Move IsoDatastore from core

[nasark]

• since iso datastores are only used by oVirt/RHV, we can move its model from core and into the provider plugin
• added associations to model iso_images -> storage relationship

Depends on:

• Subclass IsoDatastore and transfer from core manageiq-providers-ovirt#621

@miq-bot add_labels pluggability/providers, technical debt, enhancement
@miq-bot assign @agrare

[kbrock]

Lets keep in mind that our view layer has trouble looking up these relationships if it is not defined in the base class that is used for the query.

meaning that after this change:

ExtManagementSystem.includes(:iso_datastore).all # fails
RedHat::Ovirt::ExtManagementSystem.includes(:iso_datastore).all # succeeds

Any views that are based upon EMS will no longer be able to display this data, even if only OVirt providers are displayed.

But that may not be a real use case and we may only be viewing these fields from an OVirt provider.

UPDATE: I am excited for this change.
I think we will be using includes(:datastores) instead, so my point is moot.

[agrare]

Love this because it opens us up to creating these from other provider storage types like VMware when we do a datastore ssa. This would make it a lot simpler to get a list of ISOs when doing vm reconfigure to connect a cdrom or provision from an ISO

[agrare]

@nasark can you double check that there are no more references to IsoDatastore?
E.g. I see

manageiq/app/models/ext_management_system.rb

Lines 995 to 998 in d178e29

	# @return [Boolean] true if a datastore exists for this type of ems
	def self.datastore?
	IsoDatastore.where(:ems_id => all).exists?
	end

isn't deleted by this PR

[kbrock]

may also want to grep for iso_datastore

found

app/models/miq_request_workflow.rb
1408:    template.try(:ext_management_system).try(:iso_datastore).try(:iso_images) || []

and noticed (but not sure the ramifications)

  supports_not :create_iso_datastore

[agrare]

Good catch @kbrock I think we'll want template.try(:ext_management_system).try(:iso_images) || [] with a has_many :iso_images, :through => :storages

[miq-bot]

Checked commits nasark/manageiq@d7081e7~...98977e0 with ruby 2.6.10, rubocop 1.28.2, haml-lint 0.35.0, and yamllint
5 files checked, 0 offenses detected
Everything looks fine. 🍪