193 lines
4.5 KiB
Python
193 lines
4.5 KiB
Python
# -*- coding: utf-8 -*-
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#
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# Copyright 2015 - Mirantis, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import six
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from oslo_config import cfg
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from oslo_db import options
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from oslo_db.sqlalchemy import session as db_session
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from oslo_log import log as logging
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from lbaas import exceptions as exc
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from lbaas import utils
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LOG = logging.getLogger(__name__)
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# Note(dzimine): sqlite only works for basic testing.
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options.set_defaults(cfg.CONF, connection="sqlite:///lbaas.sqlite")
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_DB_SESSION_THREAD_LOCAL_NAME = "db_sql_alchemy_session"
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_facade = None
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def _get_facade():
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global _facade
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if not _facade:
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_facade = db_session.EngineFacade(
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cfg.CONF.database.connection,
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sqlite_fk=True,
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autocommit=False,
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**dict(six.iteritems(cfg.CONF.database))
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)
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return _facade
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def get_engine():
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return _get_facade().get_engine()
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def _get_session():
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return _get_facade().get_session()
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def _get_thread_local_session():
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return utils.get_thread_local(_DB_SESSION_THREAD_LOCAL_NAME)
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def _get_or_create_thread_local_session():
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ses = _get_thread_local_session()
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if ses:
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return ses, False
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ses = _get_session()
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_set_thread_local_session(ses)
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return ses, True
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def _set_thread_local_session(session):
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utils.set_thread_local(_DB_SESSION_THREAD_LOCAL_NAME, session)
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def session_aware(param_name="session"):
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"""Decorator for methods working within db session."""
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def _decorator(func):
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def _within_session(*args, **kw):
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# If 'created' flag is True it means that the transaction is
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# demarcated explicitly outside this module.
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ses, created = _get_or_create_thread_local_session()
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try:
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kw[param_name] = ses
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result = func(*args, **kw)
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if created:
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ses.commit()
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return result
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except Exception:
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if created:
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ses.rollback()
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raise
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finally:
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if created:
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_set_thread_local_session(None)
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ses.close()
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_within_session.__doc__ = func.__doc__
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return _within_session
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return _decorator
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# Transaction management.
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def start_tx():
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"""Starts transaction.
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Opens new database session and starts new transaction assuming
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there wasn't any opened sessions within the same thread.
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"""
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if _get_thread_local_session():
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raise exc.DataAccessException(
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"Database transaction has already been started."
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)
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_set_thread_local_session(_get_session())
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def commit_tx():
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"""Commits previously started database transaction."""
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ses = _get_thread_local_session()
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if not ses:
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raise exc.DataAccessException(
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"Nothing to commit. Database transaction"
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" has not been previously started."
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)
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ses.commit()
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def rollback_tx():
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"""Rolls back previously started database transaction."""
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ses = _get_thread_local_session()
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if not ses:
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raise exc.DataAccessException(
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"Nothing to roll back. Database transaction has not been started."
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)
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ses.rollback()
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def end_tx():
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"""Ends transaction.
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Ends current database transaction.
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It rolls back all uncommitted changes and closes database session.
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"""
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ses = _get_thread_local_session()
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if not ses:
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raise exc.DataAccessException(
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"Database transaction has not been started."
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)
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if ses.dirty:
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rollback_tx()
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ses.close()
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_set_thread_local_session(None)
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@session_aware()
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def get_driver_name(session=None):
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return session.bind.url.drivername
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@session_aware()
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def model_query(model, columns=(), session=None):
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"""Query helper.
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:param model: Base model to query.
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:param columns: Optional. Which columns to be queried.
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"""
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if columns:
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return session.query(*columns)
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return session.query(model)
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