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1 # Copyright 2014 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 """ | |
6 Function/method decorators that provide timeout and retry logic. | |
7 """ | |
8 | |
9 import functools | |
10 import os | |
11 import sys | |
12 import threading | |
13 | |
14 from pylib import cmd_helper | |
15 from pylib import constants | |
16 from pylib.device import device_errors | |
17 from pylib.utils import reraiser_thread | |
18 from pylib.utils import timeout_retry | |
19 | |
20 # TODO(jbudorick) Remove once the DeviceUtils implementations are no longer | |
21 # backed by AndroidCommands / android_testrunner. | |
22 sys.path.append(os.path.join(constants.DIR_SOURCE_ROOT, 'third_party', | |
23 'android_testrunner')) | |
24 import errors as old_errors | |
25 | |
26 DEFAULT_TIMEOUT_ATTR = '_default_timeout' | |
27 DEFAULT_RETRIES_ATTR = '_default_retries' | |
28 | |
29 | |
30 def _TimeoutRetryWrapper(f, timeout_func, retries_func, pass_values=False): | |
31 """ Wraps a funcion with timeout and retry handling logic. | |
32 | |
33 Args: | |
34 f: The function to wrap. | |
35 timeout_func: A callable that returns the timeout value. | |
36 retries_func: A callable that returns the retries value. | |
37 pass_values: If True, passes the values returned by |timeout_func| and | |
38 |retries_func| to the wrapped function as 'timeout' and | |
39 'retries' kwargs, respectively. | |
40 Returns: | |
41 The wrapped function. | |
42 """ | |
43 @functools.wraps(f) | |
44 def TimeoutRetryWrapper(*args, **kwargs): | |
45 timeout = timeout_func(*args, **kwargs) | |
46 retries = retries_func(*args, **kwargs) | |
47 if pass_values: | |
48 kwargs['timeout'] = timeout | |
49 kwargs['retries'] = retries | |
50 def impl(): | |
51 return f(*args, **kwargs) | |
52 try: | |
53 if isinstance(threading.current_thread(), | |
54 timeout_retry.TimeoutRetryThread): | |
55 return impl() | |
56 else: | |
57 return timeout_retry.Run(impl, timeout, retries) | |
58 except old_errors.WaitForResponseTimedOutError as e: | |
59 raise device_errors.CommandTimeoutError(str(e)), None, ( | |
60 sys.exc_info()[2]) | |
61 except old_errors.DeviceUnresponsiveError as e: | |
62 raise device_errors.DeviceUnreachableError(str(e)), None, ( | |
63 sys.exc_info()[2]) | |
64 except reraiser_thread.TimeoutError as e: | |
65 raise device_errors.CommandTimeoutError(str(e)), None, ( | |
66 sys.exc_info()[2]) | |
67 except cmd_helper.TimeoutError as e: | |
68 raise device_errors.CommandTimeoutError(str(e)), None, ( | |
69 sys.exc_info()[2]) | |
70 return TimeoutRetryWrapper | |
71 | |
72 | |
73 def WithTimeoutAndRetries(f): | |
74 """A decorator that handles timeouts and retries. | |
75 | |
76 'timeout' and 'retries' kwargs must be passed to the function. | |
77 | |
78 Args: | |
79 f: The function to decorate. | |
80 Returns: | |
81 The decorated function. | |
82 """ | |
83 get_timeout = lambda *a, **kw: kw['timeout'] | |
84 get_retries = lambda *a, **kw: kw['retries'] | |
85 return _TimeoutRetryWrapper(f, get_timeout, get_retries) | |
86 | |
87 | |
88 def WithExplicitTimeoutAndRetries(timeout, retries): | |
89 """Returns a decorator that handles timeouts and retries. | |
90 | |
91 The provided |timeout| and |retries| values are always used. | |
92 | |
93 Args: | |
94 timeout: The number of seconds to wait for the decorated function to | |
95 return. Always used. | |
96 retries: The number of times the decorated function should be retried on | |
97 failure. Always used. | |
98 Returns: | |
99 The actual decorator. | |
100 """ | |
101 def decorator(f): | |
102 get_timeout = lambda *a, **kw: timeout | |
103 get_retries = lambda *a, **kw: retries | |
104 return _TimeoutRetryWrapper(f, get_timeout, get_retries) | |
105 return decorator | |
106 | |
107 | |
108 def WithTimeoutAndRetriesDefaults(default_timeout, default_retries): | |
109 """Returns a decorator that handles timeouts and retries. | |
110 | |
111 The provided |default_timeout| and |default_retries| values are used only | |
112 if timeout and retries values are not provided. | |
113 | |
114 Args: | |
115 default_timeout: The number of seconds to wait for the decorated function | |
116 to return. Only used if a 'timeout' kwarg is not passed | |
117 to the decorated function. | |
118 default_retries: The number of times the decorated function should be | |
119 retried on failure. Only used if a 'retries' kwarg is not | |
120 passed to the decorated function. | |
121 Returns: | |
122 The actual decorator. | |
123 """ | |
124 def decorator(f): | |
125 get_timeout = lambda *a, **kw: kw.get('timeout', default_timeout) | |
126 get_retries = lambda *a, **kw: kw.get('retries', default_retries) | |
127 return _TimeoutRetryWrapper(f, get_timeout, get_retries, pass_values=True) | |
128 return decorator | |
129 | |
130 | |
131 def WithTimeoutAndRetriesFromInstance( | |
132 default_timeout_name=DEFAULT_TIMEOUT_ATTR, | |
133 default_retries_name=DEFAULT_RETRIES_ATTR): | |
134 """Returns a decorator that handles timeouts and retries. | |
135 | |
136 The provided |default_timeout_name| and |default_retries_name| are used to | |
137 get the default timeout value and the default retries value from the object | |
138 instance if timeout and retries values are not provided. | |
139 | |
140 Note that this should only be used to decorate methods, not functions. | |
141 | |
142 Args: | |
143 default_timeout_name: The name of the default timeout attribute of the | |
144 instance. | |
145 default_retries_name: The name of the default retries attribute of the | |
146 instance. | |
147 Returns: | |
148 The actual decorator. | |
149 """ | |
150 def decorator(f): | |
151 def get_timeout(inst, *_args, **kwargs): | |
152 return kwargs.get('timeout', getattr(inst, default_timeout_name)) | |
153 def get_retries(inst, *_args, **kwargs): | |
154 return kwargs.get('retries', getattr(inst, default_retries_name)) | |
155 return _TimeoutRetryWrapper(f, get_timeout, get_retries, pass_values=True) | |
156 return decorator | |
157 | |
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