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							352 lines
						
					
					
						
							11 KiB
						
					
					
				
			
		
		
	
	
							352 lines
						
					
					
						
							11 KiB
						
					
					
				import functools
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import threading
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import inspect
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import sys
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import select
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import struct
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from math import sqrt
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from collections import OrderedDict, deque
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from time import time
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from tools.lib.pollable_queue import PollableQueue, Empty, Full, ExistentialError
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EndSentinel = object()
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def _sync_inner_generator(input_queue, *args, **kwargs):
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  func = args[0]
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  args = args[1:]
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  get = input_queue.get
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  while True:
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    item = get()
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    if item is EndSentinel:
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      return
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    cookie, value = item
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    yield cookie, func(value, *args, **kwargs)
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def _async_streamer_async_inner(input_queue, output_queue, generator_func, args, kwargs):
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  put = output_queue.put
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  put_end = True
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  try:
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    g = generator_func(input_queue, *args, **kwargs)
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    for item in g:
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      put((time(), item))
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    g.close()
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  except ExistentialError:
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    put_end = False
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    raise
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  finally:
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    if put_end:
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      put((None, EndSentinel))
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def _running_mean_var(ltc_stats, x):
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  old_mean, var = ltc_stats
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  mean = min(600., 0.98 * old_mean + 0.02 * x)
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  var = min(5., max(0.1, 0.98 * var + 0.02 * (mean - x) * (old_mean - x)))
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  return mean, var
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def _find_next_resend(sent_messages, ltc_stats):
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  if not sent_messages:
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    return None, None
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  oldest_sent_idx = sent_messages._OrderedDict__root[1][2]
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  send_time, _ = sent_messages[oldest_sent_idx]
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  # Assume message has been lost if it is >10 standard deviations from mean.
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  mean, var = ltc_stats
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  next_resend_time = send_time + mean + 40. * sqrt(var)
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  return oldest_sent_idx, next_resend_time
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def _do_cleanup(input_queue, output_queue, num_workers, sentinels_received, num_outstanding):
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  input_fd = input_queue.put_fd()
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  output_fd = output_queue.get_fd()
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  poller = select.epoll()
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  poller.register(input_fd, select.EPOLLOUT)
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  poller.register(output_fd, select.EPOLLIN)
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  remaining_outputs = []
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  end_sentinels_to_send = num_workers - sentinels_received
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  while sentinels_received < num_workers:
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    evts = dict(poller.poll(-1 if num_outstanding > 0 else 10.))
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    if not evts:
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      # Workers aren't responding, crash.
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      break
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    if output_fd in evts:
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      _, maybe_sentinel = output_queue.get()
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      if maybe_sentinel is EndSentinel:
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        sentinels_received += 1
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      else:
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        remaining_outputs.append(maybe_sentinel[1])
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        num_outstanding -= 1
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    if input_fd in evts:
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      if end_sentinels_to_send > 0:
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        input_queue.put_nowait(EndSentinel)
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        end_sentinels_to_send -= 1
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      else:
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        poller.modify(input_fd, 0)
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  # TODO: Raise an exception when a queue thread raises one.
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  assert sentinels_received == num_workers, (sentinels_received, num_workers)
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  assert output_queue.empty()
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  return remaining_outputs
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def _generate_results(input_stream, input_queue, worker_output_queue, output_queue,
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                      num_workers, max_outstanding):
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  pack_cookie = struct.pack
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  # Maps idx -> (send_time, input)
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  sent_messages = OrderedDict()
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  oldest_sent_idx = None
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  next_resend_time = None
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  ltc_stats = 5., 10.
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  # Maps idx -> result
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  received_messages = {}
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  next_out = 0
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  # Start things off by pulling the first value.
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  next_in_item = next(input_stream, EndSentinel)
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  inputs_remain = next_in_item is not EndSentinel
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  sentinels_received = 0
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  input_fd = input_queue.put_fd()
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  worker_output_fd = worker_output_queue.get_fd()
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  output_fd = output_queue.put_fd()
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  poller = select.epoll()
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  poller.register(input_fd, select.EPOLLOUT)
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  poller.register(worker_output_fd, select.EPOLLIN)
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  poller.register(output_fd, 0)
