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| 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 | |
| 8 import logging | |
| 9 import threading | |
| 10 import time | |
| 11 import traceback | |
| 12 | |
| 13 from pylib.utils import reraiser_thread | |
| 14 from pylib.utils import watchdog_timer | |
| 15 | |
| 16 | |
| 17 class TimeoutRetryThread(reraiser_thread.ReraiserThread): | |
| 18 def __init__(self, func, timeout, name): | |
| 19 super(TimeoutRetryThread, self).__init__(func, name=name) | |
| 20 self._watcher = watchdog_timer.WatchdogTimer(timeout) | |
| 21 self._expired = False | |
| 22 | |
| 23 def GetWatcher(self): | |
| 24 """Returns the watchdog keeping track of this thread's time.""" | |
| 25 return self._watcher | |
| 26 | |
| 27 def GetElapsedTime(self): | |
| 28 return self._watcher.GetElapsed() | |
| 29 | |
| 30 def GetRemainingTime(self, required=0, msg=None): | |
| 31 """Get the remaining time before the thread times out. | |
| 32 | |
| 33 Useful to send as the |timeout| parameter of async IO operations. | |
| 34 | |
| 35 Args: | |
| 36 required: minimum amount of time that will be required to complete, e.g., | |
| 37 some sleep or IO operation. | |
| 38 msg: error message to show if timing out. | |
| 39 | |
| 40 Returns: | |
| 41 The number of seconds remaining before the thread times out, or None | |
| 42 if the thread never times out. | |
| 43 | |
| 44 Raises: | |
| 45 reraiser_thread.TimeoutError if the remaining time is less than the | |
| 46 required time. | |
| 47 """ | |
| 48 remaining = self._watcher.GetRemaining() | |
| 49 if remaining is not None and remaining < required: | |
| 50 if msg is None: | |
| 51 msg = 'Timeout expired' | |
| 52 if remaining > 0: | |
| 53 msg += (', wait of %.1f secs required but only %.1f secs left' | |
| 54 % (required, remaining)) | |
| 55 self._expired = True | |
| 56 raise reraiser_thread.TimeoutError(msg) | |
| 57 return remaining | |
| 58 | |
| 59 def LogTimeoutException(self): | |
| 60 """Log the exception that terminated this thread.""" | |
| 61 if not self._expired: | |
| 62 return | |
| 63 logging.critical('*' * 80) | |
| 64 logging.critical('%s on thread %r', self._exc_info[0].__name__, self.name) | |
| 65 logging.critical('*' * 80) | |
| 66 fmt_exc = ''.join(traceback.format_exception(*self._exc_info)) | |
| 67 for line in fmt_exc.splitlines(): | |
| 68 logging.critical(line.rstrip()) | |
| 69 logging.critical('*' * 80) | |
| 70 | |
| 71 | |
| 72 def CurrentTimeoutThread(): | |
| 73 """Get the current thread if it is a TimeoutRetryThread. | |
| 74 | |
| 75 Returns: | |
| 76 The current thread if it is a TimeoutRetryThread, otherwise None. | |
| 77 """ | |
| 78 current_thread = threading.current_thread() | |
| 79 if isinstance(current_thread, TimeoutRetryThread): | |
| 80 return current_thread | |
| 81 else: | |
| 82 return None | |
| 83 | |
| 84 | |
| 85 def WaitFor(condition, wait_period=5, max_tries=None): | |
| 86 """Wait for a condition to become true. | |
| 87 | |
| 88 Repeadly call the function condition(), with no arguments, until it returns | |
| 89 a true value. | |
| 90 | |
| 91 If called within a TimeoutRetryThread, it cooperates nicely with it. | |
| 92 | |
| 93 Args: | |
| 94 condition: function with the condition to check | |
| 95 wait_period: number of seconds to wait before retrying to check the | |
| 96 condition | |
| 97 max_tries: maximum number of checks to make, the default tries forever | |
| 98 or until the TimeoutRetryThread expires. | |
| 99 | |
| 100 Returns: | |
| 101 The true value returned by the condition, or None if the condition was | |
| 102 not met after max_tries. | |
| 103 | |
| 104 Raises: | |
| 105 reraiser_thread.TimeoutError if the current thread is a TimeoutRetryThread | |
| 106 and the timeout expires. | |
| 107 """ | |
| 108 condition_name = condition.__name__ | |
| 109 timeout_thread = CurrentTimeoutThread() | |
| 110 while max_tries is None or max_tries > 0: | |
| 111 result = condition() | |
| 112 if max_tries is not None: | |
| 113 max_tries -= 1 | |
| 114 msg = ['condition', repr(condition_name), 'met' if result else 'not met'] | |
| 115 if timeout_thread: | |
| 116 msg.append('(%.1fs)' % timeout_thread.GetElapsedTime()) | |
| 117 logging.info(' '.join(msg)) | |
| 118 if result: | |
| 119 return result | |
| 120 if timeout_thread: | |
| 121 timeout_thread.GetRemainingTime(wait_period, | |
| 122 msg='Timed out waiting for %r' % condition_name) | |
| 123 time.sleep(wait_period) | |
| 124 return None | |
| 125 | |
| 126 | |
| 127 def Run(func, timeout, retries, args=None, kwargs=None): | |
| 128 """Runs the passed function in a separate thread with timeouts and retries. | |
| 129 | |
| 130 Args: | |
| 131 func: the function to be wrapped. | |
| 132 timeout: the timeout in seconds for each try. | |
| 133 retries: the number of retries. | |
| 134 args: list of positional args to pass to |func|. | |
| 135 kwargs: dictionary of keyword args to pass to |func|. | |
| 136 | |
| 137 Returns: | |
| 138 The return value of func(*args, **kwargs). | |
| 139 """ | |
| 140 if not args: | |
| 141 args = [] | |
| 142 if not kwargs: | |
| 143 kwargs = {} | |
| 144 | |
| 145 # The return value uses a list because Python variables are references, not | |
| 146 # values. Closures make a copy of the reference, so updating the closure's | |
| 147 # reference wouldn't update where the original reference pointed. | |
| 148 ret = [None] | |
| 149 def RunOnTimeoutThread(): | |
| 150 ret[0] = func(*args, **kwargs) | |
| 151 | |
| 152 num_try = 1 | |
| 153 while True: | |
| 154 child_thread = TimeoutRetryThread( | |
| 155 RunOnTimeoutThread, timeout, | |
| 156 name='TimeoutThread-%d-for-%s' % (num_try, | |
| 157 threading.current_thread().name)) | |
| 158 try: | |
| 159 thread_group = reraiser_thread.ReraiserThreadGroup([child_thread]) | |
| 160 thread_group.StartAll() | |
| 161 thread_group.JoinAll(child_thread.GetWatcher()) | |
| 162 return ret[0] | |
| 163 except: | |
| 164 child_thread.LogTimeoutException() | |
| 165 if num_try > retries: | |
| 166 raise | |
| 167 num_try += 1 | |
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Chromium Code Reviews
Issue 2392643003:
Removes files from //build that we don't need (Closed)
