| Index: gslib/third_party/storage_apitools/http_wrapper.py
|
| ===================================================================
|
| --- gslib/third_party/storage_apitools/http_wrapper.py (revision 0)
|
| +++ gslib/third_party/storage_apitools/http_wrapper.py (revision 0)
|
| @@ -0,0 +1,337 @@
|
| +# Copyright 2014 Google Inc. All Rights Reserved.
|
| +#
|
| +# Licensed under the Apache License, Version 2.0 (the "License");
|
| +# you may not use this file except in compliance with the License.
|
| +# You may obtain a copy of the License at
|
| +#
|
| +# http://www.apache.org/licenses/LICENSE-2.0
|
| +#
|
| +# Unless required by applicable law or agreed to in writing, software
|
| +# distributed under the License is distributed on an "AS IS" BASIS,
|
| +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
| +# See the License for the specific language governing permissions and
|
| +# limitations under the License.
|
| +"""HTTP wrapper for apitools.
|
| +
|
| +This library wraps the underlying http library we use, which is
|
| +currently httplib2.
|
| +"""
|
| +
|
| +import collections
|
| +import contextlib
|
| +import httplib
|
| +import logging
|
| +import socket
|
| +import time
|
| +import urlparse
|
| +
|
| +import httplib2
|
| +
|
| +from gslib.third_party.storage_apitools import exceptions
|
| +from gslib.third_party.storage_apitools import util
|
| +
|
| +__all__ = [
|
| + 'GetHttp',
|
| + 'MakeRequest',
|
| +]
|
| +
|
| +
|
| +# 308 and 429 don't have names in httplib.
|
| +RESUME_INCOMPLETE = 308
|
| +TOO_MANY_REQUESTS = 429
|
| +_REDIRECT_STATUS_CODES = (
|
| + httplib.MOVED_PERMANENTLY,
|
| + httplib.FOUND,
|
| + httplib.SEE_OTHER,
|
| + httplib.TEMPORARY_REDIRECT,
|
| + RESUME_INCOMPLETE,
|
| +)
|
| +
|
| +# http: An httplib2.Http instance.
|
| +# http_request: A http_wrapper.Request.
|
| +# exc: Exception being raised.
|
| +# num_retries: Number of retries consumed; used for exponential backoff.
|
| +ExceptionRetryArgs = collections.namedtuple('ExceptionRetryArgs',
|
| + ['http', 'http_request', 'exc',
|
| + 'num_retries'])
|
| +
|
| +
|
| +@contextlib.contextmanager
|
| +def _Httplib2Debuglevel(http_request, level, http=None):
|
| + """Temporarily change the value of httplib2.debuglevel if needed.
|
| +
|
| + If http_request has a `loggable_body` distinct from `body`, then we
|
| + need to prevent httplib2 from logging the full body. This sets
|
| + httplib2.debuglevel for the duration of the `with` block; however,
|
| + that alone won't change the value of existing HTTP connections. If
|
| + an httplib2.Http object is provided, we'll also change the level on
|
| + any cached connections attached to it.
|
| + """
|
| + if http_request.loggable_body is None:
|
| + yield
|
| + return
|
| + old_level = httplib2.debuglevel
|
| + http_levels = {}
|
| + httplib2.debuglevel = level
|
| + if http is not None:
|
| + for connection_key, connection in http.connections.iteritems():
|
| + # httplib2 stores two kinds of values in this dict, connection
|
| + # classes and instances. Since the connection types are all
|
| + # old-style classes, we can't easily distinguish by connection
|
| + # type -- so instead we use the key pattern.
|
| + if ':' not in connection_key:
|
| + continue
|
| + http_levels[connection_key] = connection.debuglevel
|
| + connection.set_debuglevel(level)
|
| + yield
|
| + httplib2.debuglevel = old_level
|
| + if http is not None:
|
| + for connection_key, old_level in http_levels:
|
| + if connection_key in http.connections:
|
| + http.connections[connection_key].set_debuglevel(old_level)
|
| +
|
| +
|
| +class Request(object):
|
| + """Class encapsulating the data for an HTTP request."""
|
| +
|
| + def __init__(self, url='', http_method='GET', headers=None, body=''):
|
| + self.url = url
|
| + self.http_method = http_method
|
| + self.headers = headers or {}
|
| + self.__body = None
|
| + self.__loggable_body = None
|
| + self.body = body
|
| +
|
| + @property
|
| + def loggable_body(self):
|
| + return self.__loggable_body
|
| +
|
| + @loggable_body.setter
|
| + def loggable_body(self, value):
|
| + if self.body is None:
|
| + raise exceptions.RequestError(
|
| + 'Cannot set loggable body on request with no body')
|
| + self.__loggable_body = value
|
| +
|
| + @property
|
| + def body(self):
|
| + return self.__body
|
| +
|
| + @body.setter
|
| + def body(self, value):
|
| + self.__body = value
|
| + if value is not None:
|
| + self.headers['content-length'] = str(len(self.__body))
|
| + else:
|
| + self.headers.pop('content-length', None)
|
| + # This line ensures we don't try to print large requests.
