Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/retrying.py: 58%
Shortcuts on this page
r m x toggle line displays
j k next/prev highlighted chunk
0 (zero) top of page
1 (one) first highlighted chunk
1# Copyright 2013-2014 Ray Holder
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7# http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14import logging
15import random
16import sys
17import time
18import traceback
19from functools import wraps
21# sys.maxint / 2, since Python 3.2 doesn't have a sys.maxint...
22MAX_WAIT = 1073741823
25def _retry_if_exception_of_type(retryable_types):
26 def _retry_if_exception_these_types(exception):
27 return isinstance(exception, retryable_types)
29 return _retry_if_exception_these_types
32def retry(*dargs, **dkw):
33 """
34 Decorator function that instantiates the Retrying object
35 @param *dargs: positional arguments passed to Retrying object
36 @param **dkw: keyword arguments passed to the Retrying object
37 """
38 # support both @retry and @retry() as valid syntax
39 if len(dargs) == 1 and callable(dargs[0]):
41 def wrap_simple(f):
42 @wraps(f)
43 def wrapped_f(*args, **kw):
44 return Retrying().call(f, *args, **kw)
46 return wrapped_f
48 return wrap_simple(dargs[0])
50 else:
52 def wrap(f):
53 @wraps(f)
54 def wrapped_f(*args, **kw):
55 return Retrying(*dargs, **dkw).call(f, *args, **kw)
57 return wrapped_f
59 return wrap
62class Retrying(object):
63 def __init__(
64 self,
65 stop=None,
66 wait=None,
67 stop_max_attempt_number=None,
68 stop_max_delay=None,
69 wait_fixed=None,
70 wait_random_min=None,
71 wait_random_max=None,
72 wait_incrementing_start=None,
73 wait_incrementing_increment=None,
74 wait_incrementing_max=None,
75 wait_exponential_multiplier=None,
76 wait_exponential_max=None,
77 retry_on_exception=None,
78 retry_on_result=None,
79 wrap_exception=False,
80 stop_func=None,
81 wait_func=None,
82 wait_jitter_max=None,
83 before_attempts=None,
84 after_attempts=None,
85 logger=None,
86 ):
88 self._stop_max_attempt_number = (
89 5 if stop_max_attempt_number is None else stop_max_attempt_number
90 )
91 self._stop_max_delay = 100 if stop_max_delay is None else stop_max_delay
92 self._wait_fixed = 1000 if wait_fixed is None else wait_fixed
93 self._wait_random_min = 0 if wait_random_min is None else wait_random_min
94 self._wait_random_max = 1000 if wait_random_max is None else wait_random_max
95 self._wait_incrementing_start = (
96 0 if wait_incrementing_start is None else wait_incrementing_start
97 )
98 self._wait_incrementing_increment = (
99 100 if wait_incrementing_increment is None else wait_incrementing_increment
100 )
101 self._wait_exponential_multiplier = (
102 1 if wait_exponential_multiplier is None else wait_exponential_multiplier
103 )
104 self._wait_exponential_max = (
105 MAX_WAIT if wait_exponential_max is None else wait_exponential_max
106 )
107 self._wait_incrementing_max = (
108 MAX_WAIT if wait_incrementing_max is None else wait_incrementing_max
109 )
110 self._wait_jitter_max = 0 if wait_jitter_max is None else wait_jitter_max
111 self._before_attempts = before_attempts
112 self._after_attempts = after_attempts
114 if logger in (True, None):
115 self._logger = logging.getLogger(__name__)
116 if logger is None:
117 self._logger.addHandler(logging.NullHandler())
118 self._logger.propagate = False
119 elif logger:
120 self._logger = logger
122 # TODO add chaining of stop behaviors
123 # stop behavior
124 stop_funcs = []
125 if stop_max_attempt_number is not None:
126 stop_funcs.append(self.stop_after_attempt)
128 if stop_max_delay is not None:
129 stop_funcs.append(self.stop_after_delay)
131 if stop_func is not None:
132 self.stop = stop_func
134 elif stop is None:
135 self.stop = lambda attempts, delay: any(
136 f(attempts, delay) for f in stop_funcs
137 )
139 else:
140 self.stop = getattr(self, stop)
142 # TODO add chaining of wait behaviors
143 # wait behavior
144 wait_funcs = [lambda *args, **kwargs: 0]
145 if wait_fixed is not None:
146 wait_funcs.append(self.fixed_sleep)
148 if wait_random_min is not None or wait_random_max is not None:
149 wait_funcs.append(self.random_sleep)
151 if (
152 wait_incrementing_start is not None
153 or wait_incrementing_increment is not None
154 ):
155 wait_funcs.append(self.incrementing_sleep)
157 if wait_exponential_multiplier is not None or wait_exponential_max is not None:
158 wait_funcs.append(self.exponential_sleep)
160 if wait_func is not None:
161 self.wait = wait_func
163 elif wait is None:
164 self.wait = lambda attempts, delay: max(
165 f(attempts, delay) for f in wait_funcs
166 )
168 else:
169 self.wait = getattr(self, wait)
171 # retry on exception filter
172 if retry_on_exception is None:
173 self._retry_on_exception = self.always_reject
174 else:
175 # this allows for providing a tuple of exception types that
176 # should be allowed to retry on, and avoids having to create
177 # a callback that does the same thing
178 if isinstance(retry_on_exception, (tuple, Exception)):
179 retry_on_exception = _retry_if_exception_of_type(retry_on_exception)
180 self._retry_on_exception = retry_on_exception
182 # retry on result filter
183 if retry_on_result is None:
184 self._retry_on_result = self.never_reject
185 else:
186 self._retry_on_result = retry_on_result
188 self._wrap_exception = wrap_exception
190 def stop_after_attempt(self, previous_attempt_number, delay_since_first_attempt_ms):
191 """Stop after the previous attempt >= stop_max_attempt_number."""
