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 7import functools 8import threading 9 10import reraiser_thread 11import watchdog_timer 12 13 14def Run(func, timeout, retries, args=[], kwargs={}): 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 # The return value uses a list because Python variables are references, not 28 # values. Closures make a copy of the reference, so updating the closure's 29 # reference wouldn't update where the original reference pointed. 30 ret = [None] 31 def RunOnTimeoutThread(): 32 ret[0] = func(*args, **kwargs) 33 34 while True: 35 try: 36 name = 'TimeoutThread-for-%s' % threading.current_thread().name 37 thread_group = reraiser_thread.ReraiserThreadGroup( 38 [reraiser_thread.ReraiserThread(RunOnTimeoutThread, name=name)]) 39 thread_group.StartAll() 40 thread_group.JoinAll(watchdog_timer.WatchdogTimer(timeout)) 41 return ret[0] 42 except: 43 if retries <= 0: 44 raise 45 retries -= 1 46