[ZODB-Dev] ZEO client with Asyncore loop

[Matthew Pontefract]

Thanks for the pointer - I found the client_loop in ZEO.zrpc.connection 
which starts on importing that module. A quick check with my bit of code 
didn't see things working any better but I fear I may be completely 
missing the point somewhere... I'll try again in the morning. Thanks 
again for the pointer to the new version.

Matthew

Jim Fulton wrote:
> 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!
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