python-botocore/botocore/client.py

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# Copyright 2014 Amazon.com, Inc. or its affiliates. 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. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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.
import logging
import functools
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from botocore import waiter, xform_name
from botocore.auth import AUTH_TYPE_MAPS
from botocore.awsrequest import prepare_request_dict
from botocore.docs.docstring import ClientMethodDocstring
from botocore.docs.docstring import PaginatorDocstring
from botocore.exceptions import ClientError, DataNotFoundError
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from botocore.exceptions import OperationNotPageableError
from botocore.exceptions import UnknownSignatureVersionError
from botocore.hooks import first_non_none_response
from botocore.model import ServiceModel
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from botocore.paginate import Paginator
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from botocore.utils import CachedProperty
from botocore.utils import fix_s3_host
from botocore.utils import get_service_module_name
from botocore.utils import switch_to_virtual_host_style
from botocore.utils import switch_host_s3_accelerate
from botocore.utils import S3_ACCELERATE_ENDPOINT
from botocore.utils import S3RegionRedirector
from botocore.args import ClientArgsCreator
# Keep this imported. There's pre-existing code that uses
# "from botocore.client import Config".
from botocore.config import Config
logger = logging.getLogger(__name__)
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class ClientCreator(object):
"""Creates client objects for a service."""
def __init__(self, loader, endpoint_resolver, user_agent, event_emitter,
retry_handler_factory, retry_config_translator,
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response_parser_factory=None):
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self._loader = loader
self._endpoint_resolver = endpoint_resolver
self._user_agent = user_agent
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self._event_emitter = event_emitter
self._retry_handler_factory = retry_handler_factory
self._retry_config_translator = retry_config_translator
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self._response_parser_factory = response_parser_factory
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def create_client(self, service_name, region_name, is_secure=True,
endpoint_url=None, verify=None,
credentials=None, scoped_config=None,
api_version=None,
client_config=None):
service_model = self._load_service_model(service_name, api_version)
cls = self._create_client_class(service_name, service_model)
endpoint_bridge = ClientEndpointBridge(
self._endpoint_resolver, scoped_config, client_config,
service_signing_name=service_model.metadata.get('signingName'))
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client_args = self._get_client_args(
service_model, region_name, is_secure, endpoint_url,
verify, credentials, scoped_config, client_config, endpoint_bridge)
service_client = cls(**client_args)
self._create_s3_redirector(service_client, endpoint_bridge)
return service_client
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def create_client_class(self, service_name, api_version=None):
service_model = self._load_service_model(service_name, api_version)
return self._create_client_class(service_name, service_model)
def _create_client_class(self, service_name, service_model):
class_attributes = self._create_methods(service_model)
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py_name_to_operation_name = self._create_name_mapping(service_model)
class_attributes['_PY_TO_OP_NAME'] = py_name_to_operation_name
bases = [BaseClient]
self._event_emitter.emit('creating-client-class.%s' % service_name,
class_attributes=class_attributes,
base_classes=bases)
class_name = get_service_module_name(service_model)
cls = type(str(class_name), tuple(bases), class_attributes)
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return cls
def _load_service_model(self, service_name, api_version=None):
json_model = self._loader.load_service_model(service_name, 'service-2',
api_version=api_version)
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service_model = ServiceModel(json_model, service_name=service_name)
self._register_retries(service_model)
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return service_model
def _register_retries(self, service_model):
endpoint_prefix = service_model.endpoint_prefix
# First, we load the entire retry config for all services,
# then pull out just the information we need.
original_config = self._loader.load_data('_retry')
if not original_config:
return
retry_config = self._retry_config_translator.build_retry_config(
endpoint_prefix, original_config.get('retry', {}),
original_config.get('definitions', {}))
logger.debug("Registering retry handlers for service: %s",
service_model.service_name)
handler = self._retry_handler_factory.create_retry_handler(
retry_config, endpoint_prefix)
unique_id = 'retry-config-%s' % endpoint_prefix
self._event_emitter.register('needs-retry.%s' % endpoint_prefix,
handler, unique_id=unique_id)
def _create_s3_redirector(self, client, endpoint_bridge):
if client.meta.service_model.service_name != 's3':
return
S3RegionRedirector(endpoint_bridge, client).register()
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def _get_client_args(self, service_model, region_name, is_secure,
endpoint_url, verify, credentials,
scoped_config, client_config, endpoint_bridge):
args_creator = ClientArgsCreator(
self._event_emitter, self._user_agent,
self._response_parser_factory, self._loader)
return args_creator.get_client_args(
service_model, region_name, is_secure, endpoint_url,
verify, credentials, scoped_config, client_config, endpoint_bridge)
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def _create_methods(self, service_model):
op_dict = {}
for operation_name in service_model.operation_names:
py_operation_name = xform_name(operation_name)
op_dict[py_operation_name] = self._create_api_method(
py_operation_name, operation_name, service_model)
return op_dict
def _create_name_mapping(self, service_model):
