270 lines
11 KiB
Python
270 lines
11 KiB
Python
# Copyright (c) 2012-2013 Mitch Garnaat http://garnaat.org/
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# Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"). You
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# may not use this file except in compliance with the License. A copy of
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# the License is located at
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#
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# http://aws.amazon.com/apache2.0/
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#
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# or in the "license" file accompanying this file. This file is
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# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
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# ANY KIND, either express or implied. See the License for the specific
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# language governing permissions and limitations under the License.
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import os
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import logging
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import time
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import threading
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from botocore.vendored import six
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from botocore.awsrequest import create_request_object
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from botocore.exceptions import HTTPClientError
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from botocore.httpsession import URLLib3Session
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from botocore.utils import is_valid_endpoint_url, get_environ_proxies
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from botocore.hooks import first_non_none_response
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from botocore.history import get_global_history_recorder
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from botocore.response import StreamingBody
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from botocore import parsers
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logger = logging.getLogger(__name__)
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history_recorder = get_global_history_recorder()
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DEFAULT_TIMEOUT = 60
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MAX_POOL_CONNECTIONS = 10
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def convert_to_response_dict(http_response, operation_model):
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"""Convert an HTTP response object to a request dict.
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This converts the requests library's HTTP response object to
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a dictionary.
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:type http_response: botocore.vendored.requests.model.Response
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:param http_response: The HTTP response from an AWS service request.
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:rtype: dict
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:return: A response dictionary which will contain the following keys:
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* headers (dict)
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* status_code (int)
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* body (string or file-like object)
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"""
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response_dict = {
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'headers': http_response.headers,
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'status_code': http_response.status_code,
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'context': {
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'operation_name': operation_model.name,
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}
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}
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if response_dict['status_code'] >= 300:
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response_dict['body'] = http_response.content
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elif operation_model.has_event_stream_output:
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response_dict['body'] = http_response.raw
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elif operation_model.has_streaming_output:
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length = response_dict['headers'].get('content-length')
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response_dict['body'] = StreamingBody(http_response.raw, length)
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else:
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response_dict['body'] = http_response.content
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return response_dict
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class Endpoint(object):
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"""
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Represents an endpoint for a particular service in a specific
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region. Only an endpoint can make requests.
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:ivar service: The Service object that describes this endpoints
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service.
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:ivar host: The fully qualified endpoint hostname.
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:ivar session: The session object.
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"""
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def __init__(self, host, endpoint_prefix, event_emitter,
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response_parser_factory=None, http_session=None):
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self._endpoint_prefix = endpoint_prefix
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self._event_emitter = event_emitter
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self.host = host
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self._lock = threading.Lock()
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if response_parser_factory is None:
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response_parser_factory = parsers.ResponseParserFactory()
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self._response_parser_factory = response_parser_factory
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self.http_session = http_session
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if self.http_session is None:
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self.http_session = URLLib3Session()
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def __repr__(self):
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return '%s(%s)' % (self._endpoint_prefix, self.host)
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def make_request(self, operation_model, request_dict):
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logger.debug("Making request for %s with params: %s",
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operation_model, request_dict)
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return self._send_request(request_dict, operation_model)
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def create_request(self, params, operation_model=None):
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request = create_request_object(params)
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if operation_model:
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request.stream_output = any([
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operation_model.has_streaming_output,
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operation_model.has_event_stream_output
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])
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service_id = operation_model.service_model.service_id.hyphenize()
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event_name = 'request-created.{service_id}.{op_name}'.format(
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service_id=service_id,
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op_name=operation_model.name)
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self._event_emitter.emit(event_name, request=request,
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operation_name=operation_model.name)
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prepared_request = self.prepare_request(request)
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return prepared_request
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def _encode_headers(self, headers):
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# In place encoding of headers to utf-8 if they are unicode.
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for key, value in headers.items():
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if isinstance(value, six.text_type):
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headers[key] = value.encode('utf-8')
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def prepare_request(self, request):
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self._encode_headers(request.headers)
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return request.prepare()
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def _send_request(self, request_dict, operation_model):
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attempts = 1
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request = self.create_request(request_dict, operation_model)
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success_response, exception = self._get_response(
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request, operation_model, attempts)
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while self._needs_retry(attempts, operation_model, request_dict,
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success_response, exception):
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attempts += 1
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# If there is a stream associated with the request, we need
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# to reset it before attempting to send the request again.
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# This will ensure that we resend the entire contents of the
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# body.
