# Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
# 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.

"""
Backup manager manages volume backups.

Volume Backups are full copies of persistent volumes stored in a backup
store e.g. an object store or any other backup store if and when support is
added. They are usable without the original object being available. A
volume backup can be restored to the original volume it was created from or
any other available volume with a minimum size of the original volume.
Volume backups can be created, restored, deleted and listed.

**Related Flags**

:backup_topic:  What :mod:`rpc` topic to listen to (default:
                        `cinder-backup`).
:backup_manager:  The module name of a class derived from
                          :class:`manager.Manager` (default:
                          :class:`cinder.backup.manager.Manager`).

"""

from oslo_config import cfg
from oslo_log import log as logging
import oslo_messaging as messaging
from oslo_utils import excutils
from oslo_utils import importutils
import six

from cinder.backup import driver
from cinder.backup import rpcapi as backup_rpcapi
from cinder import context
from cinder import exception
from cinder.i18n import _, _LE, _LI, _LW
from cinder import manager
from cinder import objects
from cinder.objects import fields
from cinder import quota
from cinder import rpc
from cinder import utils
from cinder.volume import rpcapi as volume_rpcapi
from cinder.volume import utils as volume_utils

LOG = logging.getLogger(__name__)

backup_manager_opts = [
    cfg.StrOpt('backup_driver',
               default='cinder.backup.drivers.swift',
               help='Driver to use for backups.',),
    cfg.BoolOpt('backup_service_inithost_offload',
                default=False,
                help='Offload pending backup delete during '
                     'backup service startup.',),
]

# This map doesn't need to be extended in the future since it's only
# for old backup services
mapper = {'cinder.backup.services.swift': 'cinder.backup.drivers.swift',
          'cinder.backup.services.ceph': 'cinder.backup.drivers.ceph'}

CONF = cfg.CONF
CONF.register_opts(backup_manager_opts)
CONF.import_opt('use_multipath_for_image_xfer', 'cinder.volume.driver')
CONF.import_opt('num_volume_device_scan_tries', 'cinder.volume.driver')
QUOTAS = quota.QUOTAS


class BackupManager(manager.SchedulerDependentManager):
    """Manages backup of block storage devices."""

    RPC_API_VERSION = '1.3'

    target = messaging.Target(version=RPC_API_VERSION)

    def __init__(self, service_name=None, *args, **kwargs):
        self.service = importutils.import_module(self.driver_name)
        self.az = CONF.storage_availability_zone
        self.volume_managers = {}
        self.backup_rpcapi = backup_rpcapi.BackupAPI()
        self.volume_rpcapi = volume_rpcapi.VolumeAPI()
        super(BackupManager, self).__init__(service_name='backup',
                                            *args, **kwargs)

    @property
    def driver_name(self):
        """This function maps old backup services to backup drivers."""

        return self._map_service_to_driver(CONF.backup_driver)

    def _map_service_to_driver(self, service):
        """Maps services to drivers."""

        if service in mapper:
            return mapper[service]
        return service

    def _update_backup_error(self, backup, context, err):
        backup.status = fields.BackupStatus.ERROR
        backup.fail_reason = err
        backup.save()

    def init_host(self):
        """Run initialization needed for a standalone service."""
        ctxt = context.get_admin_context()

        try:
            self._cleanup_incomplete_backup_operations(ctxt)
        except Exception:
            # Don't block startup of the backup service.
            LOG.exception(_LE("Problem cleaning incomplete backup "
                              "operations."))

    def reset(self):
        super(BackupManager, self).reset()
        self.backup_rpcapi = backup_rpcapi.BackupAPI()
        self.volume_rpcapi = volume_rpcapi.VolumeAPI()

    def _cleanup_incomplete_backup_operations(self, ctxt):
        LOG.info(_LI("Cleaning up incomplete backup operations."))

