[openstack-dev] [Heat] How to model resources in Heat

Jay Pipes jaypipes at gmail.com
Thu Jan 30 00:40:16 UTC 2014

On Wed, 2014-01-29 at 18:55 -0500, Zane Bitter wrote:
> I've noticed a few code reviews for new Heat resource types - 
> particularly Neutron resource types - where folks are struggling to find 
> the appropriate way to model the underlying API in Heat. This is a 
> really hard problem, and is often non-obvious even to Heat experts, so 
> here are a few tips that might help.
> Resources are nouns, they model Things. Ideally Things that have UUIDs. 
> The main reason to have a resource is so you can reference its UUID (or 
> some attribute) and pass it to another resource or to the user via an 
> output.
> If two resources _have_ to be used together, they're really only one 
> resource. Don't split them up - especially if the one whose UUID other 
> resources depend on is the first to be created but not the only one 
> actually required by the resource depending on it.

Right. The above is precisely why I raised concerns about the "image
import/upload tasks" work ongoing in Glance.



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