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OpenStack Study: utils.py**** CubicPower OpenStack Study ****
# Copyright 2013 OpenStack Foundation # 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. import shutil import tarfile from nova.image import glance
**** CubicPower OpenStack Study **** class GlanceImage(object):
**** CubicPower OpenStack Study **** def __init__(self, context, image_href_or_id): self._context = context self._image_service, self._image_id = glance.get_remote_image_service( context, image_href_or_id) self._cached_meta = None @property
**** CubicPower OpenStack Study **** def meta(self): if self._cached_meta is None: self._cached_meta = self._image_service.show( self._context, self._image_id) return self._cached_meta
**** CubicPower OpenStack Study **** def download_to(self, fileobj): return self._image_service.download( self._context, self._image_id, fileobj)
**** CubicPower OpenStack Study **** def is_raw_tgz(self): return ['raw', 'tgz'] == [ self.meta.get(key) for key in ('disk_format', 'container_format')]
**** CubicPower OpenStack Study **** def data(self): return self._image_service.download(self._context, self._image_id)
**** CubicPower OpenStack Study **** class RawImage(object):
**** CubicPower OpenStack Study **** def __init__(self, glance_image): self.glance_image = glance_image
**** CubicPower OpenStack Study **** def get_size(self): return int(self.glance_image.meta['size'])
**** CubicPower OpenStack Study **** def stream_to(self, fileobj): return self.glance_image.download_to(fileobj)
**** CubicPower OpenStack Study **** class IterableToFileAdapter(object): """A degenerate file-like so that an iterable could be read like a file. As Glance client returns an iterable, but tarfile requires a file like, this is the adapter between the two. This allows tarfile to access the glance stream. """
**** CubicPower OpenStack Study **** def __init__(self, iterable): self.iterator = iterable.__iter__() self.remaining_data = ''
**** CubicPower OpenStack Study **** def read(self, size): chunk = self.remaining_data try: while not chunk: chunk = self.iterator.next() except StopIteration: return '' return_value = chunk[0:size] self.remaining_data = chunk[size:] return return_value
**** CubicPower OpenStack Study **** class RawTGZImage(object):
**** CubicPower OpenStack Study **** def __init__(self, glance_image): self.glance_image = glance_image self._tar_info = None self._tar_file = None
**** CubicPower OpenStack Study **** def _as_file(self): return IterableToFileAdapter(self.glance_image.data())
**** CubicPower OpenStack Study **** def _as_tarfile(self): return tarfile.open(mode='r|gz', fileobj=self._as_file())
**** CubicPower OpenStack Study **** def get_size(self): if self._tar_file is None: self._tar_file = self._as_tarfile() self._tar_info = self._tar_file.next() return self._tar_info.size
**** CubicPower OpenStack Study **** def stream_to(self, target_file): if self._tar_file is None: self._tar_file = self._as_tarfile() self._tar_info = self._tar_file.next() source_file = self._tar_file.extractfile(self._tar_info) shutil.copyfileobj(source_file, target_file) self._tar_file.close()
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