Display a deprecated message when Service uses plugin deployment

app/models/service.rb

@@ -521,6 +521,11 @@ def can_use_backends?
     proxy.apicast_configuration_driven && !proxy.service_mesh_integration?
   end
 
+  # TODO: Remove this when no one use plugins
+  def plugin_deployment?
+    DeploymentOption.plugins.include?(deployment_option)
+  end
+
   private
 
   def archive_as_deleted

app/views/api/services/settings_apiap.html.slim

@@ -1,4 +1,5 @@
 - content_for :sublayout_title, 'Settings'
+
 = semantic_form_for @service, :url => admin_service_path(@service) do |form|
   = render :partial => 'api/services/forms/integration_settings_apiap', :locals => {:form => form}
   = form.buttons do

app/views/layouts/api/_service.html.slim

@@ -2,4 +2,7 @@
   h1
     = yield :sublayout_title
 
+/ TODO: Remove this when no one use plugins
+= render 'shared/service/deprecated_plugin_warning'
+
 = yield

app/views/shared/service/_deprecated_plugin_warning.html.slim

@@ -0,0 +1,4 @@
+- if @service&.plugin_deployment?
+  .deprecated_plugin_message
+    p.InfoBox--notice.InfoBox
+      i This Product currently uses a plugin as the deployment option. Your integration will keep on working but we no longer support plugins.

test/unit/helpers/services_helper_test.rb

@@ -7,8 +7,5 @@ def test_show_mappings?
 
     @service.deployment_option = 'hosted'
     assert show_mappings?
-
-    @service.deployment_option = 'plugin_java'
-    refute show_mappings?
   end
 end

test/unit/service_test.rb

@@ -318,6 +318,16 @@ def test_update_account_default_service
     assert_raise(ActiveRecord::RecordNotFound) { service.reload }
   end
 
+  test '#plugin_deployment? returns true when using a plugin as deployment option' do
+    service = FactoryBot.build(:service, deployment_option: 'plugin_ruby')
+
+    assert service.plugin_deployment?
+
+    service = FactoryBot.build(:service, deployment_option: 'hosted')
+
+    refute service.plugin_deployment?
+  end
+
   def test_default_service_plan
     service = FactoryBot.build(:simple_service)
     service.account.settings.service_plans_ui_visible = true