[Web-SIG] more comments on Paste Deploy

[Ian Bicking]

Joseph Tate wrote:
> On Saturday 03 March 2007 15:54:41 Ian Bicking wrote:
>> Chad Whitacre wrote:
>>> I suggest that a system with multiple simple config files is much
>>> more scalable than a single complex config file syntax. Imagine
>>> if all of Unix were configured using a single syntax!
>> There's other cases where having both options is nice.  Because Paste
>> Deploy doesn't fold config files together, you can also reuse them from
>> different contexts.  (A more common way to use multiple config files --
>> what ConfigParser.load supports -- is to just overlap all the sections,
>> usually totally clobbering each other.  I like this more explicit way of
>> bringing in configuration, which treats configuration like a composable
>> set of configurations instead of a system where all the configuration
>> files are pretty tightly bound to each other.)
> 
> I find that multiple files gives you a nice way to override defaults.  As long 
> as the files are read in a way that's predictable and documentable, and 
> ultimately appear as if read from a single file (and possible displayable via 
> some diagnostics link in an application).

Allowing this sort of thing means that the application carries around a 
complete config object of some sort, which I rather dislike -- it allows 
for smart applications, but it makes it much harder to understand the 
configuration and any possible side effects.  If we resolve the 
configuration down to something more limited (as the Paste Deploy entry 
points do) you can't really reconstruct the config from there. 
*Something* could still reconstruct the config (an alternate config 
loader, via logs, via debug settings, etc), just not the application itself.

This is somewhat problematic for applications that have particularly 
complex config requirements, or want to support self-configuration.  The 
best solution that I can think of with Paste Deploy in that case is to 
just use the Paste Deploy configuration to point to the "real" 
configuration.

-- 
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org