[Zope] Hourly restarts of Zope

[Jim Fulton]

Jason Abate wrote:
> 
> Michel-
> 
> > Are you calling Persistent.__setstate__(self, state) in your setstate
> > method?  If you don't call it, the persistent machinery would probably
> > be very unhappy, and since it's written in C, might core dump... just an
> > idea.
> 
> Where is the Persistent class defined? 

It's a C class, defined in lib/python/ZODB/cPersistent.c.

> All I can find is
> lib/python/Persistence.py,

Persistence.py can be thought of as a registry.  A database, 
like BoboPOS or ZODB stuffs it's persist class there
when it is imported.  This allows application code to be written that
doesn't depend on the specific database used.


> but that only contains the Zope license
> information and a doc. string.  No actual classes are defined there.  When I
> try to subclass Persistent, I get an error about the class not being found:
> 
>   >>> import Persistence
>   >>> class myclass(Persistence.Persistent):
>   ...     def __init__(self):
>   ...         print "In init"
>   ...
>   Traceback (innermost last):
>     File "<stdin>", line 1, in ?
>   AttributeError: Persistent
> 
> Am I missing something here? 

You need to import ZODB first.

 import ZODB, Persistence
 class myclass(Persistence.Persistent):
   ...


The idea is that a "main" module (like Zope)
imports ZODB before ant application modules 
are imported so that Persistence has Persistent 
when needed.

> Do things work differently if the module is
> written in C?

In this case, the difference arises from the
way the Perssitence module is used as a sort of
registry.

Jim

--
Jim Fulton           mailto:jim@digicool.com
Technical Director   (888) 344-4332              Python Powered!
Digital Creations    http://www.digicool.com     http://www.python.org

Under US Code Title 47, Sec.227(b)(1)(C), Sec.227(a)(2)(B) This email
address may not be added to any commercial mail list with out my
permission.  Violation of my privacy with advertising or SPAM will
result in a suit for a MINIMUM of $500 damages/incident, $1500 for
repeats.