OpenStack Block Storage (Cinder)
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# Copyright 2010 OpenStack Foundation
# Copyright 2013 NTT corp.
# 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
# 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 random
import shutil
import sys
import time
import glanceclient.exc
from oslo_config import cfg
from oslo_log import log as logging
from oslo_serialization import jsonutils
from oslo_utils import timeutils
import six
from six.moves import range
from six.moves import urllib
from cinder import exception
from cinder.i18n import _LE, _LW
glance_opts = [
help='A list of url schemes that can be downloaded directly '
'via the direct_url. Currently supported schemes: '
glance_core_properties = [
default=['checksum', 'container_format',
'disk_format', 'image_name', 'image_id',
'min_disk', 'min_ram', 'name', 'size'],
help='Default core properties of image')
CONF.import_opt('glance_api_version', 'cinder.common.config')
LOG = logging.getLogger(__name__)
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, netloc, use_ssl)
:raises ValueError
url = urllib.parse.urlparse(image_href)
netloc = url.netloc
image_id = url.path.split('/')[-1]
use_ssl = (url.scheme == 'https')
return (image_id, netloc, use_ssl)
def _create_glance_client(context, netloc, use_ssl, version=None):
"""Instantiate a new glanceclient.Client object."""
if version is None:
version = CONF.glance_api_version
params = {}
if use_ssl:
scheme = 'https'
# https specific params
params['insecure'] = CONF.glance_api_insecure
params['ssl_compression'] = CONF.glance_api_ssl_compression
params['cacert'] = CONF.glance_ca_certificates_file
scheme = 'http'
if CONF.auth_strategy == 'keystone':
params['token'] = context.auth_token
if CONF.glance_request_timeout is not None:
params['timeout'] = CONF.glance_request_timeout
endpoint = '%s://%s' % (scheme, netloc)
return glanceclient.Client(str(version), endpoint, **params)
def get_api_servers():
"""Return Iterable over shuffled 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
url = urllib.parse.urlparse(api_server)
netloc = url.netloc
use_ssl = (url.scheme == 'https')
api_servers.append((netloc, use_ssl))
return itertools.cycle(api_servers)
class GlanceClientWrapper(object):
"""Glance client wrapper class that implements retries."""
def __init__(self, context=None, netloc=None, use_ssl=False,
if netloc is not None:
self.client = self._create_static_client(context,
use_ssl, version)
self.client = None
self.api_servers = None
self.version = version
if CONF.glance_num_retries < 0:
"glance_num_retries shouldn't be a negative value. "
"The number of retries will be set to 0 until this is"
"corrected in the cinder.conf."))
CONF.set_override('glance_num_retries', 0)
def _create_static_client(self, context, netloc, use_ssl, version):
"""Create a client that we'll use for every call."""
self.netloc = netloc
self.use_ssl = use_ssl
self.version = version
return _create_glance_client(context,
self.use_ssl, self.version)
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.netloc, self.use_ssl = next(self.api_servers)
return _create_glance_client(context,
self.use_ssl, version)
def call(self, context, method, *args, **kwargs):
"""Call a glance client method.
If we get a connection error,
retry the request according to CONF.glance_num_retries.
version = kwargs.pop('version', self.version)
retry_excs = (glanceclient.exc.ServiceUnavailable,
num_attempts = 1 + CONF.glance_num_retries
for attempt in range(1, num_attempts + 1):
client = self.client or self._create_onetime_client(context,
controller = getattr(client,
kwargs.pop('controller', 'images'))
return getattr(controller, method)(*args, **kwargs)
except retry_excs as e:
netloc = self.netloc
extra = "retrying"
error_msg = _LE("Error contacting glance server "
"'%(netloc)s' for '%(method)s', "
if attempt == num_attempts:
extra = 'done trying'
LOG.exception(error_msg, {'netloc': netloc,
'method': method,
'extra': extra})
raise exception.GlanceConnectionFailed(reason=e)
LOG.exception(error_msg, {'netloc': netloc,
'method': method,
'extra': extra})
class GlanceImageService(object):
"""Provides storage and retrieval of disk image objects within Glance."""
def __init__(self, client=None):
self._client = client or GlanceClientWrapper()
self._image_schema = None
def detail(self, context, **kwargs):
"""Calls out to Glance for a list of detailed image information."""
params = self._extract_query_params(kwargs)
images =, 'list', **params)
except Exception:
_images = []
for image in images:
if self._is_image_available(context, image):
_images.append(self._translate_from_glance(context, image))
return _images
def _extract_query_params(self, params):
_params = {}
accepted_params = ('filters', 'marker', 'limit',
'sort_key', 'sort_dir')
for param in accepted_params:
if param in params:
_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 show(self, context, image_id):
"""Returns a dict with image data for the given opaque image id."""
image =, 'get', image_id)
except Exception:
if not self._is_image_available(context, image):
raise exception.ImageNotFound(image_id=image_id)
base_image_meta = self._translate_from_glance(context, image)
return base_image_meta
def get_location(self, context, image_id):
"""Returns a tuple of the direct url and locations representing the
backend storage location, or (None, None) if these attributes are not
shown by Glance.
