Module threading
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Source Code for Module threading

  1  """Thread module emulating a subset of Java's threading model.""" 
  2   
  3  import sys as _sys 
  4   
  5  try: 
  6      import thread 
  7  except ImportError: 
  8      del _sys.modules[__name__] 
  9      raise 
 10   
 11  from time import time as _time, sleep as _sleep 
 12  from traceback import format_exc as _format_exc 
 13  from collections import deque 
 14   
 15  # Rename some stuff so "from threading import *" is safe 
 16  __all__ = ['activeCount', 'Condition', 'currentThread', 'enumerate', 'Event', 
 17             'Lock', 'RLock', 'Semaphore', 'BoundedSemaphore', 'Thread', 
 18             'Timer', 'setprofile', 'settrace', 'local', 'stack_size'] 
 19   
 20  _start_new_thread = thread.start_new_thread 
 21  _allocate_lock = thread.allocate_lock 
 22  _get_ident = thread.get_ident 
 23  ThreadError = thread.error 
 24  del thread 
 25   
 26   
 27  # Debug support (adapted from ihooks.py). 
 28  # All the major classes here derive from _Verbose.  We force that to 
 29  # be a new-style class so that all the major classes here are new-style. 
 30  # This helps debugging (type(instance) is more revealing for instances 
 31  # of new-style classes). 
 32   
 33  _VERBOSE = False 
 34   
 35  if __debug__: 
 36   
37 - class _Verbose(object):
38
39 - def __init__(self, verbose=None):
40 if verbose is None: 41 verbose = _VERBOSE 42 self.__verbose = verbose
43
44 - def _note(self, format, *args):
45 if self.__verbose: 46 format = format % args 47 format = "%s: %s\n" % ( 48 currentThread().getName(), format) 49 _sys.stderr.write(format)
50 51 else: 52 # Disable this when using "python -O"
53 - class _Verbose(object):
54 - def __init__(self, verbose=None):
55 pass
56 - def _note(self, *args):
57 pass
58 59 # Support for profile and trace hooks 60 61 _profile_hook = None 62 _trace_hook = None 63
64 -def setprofile(func):
65 global _profile_hook 66 _profile_hook = func
67
68 -def settrace(func):
69 global _trace_hook 70 _trace_hook = func
71 72 # Synchronization classes 73 74 Lock = _allocate_lock 75
76 -def RLock(*args, **kwargs):
77 return _RLock(*args, **kwargs)
78
79 -class _RLock(_Verbose):
80
81 - def __init__(self, verbose=None):
82 _Verbose.__init__(self, verbose) 83 self.__block = _allocate_lock() 84 self.__owner = None 85 self.__count = 0
86
87 - def __repr__(self):
88 owner = self.__owner 89 return "<%s(%s, %d)>" % ( 90 self.__class__.__name__, 91 owner and owner.getName(), 92 self.__count)
93
94 - def acquire(self, blocking=1):
95 me = currentThread() 96 if self.__owner is me: 97 self.__count = self.__count + 1 98 if __debug__: 99 self._note("%s.acquire(%s): recursive success", self, blocking) 100 return 1 101 rc = self.__block.acquire(blocking) 102 if rc: 103 self.__owner = me 104 self.__count = 1 105 if __debug__: 106 self._note("%s.acquire(%s): initial success", self, blocking) 107 else: 108 if __debug__: 109 self._note("%s.acquire(%s): failure", self, blocking) 110 return rc
111 112 __enter__ = acquire 113
114 - def release(self):
115 if self.__owner is not currentThread(): 116 raise RuntimeError("cannot release un-aquired lock") 117 self.__count = count = self.__count - 1 118 if not count: 119 self.__owner = None 120 self.__block.release() 121 if __debug__: 122 self._note("%s.release(): final release", self) 123 else: 124 if __debug__: 125 self._note("%s.release(): non-final release", self)
126
127 - def __exit__(self, t, v, tb):
128 self.release()
129 130 # Internal methods used by condition variables 131
132 - def _acquire_restore(self, (count, owner)):
133 self.__block.acquire() 134 self.__count = count 135 self.__owner = owner 136 if __debug__: 137 self._note("%s._acquire_restore()", self)
138
139 - def _release_save(self):
140 if __debug__: 141 self._note("%s._release_save()", self) 142 count = self.__count 143 self.__count = 0 144 owner = self.__owner 145 self.__owner = None 146 self.__block.release() 147 return (count, owner)
148
149 - def _is_owned(self):
150 return self.__owner is currentThread()