        # TODO(smulcahy) implement full resume of backup and restore
        # operations on restart (rather than simply resetting)
        backups = objects.BackupList.get_all_by_host(ctxt, self.host)
        for backup in backups:
            try:
                self._cleanup_one_backup(ctxt, backup)
            except Exception:
                LOG.exception(_LE("Problem cleaning up backup %(bkup)s."),
                              {'bkup': backup['id']})
            try:
                self._cleanup_temp_volumes_snapshots_for_one_backup(ctxt,
                                                                    backup)
            except Exception:
                LOG.exception(_LE("Problem cleaning temp volumes and "
                                  "snapshots for backup %(bkup)s."),
                              {'bkup': backup['id']})

    def _cleanup_one_volume(self, ctxt, volume):
        if volume['status'] == 'backing-up':
            self._detach_all_attachments(ctxt, volume)
            LOG.info(_LI('Resetting volume %(vol_id)s to previous '
                         'status %(status)s (was backing-up).'),
                     {'vol_id': volume['id'],
                      'status': volume['previous_status']})
            self.db.volume_update(ctxt, volume['id'],
                                  {'status': volume['previous_status']})
        elif volume['status'] == 'restoring-backup':
            self._detach_all_attachments(ctxt, volume)
            LOG.info(_LI('setting volume %s to error_restoring '
                         '(was restoring-backup).'), volume['id'])
            self.db.volume_update(ctxt, volume['id'],
                                  {'status': 'error_restoring'})

    def _cleanup_one_backup(self, ctxt, backup):
        if backup['status'] == fields.BackupStatus.CREATING:
            LOG.info(_LI('Resetting backup %s to error (was creating).'),
                     backup['id'])

            volume = objects.Volume.get_by_id(ctxt, backup.volume_id)
            self._cleanup_one_volume(ctxt, volume)

            err = 'incomplete backup reset on manager restart'
            self._update_backup_error(backup, ctxt, err)
        elif backup['status'] == fields.BackupStatus.RESTORING:
            LOG.info(_LI('Resetting backup %s to '
                         'available (was restoring).'),
                     backup['id'])
            volume = objects.Volume.get_by_id(ctxt, backup.restore_volume_id)
            self._cleanup_one_volume(ctxt, volume)

            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
        elif backup['status'] == fields.BackupStatus.DELETING:
            LOG.info(_LI('Resuming delete on backup: %s.'), backup['id'])
            if CONF.backup_service_inithost_offload:
                # Offload all the pending backup delete operations to the
                # threadpool to prevent the main backup service thread
                # from being blocked.
                self._add_to_threadpool(self.delete_backup, ctxt, backup)
            else:
                # By default, delete backups sequentially
                self.delete_backup(ctxt, backup)

    def _detach_all_attachments(self, ctxt, volume):
        attachments = volume['volume_attachment'] or []
        for attachment in attachments:
            if (attachment['attached_host'] == self.host and
                    attachment['instance_uuid'] is None):
                try:
                    rpcapi = self.volume_rpcapi
                    rpcapi.detach_volume(ctxt, volume, attachment['id'])
                except Exception:
                    LOG.exception(_LE("Detach attachment %(attach_id)s"
                                      " failed."),
                                  {'attach_id': attachment['id']},
                                  resource=volume)

    def _delete_temp_volume(self, ctxt, backup):
        try:
            temp_volume = objects.Volume.get_by_id(
                ctxt, backup.temp_volume_id)
            self.volume_rpcapi.delete_volume(ctxt, temp_volume)
        except exception.VolumeNotFound:
            LOG.debug("Could not find temp volume %(vol)s to clean up "
                      "for backup %(backup)s.",
                      {'vol': backup.temp_volume_id,
                       'backup': backup.id})
        backup.temp_volume_id = None
        backup.save()

    def _delete_temp_snapshot(self, ctxt, backup):
        try:
            temp_snapshot = objects.Snapshot.get_by_id(
                ctxt, backup.temp_snapshot_id)
            volume = objects.Volume.get_by_id(
                ctxt, backup.volume_id)
            # The temp snapshot should be deleted directly thru the
            # volume driver, not thru the volume manager.
            self.volume_rpcapi.delete_snapshot(ctxt, temp_snapshot,
                                               volume.host)
        except exception.SnapshotNotFound:
            LOG.debug("Could not find temp snapshot %(snap)s to clean "
                      "up for backup %(backup)s.",
                      {'snap': backup.temp_snapshot_id,
                       'backup': backup.id})
        backup.temp_snapshot_id = None
        backup.save()

    def _cleanup_temp_volumes_snapshots_for_one_backup(self, ctxt, backup):
        # NOTE(xyang): If the service crashes or gets restarted during the
        # backup operation, there could be temporary volumes or snapshots
        # that are not deleted. Make sure any temporary volumes or snapshots
        # create by the backup job are deleted when service is started.
        if (backup.temp_volume_id
                and backup.status == fields.BackupStatus.ERROR):
            self._delete_temp_volume(ctxt, backup)

