# 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_manager:  The module name of a class derived from
                          :class:`manager.Manager` (default:
                          :class:`cinder.backup.manager.Manager`).

"""

import contextlib
import os
import typing

from castellan import key_manager
from eventlet import tpool
from oslo_config import cfg
from oslo_log import log as logging
import oslo_messaging as messaging
from oslo_service import loopingcall
from oslo_service import periodic_task
from oslo_utils import excutils
from oslo_utils import importutils
from oslo_utils import timeutils

from cinder.backup import rpcapi as backup_rpcapi
from cinder import context
from cinder import exception
from cinder.i18n import _
from cinder.keymgr import migration as key_migration
from cinder import manager
from cinder.message import api as message_api
from cinder.message import message_field
from cinder import objects
from cinder.objects import fields
from cinder import quota
from cinder import utils
from cinder.volume import rpcapi as volume_rpcapi
from cinder.volume import volume_utils

LOG = logging.getLogger(__name__)

backup_manager_opts = [
    cfg.StrOpt('backup_driver',
               default='cinder.backup.drivers.swift.SwiftBackupDriver',
               help='Driver to use for backups.',),
    cfg.IntOpt('backup_driver_init_check_interval',
               default=60,
               min=5,
               help='Time in seconds between checks to see if the backup '
                    'driver has been successfully initialized, any time '
                    'the driver is restarted.'),
    cfg.IntOpt('backup_driver_stats_polling_interval',
               default=60,
               min=10,
               deprecated_name='backup_driver_status_check_interval',
               help='Time in seconds between checks of the backup driver '
                    'status.  If does not report as working, it is '
                    'restarted.'),
    cfg.BoolOpt('backup_service_inithost_offload',
                default=True,
                help='Offload pending backup delete during '
                     'backup service startup. If false, the backup service '
                     'will remain down until all pending backups are '
                     'deleted.',),
    cfg.IntOpt('backup_native_threads_pool_size',
               default=60,
               min=20,
               help='Size of the native threads pool for the backups.  '
                    'Most backup drivers rely heavily on this, it can be '
                    'decreased for specific drivers that don\'t.'),
]

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
MAPPING = {
    # Module name "google" conflicts with google library namespace inside the
    # driver when it imports google.auth
    'cinder.backup.drivers.google.GoogleBackupDriver':
    'cinder.backup.drivers.gcs.GoogleBackupDriver',
}
SERVICE_PGRP = os.getpgrp()


# TODO(geguileo): Once Eventlet issue #432 gets fixed we can just tpool.execute
# the whole call to the driver's backup and restore methods instead of proxy
# wrapping the device_file and having the drivers also proxy wrap their
# writes/reads and the compression/decompression calls.
# (https://github.com/eventlet/eventlet/issues/432)

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

    RPC_API_VERSION = backup_rpcapi.BackupAPI.RPC_API_VERSION

    target = messaging.Target(version=RPC_API_VERSION)

    def __init__(self, *args, **kwargs):
        self.az = CONF.storage_availability_zone
        self.backup_rpcapi = backup_rpcapi.BackupAPI()
        self.volume_rpcapi = volume_rpcapi.VolumeAPI()
        super(BackupManager, self).__init__(*args, **kwargs)
        self.is_initialized = False
        self._set_tpool_size(CONF.backup_native_threads_pool_size)
        self._process_number = kwargs.get('process_number', 1)
        self._semaphore = kwargs.get('semaphore', contextlib.suppress())
        self.driver_name = CONF.backup_driver
        if self.driver_name in MAPPING:
            new_name = MAPPING[self.driver_name]
            LOG.warning('Backup driver path %s is deprecated, update your '
                        'configuration to the new path %s',
                        self.driver_name, new_name)
            self.driver_name = new_name
        self.service = importutils.import_class(self.driver_name)
        self.message_api = message_api.API()

    @typing.no_type_check
    def init_host(self, **kwargs):
        """Run initialization needed for a standalone service."""
        ctxt = context.get_admin_context()
        self.setup_backup_backend(ctxt)

