Make for a dependent to decide whether the associated resource should be created dynamically

[metacosm]

There are cases where whether or not a resource needs to be created / updated / deleted, depends on the content of the primary (or even secondary) resource(s). This isn't currently possible but should be supported. A relatively easy to support this use case would be to introduce isCreatable(P primary, Context context) (and associated) methods on AbstractDependentResource so that implementations could provide their own logic if needed.

[metacosm]

See https://github.com/java-operator-sdk/java-operator-sdk/pull/1111/files#r840509251

[csviri]

IMO this should be covered by Conditions, not decided dynamically.

The current logic is that if a Dependent Resource is marked with Creator, Updater , Deleter interface, the respected operation should be executed. It could be very confusing, if something is marked for example Creator, reconcile() is called but its not created.

[csviri]

I changed the design proposal a bit here: #850 (comment)

Basically this will cover this issue nicely.

[csviri]

This is now covered with reconcileCondition: #850

[csviri]

if no objections will close this issue, since it is now implemented as reconcilePrecondition.