[ZODB-Dev] ZEO client with Asyncore loop

[Jim Fulton]

Note that ZODB 3.7 already provides a separate dedicated  client  
asyncore loop. You might try using that.  There is a beta release at:

   http://download.zope.org/distribution/ZODB3-3.7.0b3.tar.gz

Note that this release should work well with easy_install or  
zc.buildout.  It doesn't include ZConfig, zdaemon, zope.interface,   
zope.proxy, or zope.testing,  as these are now handled as  dependencies.

Also note that while the release is still beta, because I haven't had  
time to make a final release, this release is being used in current  
versions of Zope.

Jim

On Dec 7, 2006, at 12:44 PM, Matthew Pontefract wrote:

> Hello
>
> I'm writing client code that uses ZODB over a ZEO connection. In  
> order not to have to call connection.sync() to synchronise the  
> cache with the server I wish to provide the ZEO client with an  
> asyncore mainloop to which it can attach itself. No matter how I do  
> this, however, my clients
> do not seem to be processing cache invalidation/update messages  
> asynchronously.
>
> My client code does not make use of asyncore itself so the thread  
> is started especially for ZEO's use. I've tried starting the loop  
> thread *after* getting the ZEO connection:
>
> ==============================
> class AsyncoreRunner(threading.Thread):
>     def __init__(self,env):
>         threading.Thread.__init__(self)
>         self.env=env
>         self.setDaemon(True)
>
>     def run(self):
>         self.env.sys.logger.info("Asyncore loop starting")
>         try:
>             asyncore.loop()
>         except Exception,ex:
>             self.env.sys.logger.error("Asyncore loop quitting: %s"% 
> str(ex))
>         self.env.sys.logger.info("Asycore loop ended")
>
>
>
> addr = host, port
> storage=ClientStorage.ClientStorage(addr)
> db = DB(self.storage)
> conn = self.db.open()
> mt = AsyncoreRunner(self.env)
> mt.start()
> ==============================
>
> ... and I've tried starting it BEFORE getting the connection  
> (providing a dummy dispatcher so that the asyncore.loop() does not  
> return immediately).
>
> In either case, if I run two clients the following does not work  
> where I would imagine it should if the messages were being  
> processed on the asyncore thread.
>
> CLIENT 1:
> root = conn.root()
> root['test']=10
> transaction.commit()
>
> CLIENT 2:
> root['test']
> ... KeyError...
> conn.sync()
> root['test']
> 10
> root['test'] = 20
> transaction.commit()
>
> CLIENT1:
> root['test']
> 10            <----- Not 20!
> conn.sync()
> root['test']
> 20            <----- now it is!
>
>
> Have I misunderstood things very badly? Am I approaching things too  
> simplistically?
>
> I have googled and searched a lot of documentation but I just can't  
> find the key to my problem! Here's hoping that someone on this list  
> can help!
>
> Many thanks in advance,
> Matthew
>
> _______________________________________________
> For more information about ZODB, see the ZODB Wiki:
> http://www.zope.org/Wikis/ZODB/
>
> ZODB-Dev mailing list  -  ZODB-Dev at zope.org
> http://mail.zope.org/mailman/listinfo/zodb-dev

--
Jim Fulton			mailto:jim at zope.com		Python Powered!
CTO 				(540) 361-1714			http://www.python.org
Zope Corporation	http://www.zope.com		http://www.zope.org