151 152
153 -def Condition(*args, **kwargs):
154 return _Condition(*args, **kwargs)
155
156 -class _Condition(_Verbose):
157
158 - def __init__(self, lock=None, verbose=None):
159 _Verbose.__init__(self, verbose) 160 if lock is None: 161 lock = RLock() 162 self.__lock = lock 163 # Export the lock's acquire() and release() methods 164 self.acquire = lock.acquire 165 self.release = lock.release 166 # If the lock defines _release_save() and/or _acquire_restore(), 167 # these override the default implementations (which just call 168 # release() and acquire() on the lock). Ditto for _is_owned(). 169 try: 170 self._release_save = lock._release_save 171 except AttributeError: 172 pass 173 try: 174 self._acquire_restore = lock._acquire_restore 175 except AttributeError: 176 pass 177 try: 178 self._is_owned = lock._is_owned 179 except AttributeError: 180 pass 181 self.__waiters = []
182
183 - def __enter__(self):
184 return self.__lock.__enter__()
185
186 - def __exit__(self, *args):
187 return self.__lock.__exit__(*args)
188
189 - def __repr__(self):
190 return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
191
192 - def _release_save(self):
193 self.__lock.release() # No state to save
194
195 - def _acquire_restore(self, x):
196 self.__lock.acquire() # Ignore saved state
197
198 - def _is_owned(self):
199 # Return True if lock is owned by currentThread. 200 # This method is called only if __lock doesn't have _is_owned(). 201 if self.__lock.acquire(0): 202 self.__lock.release() 203 return False 204 else: 205 return True
206
207 - def wait(self, timeout=None):
208 if not self._is_owned(): 209 raise RuntimeError("cannot wait on un-aquired lock") 210 waiter = _allocate_lock() 211 waiter.acquire() 212 self.__waiters.append(waiter) 213 saved_state = self._release_save() 214 try: # restore state no matter what (e.g., KeyboardInterrupt) 215 if timeout is None: 216 waiter.acquire() 217 if __debug__: 218 self._note("%s.wait(): got it", self) 219 else: 220 # Balancing act: We can't afford a pure busy loop, so we 221 # have to sleep; but if we sleep the whole timeout time, 222 # we'll be unresponsive. The scheme here sleeps very 223 # little at first, longer as time goes on, but never longer 224 # than 20 times per second (or the timeout time remaining). 225 endtime = _time() + timeout 226 delay = 0.0005 # 500 us -> initial delay of 1 ms 227 while True: 228 gotit = waiter.acquire(0) 229 if gotit: 230 break 231 remaining = endtime - _time() 232 if remaining <= 0: 233 break 234 delay = min(delay * 2, remaining, .05) 235 _sleep(delay) 236 if not gotit: 237 if __debug__: 238 self._note("%s.wait(%s): timed out", self, timeout) 239 try: 240 self.__waiters.remove(waiter) 241 except ValueError: 242 pass 243 else: 244 if __debug__: 245 self._note("%s.wait(%s): got it", self, timeout) 246 finally: 247 self._acquire_restore(saved_state)
248
249 - def notify(self, n=1):
250 if not self._is_owned(): 251 raise RuntimeError("cannot notify on un-aquired lock") 252 __waiters = self.__waiters 253 waiters = __waiters[:n] 254 if not waiters: 255 if __debug__: 256 self._note("%s.notify(): no waiters", self) 257 return 258 self._note("%s.notify(): notifying %d waiter%s", self, n, 259 n!=1 and "s" or "") 260 for waiter in waiters: 261 waiter.release() 262 try: 263 __waiters.remove(waiter) 264 except ValueError: 265 pass
266
267 - def notifyAll(self):
268 self.notify(len(self.__waiters))
269 270
271 -def Semaphore(*args, **kwargs):
272 return _Semaphore(*args, **kwargs)
273
274 -class _Semaphore(_Verbose):
275 276 # After Tim Peters' semaphore class, but not quite the same (no maximum) 277
278 - def __init__(self, value=1, verbose=None):
279 if value < 0: 280 raise ValueError("semaphore initial value must be >= 0") 281 _Verbose.__init__(self, verbose) 282 self.__cond = Condition(Lock()) 283 self.__value = value
284
285 - def acquire(self, blocking=1):
