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calibre-web/lib/sqlalchemy/dialects/mysql/gaerdbms.py

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# mysql/gaerdbms.py
# Copyright (C) 2005-2013 the SQLAlchemy authors and contributors <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""
.. dialect:: mysql+gaerdbms
:name: Google Cloud SQL
:dbapi: rdbms
:connectstring: mysql+gaerdbms:///<dbname>?instance=<instancename>
:url: https://developers.google.com/appengine/docs/python/cloud-sql/developers-guide
This dialect is based primarily on the :mod:`.mysql.mysqldb` dialect with minimal
changes.
.. versionadded:: 0.7.8
Pooling
-------
Google App Engine connections appear to be randomly recycled,
so the dialect does not pool connections. The :class:`.NullPool`
implementation is installed within the :class:`.Engine` by
default.
"""
import os
from .mysqldb import MySQLDialect_mysqldb
from ...pool import NullPool
import re
def _is_dev_environment():
return os.environ.get('SERVER_SOFTWARE', '').startswith('Development/')
class MySQLDialect_gaerdbms(MySQLDialect_mysqldb):
@classmethod
def dbapi(cls):
# from django:
# http://code.google.com/p/googleappengine/source/
# browse/trunk/python/google/storage/speckle/
# python/django/backend/base.py#118
# see also [ticket:2649]
# see also http://stackoverflow.com/q/14224679/34549
from google.appengine.api import apiproxy_stub_map
if _is_dev_environment():
from google.appengine.api import rdbms_mysqldb
return rdbms_mysqldb
elif apiproxy_stub_map.apiproxy.GetStub('rdbms'):
from google.storage.speckle.python.api import rdbms_apiproxy
return rdbms_apiproxy
else:
from google.storage.speckle.python.api import rdbms_googleapi
return rdbms_googleapi
@classmethod
def get_pool_class(cls, url):
# Cloud SQL connections die at any moment
return NullPool
def create_connect_args(self, url):
opts = url.translate_connect_args()
if not _is_dev_environment():
# 'dsn' and 'instance' are because we are skipping
# the traditional google.api.rdbms wrapper
opts['dsn'] = ''
opts['instance'] = url.query['instance']
return [], opts
def _extract_error_code(self, exception):
match = re.compile(r"^(\d+)L?:|^\((\d+)L?,").match(str(exception))
# The rdbms api will wrap then re-raise some types of errors
# making this regex return no matches.
code = match.group(1) or match.group(2) if match else None
if code:
return int(code)
dialect = MySQLDialect_gaerdbms