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

        # Migrate any ConfKeyManager keys based on fixed_key to the currently
        # configured key manager.
        backups = objects.BackupList.get_all_by_host(ctxt, self.host)
        self._add_to_threadpool(key_migration.migrate_fixed_key,
                                backups=backups)
        self.publish_service_capabilities(ctxt)

    def _setup_backup_driver(self, ctxt):
        backup_service = self.service(context=ctxt)
        backup_service.check_for_setup_error()
        self.is_initialized = True
        raise loopingcall.LoopingCallDone()

    def setup_backup_backend(self, ctxt):
        try:
            init_loop = loopingcall.FixedIntervalLoopingCall(
                self._setup_backup_driver, ctxt)
            init_loop.start(interval=CONF.backup_driver_init_check_interval)
        except loopingcall.LoopingCallDone:
            LOG.info("Backup driver was successfully initialized.")
        except Exception:
            LOG.exception("Failed to initialize driver.",
                          resource={'type': 'driver',
                                    'id': self.__class__.__name__})

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

    @utils.synchronized('cleanup_incomplete_backups_%s' % SERVICE_PGRP,
                        external=True, delay=0.1)
    def _cleanup_incomplete_backup_operations(self, ctxt):
        # Only the first launched process should do the cleanup, the others
        # have waited on the lock for the first one to finish the cleanup and
        # can now continue with the start process.
        if self._process_number != 1:
            LOG.debug("Process #%s %sskips cleanup.",
                      self._process_number,
                      '(pgid=%s) ' % SERVICE_PGRP if SERVICE_PGRP else '')
            return

        LOG.info("Cleaning up incomplete backup operations.")

        # TODO(smulcahy) implement full resume of backup and restore
        # operations on restart (rather than simply resetting).
        # We only need to deal with the backups that aren't complete.
        # N.B. NULL status is possible and we consider it incomplete.
        incomplete_status = list(fields.BackupStatus.ALL)
        incomplete_status.remove(fields.BackupStatus.AVAILABLE)
        incomplete_status.append(None)
        backups = objects.BackupList.get_all(
            ctxt, filters={'host': self.host, 'status': incomplete_status})
        for backup in backups:
            try:
                self._cleanup_one_backup(ctxt, backup)
            except Exception:
                LOG.exception("Problem cleaning up backup %(bkup)s.",
                              {'bkup': backup['id']})
            try:
                self._cleanup_temp_volumes_snapshots_for_one_backup(ctxt,
                                                                    backup)
            except Exception:
                LOG.exception("Problem cleaning temp volumes and "
                              "snapshots for backup %(bkup)s.",
                              {'bkup': backup['id']})

    def _cleanup_one_volume(self, ctxt, volume_id):
        try:
            volume = objects.Volume.get_by_id(ctxt, volume_id)
        except exception.VolumeNotFound:
            LOG.info('Volume %s does not exist anymore. Ignoring.', volume_id)
            return

        if volume['status'] == 'backing-up':
            self._detach_all_attachments(ctxt, volume)
            LOG.info('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('Setting volume %s to error_restoring '
                     '(was restoring-backup).', volume['id'])
            self.db.volume_update(ctxt, volume['id'],
                                  {'status': 'error_restoring'})

    def _cleanup_one_snapshot(self, ctxt, snapshot_id):
        try:
            snapshot = objects.Snapshot.get_by_id(ctxt, snapshot_id)
        except exception.SnapshotNotFound:
            LOG.info('Snapshot %s does not exist anymore. Ignoring.',
                     snapshot_id)
            return
        if snapshot['status'] == 'backing-up':
            LOG.info('Resetting snapshot %(snap_id)s to previous '
                     'status %(status)s (was backing-up).',
                     {'snap_id': snapshot['id'],
                      'status': fields.SnapshotStatus.AVAILABLE})

            snapshot.status = fields.SnapshotStatus.AVAILABLE
            snapshot.save()

