Expire etag cache to force environments.json reload

app/assets/javascripts/environments/components/deploy_board_component.vue

@@ -41,7 +41,7 @@
         return !this.isLoading && this.isEmpty;
       },
       instanceTitle() {
-        return n__('Instance', 'Instances', this.deployBoardData.instances);
+        return n__('Instance', 'Instances', this.deployBoardData.instances.length);
       },
       projectName() {
         return '<projectname>';

app/controllers/projects/environments_controller.rb

@@ -7,7 +7,7 @@ class Projects::EnvironmentsController < Projects::ApplicationController
   before_action :authorize_admin_environment!, only: [:terminal, :terminal_websocket_authorize]
   before_action :environment, only: [:show, :edit, :update, :stop, :terminal, :terminal_websocket_authorize, :metrics]
   before_action :verify_api_request!, only: :terminal_websocket_authorize
-  before_action :refresh_rollout_status, only: [:index]
+  before_action :expire_etag_cache, only: [:index]
 
   def index
     @environments = project.environments
@@ -148,8 +148,13 @@ class Projects::EnvironmentsController < Projects::ApplicationController
     Gitlab::Workhorse.verify_api_request!(request.headers)
   end
 
-  def refresh_rollout_status
-    environment.rollout_status
+  def expire_etag_cache
+    return if request.format.json?
+
+    # this forces to reload json content
+    Gitlab::EtagCaching::Store.new.tap do |store|
+      store.touch(project_environments_path(project, format: :json))
+    end
   end
 
   def environment_params

app/models/concerns/reactive_caching.rb

@@ -80,9 +80,11 @@ module ReactiveCaching
       locking_reactive_cache(*args) do
         within_reactive_cache_lifetime(*args) do
           enqueuing_update(*args) do
-            value = calculate_reactive_cache(*args)
-            Rails.cache.write(full_reactive_cache_key(*args), value)
-            reactive_cache_updated(*args)
+            key = full_reactive_cache_key(*args)
+            new_value = calculate_reactive_cache(*args)
+            old_value = Rails.cache.read(key)
+            Rails.cache.write(key, new_value)
+            reactive_cache_updated(*args) if new_value != old_value
           end
         end
       end

ee/app/models/concerns/ee/kubernetes_service.rb

@@ -19,9 +19,9 @@ module EE
     def reactive_cache_updated
       super
 
-      Gitlab::EtagCaching::Store.new.tap do |store|
+      ::Gitlab::EtagCaching::Store.new.tap do |store|
         store.touch(
-          Gitlab::Routing.url_helpers.project_environments_path(project, format: :json))
+          ::Gitlab::Routing.url_helpers.project_environments_path(project, format: :json))
       end
     end
 

spec/controllers/projects/environments_controller_spec.rb

@@ -23,6 +23,13 @@ describe Projects::EnvironmentsController do
 
         expect(response).to have_http_status(:ok)
       end
+
+      it 'expires etag cache to force reload environments list' do
+        expect_any_instance_of(Gitlab::EtagCaching::Store)
+          .to receive(:touch).with(project_environments_path(project, format: :json))
+
+        get :index, environment_params
+      end
     end
 
     context 'when requesting JSON response for folders' do

spec/models/concerns/reactive_caching_spec.rb

@@ -115,10 +115,11 @@ describe ReactiveCaching, :use_clean_rails_memory_store_caching do
         go!
       end
 
-      it "calls a reactive_cache_updated after updated" do
-        expect(instance).to receive(:reactive_cache_updated)
+      it "calls a reactive_cache_updated only once if content did not change on subsequent update" do
+        expect(instance).to receive(:calculate_reactive_cache).twice
+        expect(instance).to receive(:reactive_cache_updated).once
 
-        go!
+        2.times { instance.exclusively_update_reactive_cache! }
       end
 
       context 'and #calculate_reactive_cache raises an exception' do