        if (backup.temp_snapshot_id
                and backup.status == fields.BackupStatus.ERROR):
            self._delete_temp_snapshot(ctxt, backup)

    def _cleanup_temp_volumes_snapshots_when_backup_created(
            self, ctxt, backup):
        # Delete temp volumes or snapshots when backup creation is completed.
        if backup.temp_volume_id:
            self._delete_temp_volume(ctxt, backup)

        if backup.temp_snapshot_id:
            self._delete_temp_snapshot(ctxt, backup)

    def create_backup(self, context, backup):
        """Create volume backups using configured backup service."""
        volume_id = backup.volume_id
        volume = objects.Volume.get_by_id(context, volume_id)
        previous_status = volume.get('previous_status', None)
        LOG.info(_LI('Create backup started, backup: %(backup_id)s '
                     'volume: %(volume_id)s.'),
                 {'backup_id': backup.id, 'volume_id': volume_id})

        self._notify_about_backup_usage(context, backup, "create.start")

        backup.host = self.host
        backup.service = self.driver_name
        backup.availability_zone = self.az
        backup.save()

        expected_status = 'backing-up'
        actual_status = volume['status']
        if actual_status != expected_status:
            err = _('Create backup aborted, expected volume status '
                    '%(expected_status)s but got %(actual_status)s.') % {
                'expected_status': expected_status,
                'actual_status': actual_status,
            }
            self._update_backup_error(backup, context, err)
            raise exception.InvalidVolume(reason=err)

        expected_status = fields.BackupStatus.CREATING
        actual_status = backup.status
        if actual_status != expected_status:
            err = _('Create backup aborted, expected backup status '
                    '%(expected_status)s but got %(actual_status)s.') % {
                'expected_status': expected_status,
                'actual_status': actual_status,
            }
            self._update_backup_error(backup, context, err)
            backup.save()
            raise exception.InvalidBackup(reason=err)

        try:
            self._run_backup(context, backup, volume)
        except Exception as err:
            with excutils.save_and_reraise_exception():
                self.db.volume_update(context, volume_id,
                                      {'status': previous_status,
                                       'previous_status': 'error_backing-up'})
                self._update_backup_error(backup, context, six.text_type(err))

        # Restore the original status.
        self.db.volume_update(context, volume_id,
                              {'status': previous_status,
                               'previous_status': 'backing-up'})
        backup.status = fields.BackupStatus.AVAILABLE
        backup.size = volume['size']
        backup.save()

        # Handle the num_dependent_backups of parent backup when child backup
        # has created successfully.
        if backup.parent_id:
            parent_backup = objects.Backup.get_by_id(context,
                                                     backup.parent_id)
            parent_backup.num_dependent_backups += 1
            parent_backup.save()
        LOG.info(_LI('Create backup finished. backup: %s.'), backup.id)
        self._notify_about_backup_usage(context, backup, "create.end")

    def _run_backup(self, context, backup, volume):
        backup_service = self.service.get_backup_driver(context)

        properties = utils.brick_get_connector_properties()
        backup_dic = self.volume_rpcapi.get_backup_device(context,
                                                          backup, volume)
        try:
            backup_device = backup_dic.get('backup_device')
            is_snapshot = backup_dic.get('is_snapshot')
            attach_info = self._attach_device(context, backup_device,
                                              properties, is_snapshot)
            try:
                device_path = attach_info['device']['path']
                if isinstance(device_path, six.string_types):
                    if backup_dic.get('secure_enabled', False):
                        with open(device_path) as device_file:
                            backup_service.backup(backup, device_file)
                    else:
                        with utils.temporary_chown(device_path):
                            with open(device_path) as device_file:
                                backup_service.backup(backup, device_file)
                else:
                    backup_service.backup(backup, device_path)

            finally:
                self._detach_device(context, attach_info,
                                    backup_device, properties,
                                    is_snapshot)
        finally:
            backup = objects.Backup.get_by_id(context, backup.id)
            self._cleanup_temp_volumes_snapshots_when_backup_created(
                context, backup)

    def restore_backup(self, context, backup, volume_id):
        """Restore volume backups from configured backup service."""
        LOG.info(_LI('Restore backup started, backup: %(backup_id)s '
                     'volume: %(volume_id)s.'),
                 {'backup_id': backup.id, 'volume_id': volume_id})

