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OpenStack Study: gridfs.py**** CubicPower OpenStack Study ****
# 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. """Storage backend for GridFS""" from __future__ import absolute_import from oslo.config import cfg import six.moves.urllib.parse as urlparse from glance.common import exception from glance.openstack.common import excutils import glance.openstack.common.log as logging import glance.store.base import glance.store.location try: import gridfs import gridfs.errors import pymongo import pymongo.uri_parser as uri_parser except ImportError: pymongo = None LOG = logging.getLogger(__name__) gridfs_opts = [ cfg.StrOpt('mongodb_store_uri', help="Hostname or IP address of the instance to connect to, " "or a mongodb URI, or a list of hostnames / mongodb URIs. " "If host is an IPv6 literal it must be enclosed " "in '[' and ']' characters following the RFC2732 " "URL syntax (e.g. '[::1]' for localhost)."), cfg.StrOpt('mongodb_store_db', default=None, help='Database to use.'), ] CONF = cfg.CONF CONF.register_opts(gridfs_opts)
**** CubicPower OpenStack Study **** class StoreLocation(glance.store.location.StoreLocation): """ Class describing an gridfs URI: gridfs:// Connection information has been consciously omitted for security reasons, since this location will be stored in glance's database and can be queried from outside. Note(flaper87): Make connection info available if user wants so by adding a new configuration parameter `mongdb_store_insecure`. """
**** CubicPower OpenStack Study **** def get_uri(self): return "gridfs://%s" % self.specs.get("image_id")
**** CubicPower OpenStack Study **** def parse_uri(self, uri): """ This method should fix any issue with the passed URI. Right now, it just sets image_id value in the specs dict. :param uri: Current set URI """ parsed = urlparse.urlparse(uri) assert parsed.scheme in ('gridfs',) self.specs["image_id"] = parsed.netloc
**** CubicPower OpenStack Study **** class Store(glance.store.base.Store): """GridFS adapter""" EXAMPLE_URL = "gridfs://
**** CubicPower OpenStack Study **** def get_schemes(self): return ('gridfs',)
**** CubicPower OpenStack Study **** def configure_add(self): """ Configure the Store to use the stored configuration options Any store that needs special configuration should implement this method. If the store was not able to successfully configure itself, it should raise `exception.BadStoreConfiguration` """ if pymongo is None: msg = _("Missing dependencies: pymongo") raise exception.BadStoreConfiguration(store_name="gridfs", reason=msg) self.mongodb_uri = self._option_get('mongodb_store_uri') parsed = uri_parser.parse_uri(self.mongodb_uri) self.mongodb_db = self._option_get('mongodb_store_db') or \ parsed.get("database") self.mongodb = pymongo.MongoClient(self.mongodb_uri) self.fs = gridfs.GridFS(self.mongodb[self.mongodb_db])
**** CubicPower OpenStack Study **** def _option_get(self, param): result = getattr(CONF, param) if not result: reason = (_("Could not find %(param)s in configuration " "options.") % {'param': param}) LOG.debug(reason) raise exception.BadStoreConfiguration(store_name="gridfs", reason=reason) return result
**** 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 """ image = self._get_file(location) return (image, image.length)
**** 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 image_size (or 0 if unavailable) :param location `glance.store.location.Location` object, supplied from glance.store.location.get_location_from_uri() """ try: key = self._get_file(location) return key.length except Exception: return 0
**** CubicPower OpenStack Study **** def _get_file(self, location): store_location = location if isinstance(location, glance.store.location.Location): store_location = location.store_location try: parsed = urlparse.urlparse(store_location.get_uri()) return self.fs.get(parsed.netloc) except gridfs.errors.NoFile: msg = _("Could not find %s image in GridFS") % \ store_location.get_uri() LOG.debug(msg) raise exception.NotFound(msg)
**** 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 """ loc = StoreLocation({'image_id': image_id}) if self.fs.exists(image_id): raise exception.Duplicate(_("GridFS already has an image at " "location %s") % loc.get_uri()) LOG.debug(_("Adding a new image to GridFS with id %(id)s and " "size %(size)s") % {'id': image_id, 'size': image_size}) try: self.fs.put(image_file, _id=image_id) image = self._get_file(loc) except Exception: # Note(zhiyan): clean up already received data when # error occurs such as ImageSizeLimitExceeded exception. with excutils.save_and_reraise_exception(): self.fs.delete(image_id) LOG.debug(_("Uploaded image %(id)s, md5 %(md5)s, length %(length)s " "to GridFS") % {'id': image._id, 'md5': image.md5, 'length': image.length}) return (loc.get_uri(), image.length, image.md5, {})
**** 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 NotFound if image does not exist """ image = self._get_file(location) self.fs.delete(image._id) LOG.debug("Deleted image %s from GridFS")
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