On Wed, Jan 29, 2014 at 5:03 PM, Zane Bitter <zbit...@redhat.com> wrote:
> On 29/01/14 19:40, Jay Pipes wrote: > >> 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. >> >> https://wiki.openstack.org/wiki/Glance-tasks-import# >> Initial_Import_Request >> > > At least the dependencies there would be in the right order: > > ImportTask <- Image <- Server > > but if you were to model this in Heat, there should just be an Image > resource that does the importing internally. > > (I'm not touching the question of whether Heat should have a Glance Image > resource at all, which I'm deeply ambivalent about.) > Maybe I'm just missing the use case, but it seems like modeling anything Glance-y in Heat doesn't quite make sense. If at all, the dependency would run the other way (model heat-things in glance, just as we presently model nova-things in glance). So I think we're in agreement. > > cheers, > Zane. > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >
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