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# Copyright 2013 Red Hat, 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.
import logging
from oslo.config import cfg
from nova import exception
import nova.image.download.base as xfer_base
from nova.openstack.common.gettextutils import _
import nova.virt.libvirt.utils as lv_utils
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
opt_group = cfg.ListOpt(name='filesystems', default=[],
help=_('List of file systems that are configured '
'in this file in the '
'image_file_url:<list entry name> '
'sections'))
CONF.register_opt(opt_group, group="image_file_url")
# This module extends the configuration options for nova.conf. If the user
# wishes to use the specific configuration settings the following needs to
# be added to nova.conf:
# [image_file_url]
# filesystem = <a list of strings referencing a config section>
#
# For each entry in the filesystem list a new configuration section must be
# added with the following format:
# [image_file_url:<list entry>]
# id = <string>
# mountpoint = <string>
#
# id:
# An opaque string. In order for this module to know that the remote
# FS is the same one that is mounted locally it must share information
# with the glance deployment. Both glance and nova-compute must be
# configured with a unique matching string. This ensures that the
# file:// advertised URL is describing a file system that is known
# to nova-compute
# mountpoint:
# The location at which the file system is locally mounted. Glance
# may mount a shared file system on a different path than nova-compute.
# This value will be compared against the metadata advertised with
# glance and paths will be adjusted to ensure that the correct file
# file is copied.
#
# If these values are not added to nova.conf and the file module is in the
# allowed_direct_url_schemes list, then the legacy behavior will occur such
# that a copy will be attempted assuming that the glance and nova file systems
# are the same.
class FileTransfer(xfer_base.TransferBase):
desc_required_keys = ['id', 'mountpoint']
#NOTE(jbresnah) because the group under which these options are added is
# dyncamically determined these options need to stay out of global space
# or they will confuse generate_sample.sh
filesystem_opts = [
cfg.StrOpt('id',
help=_('A unique ID given to each file system. This is '
'value is set in Glance and agreed upon here so '
'that the operator knowns they are dealing with '
'the same file system.')),
cfg.StrOpt('mountpoint',
help=_('The path at which the file system is mounted.')),
]
def _get_options(self):
fs_dict = {}
for fs in CONF.image_file_url.filesystems:
group_name = 'image_file_url:' + fs
conf_group = CONF[group_name]
if conf_group.id is None:
msg = _('The group %s(group_name) must be configured with '
'an id.')
raise exception.ImageDownloadModuleConfigurationError(
module=str(self), reason=msg)
fs_dict[CONF[group_name].id] = CONF[group_name]
return fs_dict
def __init__(self):
# create the needed options
for fs in CONF.image_file_url.filesystems:
group_name = 'image_file_url:' + fs
CONF.register_opts(self.filesystem_opts, group=group_name)
def _verify_config(self):
for fs_key in self.filesystems:
for r in self.desc_required_keys:
fs_ent = self.filesystems[fs_key]
if fs_ent[r] is None:
msg = _('The key %s is required in all file system '
'descriptions.')
LOG.error(msg)
raise exception.ImageDownloadModuleConfigurationError(
module=str(self), reason=msg)
def _file_system_lookup(self, metadata, url_parts):
for r in self.desc_required_keys:
if r not in metadata:
url = url_parts.geturl()
msg = _('The key %(r)s is required in the location metadata '
'to access the url %(url)s.') % {'r': r, 'url': url}
LOG.info(msg)
raise exception.ImageDownloadModuleMetaDataError(
module=str(self), reason=msg)
id = metadata['id']
if id not in self.filesystems:
msg = _('The ID %(id)s is unknown.') % {'id': id}
LOG.info(msg)
return
fs_descriptor = self.filesystems[id]
return fs_descriptor
def _normalize_destination(self, nova_mount, glance_mount, path):
if not path.startswith(glance_mount):
msg = (_('The mount point advertised by glance: %(glance_mount)s, '
'does not match the URL path: %(path)s') %
{'glance_mount': glance_mount, 'path': path})
raise exception.ImageDownloadModuleMetaDataError(
module=str(self), reason=msg)
new_path = path.replace(glance_mount, nova_mount, 1)
return new_path
def download(self, context, url_parts, dst_file, metadata, **kwargs):
self.filesystems = self._get_options()
if not self.filesystems:
#NOTE(jbresnah) when nothing is configured assume legacy behavior
nova_mountpoint = '/'
glance_mountpoint = '/'
else:
self._verify_config()
fs_descriptor = self._file_system_lookup(metadata, url_parts)
if fs_descriptor is None:
msg = (_('No matching ID for the URL %s was found.') %
url_parts.geturl())
raise exception.ImageDownloadModuleError(reason=msg,
module=str(self))
nova_mountpoint = fs_descriptor['mountpoint']
glance_mountpoint = metadata['mountpoint']
source_file = self._normalize_destination(nova_mountpoint,
glance_mountpoint,
url_parts.path)
lv_utils.copy_image(source_file, dst_file)
LOG.info(_('Copied %(source_file)s using %(module_str)s') %
{'source_file': source_file, 'module_str': str(self)})
def get_download_handler(**kwargs):
return FileTransfer()
def get_schemes():
return ['file', 'filesystem']
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