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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 boto3
logger = logging.getLogger(__name__)
class ResourceMeta(object):
"""
An object containing metadata about a resource.
"""
def __init__(self, service_name, identifiers=None, client=None,
data=None):
#: (``string``) The service name, e.g. 's3'
self.service_name = service_name
if identifiers is None:
identifiers = []
#: (``list``) List of identifier names
self.identifiers = identifiers
#: (:py:class:`~botocore.client.BaseClient`) Low-level Botocore client
self.client = client
#: (``dict``) Loaded resource data attributes
self.data = data
def __repr__(self):
return 'ResourceMeta(\'{0}\', identifiers={1})'.format(
self.service_name, self.identifiers)
def __eq__(self, other):
# Two metas are equal if their components are all equal
if other.__class__.__name__ != self.__class__.__name__:
return False
return self.__dict__ == other.__dict__
def copy(self):
"""
Create a copy of this metadata object.
"""
params = self.__dict__.copy()
service_name = params.pop('service_name')
return ResourceMeta(service_name, **params)
class ServiceResource(object):
"""
A base class for resources.
:type client: botocore.client
:param client: A low-level Botocore client instance
"""
meta = None
"""
Stores metadata about this resource instance, such as the
``service_name``, the low-level ``client`` and any cached ``data``
from when the instance was hydrated. For example::
# Get a low-level client from a resource instance
client = resource.meta.client
response = client.operation(Param='foo')
# Print the resource instance's service short name
print(resource.meta.service_name)
See :py:class:`ResourceMeta` for more information.
"""
def __init__(self, *args, **kwargs):
# Always work on a copy of meta, otherwise we would affect other
# instances of the same subclass.
self.meta = self.meta.copy()
# Create a default client if none was passed
if kwargs.get('client') is not None:
self.meta.client = kwargs.get('client')
else:
self.meta.client = boto3.client(self.meta.service_name)
# Allow setting identifiers as positional arguments in the order
# in which they were defined in the ResourceJSON.
for i, value in enumerate(args):
setattr(self, self.meta.identifiers[i], value)
# Allow setting identifiers via keyword arguments. Here we need
# extra logic to ignore other keyword arguments like ``client``.
for name, value in kwargs.items():
if name == 'client':
continue
if name not in self.meta.identifiers:
raise ValueError('Unknown keyword argument: {0}'.format(name))
setattr(self, name, value)
# Validate that all identifiers have been set.
for identifier in self.meta.identifiers:
if getattr(self, identifier) is None:
raise ValueError(
'Required parameter {0} not set'.format(identifier))
def __repr__(self):
identifiers = []
for identifier in self.meta.identifiers:
identifiers.append('{0}={1}'.format(
identifier, repr(getattr(self, identifier))))
return "{0}({1})".format(
self.__class__.__name__,
', '.join(identifiers),
)
def __eq__(self, other):
# Should be instances of the same resource class
if other.__class__.__name__ != self.__class__.__name__:
return False
# Each of the identifiers should have the same value in both
# instances, e.g. two buckets need the same name to be equal.
for identifier in self.meta.identifiers:
if getattr(self, identifier) != getattr(other, identifier):
return False
return True
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