def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def test_attach_detach_volume_to_instance(self):
        """Test attaching and detaching volume to instance"""
        # Create a server
        server = self.create_server()
        # Volume is attached and detached successfully from an instance
        self.volumes_client.attach_volume(self.volume['id'],
                                          instance_uuid=server['id'],
                                          mountpoint='/dev/%s' %
                                          CONF.compute.volume_device_name)
        waiters.wait_for_volume_resource_status(self.volumes_client,
                                                self.volume['id'], 'in-use')
        self.volumes_client.detach_volume(self.volume['id'])
        waiters.wait_for_volume_resource_status(self.volumes_client,
                                                self.volume['id'], 'available')