Utility function to update PxeMenu list

app/models/pxe_server.rb

@@ -198,6 +198,16 @@ def delete_provisioning_files(pxe_image, mac_address, windows_image = nil, custo
     _log.info("#{log_message}...Complete")
   end
 
+  def ensure_menu_list(menu_list)
+    current_menus = pxe_menus.map(&:file_name)
+    to_destroy = current_menus - menu_list
+    to_create = menu_list - current_menus
+    transaction do
+      pxe_menus.where(:file_name => to_destroy).destroy_all
+      to_create.each { |menu| pxe_menus << PxeMenu.create!(:file_name => menu) }
+    end
+  end
+
   def self.display_name(number = 1)
     n_('PXE Server', 'PXE Servers', number)
   end

spec/models/pxe_server_spec.rb

@@ -4,6 +4,8 @@
     @pxe_server = FactoryBot.create(:pxe_server)
   end
 
+  subject { FactoryBot.create(:pxe_server) }
+
   context "#sync_images_queue" do
     it "should create a queue entry with the correct parameters" do
       msg = @pxe_server.sync_images_queue
@@ -310,4 +312,79 @@ def file_write(file, contents)
       expect(@pxe_server.discovered_pxe_images).to eq([@discovered_image])
     end
   end
+
+  describe '#ensure_menu_list' do
+    context 'when creating server' do
+      subject { FactoryBot.build(:pxe_server) }
+      it 'existing menus remain' do
+        subject.ensure_menu_list(%w[new])
+        subject.save!
+        expect(PxeMenu.count).to eq(1)
+        expect(subject.pxe_menus.count).to eq(1)
+      end
+    end
+
+    context 'when updating server' do
+      let!(:pxe_menu_1)  { FactoryBot.create(:pxe_menu, :pxe_server => subject, :file_name => 'existing1') }
+      let!(:pxe_image_1) { FactoryBot.create(:pxe_image, :pxe_server => subject, :pxe_menu => pxe_menu_1) }
+      let!(:pxe_menu_2)  { FactoryBot.create(:pxe_menu, :pxe_server => subject, :file_name => 'existing2') }
+      let!(:pxe_image_2) { FactoryBot.create(:pxe_image, :pxe_server => subject, :pxe_menu => pxe_menu_2) }
+
+      context 'when nothing changed' do
+        let(:menus) { %w[existing1 existing2] }
+        it 'all menus remain' do
+          subject.ensure_menu_list(menus)
+          expect(PxeMenu.count).to eq(2)
+          expect(PxeImage.count).to eq(2)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_1.id)).to eq(pxe_menu_1)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_2.id)).to eq(pxe_menu_2)
+        end
+      end
+
+      context 'when new menus are added' do
+        let(:menus) { %w[existing1 existing2 new] }
+        it 'existing menus remain' do
+          subject.ensure_menu_list(menus)
+          expect(PxeMenu.count).to eq(3)
+          expect(PxeImage.count).to eq(2)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_1.id)).to eq(pxe_menu_1)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_2.id)).to eq(pxe_menu_2)
+          expect(subject.pxe_menus.find_by(:file_name => 'new')).not_to be_nil
+        end
+      end
+
+      context 'when menus are deleted' do
+        let(:menus) { %w[existing1] }
+        it 'menus are destroyed' do
+          subject.ensure_menu_list(menus)
+          expect(PxeMenu.count).to eq(1)
+          expect(PxeImage.count).to eq(1)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_1.id)).to eq(pxe_menu_1)
+          expect(subject.pxe_menus.find_by(:id => pxe_menu_2.id)).to be_nil
+        end
+      end
+
+      context 'when different menus are specified' do
+        let(:menus) { %w[new] }
+        it 'old menus are destroyed' do
+          subject.ensure_menu_list(menus)
+          expect(PxeMenu.count).to eq(1)
+          expect(PxeImage.count).to eq(0)
+          expect(subject.pxe_menus.find_by(:file_name => 'new')).not_to be_nil
+        end
+      end
+    end
+
+    context 'when two servers have similar menu' do
+      let(:other_server) { FactoryBot.create(:pxe_server) }
+      it 'they are not mixed up' do
+        subject.ensure_menu_list(%w[new])
+        other_server.ensure_menu_list(%w[new])
+        expect(PxeMenu.count).to eq(2)
+        expect(subject.pxe_menus.count).to eq(1)
+        expect(other_server.pxe_menus.count).to eq(1)
+        expect(subject.pxe_menus.map(&:id)).not_to eq(other_server.pxe_menus.map(&:id))
+      end
+    end
+  end
 end