: %s' % (threading.currentThread(), arg)
time.sleep(0.1)
list(make_work(worker, tasks, 10))
|
