- [feature] Added a new dialect for Google App

Engine.  [ticket:2484]

diff --git a/CHANGES b/CHANGES
index f8aba424e4b1d2f8f94ad2f10bada54063a2fe58..938b9babbfc20e11f933f4a303529c482ba81be3 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -27,6 +27,11 @@ CHANGES
 - oracle
   - [bug] Added ROWID to oracle.*, [ticket:2483]
 
+- mysql
+  - [feature] Added a new dialect for Google App
+    Engine.  [ticket:2484]
+
+
 0.7.7
 =====
 - orm

diff --git a/lib/sqlalchemy/dialects/mysql/gaerdbms.py b/lib/sqlalchemy/dialects/mysql/gaerdbms.py
new file mode 100644 (file)
index 0000000..f84a5d2
--- /dev/null
+++ b/lib/sqlalchemy/dialects/mysql/gaerdbms.py
@@ -0,0 +1,61 @@
+# mysql/gaerdbms.py
+# Copyright (C) 2005-2012 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
+"""Support for Google Cloud SQL on Google App Engine.
+
+This dialect is based primarily on the :mod:`.mysql.mysqldb` dialect with minimal
+changes.
+
+.. versionadded:: 0.7.8
+
+Connecting
+----------
+
+Connect string format::
+
+    mysql+gaerdbms:///<dbname>
+
+E.g.::
+
+  create_engine('mysql+gaerdbms:///mydb',
+                 connect_args={"instance":"instancename"})
+
+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.
+
+"""
+
+from sqlalchemy.dialects.mysql.mysqldb import MySQLDialect_mysqldb
+from sqlalchemy.pool import NullPool
+import re
+
+
+class MySQLDialect_gaerdbms(MySQLDialect_mysqldb): 
+
+    @classmethod 
+    def dbapi(cls): 
+        from google.appengine.api import rdbms
+        return rdbms
+
+    @classmethod
+    def get_pool_class(cls, url):
+        # Cloud SQL connections die at any moment
+        return NullPool
+
+    def create_connect_args(self, url):
+        return [[],{'database':url.database}]
+
+    def _extract_error_code(self, exception):
+        match = re.compile(r"^(\d+):").match(str(exception))
+        code = match.group(1)
+        if code:
+            return int(code)
+
+dialect = MySQLDialect_gaerdbms
\ No newline at end of file