        volume = objects.Volume.get_by_id(context, volume_id)
        self._notify_about_backup_usage(context, backup, "restore.start")

        backup.host = self.host
        backup.save()

        expected_status = 'restoring-backup'
        actual_status = volume['status']
        if actual_status != expected_status:
            err = (_('Restore backup aborted, expected volume status '
                     '%(expected_status)s but got %(actual_status)s.') %
                   {'expected_status': expected_status,
                    'actual_status': actual_status})
            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
            raise exception.InvalidVolume(reason=err)

        expected_status = fields.BackupStatus.RESTORING
        actual_status = backup['status']
        if actual_status != expected_status:
            err = (_('Restore backup aborted: expected backup status '
                     '%(expected_status)s but got %(actual_status)s.') %
                   {'expected_status': expected_status,
                    'actual_status': actual_status})
            self._update_backup_error(backup, context, err)
            self.db.volume_update(context, volume_id, {'status': 'error'})
            raise exception.InvalidBackup(reason=err)

        if volume['size'] > backup['size']:
            LOG.info(_LI('Volume: %(vol_id)s, size: %(vol_size)d is '
                         'larger than backup: %(backup_id)s, '
                         'size: %(backup_size)d, continuing with restore.'),
                     {'vol_id': volume['id'],
                      'vol_size': volume['size'],
                      'backup_id': backup['id'],
                      'backup_size': backup['size']})

        backup_service = self._map_service_to_driver(backup['service'])
        configured_service = self.driver_name
        if backup_service != configured_service:
            err = _('Restore backup aborted, the backup service currently'
                    ' configured [%(configured_service)s] is not the'
                    ' backup service that was used to create this'
                    ' backup [%(backup_service)s].') % {
                'configured_service': configured_service,
                'backup_service': backup_service,
            }
            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
            self.db.volume_update(context, volume_id, {'status': 'error'})
            raise exception.InvalidBackup(reason=err)

        try:
            self._run_restore(context, backup, volume)
        except Exception:
            with excutils.save_and_reraise_exception():
                self.db.volume_update(context, volume_id,
                                      {'status': 'error_restoring'})
                backup.status = fields.BackupStatus.AVAILABLE
                backup.save()

        self.db.volume_update(context, volume_id, {'status': 'available'})
        backup.status = fields.BackupStatus.AVAILABLE
        backup.save()
        LOG.info(_LI('Restore backup finished, backup %(backup_id)s restored'
                     ' to volume %(volume_id)s.'),
                 {'backup_id': backup.id, 'volume_id': volume_id})
        self._notify_about_backup_usage(context, backup, "restore.end")

    def _run_restore(self, context, backup, volume):
        backup_service = self.service.get_backup_driver(context)

        properties = utils.brick_get_connector_properties()
        secure_enabled = (
            self.volume_rpcapi.secure_file_operations_enabled(context,
                                                              volume))
        attach_info = self._attach_device(context, volume, properties)
        try:
            device_path = attach_info['device']['path']
            if isinstance(device_path, six.string_types):
                if secure_enabled:
                    with open(device_path, 'wb') as device_file:
                        backup_service.restore(backup, volume.id, device_file)
                else:
                    with utils.temporary_chown(device_path):
                        with open(device_path, 'wb') as device_file:
                            backup_service.restore(backup, volume.id,
                                                   device_file)
            else:
                backup_service.restore(backup, volume.id, device_path)
        finally:
            self._detach_device(context, attach_info, volume, properties)

    def delete_backup(self, context, backup):
        """Delete volume backup from configured backup service."""
        LOG.info(_LI('Delete backup started, backup: %s.'), backup.id)

        self._notify_about_backup_usage(context, backup, "delete.start")
        backup.host = self.host
        backup.save()

        expected_status = fields.BackupStatus.DELETING
        actual_status = backup.status
        if actual_status != expected_status:
            err = _('Delete_backup aborted, expected backup status '
                    '%(expected_status)s but got %(actual_status)s.') \
                % {'expected_status': expected_status,
                   'actual_status': actual_status}
            self._update_backup_error(backup, context, err)
            raise exception.InvalidBackup(reason=err)