    def _cleanup_one_backup(self, ctxt, backup):
        if backup['status'] == fields.BackupStatus.CREATING:
            LOG.info('Resetting backup %s to error (was creating).',
                     backup['id'])
            self._cleanup_one_volume(ctxt, backup.volume_id)
            if backup.snapshot_id:
                self._cleanup_one_snapshot(ctxt, backup.snapshot_id)
            err = 'incomplete backup reset on manager restart'
            volume_utils.update_backup_error(backup, err)
        elif backup['status'] == fields.BackupStatus.RESTORING:
            LOG.info('Resetting backup %s to '
                     'available (was restoring).',
                     backup['id'])
            self._cleanup_one_volume(ctxt, backup.restore_volume_id)
            if backup.snapshot_id:
                self._cleanup_one_snapshot(ctxt, backup.snapshot_id)
            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
        elif backup['status'] == fields.BackupStatus.DELETING:
            # Don't resume deleting the backup of an encrypted volume. The
            # admin context won't be sufficient to delete the backup's copy
            # of the encryption key ID (a real user context is required).
            if backup.encryption_key_id is None:
                LOG.info('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:
                    # Delete backups sequentially
                    self.delete_backup(ctxt, backup)
            else:
                LOG.info('Unable to resume deleting backup of an encrypted '
                         'volume, resetting backup %s to error_deleting '
                         '(was deleting).',
                         backup.id)
                backup.status = fields.BackupStatus.ERROR_DELETING
                backup.save()

    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("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)
            # We may want to consider routing those calls through the
            # cinder API.
            temp_snapshot.status = fields.SnapshotStatus.DELETING
            temp_snapshot.save()
            self.volume_rpcapi.delete_snapshot(ctxt, temp_snapshot)
        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
        snapshot_id = backup.snapshot_id
        volume = objects.Volume.get_by_id(context, volume_id)
        snapshot = objects.Snapshot.get_by_id(
            context, snapshot_id) if snapshot_id else None
        previous_status = volume.get('previous_status', None)
        context.message_resource_id = backup.id
        context.message_resource_type = message_field.Resource.VOLUME_BACKUP
        context.message_action = message_field.Action.BACKUP_CREATE
        if snapshot_id:
            log_message = ('Create backup started, backup: %(backup_id)s '
                           'volume: %(volume_id)s snapshot: %(snapshot_id)s.'
                           % {'backup_id': backup.id,
                              'volume_id': volume_id,
                              'snapshot_id': snapshot_id})
        else:
            log_message = ('Create backup started, backup: %(backup_id)s '
                           'volume: %(volume_id)s.'
                           % {'backup_id': backup.id,
                              'volume_id': volume_id})
        LOG.info(log_message)

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

        expected_status = "backing-up"
        if snapshot:
            actual_status = snapshot['status']
            if actual_status != expected_status:
                err = _('Create backup aborted, expected snapshot status '
                        '%(expected_status)s but got %(actual_status)s.') % {
                    'expected_status': expected_status,
                    'actual_status': actual_status,
                }
                volume_utils.update_backup_error(backup, err)
                raise exception.InvalidSnapshot(reason=err)
        else:
            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,
                }
                volume_utils.update_backup_error(backup, 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,
            }
            volume_utils.update_backup_error(backup, err)
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.BACKUP_INVALID_STATE)
            raise exception.InvalidBackup(reason=err)

        try:
            if not self.is_working():
                err = _('Create backup aborted due to backup service is down.')
                volume_utils.update_backup_error(backup, err)
                self.message_api.create_from_request_context(
                    context,
                    detail=message_field.Detail.BACKUP_SERVICE_DOWN)
                raise exception.InvalidBackup(reason=err)

            if not backup.availability_zone:
                backup.availability_zone = self.az

            backup.service = self.driver_name
            backup.save()

            # Start backup, then continue_backup, then finish_backup
            self._start_backup(context, backup, volume)
        except Exception as err:
            with excutils.save_and_reraise_exception():
                if snapshot_id:
                    assert snapshot is not None
                    snapshot.status = fields.SnapshotStatus.AVAILABLE
                    snapshot.save()
                else:
                    try:
                        self.db.volume_update(
                            context, volume_id,
                            {'status': previous_status,
                             'previous_status': 'error_backing-up'})
                    except exception.VolumeNotFound:
                        # If the volume was deleted we cannot update its
                        # status but we still want to set the backup to error.
                        pass
                volume_utils.update_backup_error(backup, str(err))

    def _start_backup(self, context, backup, volume):
        """This starts the backup process.

