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# Copyright 2010 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.

"""Implementation of an image service that uses Glance as the backend."""

from __future__ import absolute_import

import copy

import itertools

import json

import random

import sys

import time

import glanceclient

import glanceclient.exc

from oslo.config import cfg

import six

import six.moves.urllib.parse as urlparse

from nova import exception

import nova.image.download as image_xfers

from nova.openstack.common.gettextutils import _

from nova.openstack.common import jsonutils

from nova.openstack.common import log as logging

from nova.openstack.common import timeutils

from nova import utils

glance_opts = [

cfg.StrOpt('glance_host',

default='$my_ip',

help='Default glance hostname or IP address'),

cfg.IntOpt('glance_port',

default=9292,

help='Default glance port'),

cfg.StrOpt('glance_protocol',

default='http',

help='Default protocol to use when connecting to glance. '

'Set to https for SSL.'),

cfg.ListOpt('glance_api_servers',

default=['$glance_host:$glance_port'],

help='A list of the glance api servers available to nova. '

'Prefix with https:// for ssl-based glance api servers. '

'([hostname|ip]:port)'),

cfg.BoolOpt('glance_api_insecure',

default=False,

help='Allow to perform insecure SSL (https) requests to '

'glance'),

cfg.IntOpt('glance_num_retries',

default=0,

help='Number of retries when downloading an image from glance'),

cfg.ListOpt('allowed_direct_url_schemes',

default=[],

help='A list of url scheme that can be downloaded directly '

'via the direct_url. Currently supported schemes: '

'[file].'),

]

LOG = logging.getLogger(__name__)

CONF = cfg.CONF

CONF.register_opts(glance_opts)

CONF.import_opt('auth_strategy', 'nova.api.auth')

CONF.import_opt('my_ip', 'nova.netconf')

**** CubicPower OpenStack Study ****

def generate_glance_url():

    """Generate the URL to glance."""

    glance_host = CONF.glance_host

    if utils.is_valid_ipv6(glance_host):

        glance_host = '[%s]' % glance_host

    return "%s://%s:%d" % (CONF.glance_protocol, glance_host,

                           CONF.glance_port)

**** CubicPower OpenStack Study ****

def generate_image_url(image_ref):

    """Generate an image URL from an image_ref."""

    return "%s/images/%s" % (generate_glance_url(), image_ref)

**** CubicPower OpenStack Study ****

def _parse_image_ref(image_href):

    """Parse an image href into composite parts.

    :param image_href: href of an image

    :returns: a tuple of the form (image_id, host, port)

    :raises ValueError

    """

    o = urlparse.urlparse(image_href)

    port = o.port or 80

    host = o.netloc.rsplit(':', 1)[0]

    image_id = o.path.split('/')[-1]

    use_ssl = (o.scheme == 'https')

    return (image_id, host, port, use_ssl)

**** CubicPower OpenStack Study ****

def generate_identity_headers(context, status='Confirmed'):

    return {

        'X-Auth-Token': getattr(context, 'auth_token', None),

        'X-User-Id': getattr(context, 'user', None),

        'X-Tenant-Id': getattr(context, 'tenant', None),

        'X-Roles': ','.join(context.roles),

        'X-Identity-Status': status,

        'X-Service-Catalog': json.dumps(context.service_catalog),

    }

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def _create_glance_client(context, host, port, use_ssl, version=1):

    """Instantiate a new glanceclient.Client object."""

    params = {}

    if use_ssl:

        scheme = 'https'

        # https specific params

        params['insecure'] = CONF.glance_api_insecure

        params['ssl_compression'] = False

    else:

        scheme = 'http'

    if CONF.auth_strategy == 'keystone':

        # NOTE(isethi): Glanceclient <= 0.9.0.49 accepts only

        # keyword 'token', but later versions accept both the

        # header 'X-Auth-Token' and 'token'

        params['token'] = context.auth_token

        params['identity_headers'] = generate_identity_headers(context)

    if utils.is_valid_ipv6(host):

        #if so, it is ipv6 address, need to wrap it with '[]'

        host = '[%s]' % host

    endpoint = '%s://%s:%s' % (scheme, host, port)

    return glanceclient.Client(str(version), endpoint, **params)

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def get_api_servers():

    """Shuffle a list of CONF.glance_api_servers and return an iterator

    that will cycle through the list, looping around to the beginning

    if necessary.

