Code review comment for lp://qastaging/~johannes.erdfelt/nova/deferred-delete-instance

blamar: the rest of delete and force_delete are identical, but the preconditions are different. Both require different states to perform the action requested. This is to ensure that if you delete an instance twice, it doesn't get hard deleted. And that if the forceDelete action is called, it doesn't do a hard delete unless it's already in a soft delete state.

The logic can be pushed up into the OS API level, but that leaves the compute API level open to being called incorrectly.

An alternative would be to pass a flag to delete() to differentiate between the two. Or the common logic could be split out to a _delete() method leaving delete() and force_delete() to just check with the correct state.

After thinking about it, I'm leaning towards a flag to delete().