RETIRED, Function as a Service for OpenStack
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

186 lines
4.6 KiB

# Copyright 2017 Catalyst IT Limited
#
# 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 functools
from oslo_config import cfg
from oslo_db import options as db_options
from oslo_db.sqlalchemy import session as db_session
from qinling import context
from qinling import exceptions as exc
from qinling.utils import thread_local
# Note(dzimine): sqlite only works for basic testing.
db_options.set_defaults(cfg.CONF, connection="sqlite:///qinling.sqlite")
_FACADE = None
_DB_SESSION_THREAD_LOCAL_NAME = "db_sql_alchemy_session"
def _get_facade():
global _FACADE
if _FACADE is None:
_FACADE = db_session.EngineFacade.from_config(cfg.CONF, sqlite_fk=True)
return _FACADE
def get_session(expire_on_commit=False, autocommit=False):
"""Helper method to grab session."""
facade = _get_facade()
return facade.get_session(expire_on_commit=expire_on_commit,
autocommit=autocommit)
def get_engine():
facade = _get_facade()
return facade.get_engine()
def _get_thread_local_session():
return thread_local.get_thread_local(_DB_SESSION_THREAD_LOCAL_NAME)
def _get_or_create_thread_local_session():
ses = _get_thread_local_session()
if ses:
return ses, False
ses = get_session()
_set_thread_local_session(ses)
return ses, True
def _set_thread_local_session(session):
thread_local.set_thread_local(_DB_SESSION_THREAD_LOCAL_NAME, session)
def start_tx():
"""Starts transaction.
Opens new database session and starts new transaction assuming
there wasn't any opened sessions within the same thread.
"""
if _get_thread_local_session():
raise exc.DBError(
"Database transaction has already been started."
)
_set_thread_local_session(get_session())
def commit_tx():
"""Commits previously started database transaction."""
ses = _get_thread_local_session()
if not ses:
raise exc.DBError(
"Nothing to commit. Database transaction"
" has not been previously started."
)
ses.commit()
def rollback_tx():
"""Rolls back previously started database transaction."""
ses = _get_thread_local_session()
if not ses:
raise exc.DBError(
"Nothing to roll back. Database transaction has not been started."
)
ses.rollback()
def end_tx():
"""Ends transaction.
Ends current database transaction.
It rolls back all uncommitted changes and closes database session.
"""
ses = _get_thread_local_session()
if not ses:
raise exc.DBError(
"Database transaction has not been started."
)
if ses.dirty:
rollback_tx()
ses.close()
_set_thread_local_session(None)
def session_aware():
"""Decorator for methods working within db session."""
def _decorator(func):
@functools.wraps(func)
def _within_session(*args, **kw):
ses, created = _get_or_create_thread_local_session()
try:
kw['session'] = ses
result = func(*args, **kw)
if created:
ses.commit()
return result
except Exception:
if created:
ses.rollback()
raise
finally:
if created:
_set_thread_local_session(None)
ses.close()
return _within_session
return _decorator
def insecure_aware():
"""Decorator for methods working within insecure db query or not."""
def _decorator(func):
@functools.wraps(func)
def _with_insecure(*args, **kw):
if kw.get('insecure') is None:
insecure = context.get_ctx().is_admin
kw['insecure'] = insecure
return func(*args, **kw)
return _with_insecure
return _decorator
@session_aware()
def model_query(model, columns=(), session=None):
"""Query helper.
:param model: Base model to query.
:param columns: Optional. Which columns to be queried.
"""
if columns:
return session.query(*columns)
return session.query(model)