    """

    api_servers = []

    for api_server in CONF.glance_api_servers:

        if '//' not in api_server:

            api_server = 'http://' + api_server

        o = urlparse.urlparse(api_server)

        port = o.port or 80

        host = o.netloc.rsplit(':', 1)[0]

        if host[0] == '[' and host[-1] == ']':

            host = host[1:-1]

        use_ssl = (o.scheme == 'https')

        api_servers.append((host, port, use_ssl))

    random.shuffle(api_servers)

    return itertools.cycle(api_servers)

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class GlanceClientWrapper(object):

"""Glance client wrapper class that implements retries."""

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    def __init__(self, context=None, host=None, port=None, use_ssl=False,

                 version=1):

        if host is not None:

            self.client = self._create_static_client(context,

                                                     host, port,

                                                     use_ssl, version)

        else:

            self.client = None

        self.api_servers = None

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    def _create_static_client(self, context, host, port, use_ssl, version):

        """Create a client that we'll use for every call."""

        self.host = host

        self.port = port

        self.use_ssl = use_ssl

        self.version = version

        return _create_glance_client(context,

                                     self.host, self.port,

                                     self.use_ssl, self.version)

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    def _create_onetime_client(self, context, version):

        """Create a client that will be used for one call."""

        if self.api_servers is None:

            self.api_servers = get_api_servers()

        self.host, self.port, self.use_ssl = self.api_servers.next()

        return _create_glance_client(context,

                                     self.host, self.port,

                                     self.use_ssl, version)

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    def call(self, context, version, method, *args, **kwargs):

        """Call a glance client method.  If we get a connection error,

        retry the request according to CONF.glance_num_retries.

        """

        retry_excs = (glanceclient.exc.ServiceUnavailable,

                glanceclient.exc.InvalidEndpoint,

                glanceclient.exc.CommunicationError)

        num_attempts = 1 + CONF.glance_num_retries

        for attempt in xrange(1, num_attempts + 1):

            client = self.client or self._create_onetime_client(context,

                                                                version)

            try:

                return getattr(client.images, method)(*args, **kwargs)

            except retry_excs as e:

                host = self.host

                port = self.port

                extra = "retrying"

                error_msg = (_("Error contacting glance server "

                               "'%(host)s:%(port)s' for '%(method)s', "

                               "%(extra)s.") %

                             {'host': host, 'port': port,

                              'method': method, 'extra': extra})

                if attempt == num_attempts:

                    extra = 'done trying'

                    LOG.exception(error_msg)

                    raise exception.GlanceConnectionFailed(

                            host=host, port=port, reason=str(e))

                LOG.exception(error_msg)

                time.sleep(1)

**** CubicPower OpenStack Study ****

class GlanceImageService(object):

"""Provides storage and retrieval of disk image objects within Glance."""

**** CubicPower OpenStack Study ****

    def __init__(self, client=None):

        self._client = client or GlanceClientWrapper()

        #NOTE(jbresnah) build the table of download handlers at the beginning

        # so that operators can catch errors at load time rather than whenever

        # a user attempts to use a module.  Note this cannot be done in glance

        # space when this python module is loaded because the download module

        # may require configuration options to be parsed.

        self._download_handlers = {}

        download_modules = image_xfers.load_transfer_modules()

        for scheme, mod in download_modules.iteritems():

            if scheme not in CONF.allowed_direct_url_schemes:

                continue

            try:

                self._download_handlers[scheme] = mod.get_download_handler()

            except Exception as ex:

                fmt = _('When loading the module %(module_str)s the '

                         'following error occurred: %(ex)s')

                LOG.error(fmt % {'module_str': str(mod), 'ex': ex})

**** CubicPower OpenStack Study ****

    def detail(self, context, **kwargs):

        """Calls out to Glance for a list of detailed image information."""

        params = _extract_query_params(kwargs)

        try:

            images = self._client.call(context, 1, 'list', **params)

        except Exception:

            _reraise_translated_exception()

        _images = []

        for image in images:

            if _is_image_available(context, image):

                _images.append(_translate_from_glance(image))

        return _images

**** CubicPower OpenStack Study ****

    def show(self, context, image_id):

        """Returns a dict with image data for the given opaque image id."""

        try:

            image = self._client.call(context, 1, 'get', image_id)

        except Exception:

            _reraise_translated_image_exception(image_id)

        if not _is_image_available(context, image):

            raise exception.ImageNotFound(image_id=image_id)

        base_image_meta = _translate_from_glance(image)

        return base_image_meta

**** CubicPower OpenStack Study ****

    def _get_locations(self, context, image_id):

        """Returns the direct url representing the backend storage location,

        or None if this attribute is not shown by Glance.