           First we have to get the backup device from the volume manager.
           This can take a long time to complete.  Once the volume manager
           is done creating/getting the backup device, then we get a callback
           to complete the process of backing up the volume.

        """
        # Save a copy of the encryption key ID in case the volume is deleted.
        if (volume.encryption_key_id is not None and
                backup.encryption_key_id is None):
            backup.encryption_key_id = volume_utils.clone_encryption_key(
                context,
                key_manager.API(CONF),
                volume.encryption_key_id)
            backup.save()

        # This is an async call to the volume manager.  We will get a
        # callback from the volume manager to continue once it's done.
        LOG.info("Call Volume Manager to get_backup_device for %s", backup)
        self.volume_rpcapi.get_backup_device(context, backup, volume)

    @utils.limit_operations
    def continue_backup(self, context, backup, backup_device):
        """This is the callback from the volume manager to continue."""
        message_created = False
        volume_id = backup.volume_id
        volume = objects.Volume.get_by_id(context, volume_id)
        snapshot_id = backup.snapshot_id
        snapshot = objects.Snapshot.get_by_id(
            context, snapshot_id) if snapshot_id else None
        previous_status = volume.get('previous_status', None)

        backup_service = self.service(context)
        properties = volume_utils.brick_get_connector_properties(
            CONF.use_multipath_for_image_xfer, enforce_multipath=False)

        updates = {}
        try:
            try:
                attach_info = self._attach_device(context,
                                                  backup_device.device_obj,
                                                  properties,
                                                  backup_device.is_snapshot)
            except Exception:
                with excutils.save_and_reraise_exception():
                    if not message_created:
                        message_created = True
                        self.message_api.create_from_request_context(
                            context,
                            detail=message_field.Detail.ATTACH_ERROR)

            try:
                device_path = attach_info['device']['path']
                if (isinstance(device_path, str) and
                        not os.path.isdir(device_path)):
                    if backup_device.secure_enabled:
                        with open(device_path, 'rb') as device_file:
                            updates = backup_service.backup(
                                backup, tpool.Proxy(device_file))
                    else:
                        with utils.temporary_chown(device_path):
                            with open(device_path, 'rb') as device_file:
                                updates = backup_service.backup(
                                    backup, tpool.Proxy(device_file))
                # device_path is already file-like so no need to open it
                else:
                    updates = backup_service.backup(backup,
                                                    tpool.Proxy(device_path))
            except Exception:
                with excutils.save_and_reraise_exception():
                    if not message_created:
                        message_created = True
                        self.message_api.create_from_request_context(
                            context,
                            detail=
                            message_field.Detail.BACKUP_CREATE_DRIVER_ERROR)
            finally:
                try:
                    self._detach_device(context, attach_info,
                                        backup_device.device_obj, properties,
                                        backup_device.is_snapshot, force=True,
                                        ignore_errors=True)
                except Exception:
                    with excutils.save_and_reraise_exception():
                        if not message_created:
                            message_created = True
                            self.message_api.create_from_request_context(
                                context,
                                detail=
                                message_field.Detail.DETACH_ERROR)
        except Exception as err:
            with excutils.save_and_reraise_exception():
                if snapshot:
                    snapshot.status = fields.SnapshotStatus.AVAILABLE
                    snapshot.save()
                else:
                    self.db.volume_update(
                        context, volume_id,
                        {'status': previous_status,
                         'previous_status': 'error_backing-up'})
                volume_utils.update_backup_error(backup, str(err))
        finally:
            with backup.as_read_deleted():
                backup.refresh()
            try:
                self._cleanup_temp_volumes_snapshots_when_backup_created(
                    context, backup)
            except Exception:
                with excutils.save_and_reraise_exception():
                    if not message_created:
                        self.message_api.create_from_request_context(
                            context,
                            detail=
                            message_field.Detail.BACKUP_CREATE_CLEANUP_ERROR)

