Clean up mapped tenants after a CloudManager is destroyed

[mansam]

Tenants created by cloud tenant mapping are not destroyed when their provider is destroyed, which prevents tenant mapping from working if the provider is readded with the same name. This PR causes the mapped tenant tree to be destroyed along with the provider.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1547740

[mansam]

@agrare do you know who could review this?

[agrare]

You should be able to just do after_destroy :destroy_mapped_tenants

[agrare]

Is it possible for these to be shared by any other providers?

[mansam]

I don't believe so, the mappings should be unique to one provider as far as I understand it.

[agrare]

@mansam could you just add a :dependent => :destroy to the has_one :source_tenant and let cascade deletion take care of the rest?

[mansam]

@agrare I'll give that a shot, I hadn't considered it.

[mansam]

Turns out I had actually already tried that when I first worked on this in August and just forgot. Trying to use :dependent => :destroy hits a constraint on destroying mapped tenants, hence having to destroy the subtenants first. I'm not sure if there would be a better way to get around this.

     Failure/Error: raise _("A tenant created by tenant mapping cannot be deleted") if source
     
     RuntimeError:
       A tenant created by tenant mapping cannot be deleted
     # ./app/models/tenant.rb:330:in `ensure_can_be_destroyed'
     # ./app/models/ext_management_system.rb:496:in `destroy'
     # ./spec/models/manageiq/providers/cloud_manager_spec.rb:200:in `block (5 levels) in <top (required)>'

[miq-bot]

Checked commit mansam@f58bfc9 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 0 offenses detected
Everything looks fine. 🍪

[agrare]

Hm okay so you'd have to have some before_destroy to clear the sub-tenants first, and there isn't an actual relation for the sub tenants so I was hoping we could dependent destroy those as well but I guess not.

[mansam]

@miq-bot add_label hammer/yes

[agrare]

Sorry @mansam I kicked the tests then forgot to come back and check if it passed

[mansam]

@agrare no worries, I figured you'd get to it eventually :) thanks for the merge!

[simaishi]

Hammer backport details:

$ git log -1
commit 051d05f4ea7f061721720b8202bd3b7a96ec6dce
Author: Adam Grare <[email protected]>
Date:   Wed Oct 17 14:26:15 2018 -0400

    Merge pull request #17866 from mansam/cleanup-mapped-tenants-after-ems-destroy
    
    Clean up mapped tenants after a CloudManager is destroyed
    
    (cherry picked from commit 89a1ebf0dadecf532b557f74adbb68dce82c1dae)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1547740