Renaming maintenance zone's string associations.

Like Job,MiqTask,MiqQueue + raises error when renaming existing zone to another existing.

db/migrate/20180626125655_rename_user_maintenance_zone_record.rb

@@ -1,30 +1,96 @@
 class RenameUserMaintenanceZoneRecord < ActiveRecord::Migration[5.0]
+  class UniqueWithinRegionValidator < ActiveModel::EachValidator
+    def validate_each(record, attribute, value)
+      return if value.nil?
+      match_case = options.key?(:match_case) ? options[:match_case] : true
+      record_base_class = record.class.base_class
+      field_matches =
+        if match_case
+          record_base_class.where(attribute => value)
+        else
+          record_base_class.where(record_base_class.arel_attribute(attribute).lower.eq(value.downcase))
+        end
+      unless field_matches.in_region(record.region_id).where.not(:id => record.id).empty?
+        record.errors.add(attribute, "is not unique within region #{record.region_id}")
+      end
+    end
+  end
+
   class Zone < ActiveRecord::Base
     include ActiveRecord::IdRegions
 
-    validates_presence_of   :name
+    validates_presence_of :name
+    validates :name, "rename_user_maintenance_zone_record/unique_within_region" => true
 
     MAINTENANCE_ZONE_NAME = "__maintenance__".freeze
   end
 
+  class Job < ActiveRecord::Base
+    self.inheritance_column = :_type_disabled
+
+    belongs_to :miq_task, :dependent => :delete
+    after_update_commit :update_linked_task
+
+    def update_linked_task
+      miq_task&.update_attributes!(:zone => zone)
+    end
+  end
+
+  class MiqTask < ActiveRecord::Base
+    has_one :job, :dependent => :destroy
+    has_one :miq_queue
+  end
+
+  class MiqQueue < ActiveRecord::Base
+    belongs_to :miq_task
+  end
+
   def up
     say_with_time("Renaming user-defined Maintenance Zone") do
-      zone = Zone.in_my_region.where(:name => Zone::MAINTENANCE_ZONE_NAME).first
+      zone = Zone.in_my_region.find_by(:name => Zone::MAINTENANCE_ZONE_NAME)
       if zone.present?
-        zone.name = "#{zone.name}_0"
-        zone.save
+        # STEP 1 - rename zone
+        zone.name = "#{zone.name}_#{Zone.my_region_number}"
+        if zone.save
+          # STEP 2 - rename string associations
+          rename_string_associations(Zone::MAINTENANCE_ZONE_NAME, zone.name)
+        else
+          raise "Zone '#{Zone::MAINTENANCE_ZONE_NAME}' cannot be renamed to #{zone.name}. Reason: #{zone.errors.messages.inspect}"
+        end
       end
     end
   end
 
   def down
     say_with_time("Renaming user-defined Maintenance Zone") do
-      Zone.in_my_region.where(:name => Zone::MAINTENANCE_ZONE_NAME).where(:visible => false).destroy_all
+      Zone.in_my_region.where(:name    => Zone::MAINTENANCE_ZONE_NAME,
+                              :visible => false).destroy_all
 
-      orig = Zone.in_my_region.where(:name => "#{Zone::MAINTENANCE_ZONE_NAME}_0").first
+      user_zone_name = "#{Zone::MAINTENANCE_ZONE_NAME}_#{Zone.my_region_number}"
+      orig = Zone.in_my_region.find_by(:name => user_zone_name)
       if orig.present?
-        orig.name = orig.name[0..orig.name.size - 3]
-        orig.save
+        # STEP 1 - rename user's zone back
+        orig.name = Zone::MAINTENANCE_ZONE_NAME
+        if orig.save
+          # STEP 2 - rename string associations
+          rename_string_associations(user_zone_name, Zone::MAINTENANCE_ZONE_NAME)
+        else
+          raise "Zone '#{user_zone_name}' cannot be renamed to #{Zone::MAINTENANCE_ZONE_NAME}. Reason: #{orig.errors.messages.inspect}"
+        end
+      end
+    end
+  end
+
+  private
+
+  def rename_string_associations(old_zone_name, new_zone_name)
+    [Job, MiqQueue].each do |klass|
+      klass.where(:zone => old_zone_name).each do |record|
+        record.zone = new_zone_name
+        unless record.save
+          # This is not critical, migrations can continue
+          say("WARN: #{klass.name}'s (id: #{record.id}) zone not renamed. Reason: #{record.errors.messages.inspect}")
+        end
       end
     end
   end

