threadpool.py

'''
file: threadpool.py
description: Inspired by http://stackoverflow.com/a/7257510
'''

from queue import Queue
from threading import Thread


class Worker(Thread):
    ''' Thread executing tasks from a given tasks queue '''

    def __init__(self, tasks):
        Thread.__init__(self)
        self.tasks = tasks
        self.daemon = True
        self.start()

    def run(self):
        while True:
            func, args, kargs = self.tasks.get()
            try:
                func(*args, **kargs)
            except Exception as e:
                print(e)
            finally:
                self.tasks.task_done()


class ThreadPool:
    ''' Pool of threads consuming tasks from a queue '''

    def __init__(self, num_threads):
        self.tasks = Queue(num_threads)
        for _ in range(num_threads):
            Worker(self.tasks)

    def add_task(self, func, *args, **kargs):
        ''' Add a task to the queue '''
        self.tasks.put((func, args, kargs))

    def map(self, func, args_list):
        ''' Add a list of tasks to the queue '''
        for args in args_list:
            self.add_task(func, args)

    def wait_completion(self):
        ''' Wait for completion of all the tasks in the queue '''
        self.tasks.join()