1 # Copyright (C) 2010 Google Inc. All rights reserved.

     2 # 

     3 # Redistribution and use in source and binary forms, with or without

     4 # modification, are permitted provided that the following conditions are

     5 # met:

     6 # 

     7 #     * Redistributions of source code must retain the above copyright

     8 # notice, this list of conditions and the following disclaimer.

     9 #     * Redistributions in binary form must reproduce the above

    10 # copyright notice, this list of conditions and the following disclaimer

    11 # in the documentation and/or other materials provided with the

    12 # distribution.

    13 #     * Neither the name of Google Inc. nor the names of its

    14 # contributors may be used to endorse or promote products derived from

    15 # this software without specific prior written permission.

    16 # 

    17 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

    18 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

    19 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

    20 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

    21 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    22 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

    23 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

    24 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

    25 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    26 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    27 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    28 

    29 import logging

    30 import time

    31 

    32 from webkitpy.thirdparty.autoinstalled.mechanize import HTTPError

    33 from webkitpy.common.system.deprecated_logging import log

    34 

    35 

    36 _log = logging.getLogger(__name__)

    37 

    38 

    39 class NetworkTimeout(Exception):

    40     pass

    41 

    42 

    43 class NetworkTransaction(object):

    44     def __init__(self, initial_backoff_seconds=10, grown_factor=1.5, timeout_seconds=10*60):

    45         self._initial_backoff_seconds = initial_backoff_seconds

    46         self._grown_factor = grown_factor

    47         self._timeout_seconds = timeout_seconds

    48 

    49     def run(self, request):

    50         self._total_sleep = 0

    51         self._backoff_seconds = self._initial_backoff_seconds

    52         while True:

    53             try:

    54                 return request()

    55             except HTTPError, e:

    56                 self._check_for_timeout()

    57                 _log.warn("Received HTTP status %s from server.  Retrying in "

    58                           "%s seconds..." % (e.code, self._backoff_seconds))

    59                 self._sleep()

    60 

    61     def _check_for_timeout(self):

    62         if self._total_sleep + self._backoff_seconds > self._timeout_seconds:

    63             raise NetworkTimeout()

    64 

    65     def _sleep(self):

    66         time.sleep(self._backoff_seconds)

    67         self._total_sleep += self._backoff_seconds

    68         self._backoff_seconds *= self._grown_factor