        """

        try:

            client = GlanceClientWrapper()

            image_meta = client.call(context, 2, 'get', image_id)

        except Exception:

            _reraise_translated_image_exception(image_id)

        if not _is_image_available(context, image_meta):

            raise exception.ImageNotFound(image_id=image_id)

        locations = getattr(image_meta, 'locations', [])

        du = getattr(image_meta, 'direct_url', None)

        if du:

            locations.append({'url': du, 'metadata': {}})

        return locations

**** CubicPower OpenStack Study ****

    def _get_transfer_module(self, scheme):

        try:

            return self._download_handlers[scheme]

        except KeyError:

            return None

        except Exception as ex:

            LOG.error(_("Failed to instantiate the download handler "

                "for %(scheme)s") % {'scheme': scheme})

        return

**** CubicPower OpenStack Study ****

    def download(self, context, image_id, data=None, dst_path=None):

        """Calls out to Glance for data and writes data."""

        if CONF.allowed_direct_url_schemes and dst_path is not None:

            locations = self._get_locations(context, image_id)

            for entry in locations:

                loc_url = entry['url']

                loc_meta = entry['metadata']

                o = urlparse.urlparse(loc_url)

                xfer_mod = self._get_transfer_module(o.scheme)

                if xfer_mod:

                    try:

                        xfer_mod.download(context, o, dst_path, loc_meta)

                        msg = _("Successfully transferred "

                                "using %s") % o.scheme

                        LOG.info(msg)

                        return

                    except Exception as ex:

                        LOG.exception(ex)

        try:

            image_chunks = self._client.call(context, 1, 'data', image_id)

        except Exception:

            _reraise_translated_image_exception(image_id)

        close_file = False

        if data is None and dst_path:

            data = open(dst_path, 'wb')

            close_file = True

        if data is None:

            return image_chunks

        else:

            try:

                for chunk in image_chunks:

                    data.write(chunk)

            finally:

                if close_file:

                    data.close()

**** CubicPower OpenStack Study ****

    def create(self, context, image_meta, data=None):

        """Store the image data and return the new image object."""

        sent_service_image_meta = _translate_to_glance(image_meta)

        if data:

            sent_service_image_meta['data'] = data

        try:

            recv_service_image_meta = self._client.call(

                context, 1, 'create', **sent_service_image_meta)

        except glanceclient.exc.HTTPException:

            _reraise_translated_exception()

        return _translate_from_glance(recv_service_image_meta)

**** CubicPower OpenStack Study ****

    def update(self, context, image_id, image_meta, data=None,

            purge_props=True):

        """Modify the given image with the new data."""

        image_meta = _translate_to_glance(image_meta)

        image_meta['purge_props'] = purge_props

        #NOTE(bcwaldon): id is not an editable field, but it is likely to be

        # passed in by calling code. Let's be nice and ignore it.

        image_meta.pop('id', None)

        if data:

            image_meta['data'] = data

        try:

            image_meta = self._client.call(context, 1, 'update',

                                           image_id, **image_meta)

        except Exception:

            _reraise_translated_image_exception(image_id)

        else:

            return _translate_from_glance(image_meta)

**** CubicPower OpenStack Study ****

    def delete(self, context, image_id):

        """Delete the given image.

        :raises: ImageNotFound if the image does not exist.

        :raises: NotAuthorized if the user is not an owner.

        :raises: ImageNotAuthorized if the user is not authorized.

        """

        try:

            self._client.call(context, 1, 'delete', image_id)

        except glanceclient.exc.NotFound:

            raise exception.ImageNotFound(image_id=image_id)

        except glanceclient.exc.HTTPForbidden:

            raise exception.ImageNotAuthorized(image_id=image_id)

        return True

def _extract_query_params(params):

    _params = {}

    accepted_params = ('filters', 'marker', 'limit',

                       'page_size', 'sort_key', 'sort_dir')

    for param in accepted_params:

        if params.get(param):

            _params[param] = params.get(param)

    # ensure filters is a dict

    _params.setdefault('filters', {})

    # NOTE(vish): don't filter out private images

    _params['filters'].setdefault('is_public', 'none')

    return _params

def _is_image_available(context, image):

    """Check image availability.

