> > However, the thread has to start a new transaction each time it > > processes something - which I know how to do: > > > > while True: > > #wait until asked to do something > > import transaction > > transaction.begin() > > > > However, the thread needs access to the root object in order to turn > > the identifiers gotten from the requests into persistent objects... > > how would I go about accessing the root object in such a circumstance? > > You need to pass the database object to the thread, and the thread needs > to open a connection (connection = db.open()). Then connection.root() > will give you the root object (or you could pass OIDs to the thread and > use connection.get(oid) to find the objects you need to work with).
That makes sense. I wasn't sure where to get a db object from so here's what I ended up doing. Let me know if there's a better way. I use paster to run the webserver, so in run.py I now have: GLOBAL_CONFIG = [None] def app(global_config, **settings): GLOBAL_CONFIG = global_config #... Now in the thread I start to do the processing I have: def proc_f(self, i): from repoze.zodbconn.uri import db_from_uri import run global_config = run.GLOBAL_CONFIG uri = global_config['zodb_uri'] db = db_from_uri(uri) conn = db.open() app_root = conn.root()['app_root'] while True: #wait for request... t = conn.transaction_manager.begin() #do a bunch of read-only processing, queue results conn.abort(t) > Don't forget to commit or abort the transaction, and also don't forget > that you may need to implement some kind of retry logic if commit() > raises a ConflictError due to conflicting updates. I figure since I never write anything to the database in my worker thread I can always abort the transaction. This all seems to work. Anything horribly wrong I'm doing? Thanks muchly, - Claudiu
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