        backup_service = self._map_service_to_driver(backup['service'])
        if backup_service is not None:
            configured_service = self.driver_name
            if backup_service != configured_service:
                err = _('Delete backup aborted, the backup service currently'
                        ' configured [%(configured_service)s] is not the'
                        ' backup service that was used to create this'
                        ' backup [%(backup_service)s].')\
                    % {'configured_service': configured_service,
                       'backup_service': backup_service}
                self._update_backup_error(backup, context, err)
                raise exception.InvalidBackup(reason=err)

            try:
                backup_service = self.service.get_backup_driver(context)
                backup_service.delete(backup)
            except Exception as err:
                with excutils.save_and_reraise_exception():
                    self._update_backup_error(backup, context,
                                              six.text_type(err))

        # Get reservations
        try:
            reserve_opts = {
                'backups': -1,
                'backup_gigabytes': -backup.size,
            }
            reservations = QUOTAS.reserve(context,
                                          project_id=backup.project_id,
                                          **reserve_opts)
        except Exception:
            reservations = None
            LOG.exception(_LE("Failed to update usages deleting backup"))

        backup.destroy()
        # If this backup is incremental backup, handle the
        # num_dependent_backups of parent backup
        if backup.parent_id:
            parent_backup = objects.Backup.get_by_id(context,
                                                     backup.parent_id)
            if parent_backup.has_dependent_backups:
                parent_backup.num_dependent_backups -= 1
                parent_backup.save()
        # Commit the reservations
        if reservations:
            QUOTAS.commit(context, reservations,
                          project_id=backup.project_id)

        LOG.info(_LI('Delete backup finished, backup %s deleted.'), backup.id)
        self._notify_about_backup_usage(context, backup, "delete.end")

    def _notify_about_backup_usage(self,
                                   context,
                                   backup,
                                   event_suffix,
                                   extra_usage_info=None):
        volume_utils.notify_about_backup_usage(
            context, backup, event_suffix,
            extra_usage_info=extra_usage_info,
            host=self.host)

    def export_record(self, context, backup):
        """Export all volume backup metadata details to allow clean import.

        Export backup metadata so it could be re-imported into the database
        without any prerequisite in the backup database.

        :param context: running context
        :param backup: backup object to export
        :returns: backup_record - a description of how to import the backup
        :returns: contains 'backup_url' - how to import the backup, and
        :returns: 'backup_service' describing the needed driver.
        :raises: InvalidBackup
        """
        LOG.info(_LI('Export record started, backup: %s.'), backup.id)

        expected_status = fields.BackupStatus.AVAILABLE
        actual_status = backup.status
        if actual_status != expected_status:
            err = (_('Export backup aborted, expected backup status '
                     '%(expected_status)s but got %(actual_status)s.') %
                   {'expected_status': expected_status,
                    'actual_status': actual_status})
            raise exception.InvalidBackup(reason=err)

        backup_record = {}
        backup_record['backup_service'] = backup.service
        backup_service = self._map_service_to_driver(backup.service)
        configured_service = self.driver_name
        if backup_service != configured_service:
            err = (_('Export record aborted, the backup service currently'
                     ' configured [%(configured_service)s] is not the'
                     ' backup service that was used to create this'
                     ' backup [%(backup_service)s].') %
                   {'configured_service': configured_service,
                    'backup_service': backup_service})
            raise exception.InvalidBackup(reason=err)

        # Call driver to create backup description string
        try:
            backup_service = self.service.get_backup_driver(context)
            driver_info = backup_service.export_record(backup)
            backup_url = backup.encode_record(driver_info=driver_info)
            backup_record['backup_url'] = backup_url
        except Exception as err:
            msg = six.text_type(err)
            raise exception.InvalidBackup(reason=msg)

        LOG.info(_LI('Export record finished, backup %s exported.'), backup.id)
        return backup_record

    def import_record(self,
                      context,
                      backup,
                      backup_service,
                      backup_url,
                      backup_hosts):
        """Import all volume backup metadata details to the backup db.