        self._finish_backup(context, backup, volume, updates)

    def _finish_backup(self, context, backup, volume, updates):
        volume_id = backup.volume_id
        snapshot_id = backup.snapshot_id
        previous_status = volume.get('previous_status', None)

        # Restore the original status.
        if snapshot_id:
            self.db.snapshot_update(
                context, snapshot_id,
                {'status': fields.SnapshotStatus.AVAILABLE})
        else:
            self.db.volume_update(context, volume_id,
                                  {'status': previous_status,
                                   'previous_status': 'backing-up'})

        # continue_backup method above updated the status for the backup, so
        # it will reflect latest status, even if it is deleted
        completion_msg = 'finished'
        if backup.status in (fields.BackupStatus.DELETING,
                             fields.BackupStatus.DELETED):
            completion_msg = 'aborted'
        else:
            backup.status = fields.BackupStatus.AVAILABLE
            backup.size = volume['size']

            if updates:
                backup.update(updates)
            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('Create backup %s. backup: %s.', completion_msg, backup.id)
        self._notify_about_backup_usage(context, backup, "create.end")

    def _is_our_backup(self, backup):
        # Accept strings and Service OVO
        if not isinstance(backup, str):
            backup = backup.service

        if not backup:
            return True

        # TODO(tommylikehu): We upgraded the 'driver_name' from module
        # to class name, so we use 'in' here to match two namings,
        # this can be replaced with equal sign during next
        # release (Rocky).
        if self.driver_name.startswith(backup):
            return True

        # We support renaming of drivers, so check old names as well
        for key, value in MAPPING.items():
            if key.startswith(backup) and self.driver_name.startswith(value):
                return True

        return False

    @utils.limit_operations
    def restore_backup(self, context, backup, volume_id, volume_is_new):
        """Restore volume backups from configured backup service.

        :param context: RequestContext for the restore operation
        :param backup: Backup that we're restoring
        :param volume_id: The ID of the volume into which we're restoring
        :param volume_is_new: The volume does not have stale data, so
                              sparse backups can be restored as such.
        """
        context.message_resource_id = backup.id
        context.message_resource_type = message_field.Resource.VOLUME_BACKUP
        context.message_action = message_field.Action.BACKUP_RESTORE
        LOG.info('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")

        expected_status = [fields.VolumeStatus.RESTORING_BACKUP,
                           fields.VolumeStatus.CREATING]
        volume_previous_status = volume['status']
        if volume_previous_status not in expected_status:
            err = (_('Restore backup aborted, expected volume status '
                     '%(expected_status)s but got %(actual_status)s.') %
                   {'expected_status': ','.join(expected_status),
                    'actual_status': volume_previous_status})
            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
            self.db.volume_update(
                context, volume_id,
                {'status':
                 (fields.VolumeStatus.ERROR if
                  volume_previous_status == fields.VolumeStatus.CREATING else
                  fields.VolumeStatus.ERROR_RESTORING)})
            self.message_api.create(
                context,
                action=message_field.Action.BACKUP_RESTORE,
                resource_type=message_field.Resource.VOLUME_BACKUP,
                resource_uuid=volume.id,
                detail=message_field.Detail.VOLUME_INVALID_STATE)
            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})
            volume_utils.update_backup_error(backup, err)
            self.db.volume_update(context, volume_id,
                                  {'status': fields.VolumeStatus.ERROR})
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.BACKUP_INVALID_STATE)
            raise exception.InvalidBackup(reason=err)

        if volume['size'] > backup['size']:
            LOG.info('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']})