if CONF.glance_api_version == 1:
# image location not available in v1
return (None, None)
# direct_url is returned by v2 api
client = GlanceClientWrapper(version=2)
image_meta =, 'get', image_id)
except Exception:
if not self._is_image_available(context, image_meta):
raise exception.ImageNotFound(image_id=image_id)
# some glance stores like nfs only meta data
# is stored and returned as locations.
# so composite of two needs to be returned.
return (getattr(image_meta, 'direct_url', None),
getattr(image_meta, 'locations', None))
def download(self, context, image_id, data=None):
"""Calls out to Glance for data and writes data."""
if data and 'file' in CONF.allowed_direct_url_schemes:
direct_url, locations = self.get_location(context, image_id)
urls = [direct_url] + [loc.get('url') for loc in locations or []]
for url in urls:
if url is None:
parsed_url = urllib.parse.urlparse(url)
if parsed_url.scheme == "file":
# a system call to cp could have significant performance
# advantages, however we do not have the path to files at
# this point in the abstraction.
with open(parsed_url.path, "r") as f:
shutil.copyfileobj(f, data)
image_chunks =, 'data', image_id)
except Exception:
if not data:
return image_chunks
for chunk in image_chunks:
def create(self, context, image_meta, data=None):
"""Store the image data and return the new image object."""
sent_service_image_meta = self._translate_to_glance(image_meta)
if data:
sent_service_image_meta['data'] = data
recv_service_image_meta =, 'create',
return self._translate_from_glance(context, recv_service_image_meta)
def update(self, context, image_id,
image_meta, data=None, purge_props=True):
"""Modify the given image with the new data."""
image_meta = self._translate_to_glance(image_meta)
# NOTE(dosaboy): see comment in bug 1210467
if CONF.glance_api_version == 1:
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
# NOTE(dosaboy): the v2 api separates update from upload
if data and CONF.glance_api_version > 1:, 'upload', image_id, data)
image_meta =, 'get', image_id)
image_meta =, 'update', image_id,
except Exception:
return self._translate_from_glance(context, image_meta)
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.
try:, 'delete', image_id)
except glanceclient.exc.NotFound:
raise exception.ImageNotFound(image_id=image_id)
return True
def _translate_from_glance(self, context, image):
"""Get image metadata from glance image.
Extract metadata from image and convert it's properties
to type cinder expected.
:param image: glance image object
:return: image metadata dictionary
if CONF.glance_api_version == 2:
if self._image_schema is None:
self._image_schema =, 'get',
# NOTE(aarefiev): get base image property, store image 'schema'
# is redundant, so ignore it.
image_meta = {key: getattr(image, key)
for key in image.keys()
if self._image_schema.is_base_property(key) is True
and key != 'schema'}
# NOTE(aarefiev): nova is expected that all image properties
# (custom or defined in schema-image.json) stores in
# 'properties' key.
image_meta['properties'] = {
key: getattr(image, key) for key in image.keys()
if self._image_schema.is_base_property(key) is False}
image_meta = _extract_attributes(image)
image_meta = _convert_timestamps_to_datetimes(image_meta)
image_meta = _convert_from_string(image_meta)
return image_meta
def _translate_to_glance(image_meta):
image_meta = _convert_to_string(image_meta)
image_meta = _remove_read_only(image_meta)
return image_meta
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
if image.is_public or context.is_admin:
return True
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)
user_id = properties['user_id']
except KeyError:
return False
return str(user_id) == str(context.user_id)
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):
# NOTE(hdd): If a key is not found, base.Resource.__getattr__() may perform
# a get(), resulting in a useless request back to glance. This list is
# therefore sorted, with dependent attributes as the end
# 'deleted_at' depends on 'deleted'
# 'checksum' depends on 'status' == 'active'
IMAGE_ATTRIBUTES = ['size', 'disk_format', 'owner',
'container_format', 'status', 'id',
'name', 'created_at', 'updated_at',
'deleted', 'deleted_at', 'checksum',
'min_disk', 'min_ram', 'is_public']
output = {}
if attr == 'deleted_at' and not output['deleted']:
output[attr] = None
elif attr == 'checksum' and output['status'] != 'active':
output[attr] = None
output[attr] = getattr(image, attr, None)
output['properties'] = getattr(image, 'properties', {})
# NOTE(jbernard): Update image properties for API version 2. For UEC
# images stored in glance, the necessary boot information is stored in the
# properties dict in version 1 so there is nothing more to do. However, in
# version 2 these are standalone fields in the GET response. This bit of
# code moves them back into the properties dict as the caller expects, thus
# producing a volume with correct metadata for booting.
for attr in ('kernel_id', 'ramdisk_id'):
value = getattr(image, attr, None)
if value:
output['properties'][attr] = value
return output
def _remove_read_only(image_meta):
IMAGE_ATTRIBUTES = ['status', 'updated_at', 'created_at', 'deleted_at']
output = copy.deepcopy(image_meta)
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)
six.reraise(type(new_exc), new_exc, 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)
six.reraise(type(new_exc), new_exc, exc_trace)
def _translate_image_exception(image_id, exc_value):
if isinstance(exc_value, (glanceclient.exc.Forbidden,
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(exc_value)
return exc_value
def _translate_plain_exception(exc_value):
if isinstance(exc_value, (glanceclient.exc.Forbidden,
return exception.NotAuthorized(exc_value)
if isinstance(exc_value, glanceclient.exc.NotFound):
return exception.NotFound(exc_value)
if isinstance(exc_value, glanceclient.exc.BadRequest):
return exception.Invalid(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
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
(image_id, glance_netloc, use_ssl) = _parse_image_ref(image_href)
glance_client = GlanceClientWrapper(context=context,
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()