286 rc = False 287 self.__cond.acquire() 288 while self.__value == 0: 289 if not blocking: 290 break 291 if __debug__: 292 self._note("%s.acquire(%s): blocked waiting, value=%s", 293 self, blocking, self.__value) 294 self.__cond.wait() 295 else: 296 self.__value = self.__value - 1 297 if __debug__: 298 self._note("%s.acquire: success, value=%s", 299 self, self.__value) 300 rc = True 301 self.__cond.release() 302 return rc
303 304 __enter__ = acquire 305
306 - def release(self):
307 self.__cond.acquire() 308 self.__value = self.__value + 1 309 if __debug__: 310 self._note("%s.release: success, value=%s", 311 self, self.__value) 312 self.__cond.notify() 313 self.__cond.release()
314
315 - def __exit__(self, t, v, tb):
316 self.release()
317 318
319 -def BoundedSemaphore(*args, **kwargs):
320 return _BoundedSemaphore(*args, **kwargs)
321
322 -class _BoundedSemaphore(_Semaphore):
323 """Semaphore that checks that # releases is <= # acquires"""
324 - def __init__(self, value=1, verbose=None):
325 _Semaphore.__init__(self, value, verbose) 326 self._initial_value = value
327
328 - def release(self):
329 if self._Semaphore__value >= self._initial_value: 330 raise ValueError, "Semaphore released too many times" 331 return _Semaphore.release(self)
332 333
334 -def Event(*args, **kwargs):
335 return _Event(*args, **kwargs)
336
337 -class _Event(_Verbose):
338 339 # After Tim Peters' event class (without is_posted()) 340
341 - def __init__(self, verbose=None):
342 _Verbose.__init__(self, verbose) 343 self.__cond = Condition(Lock()) 344 self.__flag = False
345
346 - def isSet(self):
347 return self.__flag
348
349 - def set(self):
350 self.__cond.acquire() 351 try: 352 self.__flag = True 353 self.__cond.notifyAll() 354 finally: 355 self.__cond.release()
356
357 - def clear(self):
358 self.__cond.acquire() 359 try: 360 self.__flag = False 361 finally: 362 self.__cond.release()
363
364 - def wait(self, timeout=None):
365 self.__cond.acquire() 366 try: 367 if not self.__flag: 368 self.__cond.wait(timeout) 369 finally: 370 self.__cond.release()
371 372 # Helper to generate new thread names 373 _counter = 0
374 -def _newname(template="Thread-%d"):
375 global _counter 376 _counter = _counter + 1 377 return template % _counter
378 379 # Active thread administration 380 _active_limbo_lock = _allocate_lock() 381 _active = {} # maps thread id to Thread object 382 _limbo = {} 383 384 385 # Main class for threads 386
387 -class Thread(_Verbose):
388 389 __initialized = False 390 # Need to store a reference to sys.exc_info for printing 391 # out exceptions when a thread tries to use a global var. during interp. 392 # shutdown and thus raises an exception about trying to perform some 393 # operation on/with a NoneType 394 __exc_info = _sys.exc_info 395
396 - def __init__(self, group=None, target=None, name=None, 397 args=(), kwargs=None, verbose=None):
398 assert group is None, "group argument must be None for now" 399 _Verbose.__init__(self, verbose) 400 if kwargs is None: 401 kwargs = {} 402 self.__target = target 403 self.__name = str(name or _newname()) 404 self.__args = args 405 self.__kwargs = kwargs 406 self.__daemonic = self._set_daemon() 407 self.__started = False 408 self.__stopped = False 409 self.__block = Condition(Lock()) 410 self.__initialized = True 411 # sys.stderr is not stored in the class like 412 # sys.exc_info since it can be changed between instances 413 self.__stderr = _sys.stderr
414
415 - def _set_daemon(self):
416 # Overridden in _MainThread and _DummyThread 417 return currentThread().isDaemon()
418
419 - def __repr__(self):
420 assert self.__initialized, "Thread.__init__() was not called" 421 status = "initial" 422 if self.__started: 423 status = "started" 424 if self.__stopped: 425 status = "stopped" 426 if self.__daemonic: 427 status = status + " daemon" 428 return "<%s(%s, %s)>" % (self.__class__.__name__, self.__name, status)
429
430 - def start(self):
431 if not self.__initialized: 432 raise RuntimeError("thread.__init__() not called") 433 if self.__started: 434 raise RuntimeError("thread already started") 435 if __debug__: 436 self._note("%s.start(): starting thread", self) 437 _active_limbo_lock.acquire() 438 _limbo[self] = self 439 _active_limbo_lock.release() 440 _start_new_thread(self.__bootstrap, ()) 441 self.__started = True 442 _sleep(0.000001) # 1 usec, to let the thread run (Solaris hack)
