[Grok-dev] ME GROK RELOAD

[Philipp von Weitershausen]

On 6 Mar 2007, at 11:02 , Christian Theune wrote:
> I'm working on a better Zope 2 product refresh mechanism right now and
> compared that to what you did here.
>
> Guido van Rossum came up with a good approach that works a lot  
> better in
> the context of ZODB applications as he doesn't unload the existing
> module, but imports the module again into a new namespace and does
> surgical operations to apply code updates in-place and keep references
> valid.

Yes, I've seen that (I assume you're talking about xreload.py). I've  
been wanting to try that out in a grok context.

> I'm also implementing a rather gross approach on refreshing ZCML by  
> just
> simply emptying the global site manager and telling Five to  
> load_site()
> again. All in all this seems to work quite well.

Cool. Note that emptying the site manager often isn't enough. ZCML  
does other global setup. Something like the global cleanup hook we  
use for testing should probably be used in this case.

For grok, I made grokkers implement an "ungrok" method in which they  
would have to take back whatever they did in "register". That worked  
quite well and insanely fast because all the ZCML setup in Zope  
stayed as it is, it didn't have to be reloaded.

> I do have to provide a couple of very gross hacks though that I'm
> researching by using this on a large site with many products.
>
> If you want to look at the code, check launchpad.net/refreshng
>
> (The code is very gross right now as I'm still in the 'getting it  
> right'
> phase.)

Great (haven't looked at the code yet)! Perhaps it can be made so  
that grok can simply use it as a dependency. It would certainly rock  
if grok would use the same mechanism as Zope (2/3) itself.

Thanks for looking into this!

Philipp