# py_name -> OperationName, for every operation available
# for a service.
mapping = {}
for operation_name in service_model.operation_names:
py_operation_name = xform_name(operation_name)
mapping[py_operation_name] = operation_name
return mapping
def _create_api_method(self, py_operation_name, operation_name,
service_model):
def _api_call(self, *args, **kwargs):
# We're accepting *args so that we can give a more helpful
# error message than TypeError: _api_call takes exactly
# 1 argument.
if args:
raise TypeError(
"%s() only accepts keyword arguments." % py_operation_name)
# The "self" in this scope is referring to the BaseClient.
return self._make_api_call(operation_name, kwargs)
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_api_call.__name__ = str(py_operation_name)
# Add the docstring to the client method
operation_model = service_model.operation_model(operation_name)
docstring = ClientMethodDocstring(
operation_model=operation_model,
method_name=operation_name,
event_emitter=self._event_emitter,
method_description=operation_model.documentation,
example_prefix='response = client.%s' % py_operation_name,
include_signature=False
)
_api_call.__doc__ = docstring
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return _api_call
class ClientEndpointBridge(object):
"""Bridges endpoint data and client creation
This class handles taking out the relevant arguments from the endpoint
resolver and determining which values to use, taking into account any
client configuration options and scope configuration options.
This class also handles determining what, if any, region to use if no
explicit region setting is provided. For example, Amazon S3 client will
utilize "us-east-1" by default if no region can be resolved."""
DEFAULT_ENDPOINT = '{service}.{region}.amazonaws.com'
def __init__(self, endpoint_resolver, scoped_config=None,
client_config=None, default_endpoint=None,
service_signing_name=None):
self.service_signing_name = service_signing_name
self.endpoint_resolver = endpoint_resolver
self.scoped_config = scoped_config
self.client_config = client_config
self.default_endpoint = default_endpoint or self.DEFAULT_ENDPOINT
def resolve(self, service_name, region_name=None, endpoint_url=None,
is_secure=True):
region_name = self._check_default_region(service_name, region_name)
resolved = self.endpoint_resolver.construct_endpoint(
service_name, region_name)
if resolved:
return self._create_endpoint(
resolved, service_name, region_name, endpoint_url, is_secure)
else:
return self._assume_endpoint(service_name, region_name,
endpoint_url, is_secure)
def _check_default_region(self, service_name, region_name):
if region_name is not None:
return region_name
# Use the client_config region if no explicit region was provided.
if self.client_config and self.client_config.region_name is not None:
return self.client_config.region_name
def _create_endpoint(self, resolved, service_name, region_name,
endpoint_url, is_secure):
region_name, signing_region = self._pick_region_values(
resolved, region_name, endpoint_url)
if endpoint_url is None:
if self._is_s3_dualstack_mode(service_name):
endpoint_url = self._create_dualstack_endpoint(
service_name, region_name,
resolved['dnsSuffix'], is_secure)
else:
# Use the sslCommonName over the hostname for Python 2.6 compat.
hostname = resolved.get('sslCommonName', resolved.get('hostname'))
endpoint_url = self._make_url(hostname, is_secure,
resolved.get('protocols', []))
signature_version = self._resolve_signature_version(
service_name, resolved)
signing_name = self._resolve_signing_name(service_name, resolved)
return self._create_result(
service_name=service_name, region_name=region_name,
signing_region=signing_region, signing_name=signing_name,
endpoint_url=endpoint_url, metadata=resolved,
signature_version=signature_version)
def _is_s3_dualstack_mode(self, service_name):
if service_name != 's3':
return False
# TODO: This normalization logic is duplicated from the
# ClientArgsCreator class. Consolidate everything to
# ClientArgsCreator. _resolve_signature_version also has similarly
# duplicated logic.
client_config = self.client_config
if client_config is not None and client_config.s3 is not None and \
'use_dualstack_endpoint' in client_config.s3:
# Client config trumps scoped config.
return client_config.s3['use_dualstack_endpoint']
if self.scoped_config is None:
return False
enabled = self.scoped_config.get('s3', {}).get(
'use_dualstack_endpoint', False)
if enabled in [True, 'True', 'true']:
return True
return False
def _create_dualstack_endpoint(self, service_name, region_name,
dns_suffix, is_secure):
hostname = '{service}.dualstack.{region}.{dns_suffix}'.format(
service=service_name, region=region_name,
dns_suffix=dns_suffix)