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  # Keep sending/retrying until the input stream and sent messages are all done.
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  while sentinels_received < num_workers and (inputs_remain or sent_messages):
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    if max_outstanding:
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      can_send_new = (len(sent_messages) < max_outstanding and
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                      len(received_messages) < max_outstanding and inputs_remain)
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    else:
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      can_send_new = inputs_remain
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    if (next_resend_time and now >= next_resend_time) or can_send_new:
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      poller.modify(input_fd, select.EPOLLOUT)
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    else:
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      poller.modify(input_fd, 0)
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    if next_resend_time:
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      t = max(0, next_resend_time - now)
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      evts = dict(poller.poll(t))
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    else:
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      evts = dict(poller.poll())
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    now = time()
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    if output_fd in evts:
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      output_queue.put_nowait(received_messages.pop(next_out))
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      next_out += 1
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      if next_out not in received_messages:
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        poller.modify(output_fd, 0)
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    if worker_output_fd in evts:
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      for receive_time, maybe_sentinel in worker_output_queue.get_multiple_nowait():
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        # Check for EndSentinel in case of worker crash.
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        if maybe_sentinel is EndSentinel:
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          sentinels_received += 1
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          continue
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        idx_bytes, value = maybe_sentinel
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        idx = struct.unpack("<Q", idx_bytes)[0]
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        # Don't store duplicates.
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        sent_message = sent_messages.pop(idx, None)
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        if sent_message is not None:
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          received_messages[idx] = value
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          ltc_stats = _running_mean_var(ltc_stats, receive_time - sent_message[0])
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          if idx == oldest_sent_idx:
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            oldest_sent_idx, next_resend_time = _find_next_resend(sent_messages, ltc_stats)
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          if idx == next_out:
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            poller.modify(output_fd, select.EPOLLOUT)
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        else:
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          if oldest_sent_idx is not None:
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            # The message was resent, so it is at least old as the oldest tracked message.
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            ltc_stats = _running_mean_var(ltc_stats, now - sent_messages[oldest_sent_idx][0])
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    elif input_fd in evts:
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      if can_send_new:
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        # We're under the limit, get the next input.
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        send_idx, send_value = next_in_item
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        input_queue.put_nowait((pack_cookie("<Q", send_idx), send_value))
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        sent_messages[next_in_item[0]] = now, next_in_item[1]
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        next_in_item = next(input_stream, EndSentinel)
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        inputs_remain = next_in_item is not EndSentinel
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        if oldest_sent_idx is None:
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          oldest_sent_idx, next_resend_time = _find_next_resend(sent_messages, ltc_stats)
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      else:
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        # Move the resent item to the end.
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        send_time, resend_input = sent_messages.pop(oldest_sent_idx)
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        sys.stdout.write("Resending {} (ltc, mean, var) = ({}, {}, {})\n".format(
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          oldest_sent_idx, now - send_time, ltc_stats[0], ltc_stats[1]))
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        input_queue.put_nowait((pack_cookie("<Q", oldest_sent_idx), resend_input))
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        sent_messages[oldest_sent_idx] = now, resend_input
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        oldest_sent_idx, next_resend_time = _find_next_resend(sent_messages, ltc_stats)
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  # Return remaining messages.
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  while next_out in received_messages:
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    output_queue.put(received_messages.pop(next_out))
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    next_out += 1
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  _do_cleanup(input_queue, worker_output_queue, num_workers, sentinels_received, 0)
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  output_queue.put(EndSentinel)
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def _generate_results_unreliable(input_stream, input_queue, worker_output_queue,
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                                 output_queue, num_workers, max_outstanding_unused):
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  # Start things off by pulling the first value.
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  next_in_item = next(input_stream, EndSentinel)
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  inputs_remain = next_in_item is not EndSentinel
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  # TODO: Use heapq to return oldest message.
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  received_messages = deque()
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  pack_cookie = struct.pack
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  input_fd = input_queue.put_fd()
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  worker_output_fd = worker_output_queue.get_fd()
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  output_fd = output_queue.put_fd()
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  poller = select.epoll()
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  poller.register(input_fd, select.EPOLLOUT)
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  poller.register(worker_output_fd, select.EPOLLIN)
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  poller.register(output_fd, 0)
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  # Keep sending/retrying until the input stream and sent messages are all done.
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  num_outstanding = 0
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  sentinels_received = 0
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  while sentinels_received < num_workers and (inputs_remain or received_messages):
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    # Avoid poll() if we can easily detect that there is work to do.
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    evts = (input_fd if inputs_remain and not input_queue.full() else 0, output_fd
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            if not output_queue.full() and len(received_messages) else 0, worker_output_fd
