Check self.dbapi.initialized for firebird.py

I have a use case where one web application is using kinterbasdb directly and another is using sqlalchemy, both under mod_wsgi. Numerous attempts at different configuration scenarios led me to run both applications with the WSGIApplicationGroup = ${GLOBAL} setting in the conf file for httpd. It appears that firebird.py does not check if kinterbasdb has alread been initialized before making its call to init. It only checks if it has attempted to initialize.

This is the stack trace I would inevitably see:

cherrypy.server.start(init_only=True, server_class=None)
File "/usr/lib/python2.4/site-packages/cherrypy/_cpserver.py", line 72, in start
Engine.start(self)
File "/usr/lib/python2.4/site-packages/cherrypy/_cpengine.py", line 106, in start
self._start()
File "/usr/lib/python2.4/site-packages/cherrypy/_cpserver.py", line 78, in _start
Engine._start(self)
File "/usr/lib/python2.4/site-packages/cherrypy/_cpengine.py", line 110, in _start
func()
File "/usr/lib/python2.4/site-packages/turbogears/startup.py", line 227, in startTurboGears
database.get_engine()
File "/usr/lib/python2.4/site-packages/turbogears/database.py", line 45, in get_engine
_engine = sqlalchemy.create_engine(dburi, **alch_args)
File "/usr/lib/python2.4/site-packages/sqlalchemy/engine/__init__.py", line 173, in create_engine
return strategy.create(*args, **kwargs)
File "/usr/lib/python2.4/site-packages/sqlalchemy/engine/strategies.py", line 70, in create
(cargs, cparams) = dialect.create_connect_args(u)
File "/usr/lib/python2.4/site-packages/sqlalchemy/databases/firebird.py", line 294, in create_connect_args
self.dbapi.init(type_conv=type_conv, concurrency_level=concurrency_level)
File "/usr/lib/python2.4/site-packages/kinterbasdb/__init__.py", line 272, in init
_k.concurrency_level_set(concurrency_level)
ProgrammingError: (0, 'The concurrency level cannot be changed once it has been set.  Use kinterbasdb.init(concurrency_level=?) to set the concurrency level legally.')

I needed to add this:

diff -Naur SQLAlchemy-0.4.7/lib/sqlalchemy/databases/firebird.py SQLAlchemy-0.4.7.new/lib/sqlalchemy/databases/firebird.py
--- SQLAlchemy-0.4.7/lib/sqlalchemy/databases/firebird.py       2008-07-26 12:43:52.000000000 -0400
+++ SQLAlchemy-0.4.7.new/lib/sqlalchemy/databases/firebird.py   2008-10-01 10:51:22.000000000 -0400
@@ -291,7 +291,8 @@
         global _initialized_kb
         if not _initialized_kb and self.dbapi is not None:
             _initialized_kb = True
-            self.dbapi.init(type_conv=type_conv, concurrency_level=concurrency_level)
+            if not self.dbapi.initialized:
+                self.dbapi.init(type_conv=type_conv, concurrency_level=concurrency_level)
         return ([], opts)

     def create_execution_context(self, *args, **kwargs):

This configuration and patch allowed me to run both apps, one with kinterbasdb being used directly, and another with sqlalchemy. I could find no other way to do this. If there is a better method, I could not find it.

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