# Dualstack supports http and https so were hardcoding this value for
# now. This can potentially move into the endpoints.json file.
return self._make_url(hostname, is_secure, ['http', 'https'])
def _assume_endpoint(self, service_name, region_name, endpoint_url,
is_secure):
if endpoint_url is None:
# Expand the default hostname URI template.
hostname = self.default_endpoint.format(
service=service_name, region=region_name)
endpoint_url = self._make_url(hostname, is_secure,
['http', 'https'])
logger.debug('Assuming an endpoint for %s, %s: %s',
service_name, region_name, endpoint_url)
# We still want to allow the user to provide an explicit version.
signature_version = self._resolve_signature_version(
service_name, {'signatureVersions': ['v4']})
signing_name = self._resolve_signing_name(service_name, resolved={})
return self._create_result(
service_name=service_name, region_name=region_name,
signing_region=region_name, signing_name=signing_name,
signature_version=signature_version, endpoint_url=endpoint_url,
metadata={})
def _create_result(self, service_name, region_name, signing_region,
signing_name, endpoint_url, signature_version,
metadata):
return {
'service_name': service_name,
'region_name': region_name,
'signing_region': signing_region,
'signing_name': signing_name,
'endpoint_url': endpoint_url,
'signature_version': signature_version,
'metadata': metadata
}
def _make_url(self, hostname, is_secure, supported_protocols):
if is_secure and 'https' in supported_protocols:
scheme = 'https'
else:
scheme = 'http'
return '%s://%s' % (scheme, hostname)
def _resolve_signing_name(self, service_name, resolved):
# CredentialScope overrides everything else.
if 'credentialScope' in resolved \
and 'service' in resolved['credentialScope']:
return resolved['credentialScope']['service']
# Use the signingName from the model if present.
if self.service_signing_name:
return self.service_signing_name
# Just assume is the same as the service name.
return service_name
def _pick_region_values(self, resolved, region_name, endpoint_url):
signing_region = region_name
if endpoint_url is None:
# Do not use the region name or signing name from the resolved
# endpoint if the user explicitly provides an endpoint_url. This
# would happen if we resolve to an endpoint where the service has
# a "defaults" section that overrides all endpoint with a single
# hostname and credentialScope. This has been the case historically
# for how STS has worked. The only way to resolve an STS endpoint
# was to provide a region_name and an endpoint_url. In that case,
# we would still resolve an endpoint, but we would not use the
# resolved endpointName or signingRegion because we want to allow
# custom endpoints.
region_name = resolved['endpointName']
signing_region = region_name
if 'credentialScope' in resolved \
and 'region' in resolved['credentialScope']:
signing_region = resolved['credentialScope']['region']
return region_name, signing_region
def _resolve_signature_version(self, service_name, resolved):
# Client config overrides everything.
client = self.client_config
if client and client.signature_version is not None:
return client.signature_version
# Scoped config overrides picking from the endpoint metadata.
scoped = self.scoped_config
if scoped is not None:
service_config = scoped.get(service_name)
if service_config is not None and isinstance(service_config, dict):
version = service_config.get('signature_version')
if version:
logger.debug(
"Switching signature version for service %s "
"to version %s based on config file override.",
service_name, version)
return version
# Pick a signature version from the endpoint metadata if present.
if 'signatureVersions' in resolved:
potential_versions = resolved['signatureVersions']
if service_name == 's3':
# We currently prefer s3 over s3v4.
if 's3' in potential_versions:
return 's3'
elif 's3v4' in potential_versions:
return 's3v4'
if 'v4' in potential_versions:
return 'v4'
# Now just iterate over the signature versions in order until we
# find the first one that is known to Botocore.
for known in AUTH_TYPE_MAPS:
if known in potential_versions:
return known
raise UnknownSignatureVersionError(
signature_version=resolved.get('signatureVersions'))
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class BaseClient(object):