|
| + if not isinstance(value, basestring):
|
| + self.loggable_body = '<media body>'
|
| +
|
| +
|
| +# Note: currently the order of fields here is important, since we want
|
| +# to be able to pass in the result from httplib2.request.
|
| +class Response(collections.namedtuple(
|
| + 'HttpResponse', ['info', 'content', 'request_url'])):
|
| + """Class encapsulating data for an HTTP response."""
|
| + __slots__ = ()
|
| +
|
| + def __len__(self):
|
| + return self.length
|
| +
|
| + @property
|
| + def length(self):
|
| + """Return the length of this response.
|
| +
|
| + We expose this as an attribute since using len() directly can fail
|
| + for responses larger than sys.maxint.
|
| +
|
| + Returns:
|
| + Response length (as int or long)
|
| + """
|
| + def ProcessContentRange(content_range):
|
| + _, _, range_spec = content_range.partition(' ')
|
| + byte_range, _, _ = range_spec.partition('/')
|
| + start, _, end = byte_range.partition('-')
|
| + return int(end) - int(start) + 1
|
| +
|
| + if '-content-encoding' in self.info and 'content-range' in self.info:
|
| + # httplib2 rewrites content-length in the case of a compressed
|
| + # transfer; we can't trust the content-length header in that
|
| + # case, but we *can* trust content-range, if it's present.
|
| + return ProcessContentRange(self.info['content-range'])
|
| + elif 'content-length' in self.info:
|
| + return int(self.info.get('content-length'))
|
| + elif 'content-range' in self.info:
|
| + return ProcessContentRange(self.info['content-range'])
|
| + return len(self.content)
|
| +
|
| + @property
|
| + def status_code(self):
|
| + return int(self.info['status'])
|
| +
|
| + @property
|
| + def retry_after(self):
|
| + if 'retry-after' in self.info:
|
| + return int(self.info['retry-after'])
|
| +
|
| + @property
|
| + def is_redirect(self):
|
| + return (self.status_code in _REDIRECT_STATUS_CODES and
|
| + 'location' in self.info)
|
| +
|
| +
|
| +def CheckResponse(response):
|
| + if response is None:
|
| + # Caller shouldn't call us if the response is None, but handle anyway.
|
| + raise exceptions.RequestError('Request to url %s did not return a response.'
|
| + % response.request_url)
|
| + elif (response.status_code >= 500 or
|
| + response.status_code == TOO_MANY_REQUESTS):
|
| + raise exceptions.BadStatusCodeError.FromResponse(response)
|
| + elif response.status_code == httplib.UNAUTHORIZED:
|
| + # Sometimes we get a 401 after a connection break.
|
| + # TODO: this shouldn't be a retryable exception, but for now we retry.
|
| + raise exceptions.BadStatusCodeError.FromResponse(response)
|
| + elif response.retry_after:
|
| + raise exceptions.RetryAfterError.FromResponse(response)
|
| +
|
| +
|
| +def RebuildHttpConnections(http):
|
| + """Rebuilds all http connections in the httplib2.Http instance.
|
| +
|
| + httplib2 overloads the map in http.connections to contain two different
|
| + types of values:
|
| + { scheme string: connection class } and
|
| + { scheme + authority string : actual http connection }
|
| + Here we remove all of the entries for actual connections so that on the
|
| + next request httplib2 will rebuild them from the connection types.
|
| +
|
| + Args:
|
| + http: An httplib2.Http instance.
|
| + """
|
| + if getattr(http, 'connections', None):
|
| + for conn_key in http.connections.keys():
|
| + if ':' in conn_key:
|
| + del http.connections[conn_key]
|
| +
|
| +
|
| +def RethrowExceptionHandler(*unused_args):
|
| + raise
|
| +
|
| +
|
| +def HandleExceptionsAndRebuildHttpConnections(retry_args):
|
| + """Exception handler for http failures.
|
| +
|
| + This catches known failures and rebuilds the underlying HTTP connections.
|
| +
|
| + Args:
|
| + retry_args: An ExceptionRetryArgs tuple.
