Stack files dict missing from within resource plugin

[Joe D'Andrea]

Calling heat.engine.stack_resource.StackResource.preview() from within a resource plugin (e.g., during a create) throws an exception if there are nested templates referenced as local files.

ValueError: Could not fetch remote template 'include.yaml': Invalid URL scheme

The same exception is thrown when calling heat.engine.parser.preview_resources() from within a resource plugin (as this calls each resource's preview() method).

When http/s URLs are specified, the preview succeeds.

Full info: http://paste.openstack.org/show/115354/

[Steve Baker (steve-stevebaker)]

You really shouldn't be calling heat.engine.stack_resource.StackResource.preview() from within a resource plugin at all ever.

Could you describe why your resource wants to do this?

[Joe D'Andrea (jdandrea)]

I'm starting to discover that previewing from within a plugin is frowned upon, yes.

I was experimenting with dynamically adding metadata to resources that are included as a nested template. preview() lets me resolve intrinsics (to a point, since not everything is instantiated yet), made decisions, and then amend resource metadata. (... he said matter-of-factly as Steve went into shock. <!>)

Perhaps this is best handled outside of Heat. (I was originally looking to avoid a separate process.)

Meanwhile, I also saw the proposed change to deprecate HARestarter, which raises a sobering point: Heat Resources ultimately *orchestrate*. OpenStack resources *perform*. My resource experience is, in essence, performing. Moreover, resource isolation is the new reality in a convergence architecture: https://blueprints.launchpad.net/heat/+spec/convergence

Even so, apart from my own motivation, is it ok that nested file resolution does *not* work at the resource level, while http/s resolution does?

[Joe D'Andrea (jdandrea)]

Turns out it is/was a bug, fixed in time for Juno RC1:

https://bugs.launchpad.net/heat/+bug/1357433

[Joe D'Andrea (jdandrea)]

Q: Should the status of this be changed to closed/resolved because it is a duplicate? (I can't edit the status.)