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            if not worker_output_queue.empty() else 0)
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    if all(evt == 0 for evt in evts):
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      evts = dict(poller.poll())
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    if output_fd in evts:
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      output_queue.put(received_messages.pop())
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      if len(received_messages) == 0:
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        poller.modify(output_fd, 0)
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    if worker_output_fd in evts:
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      for receive_time, maybe_sentinel in worker_output_queue.get_multiple():
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        # Check for EndSentinel in case of worker crash.
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        if maybe_sentinel is EndSentinel:
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          sentinels_received += 1
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          continue
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        received_messages.appendleft(maybe_sentinel[1])
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        num_outstanding -= 1
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      poller.modify(output_fd, select.EPOLLOUT)
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    if input_fd in evts:
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      # We're under the limit, get the next input.
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      send_idx, send_value = next_in_item
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      input_queue.put((pack_cookie("<Q", send_idx), send_value))
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      next_in_item = next(input_stream, EndSentinel)
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      inputs_remain = next_in_item is not EndSentinel
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      num_outstanding += 1
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      if not inputs_remain:
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        poller.modify(input_fd, 0)
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  # TODO: Track latency even though we don't retry.
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  for value in _do_cleanup(input_queue, worker_output_queue, num_workers,
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                           sentinels_received, num_outstanding):
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    output_queue.put(value)
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  output_queue.put(EndSentinel)
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def _async_generator(func, max_workers, in_q_size, out_q_size, max_outstanding,
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                     async_inner, reliable):
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  if async_inner:
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    assert inspect.isgeneratorfunction(
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      func), "async_inner == True but {} is not a generator".format(func)
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  @functools.wraps(func)
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  def wrapper(input_sequence_or_self, *args, **kwargs):
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    # HACK: Determine whether the first arg is "self". ismethod returns False here.
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    if inspect.getargspec(func).args[0] == "self":
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      inner_func = func.__get__(input_sequence_or_self, type(input_sequence_or_self))
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      input_sequence = args[0]
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      args = args[1:]
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    else:
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      inner_func = func
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      input_sequence = input_sequence_or_self
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    input_stream = enumerate(iter(input_sequence))
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    if reliable:
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      generate_func = _generate_results
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    else:
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      generate_func = _generate_results_unreliable
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    input_queue = PollableQueue(in_q_size)
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    worker_output_queue = PollableQueue(8 * max_workers)
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    output_queue = PollableQueue(out_q_size)
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    # Start the worker threads.
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    if async_inner:
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      generator_func = inner_func
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    else:
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      args = (inner_func,) + args
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      generator_func = _sync_inner_generator
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    worker_threads = []
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    for _ in range(max_workers):
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      t = threading.Thread(
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        target=_async_streamer_async_inner,
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        args=(input_queue, worker_output_queue, generator_func, args, kwargs))
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      t.daemon = True
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      t.start()
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      worker_threads.append(t)
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    master_thread = threading.Thread(
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      target=generate_func,
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      args=(input_stream, input_queue, worker_output_queue, output_queue, max_workers,
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            max_outstanding))
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    master_thread.daemon = True
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    master_thread.start()
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    try:
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      while True:
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        for value in output_queue.get_multiple():
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          if value is EndSentinel:
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            return
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          else:
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            yield value
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    finally:
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      # Make sure work is done and the threads are stopped.
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      for t in worker_threads:
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        t.join(1)
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      master_thread.join(1)
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      input_queue.close()
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      worker_output_queue.close()
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      output_queue.close()
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  return wrapper
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def async_generator(max_workers=1,
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                    in_q_size=10,
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                    out_q_size=12,
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                    max_outstanding=10000,
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                    async_inner=False,
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                    reliable=True):
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  return (
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    lambda f: _async_generator(f, max_workers, in_q_size, out_q_size, max_outstanding, async_inner, reliable)
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  )
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 |