443
444 - def run(self):
445 if self.__target: 446 self.__target(*self.__args, **self.__kwargs)
447
448 - def __bootstrap(self):
449 # Wrapper around the real bootstrap code that ignores 450 # exceptions during interpreter cleanup. Those typically 451 # happen when a daemon thread wakes up at an unfortunate 452 # moment, finds the world around it destroyed, and raises some 453 # random exception *** while trying to report the exception in 454 # __bootstrap_inner() below ***. Those random exceptions 455 # don't help anybody, and they confuse users, so we suppress 456 # them. We suppress them only when it appears that the world 457 # indeed has already been destroyed, so that exceptions in 458 # __bootstrap_inner() during normal business hours are properly 459 # reported. Also, we only suppress them for daemonic threads; 460 # if a non-daemonic encounters this, something else is wrong. 461 try: 462 self.__bootstrap_inner() 463 except: 464 if self.__daemonic and _sys is None: 465 return 466 raise
467
468 - def __bootstrap_inner(self):
469 try: 470 self.__started = True 471 _active_limbo_lock.acquire() 472 _active[_get_ident()] = self 473 del _limbo[self] 474 _active_limbo_lock.release() 475 if __debug__: 476 self._note("%s.__bootstrap(): thread started", self) 477 478 if _trace_hook: 479 self._note("%s.__bootstrap(): registering trace hook", self) 480 _sys.settrace(_trace_hook) 481 if _profile_hook: 482 self._note("%s.__bootstrap(): registering profile hook", self) 483 _sys.setprofile(_profile_hook) 484 485 try: 486 self.run() 487 except SystemExit: 488 if __debug__: 489 self._note("%s.__bootstrap(): raised SystemExit", self) 490 except: 491 if __debug__: 492 self._note("%s.__bootstrap(): unhandled exception", self) 493 # If sys.stderr is no more (most likely from interpreter 494 # shutdown) use self.__stderr. Otherwise still use sys (as in 495 # _sys) in case sys.stderr was redefined since the creation of 496 # self. 497 if _sys: 498 _sys.stderr.write("Exception in thread %s:\n%s\n" % 499 (self.getName(), _format_exc())) 500 else: 501 # Do the best job possible w/o a huge amt. of code to 502 # approximate a traceback (code ideas from 503 # Lib/traceback.py) 504 exc_type, exc_value, exc_tb = self.__exc_info() 505 try: 506 print>>self.__stderr, ( 507 "Exception in thread " + self.getName() + 508 " (most likely raised during interpreter shutdown):") 509 print>>self.__stderr, ( 510 "Traceback (most recent call last):") 511 while exc_tb: 512 print>>self.__stderr, ( 513 ' File "%s", line %s, in %s' % 514 (exc_tb.tb_frame.f_code.co_filename, 515 exc_tb.tb_lineno, 516 exc_tb.tb_frame.f_code.co_name)) 517 exc_tb = exc_tb.tb_next 518 print>>self.__stderr, ("%s: %s" % (exc_type, exc_value)) 519 # Make sure that exc_tb gets deleted since it is a memory 520 # hog; deleting everything else is just for thoroughness 521 finally: 522 del exc_type, exc_value, exc_tb 523 else: 524 if __debug__: 525 self._note("%s.__bootstrap(): normal return", self) 526 finally: 527 _active_limbo_lock.acquire() 528 try: 529 self.__stop() 530 try: 531 # We don't call self.__delete() because it also 532 # grabs _active_limbo_lock. 533 del _active[_get_ident()] 534 except: 535 pass 536 finally: 537 _active_limbo_lock.release()
538
539 - def __stop(self):
540 self.__block.acquire() 541 self.__stopped = True 542 self.__block.notifyAll() 543 self.__block.release()
544
545 - def __delete(self):
546 "Remove current thread from the dict of currently running threads." 547 548 # Notes about running with dummy_thread: 549 # 550 # Must take care to not raise an exception if dummy_thread is being 551 # used (and thus this module is being used as an instance of 552 # dummy_threading). dummy_thread.get_ident() always returns -1 since 553 # there is only one thread if dummy_thread is being used. Thus 554 # len(_active) is always <= 1 here, and any Thread instance created 555 # overwrites the (if any) thread currently registered in _active. 