neutron/neutron/db/migration/connection.py
Ihar Hrachyshka eb084af29d neutron-db-manage: add has_offline_migrations command
This command should be used by operators and deployment tools to
determine whether full neutron-server shutdown is needed for database
upgrade.

The change also makes neutron-db-manage tool to return the cumulative
result of commands being issued (in most cases it will still be 0 only,
since our command handlers implicitly return None).

DocImpact: Update doc to add new command 'has_offline_migrations' to
'neutron-db-manage' tool. The command determines whether full
neutron-server shutdown is needed for database upgrade.

Closes-Bug: #1519118
Change-Id: I7c5a4882ad4f80459ebe69c9a9c43cc60ce50200
Co-Authored-By: Martin Hickey <martin.hickey@ie.ibm.com>
2016-01-22 13:55:40 +00:00

42 lines
1.5 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 oslo_db.sqlalchemy import session
class DBConnection(object):
"""Context manager class which handles a DB connection.
An existing connection can be passed as a parameter. When
nested block is complete the new connection will be closed.
This class is not thread safe.
"""
def __init__(self, connection_url, connection=None):
self.connection = connection
self.connection_url = connection_url
self.new_engine = False
def __enter__(self):
self.new_engine = self.connection is None
if self.new_engine:
self.engine = session.create_engine(self.connection_url)
self.connection = self.engine.connect()
return self.connection
def __exit__(self, type, value, traceback):
if self.new_engine:
try:
self.connection.close()
finally:
self.engine.dispose()