[Zope3-dev] Re: zope.viewlet breaking buildout?

[David Pratt]

Hi Jim. Yes, a tool to generate a dependency tree would be a very useful 
utility to inspect package relationships for a buildout.

Some excellent advice. I'm very interested in your approach to create 
RPM's from buildouts as well. Looking forward to seeing this. Many thanks.

Regards,
David



Jim Fulton wrote:
> 
> On Apr 17, 2007, at 9:13 AM, David Pratt wrote:
> 
>> The pre-flight is just an idea at the moment. Buildouts present 
>> constantly changing dependencies as different package releases are 
>> made. I can see some buildouts getting into the one to two hundred egg 
>> range. I guess from my perspective, it would be helpful to see some 
>> sort of globally generated dependency output for a buildout (opposed 
>> to through each package's setup or the egg info produced).
> 
> But dependencies aren't global.  Each script can have a different set of 
> dependencies.  To find out what these are, look at the generated scripts.
> 
> It might be nice to have a tool that generates a dependency tree from a 
> working set.  This tool is far more general than buildout and could be 
> used, for example, with an script or interpreter generated by  buildout.
> 
> 
>> I'm also wanting some assurance that a buildout will run to completion 
>> without fear that a recent package revision or change will break it, 
>> particularly for deployment. I don't want dependency issues to be a 
>> factor in killing the automation from executing properly - so have 
>> been thinking about this in any case. This potential exists even if 
>> the buildout has successfully run before. Many thanks.
> 
> For deployment, you're better off specifying versions so you don't get 
> accidental upgrades at deployment time.  buildout provides a number of 
> tools for doing this, most notably:
> 
>   
> http://www.python.org/pypi/zc.buildout/1.0.0b23#repeatable-buildouts-controlling-eggs-used 
> 
> 
> For greater safety, if deployments are very important to you, consider 
> building system installation packages from buildouts.  I create RPMs 
> from buildouts and we then use these RPMs to deploy. I intend to write 
> up how I've done this, although I haven't done so yet, unfortunately.
> 
> Jim
> 
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> Jim Fulton            mailto:jim at zope.com        Python Powered!
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