spec/migrations/20180626125655_rename_user_maintenance_zone_record_spec.rb

@@ -2,6 +2,9 @@
 
 describe RenameUserMaintenanceZoneRecord do
   let(:zone_stub) { migration_stub(:Zone) }
+  let(:job_stub) { migration_stub(:Job) }
+  let(:miq_task_stub) { migration_stub(:MiqTask) }
+  let(:miq_queue_stub) { migration_stub(:MiqQueue) }
 
   let(:remote_region_start) do
     anonymous_class_with_id_regions.rails_sequence_start +
@@ -15,7 +18,7 @@
       migrate
       orig.reload
 
-      expect(orig.name).to eq("#{zone_stub::MAINTENANCE_ZONE_NAME}_0")
+      expect(orig.name).to eq("#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
     end
 
     it "does not rename zone from remote regions" do
@@ -29,6 +32,47 @@
 
       expect(user_zone.name).to eq(zone_stub::MAINTENANCE_ZONE_NAME)
     end
+
+    it "renames string associations belonging to former maintenance zone" do
+      orig = zone_stub.create!(:name => zone_stub::MAINTENANCE_ZONE_NAME)
+      assoc = {}
+      assoc[:miq_task]  = miq_task_stub.create!(:zone => orig.name)
+      assoc[:job]       = job_stub.create!(:zone => orig.name, :miq_task => assoc[:miq_task])
+      assoc[:miq_queue] = miq_queue_stub.create!(:zone => orig.name, :miq_task => assoc[:miq_task])
+
+      migrate
+      orig.reload
+      assoc.each_value do |record|
+        record.reload
+        expect(record.zone).to eq(orig.name)
+      end
+    end
+
+    it "does not rename unrelated jobs, tasks and queues" do
+      orig = zone_stub.create!(:name => zone_stub::MAINTENANCE_ZONE_NAME)
+      other_zone_name = "Some other zone"
+      other = zone_stub.create!(:name => other_zone_name)
+
+      assoc = {}
+      assoc[:miq_task]  = miq_task_stub.create!(:zone => other.name)
+      assoc[:job]       = job_stub.create!(:zone => other.name, :miq_task => assoc[:miq_task])
+      assoc[:miq_queue] = miq_queue_stub.create!(:zone => other.name, :miq_task => assoc[:miq_task])
+
+      migrate
+      orig.reload
+      other.reload
+      expect(other.name).to eq(other_zone_name)
+      assoc.each_value do |record|
+        record.reload
+        expect(record.zone).to eq(other_zone_name)
+      end
+    end
+
+    it "raises error when original zone renamed to existing one" do
+      zone_stub.create!(:name => zone_stub::MAINTENANCE_ZONE_NAME)
+      zone_stub.create!(:name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
+      expect { migrate }.to raise_error(/is not unique within region/)
+    end
   end
 
   migration_context :down do
@@ -43,7 +87,7 @@
     end
 
     it "renames original maintenance zone back" do
-      orig = zone_stub.create!(:name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_0")
+      orig = zone_stub.create!(:name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
 
       migrate
       orig.reload
@@ -55,12 +99,27 @@
       id = remote_region_start
 
       user_zone = zone_stub.create!(:id   => id,
-                                    :name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_0")
+                                    :name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
 
       migrate
       user_zone.reload
 
-      expect(user_zone.name).to eq("#{zone_stub::MAINTENANCE_ZONE_NAME}_0")
+      expect(user_zone.name).to eq("#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
+    end
+
+    it "renames string associations belonging to original maintenance zone back" do
+      orig = zone_stub.create!(:name => "#{zone_stub::MAINTENANCE_ZONE_NAME}_#{zone_stub.my_region_number}")
+      assoc = {}
+      assoc[:miq_task]  = miq_task_stub.create!(:zone => orig.name)
+      assoc[:job]       = job_stub.create!(:zone => orig.name, :miq_task => assoc[:miq_task])
+      assoc[:miq_queue] = miq_queue_stub.create!(:zone => orig.name, :miq_task => assoc[:miq_task])
+
+      migrate
+      orig.reload
+      assoc.each_value do |record|
+        record.reload
+        expect(record.zone).to eq(orig.name)
+      end
     end
   end
 end