    This check is needed in case Nova and Glance are deployed

    without authentication turned on.

    """

    # The presence of an auth token implies this is an authenticated

    # request and we need not handle the noauth use-case.

    if hasattr(context, 'auth_token') and context.auth_token:

        return True

**** CubicPower OpenStack Study ****

def _extract_query_params(params):

    _params = {}

    accepted_params = ('filters', 'marker', 'limit',

                       'page_size', 'sort_key', 'sort_dir')

    for param in accepted_params:

        if params.get(param):

            _params[param] = params.get(param)

    # ensure filters is a dict

    _params.setdefault('filters', {})

    # NOTE(vish): don't filter out private images

    _params['filters'].setdefault('is_public', 'none')

    return _params

**** CubicPower OpenStack Study ****

def _is_image_available(context, image):

    """Check image availability.

    This check is needed in case Nova and Glance are deployed

    without authentication turned on.

    """

    # The presence of an auth token implies this is an authenticated

    # request and we need not handle the noauth use-case.

    if hasattr(context, 'auth_token') and context.auth_token:

        return True

**** CubicPower OpenStack Study ****

    def _is_image_public(image):

        # NOTE(jaypipes) V2 Glance API replaced the is_public attribute

        # with a visibility attribute. We do this here to prevent the

        # glanceclient for a V2 image model from throwing an

        # exception from warlock when trying to access an is_public

        # attribute.

        if hasattr(image, 'visibility'):

            return str(image.visibility).lower() == 'public'

        else:

            return image.is_public

    if context.is_admin or _is_image_public(image):

        return True

    properties = image.properties

    if context.project_id and ('owner_id' in properties):

        return str(properties['owner_id']) == str(context.project_id)

    if context.project_id and ('project_id' in properties):

        return str(properties['project_id']) == str(context.project_id)

    try:

        user_id = properties['user_id']

    except KeyError:

        return False

    return str(user_id) == str(context.user_id)

def _translate_to_glance(image_meta):

    image_meta = _convert_to_string(image_meta)

    image_meta = _remove_read_only(image_meta)

    return image_meta

def _translate_from_glance(image):

    image_meta = _extract_attributes(image)

    image_meta = _convert_timestamps_to_datetimes(image_meta)

    image_meta = _convert_from_string(image_meta)

    return image_meta

def _convert_timestamps_to_datetimes(image_meta):

    """Returns image with timestamp fields converted to datetime objects."""

    for attr in ['created_at', 'updated_at', 'deleted_at']:

        if image_meta.get(attr):

            image_meta[attr] = timeutils.parse_isotime(image_meta[attr])

    return image_meta

# NOTE(bcwaldon): used to store non-string data in glance metadata

def _json_loads(properties, attr):

    prop = properties[attr]

    if isinstance(prop, six.string_types):

        properties[attr] = jsonutils.loads(prop)

def _json_dumps(properties, attr):

    prop = properties[attr]

    if not isinstance(prop, six.string_types):

        properties[attr] = jsonutils.dumps(prop)

_CONVERT_PROPS = ('block_device_mapping', 'mappings')

def _convert(method, metadata):

    metadata = copy.deepcopy(metadata)

    properties = metadata.get('properties')

    if properties:

        for attr in _CONVERT_PROPS:

            if attr in properties:

                method(properties, attr)

    return metadata

def _convert_from_string(metadata):

    return _convert(_json_loads, metadata)

def _convert_to_string(metadata):

    return _convert(_json_dumps, metadata)

def _extract_attributes(image):

    IMAGE_ATTRIBUTES = ['size', 'disk_format', 'owner',

                        'container_format', 'checksum', 'id',

                        'name', 'created_at', 'updated_at',

                        'deleted_at', 'deleted', 'status',

                        'min_disk', 'min_ram', 'is_public']

    output = {}

    for attr in IMAGE_ATTRIBUTES:

        output[attr] = getattr(image, attr, None)

    output['properties'] = getattr(image, 'properties', {})

    return output

def _remove_read_only(image_meta):

    IMAGE_ATTRIBUTES = ['status', 'updated_at', 'created_at', 'deleted_at']

    output = copy.deepcopy(image_meta)

    for attr in IMAGE_ATTRIBUTES:

        if attr in output:

            del output[attr]

    return output

def _reraise_translated_image_exception(image_id):