        :param context: running context
        :param backup: The new backup object for the import
        :param backup_service: The needed backup driver for import
        :param backup_url: An identifier string to locate the backup
        :param backup_hosts: Potential hosts to execute the import
        :raises: InvalidBackup
        :raises: ServiceNotFound
        """
        LOG.info(_LI('Import record started, backup_url: %s.'), backup_url)

        # Can we import this backup?
        if (backup_service != self.driver_name):
            # No, are there additional potential backup hosts in the list?
            if len(backup_hosts) > 0:
                # try the next host on the list, maybe he can import
                first_host = backup_hosts.pop()
                self.backup_rpcapi.import_record(context,
                                                 first_host,
                                                 backup,
                                                 backup_service,
                                                 backup_url,
                                                 backup_hosts)
            else:
                # empty list - we are the last host on the list, fail
                err = _('Import record failed, cannot find backup '
                        'service to perform the import. Request service '
                        '%(service)s') % {'service': backup_service}
                self._update_backup_error(backup, context, err)
                raise exception.ServiceNotFound(service_id=backup_service)
        else:
            # Yes...
            try:
                # Deserialize backup record information
                backup_options = backup.decode_record(backup_url)

                # Extract driver specific info and pass it to the driver
                driver_options = backup_options.pop('driver_info', {})
                backup_service = self.service.get_backup_driver(context)
                backup_service.import_record(backup, driver_options)
            except Exception as err:
                msg = six.text_type(err)
                self._update_backup_error(backup, context, msg)
                raise exception.InvalidBackup(reason=msg)

            required_import_options = {
                'display_name',
                'display_description',
                'container',
                'size',
                'service_metadata',
                'service',
                'object_count',
                'id'
            }

            # Check for missing fields in imported data
            missing_opts = required_import_options - set(backup_options)
            if missing_opts:
                msg = (_('Driver successfully decoded imported backup data, '
                         'but there are missing fields (%s).') %
                       ', '.join(missing_opts))
                self._update_backup_error(backup, context, msg)
                raise exception.InvalidBackup(reason=msg)

            # Confirm the ID from the record in the DB is the right one
            backup_id = backup_options['id']
            if backup_id != backup.id:
                msg = (_('Trying to import backup metadata from id %(meta_id)s'
                         ' into backup %(id)s.') %
                       {'meta_id': backup_id, 'id': backup.id})
                self._update_backup_error(backup, context, msg)
                raise exception.InvalidBackup(reason=msg)

            # Overwrite some fields
            backup_options['status'] = fields.BackupStatus.AVAILABLE
            backup_options['service'] = self.driver_name
            backup_options['availability_zone'] = self.az
            backup_options['host'] = self.host

            # Remove some values which are not actual fields and some that
            # were set by the API node
            for key in ('name', 'user_id', 'project_id'):
                backup_options.pop(key, None)

            # Update the database
            backup.update(backup_options)
            backup.save()

            # Verify backup
            try:
                if isinstance(backup_service, driver.BackupDriverWithVerify):
                    backup_service.verify(backup.id)
                else:
                    LOG.warning(_LW('Backup service %(service)s does not '
                                    'support verify. Backup id %(id)s is '
                                    'not verified. Skipping verify.'),
                                {'service': self.driver_name,
                                 'id': backup.id})
            except exception.InvalidBackup as err:
                with excutils.save_and_reraise_exception():
                    self._update_backup_error(backup, context,
                                              six.text_type(err))

            LOG.info(_LI('Import record id %s metadata from driver '
                         'finished.'), backup.id)

    def reset_status(self, context, backup, status):
        """Reset volume backup status.

        :param context: running context
        :param backup: The backup object for reset status operation
        :param status: The status to be set
        :raises: InvalidBackup
        :raises: BackupVerifyUnsupportedDriver
        :raises: AttributeError
        """
        LOG.info(_LI('Reset backup status started, backup_id: '
                     '%(backup_id)s, status: %(status)s.'),
                 {'backup_id': backup.id,
                  'status': status})

