> The way you have it, a concurrent thread can easily interrupt the > ScopedSession instance attached to "meta" and replace with a new one, > with the old one being lost.
Ouch, that would be no good. Thank goodness my prod env aint really prod yet. Thank you for your help again. Much appreciated. -Alen On Aug 18, 3:13 pm, Michael Bayer <[EMAIL PROTECTED]> wrote: > On Aug 18, 2008, at 5:08 AM, Alen Ribic wrote: > > > > > > > sql.py > > ==================================== > > > class SQLAlchemyMiddleware(object): > > """ > > Middleware for providing clean SQLAlchemy Session objects for each > > Request. > > """ > > def __init__(self, application): > > self.application = application > > self.__engine = None > > > def get_engine(self): > > if self.__engine is None: > > self.__engine = create_engine( > > settings.SQLALCHEMY_DEFAULT_URL, > > pool_recycle=3600, > > pool_size=20, > > echo_pool=True > > ) > > return self.__engine > > > def init_model(self, engine): > > """Call before using any of the tables or classes in the > > model.""" > > sm = orm.sessionmaker(autoflush=True, transactional=True, > > bind=engine) > > > meta.engine = engine > > meta.Session = orm.scoped_session(sm) > > > def __call__(self, environ, start_response): > > try: > > engine = self.get_engine() > > self.init_model(engine) > > return self.application(environ, start_response) > > finally: > > if meta.Session is not None: > > meta.Session.remove() > > The big mistake here is creating a brand new ScopedSession on each > request. This is not how ScopedSession was intended to be used; its > created, like Engine, once per application. Some details on this > pattern are here: > > http://www.sqlalchemy.org/docs/05/session.html#unitofwork_contextual_... > > The way you have it, a concurrent thread can easily interrupt the > ScopedSession instance attached to "meta" and replace with a new one, > with the old one being lost. > > Here's a more reasonable approach: > > class SQLAlchemyMiddleware(object): > def __init__(self, application): > self.application = application > meta.engine = create_engine( > settings.SQLALCHEMY_DEFAULT_URL, > pool_recycle=3600, > pool_size=20, > echo_pool=True > ) > meta.Session = > orm.scoped_session(orm.sessionmaker(autoflush=True, transactional=True, > bind=meta.engine)) > > def __call__(self, environ, start_response): > try: > return self.application(environ, start_response) > except: > meta.Session.rollback() > raise > finally: > meta.Session.remove()>> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