    """Transform the exception for the image but keep its traceback intact."""

    exc_type, exc_value, exc_trace = sys.exc_info()

    new_exc = _translate_image_exception(image_id, exc_value)

    raise new_exc, None, exc_trace

def _reraise_translated_exception():

    """Transform the exception but keep its traceback intact."""

    exc_type, exc_value, exc_trace = sys.exc_info()

    new_exc = _translate_plain_exception(exc_value)

    raise new_exc, None, exc_trace

def _translate_image_exception(image_id, exc_value):

    if isinstance(exc_value, (glanceclient.exc.Forbidden,

                    glanceclient.exc.Unauthorized)):

        return exception.ImageNotAuthorized(image_id=image_id)

    if isinstance(exc_value, glanceclient.exc.NotFound):

        return exception.ImageNotFound(image_id=image_id)

    if isinstance(exc_value, glanceclient.exc.BadRequest):

        return exception.Invalid(unicode(exc_value))

    return exc_value

def _translate_plain_exception(exc_value):

    if isinstance(exc_value, (glanceclient.exc.Forbidden,

                    glanceclient.exc.Unauthorized)):

        return exception.NotAuthorized(unicode(exc_value))

    if isinstance(exc_value, glanceclient.exc.NotFound):

        return exception.NotFound(unicode(exc_value))

    if isinstance(exc_value, glanceclient.exc.BadRequest):

        return exception.Invalid(unicode(exc_value))

    return exc_value

def get_remote_image_service(context, image_href):

    """Create an image_service and parse the id from the given image_href.

    The image_href param can be an href of the form

    'http://example.com:9292/v1/images/b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3',

    or just an id such as 'b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3'. If the

    image_href is a standalone id, then the default image service is returned.

    :param image_href: href that describes the location of an image

    :returns: a tuple of the form (image_service, image_id)

    """

    #NOTE(bcwaldon): If image_href doesn't look like a URI, assume its a

    # standalone image ID

    if '/' not in str(image_href):

        image_service = get_default_image_service()

        return image_service, image_href

    try:

        (image_id, glance_host, glance_port, use_ssl) = \

            _parse_image_ref(image_href)

        glance_client = GlanceClientWrapper(context=context,

                host=glance_host, port=glance_port, use_ssl=use_ssl)

    except ValueError:

        raise exception.InvalidImageRef(image_href=image_href)

    image_service = GlanceImageService(client=glance_client)

    return image_service, image_id

def get_default_image_service():

    return GlanceImageService()

**** CubicPower OpenStack Study ****

def _translate_to_glance(image_meta):

    image_meta = _convert_to_string(image_meta)

    image_meta = _remove_read_only(image_meta)

    return image_meta

**** CubicPower OpenStack Study ****

def _translate_from_glance(image):

    image_meta = _extract_attributes(image)

    image_meta = _convert_timestamps_to_datetimes(image_meta)

    image_meta = _convert_from_string(image_meta)

    return image_meta

**** CubicPower OpenStack Study ****

def _convert_timestamps_to_datetimes(image_meta):

    """Returns image with timestamp fields converted to datetime objects."""

    for attr in ['created_at', 'updated_at', 'deleted_at']:

        if image_meta.get(attr):

            image_meta[attr] = timeutils.parse_isotime(image_meta[attr])

    return image_meta

# NOTE(bcwaldon): used to store non-string data in glance metadata

**** CubicPower OpenStack Study ****

def _json_loads(properties, attr):

    prop = properties[attr]

    if isinstance(prop, six.string_types):

        properties[attr] = jsonutils.loads(prop)

**** CubicPower OpenStack Study ****

def _json_dumps(properties, attr):

    prop = properties[attr]

    if not isinstance(prop, six.string_types):

        properties[attr] = jsonutils.dumps(prop)

_CONVERT_PROPS = ('block_device_mapping', 'mappings')

**** CubicPower OpenStack Study ****

def _convert(method, metadata):

    metadata = copy.deepcopy(metadata)

    properties = metadata.get('properties')

    if properties:

        for attr in _CONVERT_PROPS:

            if attr in properties:

                method(properties, attr)

    return metadata

**** CubicPower OpenStack Study ****

def _convert_from_string(metadata):

    return _convert(_json_loads, metadata)

