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OpenStack Study: base.py**** CubicPower OpenStack Study ****
# Copyright 2011 OpenStack Foundation # Copyright 2012 RedHat 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. """Base class for all storage backends""" from glance.common import exception from glance.openstack.common import importutils import glance.openstack.common.log as logging from glance.openstack.common import strutils from glance.openstack.common import units LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** def _exception_to_unicode(exc): try: return unicode(exc) except UnicodeError: try: return strutils.safe_decode(str(exc), errors='ignore') except UnicodeError: msg = (_("Caught '%(exception)s' exception.") % {"exception": exc.__class__.__name__}) return strutils.safe_decode(msg, errors='ignore')
**** CubicPower OpenStack Study **** class Store(object): CHUNKSIZE = 16 * units.Mi # 16M
**** CubicPower OpenStack Study **** def __init__(self, context=None, location=None): """ Initialize the Store """ self.store_location_class = None self.context = context self.configure() try: self.configure_add() except exception.BadStoreConfiguration as e: self.add = self.add_disabled msg = (_(u"Failed to configure store correctly: %s " "Disabling add method.") % _exception_to_unicode(e)) LOG.warn(msg)
**** CubicPower OpenStack Study **** def configure(self): """ Configure the Store to use the stored configuration options Any store that needs special configuration should implement this method. """ pass
**** CubicPower OpenStack Study **** def get_schemes(self): """ Returns a tuple of schemes which this store can handle. """ raise NotImplementedError
**** CubicPower OpenStack Study **** def get_store_location_class(self): """ Returns the store location class that is used by this store. """ if not self.store_location_class: class_name = "%s.StoreLocation" % (self.__module__) LOG.debug("Late loading location class %s", class_name) self.store_location_class = importutils.import_class(class_name) return self.store_location_class
**** CubicPower OpenStack Study **** def configure_add(self): """ This is like `configure` except that it's specifically for configuring the store to accept objects. If the store was not able to successfully configure itself, it should raise `exception.BadStoreConfiguration`. """ pass
**** CubicPower OpenStack Study **** def get(self, location): """ Takes a `glance.store.location.Location` object that indicates where to find the image file, and returns a tuple of generator (for reading the image file) and image_size :param location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() :raises `glance.exception.NotFound` if image does not exist """ raise NotImplementedError
**** CubicPower OpenStack Study **** def get_size(self, location): """ Takes a `glance.store.location.Location` object that indicates where to find the image file, and returns the size :param location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() :raises `glance.exception.NotFound` if image does not exist """ raise NotImplementedError
**** CubicPower OpenStack Study **** def add_disabled(self, *args, **kwargs): """ Add method that raises an exception because the Store was not able to be configured properly and therefore the add() method would error out. """ raise exception.StoreAddDisabled
**** CubicPower OpenStack Study **** def add(self, image_id, image_file, image_size): """ Stores an image file with supplied identifier to the backend storage system and returns a tuple containing information about the stored image. :param image_id: The opaque image identifier :param image_file: The image data to write, as a file-like object :param image_size: The size of the image data to write, in bytes :retval tuple of URL in backing store, bytes written, checksum and a dictionary with storage system specific information :raises `glance.common.exception.Duplicate` if the image already existed """ raise NotImplementedError
**** CubicPower OpenStack Study **** def delete(self, location): """ Takes a `glance.store.location.Location` object that indicates where to find the image file to delete :location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() :raises `glance.exception.NotFound` if image does not exist """ raise NotImplementedError
**** CubicPower OpenStack Study **** def set_acls(self, location, public=False, read_tenants=[], write_tenants=[]): """ Sets the read and write access control list for an image in the backend store. :location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() :public A boolean indicating whether the image should be public. :read_tenants A list of tenant strings which should be granted read access for an image. :write_tenants A list of tenant strings which should be granted write access for an image. """ raise NotImplementedError
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