556 # 557 # An instance of _MainThread is always created by 'threading'. This 558 # gets overwritten the instant an instance of Thread is created; both 559 # threads return -1 from dummy_thread.get_ident() and thus have the 560 # same key in the dict. So when the _MainThread instance created by 561 # 'threading' tries to clean itself up when atexit calls this method 562 # it gets a KeyError if another Thread instance was created. 563 # 564 # This all means that KeyError from trying to delete something from 565 # _active if dummy_threading is being used is a red herring. But 566 # since it isn't if dummy_threading is *not* being used then don't 567 # hide the exception. 568 569 _active_limbo_lock.acquire() 570 try: 571 try: 572 del _active[_get_ident()] 573 except KeyError: 574 if 'dummy_threading' not in _sys.modules: 575 raise 576 finally: 577 _active_limbo_lock.release()
578
579 - def join(self, timeout=None):
580 if not self.__initialized: 581 raise RuntimeError("Thread.__init__() not called") 582 if not self.__started: 583 raise RuntimeError("cannot join thread before it is started") 584 if self is currentThread(): 585 raise RuntimeError("cannot join current thread") 586 587 if __debug__: 588 if not self.__stopped: 589 self._note("%s.join(): waiting until thread stops", self) 590 self.__block.acquire() 591 try: 592 if timeout is None: 593 while not self.__stopped: 594 self.__block.wait() 595 if __debug__: 596 self._note("%s.join(): thread stopped", self) 597 else: 598 deadline = _time() + timeout 599 while not self.__stopped: 600 delay = deadline - _time() 601 if delay <= 0: 602 if __debug__: 603 self._note("%s.join(): timed out", self) 604 break 605 self.__block.wait(delay) 606 else: 607 if __debug__: 608 self._note("%s.join(): thread stopped", self) 609 finally: 610 self.__block.release()
611
612 - def getName(self):
613 assert self.__initialized, "Thread.__init__() not called" 614 return self.__name
615
616 - def setName(self, name):
617 assert self.__initialized, "Thread.__init__() not called" 618 self.__name = str(name)
619
620 - def isAlive(self):
621 assert self.__initialized, "Thread.__init__() not called" 622 return self.__started and not self.__stopped
623
624 - def isDaemon(self):
625 assert self.__initialized, "Thread.__init__() not called" 626 return self.__daemonic
627
628 - def setDaemon(self, daemonic):
629 if not self.__initialized: 630 raise RuntimeError("Thread.__init__() not called") 631 if self.__started: 632 raise RuntimeError("cannot set daemon status of active thread"); 633 self.__daemonic = daemonic
634 635 # The timer class was contributed by Itamar Shtull-Trauring 636
637 -def Timer(*args, **kwargs):
638 return _Timer(*args, **kwargs)
639
640 -class _Timer(Thread):
641 """Call a function after a specified number of seconds: 642 643 t = Timer(30.0, f, args=[], kwargs={}) 644 t.start() 645 t.cancel() # stop the timer's action if it's still waiting 646 """ 647
648 - def __init__(self, interval, function, args=[], kwargs={}):
649 Thread.__init__(self) 650 self.interval = interval 651 self.function = function 652 self.args = args 653 self.kwargs = kwargs 654 self.finished = Event()
655
656 - def cancel(self):
657 """Stop the timer if it hasn't finished yet""" 658 self.finished.set()
659
660 - def run(self):
661 self.finished.wait(self.interval) 662 if not self.finished.isSet(): 663 self.function(*self.args, **self.kwargs) 664 self.finished.set()
665 666 # Special thread class to represent the main thread 667 # This is garbage collected through an exit handler 668
669 -class _MainThread(Thread):
670
671 - def __init__(self):
672 Thread.__init__(self, name="MainThread") 673 self._Thread__started = True 674 _active_limbo_lock.acquire() 675 _active[_get_ident()] = self 676 _active_limbo_lock.release()
677
678 - def _set_daemon(self):
679 return False
680
681 - def _exitfunc(self):
682 self._Thread__stop() 683 t = _pickSomeNonDaemonThread() 684 if t: 685 if __debug__: 686 self._note("%s: waiting for other threads", self) 687 while t: 688 t.join() 689 t = _pickSomeNonDaemonThread() 690 if __debug__: 691 self._note("%s: exiting", self) 692 self._Thread__delete()
693