**** CubicPower OpenStack Study ****

def _convert_to_string(metadata):

    return _convert(_json_dumps, metadata)

**** CubicPower OpenStack Study ****

def _extract_attributes(image):

    IMAGE_ATTRIBUTES = ['size', 'disk_format', 'owner',

                        'container_format', 'checksum', 'id',

                        'name', 'created_at', 'updated_at',

                        'deleted_at', 'deleted', 'status',

                        'min_disk', 'min_ram', 'is_public']

    output = {}

    for attr in IMAGE_ATTRIBUTES:

        output[attr] = getattr(image, attr, None)

    output['properties'] = getattr(image, 'properties', {})

    return output

**** CubicPower OpenStack Study ****

def _remove_read_only(image_meta):

    IMAGE_ATTRIBUTES = ['status', 'updated_at', 'created_at', 'deleted_at']

    output = copy.deepcopy(image_meta)

    for attr in IMAGE_ATTRIBUTES:

        if attr in output:

            del output[attr]

    return output

**** CubicPower OpenStack Study ****

def _reraise_translated_image_exception(image_id):

    """Transform the exception for the image but keep its traceback intact."""

    exc_type, exc_value, exc_trace = sys.exc_info()

    new_exc = _translate_image_exception(image_id, exc_value)

    raise new_exc, None, exc_trace

**** CubicPower OpenStack Study ****

def _reraise_translated_exception():

    """Transform the exception but keep its traceback intact."""

    exc_type, exc_value, exc_trace = sys.exc_info()

    new_exc = _translate_plain_exception(exc_value)

    raise new_exc, None, exc_trace

**** CubicPower OpenStack Study ****

def _translate_image_exception(image_id, exc_value):

    if isinstance(exc_value, (glanceclient.exc.Forbidden,

                    glanceclient.exc.Unauthorized)):

        return exception.ImageNotAuthorized(image_id=image_id)

    if isinstance(exc_value, glanceclient.exc.NotFound):

        return exception.ImageNotFound(image_id=image_id)

    if isinstance(exc_value, glanceclient.exc.BadRequest):

        return exception.Invalid(unicode(exc_value))

    return exc_value

**** CubicPower OpenStack Study ****

def _translate_plain_exception(exc_value):

    if isinstance(exc_value, (glanceclient.exc.Forbidden,

                    glanceclient.exc.Unauthorized)):

        return exception.NotAuthorized(unicode(exc_value))

    if isinstance(exc_value, glanceclient.exc.NotFound):

        return exception.NotFound(unicode(exc_value))

    if isinstance(exc_value, glanceclient.exc.BadRequest):

        return exception.Invalid(unicode(exc_value))

    return exc_value

**** CubicPower OpenStack Study ****

def get_remote_image_service(context, image_href):

    """Create an image_service and parse the id from the given image_href.

    The image_href param can be an href of the form

    'http://example.com:9292/v1/images/b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3',

    or just an id such as 'b8b2c6f7-7345-4e2f-afa2-eedaba9cbbe3'. If the

    image_href is a standalone id, then the default image service is returned.

    :param image_href: href that describes the location of an image

    :returns: a tuple of the form (image_service, image_id)

    """

    #NOTE(bcwaldon): If image_href doesn't look like a URI, assume its a

    # standalone image ID

    if '/' not in str(image_href):

        image_service = get_default_image_service()

        return image_service, image_href

    try:

        (image_id, glance_host, glance_port, use_ssl) = \

            _parse_image_ref(image_href)

        glance_client = GlanceClientWrapper(context=context,

                host=glance_host, port=glance_port, use_ssl=use_ssl)

    except ValueError:

        raise exception.InvalidImageRef(image_href=image_href)

    image_service = GlanceImageService(client=glance_client)

    return image_service, image_id

**** CubicPower OpenStack Study ****

def get_default_image_service():

    return GlanceImageService()

**** CubicPower OpenStack Study ****

class UpdateGlanceImage(object):

**** CubicPower OpenStack Study ****

    def __init__(self, context, image_id, metadata, stream):

        self.context = context

        self.image_id = image_id

        self.metadata = metadata

        self.image_stream = stream

**** CubicPower OpenStack Study ****

    def start(self):

        image_service, image_id = (

            get_remote_image_service(self.context, self.image_id))

        image_service.update(self.context, image_id, self.metadata,

                             self.image_stream, purge_props=False)