A simple thread-safe queue in python

I'm trying to implement a kind of message queue. Tasks will come in at unknown random times, and must be executed FIFO. I can do multiple tasks in one hit, but the setup and tear down unavoidably takes some time, so I want to do as many in one 'burst' as I can - i.e. empty whatever is in the queue. I guess the worker thread should block when the queue is empty, but the class should not be blocked while it is working, and a bunch of tasks might queue up while I was processing the last lot.

Here is my first design, it seems to work but I can't help feeling it's a bit clunky and could be implemented more simply or elegantly.

class Foo(object):

  def __init__(self):
    import sys, threading, Queue, time

    def worker():
      while True:
        sys.stderr.write('getting some things from queue...')
        things = []
        try:
          things.append(q.get())
          while True:
            things.append(q.get_nowait())
        except Queue.Empty:
          pass
        n = len(things)
        sys.stderr.write('got {0} thing(s)\n'.format(n))

        # setup stuff
        time.sleep(1)
        # do some things        
        sys.stderr.write('hello {0}!\n'.format(', '.join(things)))
        # tear down stuff
        time.sleep(1)

        sys.stderr.write('processed {0} thing(s) in this iteration\n'.format(n))
        [q.task_done() for task in xrange(n)]

    q = Queue.Queue()
    n_worker_threads = 1
    for i in xrange(n_worker_threads):
      t = threading.Thread(target=worker)
      t.daemon = True
      t.start()

    self.queue = q


if __name__ == '__main__':
  print 'enter __main__'

  foo = Foo()

  foo.queue.put('world')
  foo.queue.put('cruel world')
  foo.queue.put('stack overflow')

  for i in xrange(20):
    foo.queue.put(str(i))
  import time
  time.sleep(1)
  foo.queue.put('a')
  foo.queue.put('b')
  time.sleep(1)
  foo.queue.put('1')
  foo.queue.put('2')
  foo.queue.put('3')
  print 'finish __main__'