1# Copyright 2013 The Chromium Authors. All rights reserved. 2# Use of this source code is governed by a BSD-style license that can be 3# found in the LICENSE file. 4 5"""A utility to run functions with timeouts and retries.""" 6# pylint: disable=W0702 7 8import threading 9 10from pylib.utils import reraiser_thread 11from pylib.utils import watchdog_timer 12 13 14def Run(func, timeout, retries, args=None, kwargs=None): 15 """Runs the passed function in a separate thread with timeouts and retries. 16 17 Args: 18 func: the function to be wrapped. 19 timeout: the timeout in seconds for each try. 20 retries: the number of retries. 21 args: list of positional args to pass to |func|. 22 kwargs: dictionary of keyword args to pass to |func|. 23 24 Returns: 25 The return value of func(*args, **kwargs). 26 """ 27 if not args: 28 args = [] 29 if not kwargs: 30 kwargs = {} 31 32 # The return value uses a list because Python variables are references, not 33 # values. Closures make a copy of the reference, so updating the closure's 34 # reference wouldn't update where the original reference pointed. 35 ret = [None] 36 def RunOnTimeoutThread(): 37 ret[0] = func(*args, **kwargs) 38 39 while True: 40 try: 41 name = 'TimeoutThread-for-%s' % threading.current_thread().name 42 thread_group = reraiser_thread.ReraiserThreadGroup( 43 [reraiser_thread.ReraiserThread(RunOnTimeoutThread, name=name)]) 44 thread_group.StartAll() 45 thread_group.JoinAll(watchdog_timer.WatchdogTimer(timeout)) 46 return ret[0] 47 except: 48 if retries <= 0: 49 raise 50 retries -= 1 51