cache zone names for MiqQueue create

We are concerned that newly created zones will not get into the cache quickly enough.
So this strategy is to lookup unknown zones every time.
Since this is not common, deciding to taking a hit here.

Author: kbrock

app/models/miq_queue.rb

@@ -105,7 +105,7 @@ def self.lower_priority?(p1, p2)
   serialize :args, Array
   serialize :miq_callback, Hash
 
-  validates :zone, :inclusion => {:in => proc { Zone.in_my_region.pluck(:name) }}, :allow_nil => true
+  validate :validate_zone_name
 
   STATE_READY   = 'ready'.freeze
   STATE_DEQUEUE = 'dequeue'.freeze
@@ -623,6 +623,16 @@ def self.display_name(number = 1)
 
   private
 
+  # NOTE: this will intentionally lookup missing zones every time
+  def validate_zone_name
+    if zone && !self.class.valid_zone_names[zone]
+      found = self.class.valid_zone_names[zone] = Zone.in_my_region.exists?(:name => zone)
+      errors.add(:zone, N_("Unknown Zone")) unless found
+    end
+  end
+
+  cache_with_timeout(:valid_zone_names, 1.minute) { Hash.new }
+
   def activate_miq_task(args)
     MiqTask.update_status(miq_task_id, MiqTask::STATE_ACTIVE, MiqTask::STATUS_OK, "Task starting") if miq_task_id
     params = args.first

spec/models/miq_queue_spec.rb

@@ -4,6 +4,40 @@
   let(:miq_server) { EvmSpecHelper.local_miq_server }
   let(:zone)       { miq_server.zone }
 
+  context "#validate" do
+    it "allows nil zones" do
+      msg = FactoryBot.build(:miq_queue)
+      expect(msg.zone).to be_nil
+      expect(msg).to be_valid
+    end
+
+    it "allows valid zone names" do
+      msg = FactoryBot.build(:miq_queue, :zone => zone.name)
+      expect(msg).to be_valid
+    end
+
+    it "complains about unknown zone names" do
+      msg = FactoryBot.build(:miq_queue, :zone => "#{zone.name}x")
+      expect(msg).not_to be_valid
+    end
+
+    it "only queries a single zone one time" do
+      # cache the value
+      msg = FactoryBot.build(:miq_queue, :zone => zone.name)
+      expect(msg).to be_valid
+      expect { expect(FactoryBot.build(:miq_queue, :zone => zone.name)).to be_valid }.not_to make_database_queries
+    end
+
+    it "can find new zones" do
+      # potentially load the cached
+      msg = FactoryBot.build(:miq_queue, :zone => zone.name)
+      expect(msg).to be_valid
+      zone2 = FactoryBot.create(:zone)
+      msg = FactoryBot.build(:miq_queue, :zone => zone2.name)
+      expect(msg).to be_valid
+    end
+  end
+
   context "#deliver" do
     before { miq_server }
     it "requires class_name" do