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Side by Side Diff: build/android/pylib/utils/timeout_retry.py

Issue 2101243005: Add a snapshot of flutter/engine/src/build to our sdk (Closed) Base URL: git@github.com:dart-lang/sdk.git@master
Patch Set: add README.dart Created 4 years, 5 months ago
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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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