59 lines
2.1 KiB
Python
59 lines
2.1 KiB
Python
# -*- coding: utf-8 -*-
|
|
################################################################################
|
|
#
|
|
# Rattail -- Retail Software Framework
|
|
# Copyright © 2010-2017 Lance Edgar
|
|
#
|
|
# This file is part of Rattail.
|
|
#
|
|
# Rattail is free software: you can redistribute it and/or modify it under the
|
|
# terms of the GNU General Public License as published by the Free Software
|
|
# Foundation, either version 3 of the License, or (at your option) any later
|
|
# version.
|
|
#
|
|
# Rattail is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
|
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
|
|
# details.
|
|
#
|
|
# You should have received a copy of the GNU General Public License along with
|
|
# Rattail. If not, see <http://www.gnu.org/licenses/>.
|
|
#
|
|
################################################################################
|
|
"""
|
|
Tween Factories
|
|
"""
|
|
|
|
from __future__ import unicode_literals, absolute_import
|
|
|
|
from sqlalchemy.exc import OperationalError
|
|
from transaction.interfaces import TransientError
|
|
|
|
|
|
def sqlerror_tween_factory(handler, registry):
|
|
"""
|
|
Produces a tween which will convert ``sqlalchemy.exc.OperationalError``
|
|
instances (caused by database server restart) into a retryable
|
|
``transaction.interfaces.TransientError`` instance, so that a second
|
|
attempt may be made to connect to the database before really giving up.
|
|
|
|
.. note::
|
|
This tween alone is not enough to cause the transaction to be retried;
|
|
it only marks the error as being *retryable*. If you wish more than one
|
|
attempt to be made, you must define the ``tm.attempts`` setting within
|
|
your Pyramid app configuration. For more info see `Retrying`_.
|
|
|
|
.. _Retrying: http://docs.pylonsproject.org/projects/pyramid_tm/en/latest/#retrying
|
|
"""
|
|
|
|
def sqlerror_tween(request):
|
|
try:
|
|
response = handler(request)
|
|
except OperationalError as error:
|
|
if error.connection_invalidated:
|
|
raise TransientError(str(error))
|
|
raise
|
|
return response
|
|
|
|
return sqlerror_tween
|