A simple threading-based task scheduler.

scheduler.py

from Queue import Queue, PriorityQueue
from threading import Thread


class Scheduler(Thread):
    def __init__(self, *args, **kwargs):
        super(Scheduler, self).__init__(*args, **kwargs)
        self.tasks = Queue()
        self.workers = PriorityQueue()

    def add_task(self, task):
        self.tasks.put(task)

    def add_worker(self, worker):
        self.workers.put(worker)

    def run(self):
        while True:
            task, worker = self.tasks.get(), self.workers.get()
            worker.handle_task(task)


class Worker(Thread):
    def __init__(self, scheduler=None, *args, **kwargs):
        super(Worker, self).__init__(*args, **kwargs)
        self.tasks = Queue()
        self.scheduler = scheduler

    def __lt__(self, worker):
        # workers is a priority queue
        return self.tasks.qsize() < worker.tasks.qsize()

    def handle_task(self, task):
        self.tasks.put(task)

    def run(self):
        while True:
            # work, then put worker back to worker pool
            task = self.tasks.get()
            self.work(task)
            self.scheduler.add_worker(self)

    def work(self, task):
        """Do real stuff here."""
        raise NotImplementedError()