|
| + """
|
| + retry_after = None
|
| + if isinstance(retry_args.exc, httplib.BadStatusLine):
|
| + logging.error('Caught BadStatusLine from httplib, retrying: %s',
|
| + retry_args.exc)
|
| + elif isinstance(retry_args.exc, socket.error):
|
| + logging.error('Caught socket error, retrying: %s', retry_args.exc)
|
| + elif isinstance(retry_args.exc, exceptions.BadStatusCodeError):
|
| + logging.error('Response returned status %s, retrying',
|
| + retry_args.exc.status_code)
|
| + elif isinstance(retry_args.exc, exceptions.RetryAfterError):
|
| + logging.error('Response returned a retry-after header, retrying')
|
| + retry_after = retry_args.exc.retry_after
|
| + elif isinstance(retry_args.exc, ValueError):
|
| + # oauth2_client tries to JSON-decode the response, which can result
|
| + # in a ValueError if the response was invalid. Until that is fixed in
|
| + # oauth2_client, need to handle it here.
|
| + logging.error('Response content was invalid (%s), retrying',
|
| + retry_args.exc)
|
| + elif isinstance(retry_args.exc, exceptions.RequestError):
|
| + logging.error('Request returned no response, retrying')
|
| + else:
|
| + raise
|
| + RebuildHttpConnections(retry_args.http)
|
| + logging.error('Retrying request to url %s after exception %s',
|
| + retry_args.http_request.url, retry_args.exc)
|
| + time.sleep(retry_after or util.CalculateWaitForRetry(retry_args.num_retries))
|
| +
|
| +
|
| +def MakeRequest(http, http_request, retries=7, redirections=5,
|
| + retry_func=HandleExceptionsAndRebuildHttpConnections,
|
| + check_response_func=CheckResponse):
|
| + """Send http_request via the given http, performing error/retry handling.
|
| +
|
| + Args:
|
| + http: An httplib2.Http instance, or a http multiplexer that delegates to
|
| + an underlying http, for example, HTTPMultiplexer.
|
| + http_request: A Request to send.
|
| + retries: (int, default 5) Number of retries to attempt on 5XX replies.
|
| + redirections: (int, default 5) Number of redirects to follow.
|
| + retry_func: Function to handle retries on exceptions. Arguments are
|
| + (Httplib2.Http, Request, Exception, int num_retries).
|
| + check_response_func: Function to validate the HTTP response. Arguments are
|
| + (Response, response content, url).
|
| +
|
| + Returns:
|
| + A Response object.
|
| + """
|
| + retry = 0
|
| + while True:
|
| + try:
|
| + return _MakeRequestNoRetry(http, http_request, redirections=redirections,
|
| + check_response_func=check_response_func)
|
| + # retry_func will consume the exception types it handles and raise.
|
| + # pylint: disable=broad-except
|
| + except Exception as e:
|
| + retry += 1
|
| + if retry >= retries:
|
| + raise
|
| + else:
|
| + retry_func(ExceptionRetryArgs(http, http_request, e, retry))
|
| +
|
| +
|
| +def _MakeRequestNoRetry(http, http_request, redirections=5,
|
| + check_response_func=CheckResponse):
|
| + """Send http_request via the given http.
|
| +
|
| + This wrapper exists to handle translation between the plain httplib2
|
| + request/response types and the Request and Response types above.
|
| +
|
| + Args:
|
| + http: An httplib2.Http instance, or a http multiplexer that delegates to
|
| + an underlying http, for example, HTTPMultiplexer.
|
| + http_request: A Request to send.
|
| + redirections: (int, default 5) Number of redirects to follow.
|
| + check_response_func: Function to validate the HTTP response. Arguments are
|
| + (Response, response content, url).
|
| +
|
| + Returns:
|
| + Response object.
|
| +
|
| + Raises:
|
| + RequestError if no response could be parsed.
|
| + """
|
| + connection_type = None
|
| + if getattr(http, 'connections', None):
|
| + url_scheme = urlparse.urlsplit(http_request.url).scheme
|
| + if url_scheme and url_scheme in http.connections:
|
| + connection_type = http.connections[url_scheme]
|
| +
|
| + # Custom printing only at debuglevel 4
|
| + new_debuglevel = 4 if httplib2.debuglevel == 4 else 0
|
| + with _Httplib2Debuglevel(http_request, new_debuglevel, http=http):
|
| + info, content = http.request(
|
| + str(http_request.url), method=str(http_request.http_method),
|
| + body=http_request.body, headers=http_request.headers,
|
| + redirections=redirections, connection_type=connection_type)
|
| +
|
| + if info is None:
|
| + raise exceptions.RequestError()
|
| +
|
| + response = Response(info, content, http_request.url)
|
| + check_response_func(response)
|
| + return response
|
| +
|
| +
|
| +def GetHttp():
|
| + return httplib2.Http()
|
|
|
| Property changes on: gslib/third_party/storage_apitools/http_wrapper.py
|
| ___________________________________________________________________
|
| Added: svn:eol-style
|
| + LF
|
|
|
|
|