        backup_service = self._map_service_to_driver(backup.service)
        LOG.info(_LI('Backup service: %s.'), backup_service)
        if backup_service is not None:
            configured_service = self.driver_name
            if backup_service != configured_service:
                err = _('Reset backup status aborted, the backup service'
                        ' currently configured [%(configured_service)s] '
                        'is not the backup service that was used to create'
                        ' this backup [%(backup_service)s].') % \
                    {'configured_service': configured_service,
                     'backup_service': backup_service}
                raise exception.InvalidBackup(reason=err)
            # Verify backup
            try:
                # check whether the backup is ok or not
                if (status == fields.BackupStatus.AVAILABLE
                        and backup['status'] != fields.BackupStatus.RESTORING):
                    # check whether we could verify the backup is ok or not
                    if isinstance(backup_service,
                                  driver.BackupDriverWithVerify):
                        backup_service.verify(backup.id)
                        backup.status = status
                        backup.save()
                    # driver does not support verify function
                    else:
                        msg = (_('Backup service %(configured_service)s '
                                 'does not support verify. Backup id'
                                 ' %(id)s is not verified. '
                                 'Skipping verify.') %
                               {'configured_service': self.driver_name,
                                'id': backup.id})
                        raise exception.BackupVerifyUnsupportedDriver(
                            reason=msg)
                # reset status to error or from restoring to available
                else:
                    if (status == fields.BackupStatus.ERROR or
                        (status == fields.BackupStatus.AVAILABLE and
                            backup.status == fields.BackupStatus.RESTORING)):
                        backup.status = status
                        backup.save()
            except exception.InvalidBackup:
                with excutils.save_and_reraise_exception():
                    LOG.error(_LE("Backup id %s is not invalid. "
                                  "Skipping reset."), backup.id)
            except exception.BackupVerifyUnsupportedDriver:
                with excutils.save_and_reraise_exception():
                    LOG.error(_LE('Backup service %(configured_service)s '
                                  'does not support verify. Backup id '
                                  '%(id)s is not verified. '
                                  'Skipping verify.'),
                              {'configured_service': self.driver_name,
                               'id': backup.id})
            except AttributeError:
                msg = (_('Backup service %(service)s does not support '
                         'verify. Backup id %(id)s is not verified. '
                         'Skipping reset.') %
                       {'service': self.driver_name,
                        'id': backup.id})
                LOG.error(msg)
                raise exception.BackupVerifyUnsupportedDriver(
                    reason=msg)

            # Needs to clean temporary volumes and snapshots.
            try:
                self._cleanup_temp_volumes_snapshots_for_one_backup(
                    context, backup)
            except Exception:
                LOG.exception(_LE("Problem cleaning temp volumes and "
                                  "snapshots for backup %(bkup)s."),
                              {'bkup': backup.id})

            # send notification to ceilometer
            notifier_info = {'id': backup.id, 'update': {'status': status}}
            notifier = rpc.get_notifier('backupStatusUpdate')
            notifier.info(context, "backups.reset_status.end",
                          notifier_info)

    def check_support_to_force_delete(self, context):
        """Check if the backup driver supports force delete operation.

        :param context: running context
        """
        backup_service = self.service.get_backup_driver(context)
        return backup_service.support_force_delete

    def _attach_device(self, context, backup_device,
                       properties, is_snapshot=False):
        """Attach backup device."""
        if not is_snapshot:
            return self._attach_volume(context, backup_device, properties)
        else:
            msg = _("Can't attach snapshot.")
            raise NotImplementedError(msg)

    def _attach_volume(self, context, volume, properties):
        """Attach a volume."""

        try:
            conn = self.volume_rpcapi.initialize_connection(context,
                                                            volume,
                                                            properties)
            return self._connect_device(conn)
        except Exception:
            with excutils.save_and_reraise_exception():
                try:
                    self.volume_rpcapi.terminate_connection(context, volume,
                                                            properties,
                                                            force=True)
                except Exception:
                    LOG.warning(_LW("Failed to terminate the connection "
                                    "of volume %(volume_id)s, but it is "
                                    "acceptable."),
                                {'volume_id', volume.id})

    def _connect_device(self, conn):
        """Establish connection to device."""
        use_multipath = CONF.use_multipath_for_image_xfer
        device_scan_attempts = CONF.num_volume_device_scan_tries
        protocol = conn['driver_volume_type']
        connector = utils.brick_get_connector(
            protocol,
            use_multipath=use_multipath,
            device_scan_attempts=device_scan_attempts,
            conn=conn)
        vol_handle = connector.connect_volume(conn['data'])

        return {'conn': conn, 'device': vol_handle, 'connector': connector}

    def _detach_device(self, context, attach_info, volume,
                       properties, is_snapshot=False, force=False):
        """Disconnect the volume from the host. """
        connector = attach_info['connector']
        connector.disconnect_volume(attach_info['conn']['data'],
                                    attach_info['device'])

        rpcapi = self.volume_rpcapi
        rpcapi.terminate_connection(context, volume, properties, force=force)
        rpcapi.remove_export(context, volume)
