[Zope3-Users] zope.scheduler and triggering actions on local objects

[Florian Lindner]

Am Donnerstag, 1. Februar 2007 13:41 schrieb Alek Kowalczyk:
> Hi,
> I need to trigger periodically activities on various local components (i.e
> stored in ZoDB). I found zope.scheduler package which seem to be nice
> cron-like tool for Zope. But I did not find a clue how to use it with local
> components - in examples it is registered as global utility.
>
> I think about few ways of doing that. Please advice which one is the
> correct one: a) make zope.scheduler call via xml-rpc some URLs to trigger
> the activities 


> b) find (how?) local objects from scheduler global utility 
> and trigger activities c) register scheduler as local utility - it seems to
> be impossible for me, as it rather cannot be persistent, can it?

You can open a connection to the database and use it this way. Here is an 
example code that works but generated an error ofter some calls:

    db = getUtility(ZODB.interfaces.IDatabase)
    conn = db.open()
    root = conn.root().data['Application']
    zope.app.component.hooks.setSite(root)
    
    utils = getUtilitiesFor(IYourInterface)
    for i in utils:
        print "Utility found:", i[0]
           
    db.close()

but after some calls it gives an error:

exceptions.ValueError: I/O operation on closed file

Don't know why.


>  d) other solution?
>
> The solution b) is the one I feel is the right one. But how to find local
> objects? Can I hook into DatabaseOpenedWithRoot event and pass the database
> reference to global utility? If yes - how to deal with transactions...?

Regards,

Florian