# This is actually reassigned with the py->op_name mapping
# when the client creator creates the subclass. This value is used
# because calls such as client.get_paginator('list_objects') use the
# snake_case name, but we need to know the ListObjects form.
# xform_name() does the ListObjects->list_objects conversion, but
# we need the reverse mapping here.
_PY_TO_OP_NAME = {}
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def __init__(self, serializer, endpoint, response_parser,
event_emitter, request_signer, service_model, loader,
client_config):
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self._serializer = serializer
self._endpoint = endpoint
self._response_parser = response_parser
self._request_signer = request_signer
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self._cache = {}
self._loader = loader
self._client_config = client_config
self.meta = ClientMeta(event_emitter, self._client_config,
endpoint.host, service_model,
self._PY_TO_OP_NAME)
self._register_handlers()
def _register_handlers(self):
# Register the handler required to sign requests.
self.meta.events.register('request-created.%s' %
self.meta.service_model.endpoint_prefix,
self._request_signer.handler)
self._register_s3_specific_handlers()
def _register_s3_specific_handlers(self):
# Register all of the s3 specific handlers
if self.meta.config.s3 is None:
s3_addressing_style = None
s3_accelerate = None
s3_dualstack = None
else:
s3_addressing_style = self.meta.config.s3.get('addressing_style')
s3_accelerate = self.meta.config.s3.get('use_accelerate_endpoint')
s3_dualstack = self.meta.config.s3.get('use_dualstack_endpoint')
# Enable accelerate if the configuration is set to to true or the
# endpoint being used matches one of the Accelerate endpoints.
if s3_accelerate or S3_ACCELERATE_ENDPOINT in self._endpoint.host:
# Amazon S3 accelerate is being used then always use the virtual
# style of addressing because it is required.
self._force_virtual_style_s3_addressing()
# Also make sure that the hostname gets switched to
# s3-accelerate.amazonaws.com
self.meta.events.register_first(
'request-created.s3', switch_host_s3_accelerate)
elif s3_addressing_style:
# Otherwise go ahead with the style the user may have specified.
if s3_addressing_style == 'path':
self._force_path_style_s3_addressing()
elif s3_addressing_style == 'virtual':
self._force_virtual_style_s3_addressing()
elif s3_dualstack:
self.meta.events.unregister('before-sign.s3', fix_s3_host)
self.meta.events.register(
'before-sign.s3',
functools.partial(fix_s3_host, default_endpoint_url=None))
def _force_path_style_s3_addressing(self):
# Do not try to modify the host if path is specified. The
# ``fix_s3_host`` usually switches the addresing style to virtual.
self.meta.events.unregister('before-sign.s3', fix_s3_host)
def _force_virtual_style_s3_addressing(self):
# If the virtual host addressing style is being forced,
# switch the default fix_s3_host handler for the more general
# switch_to_virtual_host_style handler that does not have opt out
# cases (other than throwing an error if the name is DNS incompatible)
self.meta.events.unregister('before-sign.s3', fix_s3_host)
self.meta.events.register(
'before-sign.s3', switch_to_virtual_host_style)
@property
def _service_model(self):
return self.meta.service_model
def _make_api_call(self, operation_name, api_params):
operation_model = self._service_model.operation_model(operation_name)
request_context = {
'client_region': self.meta.region_name,
'client_config': self.meta.config,
'has_streaming_input': operation_model.has_streaming_input
}
request_dict = self._convert_to_request_dict(
api_params, operation_model, context=request_context)
handler, event_response = self.meta.events.emit_until_response(
'before-call.{endpoint_prefix}.{operation_name}'.format(
endpoint_prefix=self._service_model.endpoint_prefix,
operation_name=operation_name),
model=operation_model, params=request_dict,
request_signer=self._request_signer, context=request_context)
if event_response is not None:
http, parsed_response = event_response
else:
http, parsed_response = self._endpoint.make_request(
operation_model, request_dict)
self.meta.events.emit(
'after-call.{endpoint_prefix}.{operation_name}'.format(
endpoint_prefix=self._service_model.endpoint_prefix,
operation_name=operation_name),
http_response=http, parsed=parsed_response,
model=operation_model, context=request_context
)
if http.status_code >= 300:
raise ClientError(parsed_response, operation_name)
else:
return parsed_response
def _convert_to_request_dict(self, api_params, operation_model,
context=None):
# Given the API params provided by the user and the operation_model
# we can serialize the request to a request_dict.
operation_name = operation_model.name
# Emit an event that allows users to modify the parameters at the
# beginning of the method. It allows handlers to modify existing
# parameters or return a new set of parameters to use.
responses = self.meta.events.emit(
'provide-client-params.{endpoint_prefix}.{operation_name}'.format(
endpoint_prefix=self._service_model.endpoint_prefix,
operation_name=operation_name),
params=api_params, model=operation_model, context=context)
api_params = first_non_none_response(responses, default=api_params)
event_name = (
'before-parameter-build.{endpoint_prefix}.{operation_name}')
self.meta.events.emit(
event_name.format(
endpoint_prefix=self._service_model.endpoint_prefix,
operation_name=operation_name),
params=api_params, model=operation_model, context=context)
request_dict = self._serializer.serialize_to_request(
api_params, operation_model)
prepare_request_dict(request_dict, endpoint_url=self._endpoint.host,
user_agent=self._client_config.user_agent,
context=context)
return request_dict
def get_paginator(self, operation_name):
"""Create a paginator for an operation.