        if not self._is_our_backup(backup):
            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': self.driver_name,
                'backup_service': backup.service,
            }
            backup.status = fields.BackupStatus.AVAILABLE
            backup.save()
            self.db.volume_update(context, volume_id,
                                  {'status': fields.VolumeStatus.ERROR})
            raise exception.InvalidBackup(reason=err)

        canceled = False
        try:
            self._run_restore(context, backup, volume, volume_is_new)
        except exception.BackupRestoreCancel:
            canceled = True
        except Exception:
            with excutils.save_and_reraise_exception():
                self.db.volume_update(
                    context, volume_id,
                    {'status': (fields.VolumeStatus.ERROR if
                                actual_status == fields.VolumeStatus.CREATING
                                else fields.VolumeStatus.ERROR_RESTORING)})
                backup.status = fields.BackupStatus.AVAILABLE
                backup.save()

        if canceled:
            volume.status = fields.VolumeStatus.ERROR
        else:
            volume.status = fields.VolumeStatus.AVAILABLE
            # NOTE(tommylikehu): If previous status is 'creating', this is
            # just a new created volume and we need update the 'launched_at'
            # attribute as well.
            if volume_previous_status == fields.VolumeStatus.CREATING:
                volume['launched_at'] = timeutils.utcnow()
        old_src_backup_id = self.db.volume_metadata_get(
            context, volume_id).get("src_backup_id", None)
        if backup.volume_id != volume.id or (
                old_src_backup_id and old_src_backup_id != backup.id):
            self.db.volume_metadata_update(
                context,
                volume.id,
                {'src_backup_id': backup.id},
                False)

        volume.save()
        backup.status = fields.BackupStatus.AVAILABLE
        backup.save()
        LOG.info('%(result)s restoring backup %(backup_id)s to volume '
                 '%(volume_id)s.',
                 {'result': 'Canceled' if canceled else 'Finished',
                  'backup_id': backup.id,
                  'volume_id': volume_id})
        self._notify_about_backup_usage(context, backup, "restore.end")

    def _run_restore(self, context, backup, volume, volume_is_new):
        message_created = False
        orig_key_id = volume.encryption_key_id
        backup_service = self.service(context)

        properties = volume_utils.brick_get_connector_properties(
            CONF.use_multipath_for_image_xfer, enforce_multipath=False)
        secure_enabled = (
            self.volume_rpcapi.secure_file_operations_enabled(context,
                                                              volume))
        try:
            attach_info = self._attach_device(context, volume, properties)
        except Exception:
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.ATTACH_ERROR)
            raise

        # NOTE(geguileo): Not all I/O disk operations properly do greenthread
        # context switching and may end up blocking the greenthread, so we go
        # with native threads proxy-wrapping the device file object.
        try:
            device_path = attach_info['device']['path']
            if (isinstance(device_path, str) and
                    not os.path.isdir(device_path)):
                if secure_enabled:
                    with open(device_path, 'wb') as device_file:
                        backup_service.restore(backup, volume.id,
                                               tpool.Proxy(device_file),
                                               volume_is_new)
                else:
                    with utils.temporary_chown(device_path):
                        with open(device_path, 'wb') as device_file:
                            backup_service.restore(backup, volume.id,
                                                   tpool.Proxy(device_file),
                                                   volume_is_new)
            # device_path is already file-like so no need to open it
            else:
                backup_service.restore(backup, volume.id,
                                       tpool.Proxy(device_path),
                                       volume_is_new)
        except exception.BackupRestoreCancel:
            raise
        except Exception:
            LOG.exception('Restoring backup %(backup_id)s to volume '
                          '%(volume_id)s failed.', {'backup_id': backup.id,
                                                    'volume_id': volume.id})
            # We set message_create to True before creating the
            # message because if the message create call fails
            # and is catched by the base/outer exception handler
            # then we will end up storing a wrong message
            message_created = True
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.BACKUP_RESTORE_ERROR)
            raise
        finally:
            try:
                self._detach_device(context, attach_info, volume, properties,
                                    force=True)
            except Exception:
                if not message_created:
                    self.message_api.create_from_request_context(
                        context,
                        detail=message_field.Detail.DETACH_ERROR)
                raise

