neutron/neutron/db/api.py

119 lines
3.5 KiB
Python

# Copyright 2011 VMware, Inc.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import contextlib
from oslo_config import cfg
from oslo_db import api as oslo_db_api
from oslo_db.sqlalchemy import session
from oslo_utils import uuidutils
from sqlalchemy import exc
from neutron.common import exceptions as n_exc
from neutron.db import common_db_mixin
_FACADE = None
MAX_RETRIES = 10
retry_db_errors = oslo_db_api.wrap_db_retry(max_retries=MAX_RETRIES,
retry_on_deadlock=True)
def _create_facade_lazily():
global _FACADE
if _FACADE is None:
_FACADE = session.EngineFacade.from_config(cfg.CONF, sqlite_fk=True)
return _FACADE
def get_engine():
"""Helper method to grab engine."""
facade = _create_facade_lazily()
return facade.get_engine()
def dispose():
# Don't need to do anything if an enginefacade hasn't been created
if _FACADE is not None:
get_engine().pool.dispose()
def get_session(autocommit=True, expire_on_commit=False, use_slave=False):
"""Helper method to grab session."""
facade = _create_facade_lazily()
return facade.get_session(autocommit=autocommit,
expire_on_commit=expire_on_commit,
use_slave=use_slave)
@contextlib.contextmanager
def autonested_transaction(sess):
"""This is a convenience method to not bother with 'nested' parameter."""
try:
session_context = sess.begin_nested()
except exc.InvalidRequestError:
session_context = sess.begin(subtransactions=True)
finally:
with session_context as tx:
yield tx
# Common database operation implementations
def get_object(context, model, **kwargs):
with context.session.begin(subtransactions=True):
return (common_db_mixin.model_query(context, model)
.filter_by(**kwargs)
.first())
def get_objects(context, model, **kwargs):
with context.session.begin(subtransactions=True):
return (common_db_mixin.model_query(context, model)
.filter_by(**kwargs)
.all())
def create_object(context, model, values):
with context.session.begin(subtransactions=True):
if 'id' not in values:
values['id'] = uuidutils.generate_uuid()
db_obj = model(**values)
context.session.add(db_obj)
return db_obj.__dict__
def _safe_get_object(context, model, id):
db_obj = get_object(context, model, id=id)
if db_obj is None:
raise n_exc.ObjectNotFound(id=id)
return db_obj
def update_object(context, model, id, values):
with context.session.begin(subtransactions=True):
db_obj = _safe_get_object(context, model, id)
db_obj.update(values)
db_obj.save(session=context.session)
return db_obj.__dict__
def delete_object(context, model, id):
with context.session.begin(subtransactions=True):
db_obj = _safe_get_object(context, model, id)
context.session.delete(db_obj)