# octavia.db.api

# Source code for octavia.db.api

    #    Copyright 2014 Rackspace
    #
    #    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 time

    from sqlalchemy.sql.expression import select

    from oslo_config import cfg
    from oslo_db.sqlalchemy import enginefacade
    from oslo_log import log as logging

    LOG = logging.getLogger(__name__)
    _FACADE = None

    def _create_facade_lazily():
        global _FACADE
        if _FACADE is None:
            _FACADE = True
            enginefacade.configure(sqlite_fk=True, expire_on_commit=True)

    def _get_transaction_context(reader=False):
        _create_facade_lazily()
        # TODO(gthiemonge) Create and use new functions to get read-only sessions
        if reader:
            context = enginefacade.reader
        else:
            context = enginefacade.writer
        return context

    def _get_sessionmaker(reader=False):
        context = _get_transaction_context(reader)
        return context.get_sessionmaker()

    def get_engine():
        context = _get_transaction_context()
        return context.get_engine()

    def get_session():
        """Helper method to grab session."""
        return _get_sessionmaker()()

    def session():
        return _get_sessionmaker()

    def wait_for_connection(exit_event):
        """Helper method to wait for DB connection"""
        down = True
        while down and not exit_event.is_set():
            try:
                LOG.debug('Trying to re-establish connection to database.')
                get_engine().scalar(select([1]))
                down = False
                LOG.debug('Connection to database re-established.')
            except Exception:
                retry_interval = cfg.CONF.database.retry_interval
                LOG.exception('Connection to database failed. Retrying in %s '
                              'seconds.', retry_interval)
                time.sleep(retry_interval)

this page last updated: 2025-10-06 11:22:08

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