        # Regardless of whether the restore was successful, do some
        # housekeeping to ensure the restored volume's encryption key ID is
        # unique, and any previous key ID is deleted. Start by fetching fresh
        # info on the restored volume.
        restored_volume = objects.Volume.get_by_id(context, volume.id)
        restored_key_id = restored_volume.encryption_key_id
        if restored_key_id != orig_key_id:
            LOG.info('Updating encryption key ID for volume %(volume_id)s '
                     'from backup %(backup_id)s.',
                     {'volume_id': volume.id, 'backup_id': backup.id})

            key_mgr = key_manager.API(CONF)
            if orig_key_id:
                LOG.debug('Deleting original volume encryption key ID.')
                volume_utils.delete_encryption_key(context,
                                                   key_mgr,
                                                   orig_key_id)

            if backup.encryption_key_id is None:
                # This backup predates the current code that stores the cloned
                # key ID in the backup database. Fortunately, the key ID
                # restored from the backup data _is_ a clone of the original
                # volume's key ID, so grab it.
                LOG.debug('Gleaning backup encryption key ID from metadata.')
                backup.encryption_key_id = restored_key_id
                backup.save()

            # Clone the key ID again to ensure every restored volume has
            # a unique key ID. The volume's key ID should not be the same
            # as the backup.encryption_key_id (the copy made when the backup
            # was first created).
            new_key_id = volume_utils.clone_encryption_key(
                context,
                key_mgr,
                backup.encryption_key_id)
            restored_volume.encryption_key_id = new_key_id
            restored_volume.save()
        else:
            LOG.debug('Encryption key ID for volume %(volume_id)s already '
                      'matches encryption key ID in backup %(backup_id)s.',
                      {'volume_id': volume.id, 'backup_id': backup.id})

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

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

        context.message_resource_id = backup.id
        context.message_resource_type = message_field.Resource.VOLUME_BACKUP
        context.message_action = message_field.Action.BACKUP_DELETE
        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}
            volume_utils.update_backup_error(backup, err)
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.BACKUP_INVALID_STATE)
            raise exception.InvalidBackup(reason=err)

        if backup.service and not self.is_working():
            err = _('Delete backup is aborted due to backup service is down.')
            status = fields.BackupStatus.ERROR_DELETING
            volume_utils.update_backup_error(backup, err, status)
            self.message_api.create_from_request_context(
                context,
                detail=message_field.Detail.BACKUP_SERVICE_DOWN)
            raise exception.InvalidBackup(reason=err)

        if not self._is_our_backup(backup):
            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': self.driver_name,
                   'backup_service': backup.service}
            volume_utils.update_backup_error(backup, err)
            raise exception.InvalidBackup(reason=err)

        if backup.service:
            try:
                backup_service = self.service(context)
                backup_service.delete_backup(backup)
            except Exception as err:
                with excutils.save_and_reraise_exception():
                    volume_utils.update_backup_error(backup, str(err))
                    self.message_api.create_from_request_context(
                        context,
                        detail=message_field.Detail.BACKUP_DELETE_DRIVER_ERROR)

        # 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("Failed to update usages deleting backup")

        if backup.encryption_key_id is not None:
            volume_utils.delete_encryption_key(context,
                                               key_manager.API(CONF),
                                               backup.encryption_key_id)
            backup.encryption_key_id = None
            backup.save()

        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('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('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_service': backup.service}
        if not self._is_our_backup(backup):
            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': self.driver_name,
                    'backup_service': backup.service})
            raise exception.InvalidBackup(reason=err)

        # Call driver to create backup description string
        try:
            backup_service = self.service(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 = str(err)
            raise exception.InvalidBackup(reason=msg)

        LOG.info('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('Import record started, backup_url: %s.', backup_url)