:type operation_name: string
:param operation_name: The operation name. This is the same name
as the method name on the client. For example, if the
method name is ``create_foo``, and you'd normally invoke the
operation as ``client.create_foo(**kwargs)``, if the
``create_foo`` operation can be paginated, you can use the
call ``client.get_paginator("create_foo")``.
:raise OperationNotPageableError: Raised if the operation is not
pageable. You can use the ``client.can_paginate`` method to
check if an operation is pageable.
:rtype: L{botocore.paginate.Paginator}
:return: A paginator object.
"""
if not self.can_paginate(operation_name):
raise OperationNotPageableError(operation_name=operation_name)
else:
actual_operation_name = self._PY_TO_OP_NAME[operation_name]
# Create a new paginate method that will serve as a proxy to
# the underlying Paginator.paginate method. This is needed to
# attach a docstring to the method.
def paginate(self, **kwargs):
return Paginator.paginate(self, **kwargs)
paginator_config = self._cache['page_config'][
actual_operation_name]
# Add the docstring for the paginate method.
paginate.__doc__ = PaginatorDocstring(
paginator_name=actual_operation_name,
event_emitter=self.meta.events,
service_model=self.meta.service_model,
paginator_config=paginator_config,
include_signature=False
)
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# Rename the paginator class based on the type of paginator.
paginator_class_name = str('%s.Paginator.%s' % (
get_service_module_name(self.meta.service_model),
actual_operation_name))
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# Create the new paginator class
documented_paginator_cls = type(
paginator_class_name, (Paginator,), {'paginate': paginate})
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paginator = documented_paginator_cls(
getattr(self, operation_name),
paginator_config)
return paginator
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def can_paginate(self, operation_name):
"""Check if an operation can be paginated.
:type operation_name: string
:param operation_name: The operation name. This is the same name
as the method name on the client. For example, if the
method name is ``create_foo``, and you'd normally invoke the
operation as ``client.create_foo(**kwargs)``, if the
``create_foo`` operation can be paginated, you can use the
call ``client.get_paginator("create_foo")``.
:return: ``True`` if the operation can be paginated,
``False`` otherwise.
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"""
if 'page_config' not in self._cache:
try:
page_config = self._loader.load_service_model(
self._service_model.service_name,
'paginators-1',
self._service_model.api_version)['pagination']
self._cache['page_config'] = page_config
except DataNotFoundError:
self._cache['page_config'] = {}
actual_operation_name = self._PY_TO_OP_NAME[operation_name]
return actual_operation_name in self._cache['page_config']
def _get_waiter_config(self):
if 'waiter_config' not in self._cache:
try:
waiter_config = self._loader.load_service_model(
self._service_model.service_name,
'waiters-2',
self._service_model.api_version)
self._cache['waiter_config'] = waiter_config
except DataNotFoundError:
self._cache['waiter_config'] = {}
return self._cache['waiter_config']
def get_waiter(self, waiter_name):
config = self._get_waiter_config()
if not config:
raise ValueError("Waiter does not exist: %s" % waiter_name)
model = waiter.WaiterModel(config)
mapping = {}
for name in model.waiter_names:
mapping[xform_name(name)] = name
if waiter_name not in mapping:
raise ValueError("Waiter does not exist: %s" % waiter_name)
return waiter.create_waiter_with_client(
mapping[waiter_name], model, self)
@CachedProperty
def waiter_names(self):
"""Returns a list of all available waiters."""
config = self._get_waiter_config()
if not config:
return []
model = waiter.WaiterModel(config)
# Waiter configs is a dict, we just want the waiter names
# which are the keys in the dict.
return [xform_name(name) for name in model.waiter_names]
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class ClientMeta(object):
"""Holds additional client methods.
This class holds additional information for clients. It exists for
two reasons:
* To give advanced functionality to clients
* To namespace additional client attributes from the operation
names which are mapped to methods at runtime. This avoids
ever running into collisions with operation names.
"""
def __init__(self, events, client_config, endpoint_url, service_model,
method_to_api_mapping):
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self.events = events
self._client_config = client_config
self._endpoint_url = endpoint_url
self._service_model = service_model
self._method_to_api_mapping = method_to_api_mapping
@property
def service_model(self):
return self._service_model
@property
def region_name(self):
return self._client_config.region_name
@property
def endpoint_url(self):
return self._endpoint_url
@property
def config(self):
return self._client_config
@property
def method_to_api_mapping(self):
return self._method_to_api_mapping