[Zope3-dev] Re: Autoconfiguring a site.zcml

[Jim Fulton]

On Apr 23, 2007, at 2:43 PM, Martijn Faassen wrote:
...
> It'd be a lot easier. You'd still have to list it for all eggs that  
> you depend on directly. It would be nice if this could be automated  
> as well, as being in two places to add a single dependency is more  
> work than being in one place. Could be done with a special recipe,  
> I think.

Except that the information belongs in your application package's  
configure.zcml.  site.zcml should, IMO, be a very short file that
include's your application package's configure.zcml.  If you want to  
write a tool that writes your configure.zcml, go for it.

I wouldn't object to a zcml configuration directive that took a  
project name and included zcml files provided by it's dependencies at  
run time.


> Package-level ZCML include dependencies would also mean a kind of  
> duplication, too. You list dependencies in setup.py and then again  
> in the package's ZCML.

You could argue that the dependencies in setup.py duplicate  
information in your Python import statements -- if you wanted to.

>>> I also don't understand David's problem with buildout times. The  
>>> option -N helps a lot. Jim, is there anything to say for actually  
>>> making -N the default behavior of buildout?
>> No, But I can say something against it. :) Making it the default  
>> would make buildout's default behavior less deterministic.
>
> I don't understand.
>
> I can see how -o is the most deterministic buildout behavior, as it  
> will upgrade nothing. The next step in my mind would be -N, as it  
> only installs what's not there yet. Finally there's "no option",  
> which is least predictable it might start updating stuff, depending  
> on what package restrictions you have. Obviously I'm not  
> understanding what you mean by "deterministic".

The default behavior is to update all packages to the most recent  
version that satisfies your requirements.  This means that running  
buildout in 2 different buildouts with the same configuration should  
produce the same results, regardless of their history.  I think this  
is an important property that you lose with -N.

>>  It is easy for people to change the default for their own use by  
>> putting:
>>    [buildout]
>>    newest = false
>> in their ~/.buildout/default.cfg file.
>
> Ah, a trick I wasn't aware of. I will do that then in my  
> buildout.cfgs, though this will indeed might cause a few surprises  
> to people they might get used to it and be surprised when they need  
> -N in other buildouts.

That's why I suggested putting it in: ~/.buildout/default.cfg, which  
would effect only you.

Jim

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