192 return previous_attempt_number >= self._stop_max_attempt_number
194 def stop_after_delay(self, previous_attempt_number, delay_since_first_attempt_ms):
195 """Stop after the time from the first attempt >= stop_max_delay."""
196 return delay_since_first_attempt_ms >= self._stop_max_delay
198 @staticmethod
199 def no_sleep(previous_attempt_number, delay_since_first_attempt_ms):
200 """Don't sleep at all before retrying."""
201 return 0
203 def fixed_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
204 """Sleep a fixed amount of time between each retry."""
205 return self._wait_fixed
207 def random_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
208 """Sleep a random amount of time between wait_random_min and wait_random_max"""
209 return random.randint(self._wait_random_min, self._wait_random_max)
211 def incrementing_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
212 """
213 Sleep an incremental amount of time after each attempt, starting at
214 wait_incrementing_start and incrementing by wait_incrementing_increment
215 """
216 result = self._wait_incrementing_start + (
217 self._wait_incrementing_increment * (previous_attempt_number - 1)
218 )
219 if result > self._wait_incrementing_max:
220 result = self._wait_incrementing_max
221 if result < 0:
222 result = 0
223 return result
225 def exponential_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):
226 exp = 2**previous_attempt_number
227 result = self._wait_exponential_multiplier * exp
228 if result > self._wait_exponential_max:
229 result = self._wait_exponential_max
230 if result < 0:
231 result = 0
232 return result
234 @staticmethod
235 def never_reject(result):
236 return False
238 @staticmethod
239 def always_reject(result):
240 return True
242 def should_reject(self, attempt):
243 reject = False
244 if attempt.has_exception:
245 reject |= self._retry_on_exception(attempt.value[1])
246 else:
247 reject |= self._retry_on_result(attempt.value)
249 return reject
251 def call(self, fn, *args, **kwargs):
252 start_time = int(round(time.time() * 1000))
253 attempt_number = 1
254 while True:
255 if self._before_attempts:
256 self._before_attempts(attempt_number)
258 try:
259 attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
260 except Exception:
261 tb = sys.exc_info()
262 attempt = Attempt(tb, attempt_number, True)
264 if not self.should_reject(attempt):
265 return attempt.get(self._wrap_exception)
267 self._logger.warn(attempt)
268 if self._after_attempts:
269 self._after_attempts(attempt_number)
271 delay_since_first_attempt_ms = int(round(time.time() * 1000)) - start_time
272 if self.stop(attempt_number, delay_since_first_attempt_ms):
273 if not self._wrap_exception and attempt.has_exception:
274 # get() on an attempt with an exception should cause it to be raised, but raise just in case
275 raise attempt.get()
276 else:
277 raise RetryError(attempt)
278 else:
279 sleep = self.wait(attempt_number, delay_since_first_attempt_ms)
280 if self._wait_jitter_max:
281 jitter = random.random() * self._wait_jitter_max
282 sleep = sleep + max(0, jitter)
283 self._logger.info("Retrying in {0:.2f} seconds.".format(sleep / 1000.0))
284 time.sleep(sleep / 1000.0)
286 attempt_number += 1
289class Attempt(object):
290 """
291 An Attempt encapsulates a call to a target function that may end as a
292 normal return value from the function or an Exception depending on what
293 occurred during the execution.
294 """
296 def __init__(self, value, attempt_number, has_exception):
297 self.value = value
298 self.attempt_number = attempt_number
299 self.has_exception = has_exception
301 def get(self, wrap_exception=False):
302 """
303 Return the return value of this Attempt instance or raise an Exception.
304 If wrap_exception is true, this Attempt is wrapped inside of a
305 RetryError before being raised.
306 """
307 if self.has_exception:
308 if wrap_exception:
309 raise RetryError(self)
310 else:
311 exc_type, exc, tb = self.value
312 raise exc.with_traceback(tb)
313 else:
314 return self.value
316 def __repr__(self):
317 if self.has_exception:
318 return "Attempts: {0}, Error:\n{1}".format(
319 self.attempt_number, "".join(traceback.format_tb(self.value[2]))
320 )
321 else:
322 return "Attempts: {0}, Value: {1}".format(self.attempt_number, self.value)
325class RetryError(Exception):
326 """
327 A RetryError encapsulates the last Attempt instance right before giving up.
328 """
330 def __init__(self, last_attempt):
331 self.last_attempt = last_attempt
333 def __str__(self):
334 return "RetryError[{0}]".format(self.last_attempt)