694 -def _pickSomeNonDaemonThread():
695 for t in enumerate(): 696 if not t.isDaemon() and t.isAlive(): 697 return t 698 return None
699 700 701 # Dummy thread class to represent threads not started here. 702 # These aren't garbage collected when they die, nor can they be waited for. 703 # If they invoke anything in threading.py that calls currentThread(), they 704 # leave an entry in the _active dict forever after. 705 # Their purpose is to return *something* from currentThread(). 706 # They are marked as daemon threads so we won't wait for them 707 # when we exit (conform previous semantics). 708
709 -class _DummyThread(Thread):
710
711 - def __init__(self):
712 Thread.__init__(self, name=_newname("Dummy-%d")) 713 714 # Thread.__block consumes an OS-level locking primitive, which 715 # can never be used by a _DummyThread. Since a _DummyThread 716 # instance is immortal, that's bad, so release this resource. 717 del self._Thread__block 718 719 self._Thread__started = True 720 _active_limbo_lock.acquire() 721 _active[_get_ident()] = self 722 _active_limbo_lock.release()
723
724 - def _set_daemon(self):
725 return True
726
727 - def join(self, timeout=None):
728 assert False, "cannot join a dummy thread"
729 730 731 # Global API functions 732
733 -def currentThread():
734 try: 735 return _active[_get_ident()] 736 except KeyError: 737 ##print "currentThread(): no current thread for", _get_ident() 738 return _DummyThread()
739
740 -def activeCount():
741 _active_limbo_lock.acquire() 742 count = len(_active) + len(_limbo) 743 _active_limbo_lock.release() 744 return count
745
746 -def enumerate():
747 _active_limbo_lock.acquire() 748 active = _active.values() + _limbo.values() 749 _active_limbo_lock.release() 750 return active
751 752 from thread import stack_size 753 754 # Create the main thread object, 755 # and make it available for the interpreter 756 # (Py_Main) as threading._shutdown. 757 758 _shutdown = _MainThread()._exitfunc 759 760 # get thread-local implementation, either from the thread 761 # module, or from the python fallback 762 763 try: 764 from thread import _local as local 765 except ImportError: 766 from _threading_local import local 767 768 769 # Self-test code 770
771 -def _test():
772 773 class BoundedQueue(_Verbose): 774 775 def __init__(self, limit): 776 _Verbose.__init__(self) 777 self.mon = RLock() 778 self.rc = Condition(self.mon) 779 self.wc = Condition(self.mon) 780 self.limit = limit 781 self.queue = deque()
782 783 def put(self, item): 784 self.mon.acquire() 785 while len(self.queue) >= self.limit: 786 self._note("put(%s): queue full", item) 787 self.wc.wait() 788 self.queue.append(item) 789 self._note("put(%s): appended, length now %d", 790 item, len(self.queue)) 791 self.rc.notify() 792 self.mon.release() 793 794 def get(self): 795 self.mon.acquire() 796 while not self.queue: 797 self._note("get(): queue empty") 798 self.rc.wait() 799 item = self.queue.popleft() 800 self._note("get(): got %s, %d left", item, len(self.queue)) 801 self.wc.notify() 802 self.mon.release() 803 return item 804 805 class ProducerThread(Thread): 806 807 def __init__(self, queue, quota): 808 Thread.__init__(self, name="Producer") 809 self.queue = queue 810 self.quota = quota 811 812 def run(self): 813 from random import random 814 counter = 0 815 while counter < self.quota: 816 counter = counter + 1 817 self.queue.put("%s.%d" % (self.getName(), counter)) 818 _sleep(random() * 0.00001) 819 820 821 class ConsumerThread(Thread): 822 823 def __init__(self, queue, count): 824 Thread.__init__(self, name="Consumer") 825 self.queue = queue 826 self.count = count 827 828 def run(self): 829 while self.count > 0: 830 item = self.queue.get() 831 print item 832 self.count = self.count - 1 833 834 NP = 3 835 QL = 4 836 NI = 5 837 838 Q = BoundedQueue(QL) 839 P = [] 840 for i in range(NP): 841 t = ProducerThread(Q, NI) 842 t.setName("Producer-%d" % (i+1)) 843 P.append(t) 844 C = ConsumerThread(Q, NI*NP) 845 for t in P: 846 t.start() 847 _sleep(0.000001) 848 C.start() 849 for t in P: 850 t.join() 851 C.join() 852 853 if __name__ == '__main__': 854 _test() 855