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request.reset_stream()
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# Create a new request when retried (including a new signature).
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request = self.create_request(
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request_dict, operation_model)
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success_response, exception = self._get_response(
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request, operation_model, attempts)
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if success_response is not None and \
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'ResponseMetadata' in success_response[1]:
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# We want to share num retries, not num attempts.
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total_retries = attempts - 1
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success_response[1]['ResponseMetadata']['RetryAttempts'] = \
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total_retries
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if exception is not None:
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raise exception
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else:
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return success_response
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def _get_response(self, request, operation_model, attempts):
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# This will return a tuple of (success_response, exception)
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# and success_response is itself a tuple of
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# (http_response, parsed_dict).
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# If an exception occurs then the success_response is None.
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# If no exception occurs then exception is None.
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try:
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logger.debug("Sending http request: %s", request)
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history_recorder.record('HTTP_REQUEST', {
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'method': request.method,
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'headers': request.headers,
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'streaming': operation_model.has_streaming_input,
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'url': request.url,
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'body': request.body
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})
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http_response = self._send(request)
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except HTTPClientError as e:
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return (None, e)
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except Exception as e:
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logger.debug("Exception received when sending HTTP request.",
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exc_info=True)
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return (None, e)
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# This returns the http_response and the parsed_data.
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response_dict = convert_to_response_dict(http_response, operation_model)
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http_response_record_dict = response_dict.copy()
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http_response_record_dict['streaming'] = \
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operation_model.has_streaming_output
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history_recorder.record('HTTP_RESPONSE', http_response_record_dict)
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protocol = operation_model.metadata['protocol']
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parser = self._response_parser_factory.create_parser(protocol)
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parsed_response = parser.parse(
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response_dict, operation_model.output_shape)
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history_recorder.record('PARSED_RESPONSE', parsed_response)
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return (http_response, parsed_response), None
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def _needs_retry(self, attempts, operation_model, request_dict,
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response=None, caught_exception=None):
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service_id = operation_model.service_model.service_id.hyphenize()
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event_name = 'needs-retry.%s.%s' % (
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service_id,
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operation_model.name)
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responses = self._event_emitter.emit(
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event_name, response=response, endpoint=self,
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operation=operation_model, attempts=attempts,
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caught_exception=caught_exception, request_dict=request_dict)
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handler_response = first_non_none_response(responses)
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if handler_response is None:
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return False
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else:
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# Request needs to be retried, and we need to sleep
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# for the specified number of times.
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logger.debug("Response received to retry, sleeping for "
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"%s seconds", handler_response)
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time.sleep(handler_response)
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return True
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def _send(self, request):
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return self.http_session.send(request)
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class EndpointCreator(object):
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def __init__(self, event_emitter):
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self._event_emitter = event_emitter
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def create_endpoint(self, service_model, region_name, endpoint_url,
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verify=None, response_parser_factory=None,
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timeout=DEFAULT_TIMEOUT,
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max_pool_connections=MAX_POOL_CONNECTIONS,
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http_session_cls=URLLib3Session,
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proxies=None):
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if not is_valid_endpoint_url(endpoint_url):
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raise ValueError("Invalid endpoint: %s" % endpoint_url)
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if proxies is None:
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proxies = self._get_proxies(endpoint_url)
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endpoint_prefix = service_model.endpoint_prefix
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logger.debug('Setting %s timeout as %s', endpoint_prefix, timeout)
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http_session = http_session_cls(
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timeout=timeout,
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proxies=proxies,
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verify=self._get_verify_value(verify),
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max_pool_connections=max_pool_connections,
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)
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return Endpoint(
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endpoint_url,
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endpoint_prefix=endpoint_prefix,
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event_emitter=self._event_emitter,
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response_parser_factory=response_parser_factory,
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http_session=http_session
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)
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def _get_proxies(self, url):
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# We could also support getting proxies from a config file,
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# but for now proxy support is taken from the environment.
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return get_environ_proxies(url)
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def _get_verify_value(self, verify):
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# This is to account for:
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# https://github.com/kennethreitz/requests/issues/1436
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# where we need to honor REQUESTS_CA_BUNDLE because we're creating our
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# own request objects.
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# First, if verify is not None, then the user explicitly specified
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# a value so this automatically wins.
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if verify is not None:
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return verify
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# Otherwise use the value from REQUESTS_CA_BUNDLE, or default to
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# True if the env var does not exist.
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return os.environ.get('REQUESTS_CA_BUNDLE', True)
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