nova/nova/objects/host_mapping.py

142 lines
5.3 KiB
Python

# 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.
from sqlalchemy.orm import joinedload
from nova.db.sqlalchemy import api as db_api
from nova.db.sqlalchemy import api_models
from nova import exception
from nova.objects import base
from nova.objects import cell_mapping
from nova.objects import fields
def _cell_id_in_updates(updates):
cell_mapping_obj = updates.pop("cell_mapping", None)
if cell_mapping_obj:
updates["cell_id"] = cell_mapping_obj.id
@base.NovaObjectRegistry.register
class HostMapping(base.NovaTimestampObject, base.NovaObject):
# Version 1.0: Initial version
VERSION = '1.0'
fields = {
'id': fields.IntegerField(read_only=True),
'host': fields.StringField(),
'cell_mapping': fields.ObjectField('CellMapping'),
}
def _get_cell_mapping(self):
with db_api.api_context_manager.reader.using(self._context) as session:
cell_map = (session.query(api_models.CellMapping)
.join(api_models.HostMapping)
.filter(api_models.HostMapping.host == self.host)
.first())
if cell_map is not None:
return cell_mapping.CellMapping._from_db_object(
self._context, cell_mapping.CellMapping(), cell_map)
def _load_cell_mapping(self):
self.cell_mapping = self._get_cell_mapping()
def obj_load_attr(self, attrname):
if attrname == 'cell_mapping':
self._load_cell_mapping()
@staticmethod
def _from_db_object(context, host_mapping, db_host_mapping):
for key in host_mapping.fields:
db_value = db_host_mapping.get(key)
if key == "cell_mapping":
# NOTE(dheeraj): If cell_mapping is stashed in db object
# we load it here. Otherwise, lazy loading will happen
# when .cell_mapping is accessd later
if not db_value:
continue
db_value = cell_mapping.CellMapping._from_db_object(
host_mapping._context, cell_mapping.CellMapping(),
db_value)
setattr(host_mapping, key, db_value)
host_mapping.obj_reset_changes()
host_mapping._context = context
return host_mapping
@staticmethod
@db_api.api_context_manager.reader
def _get_by_host_from_db(context, host):
db_mapping = (context.session.query(api_models.HostMapping)
.options(joinedload('cell_mapping'))
.filter(api_models.HostMapping.host == host)).first()
if not db_mapping:
raise exception.HostMappingNotFound(name=host)
return db_mapping
@base.remotable_classmethod
def get_by_host(cls, context, host):
db_mapping = cls._get_by_host_from_db(context, host)
return cls._from_db_object(context, cls(), db_mapping)
@staticmethod
@db_api.api_context_manager.writer
def _create_in_db(context, updates):
db_mapping = api_models.HostMapping()
db_mapping.update(updates)
db_mapping.save(context.session)
# NOTE: This is done because a later access will trigger a lazy load
# outside of the db session so it will fail. We don't lazy load
# cell_mapping on the object later because we never need a HostMapping
# without the CellMapping.
db_mapping.cell_mapping
return db_mapping
@base.remotable
def create(self):
changes = self.obj_get_changes()
# cell_mapping must be mapped to cell_id for create
_cell_id_in_updates(changes)
db_mapping = self._create_in_db(self._context, changes)
self._from_db_object(self._context, self, db_mapping)
@staticmethod
@db_api.api_context_manager.writer
def _save_in_db(context, obj, updates):
db_mapping = context.session.query(api_models.HostMapping).filter_by(
id=obj.id).first()
if not db_mapping:
raise exception.HostMappingNotFound(name=obj.host)
db_mapping.update(updates)
return db_mapping
@base.remotable
def save(self):
changes = self.obj_get_changes()
# cell_mapping must be mapped to cell_id for updates
_cell_id_in_updates(changes)
db_mapping = self._save_in_db(self._context, self.host, changes)
self._from_db_object(self._context, self, db_mapping)
self.obj_reset_changes()
@staticmethod
@db_api.api_context_manager.writer
def _destroy_in_db(context, host):
result = context.session.query(api_models.HostMapping).filter_by(
host=host).delete()
if not result:
raise exception.HostMappingNotFound(name=host)
@base.remotable
def destroy(self):
self._destroy_in_db(self._context, self.host)