        # Can we import this backup?
        if not self._is_our_backup(backup_service):
            # 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}
                volume_utils.update_backup_error(backup, 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(context)
                backup_service.import_record(backup, driver_options)
            except Exception as err:
                msg = str(err)
                volume_utils.update_backup_error(backup, msg)
                raise exception.InvalidBackup(reason=msg)

            required_import_options = {
                'display_name',
                'display_description',
                'container',
                'size',
                'service_metadata',
                '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))
                volume_utils.update_backup_error(backup, 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})
                volume_utils.update_backup_error(backup, msg)
                raise exception.InvalidBackup(reason=msg)

            # Overwrite some fields
            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', 'deleted_at',
                        'deleted', 'fail_reason', 'status'):
                backup_options.pop(key, None)

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

            # Update the backup's status
            backup.update({"status": fields.BackupStatus.AVAILABLE})
            backup.save()

            LOG.info('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 AttributeError:
        """
        LOG.info('Reset backup status started, backup_id: '
                 '%(backup_id)s, status: %(status)s.',
                 {'backup_id': backup.id,
                  'status': status})

        LOG.info('Backup service: %s.', backup.service)
        if not self._is_our_backup(backup):
            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': self.driver_name,
                 'backup_service': backup.service}
            raise exception.InvalidBackup(reason=err)

        if backup.service is not None:
            backup.status = status
            backup.save()

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

            volume_utils.notify_about_backup_usage(context, backup,
                                                   'reset_status.end')

    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(context)
        return backup_service.support_force_delete

    def _attach_device(self, ctxt, backup_device,
                       properties, is_snapshot=False):
        """Attach backup device."""
        if not is_snapshot:
            return self._attach_volume(ctxt, backup_device, properties)
        else:
            return self._attach_snapshot(ctxt, backup_device, properties)

    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("Failed to terminate the connection "
                                "of volume %(volume_id)s, but it is "
                                "acceptable.",
                                {'volume_id': volume.id})

    def _attach_snapshot(self, ctxt, snapshot, properties):
        """Attach a snapshot."""

        try:
            conn = self.volume_rpcapi.initialize_connection_snapshot(
                ctxt, snapshot, properties)
            return self._connect_device(conn)
        except Exception:
            with excutils.save_and_reraise_exception():
                try:
                    self.volume_rpcapi.terminate_connection_snapshot(
                        ctxt, snapshot, properties, force=True)
                except Exception:
                    LOG.warning("Failed to terminate the connection "
                                "of snapshot %(snapshot_id)s, but it is "
                                "acceptable.",
                                {'snapshot_id': snapshot.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 = volume_utils.brick_get_connector(
            protocol,
            use_multipath=use_multipath,
            device_scan_attempts=device_scan_attempts,
            conn=conn,
            expect_raw_disk=True)
        vol_handle = connector.connect_volume(conn['data'])

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

    def _detach_device(self, ctxt, attach_info, device,
                       properties, is_snapshot=False, force=False,
                       ignore_errors=False):
        """Disconnect the volume or snapshot from the host. """
        connector = attach_info['connector']
        connector.disconnect_volume(attach_info['conn']['data'],
                                    attach_info['device'],
                                    force=force, ignore_errors=ignore_errors)
        rpcapi = self.volume_rpcapi
        if not is_snapshot:
            rpcapi.terminate_connection(ctxt, device, properties,
                                        force=force)
            rpcapi.remove_export(ctxt, device, sync=True)
        else:
            rpcapi.terminate_connection_snapshot(ctxt, device,
                                                 properties, force=force)
            rpcapi.remove_export_snapshot(ctxt, device, sync=True)

    def is_working(self):
        return self.is_initialized

    @periodic_task.periodic_task(
        spacing=CONF.backup_driver_stats_polling_interval)
    def publish_service_capabilities(self, context):
        """Collect driver status and then publish."""
        self._report_driver_status(context)
        self._publish_service_capabilities(context)

    def _report_driver_status(self, context):
        backup_stats = {
            'backend_state': self.is_working(),
            'driver_name': self.driver_name,
            'availability_zone': self.az
        }
        self.update_service_capabilities(backup_stats)
