Move PrometheusController to Prometheus module

app/controllers/projects/prometheus/metrics_controller.rb

+module Projects
+  module Prometheus
+    class MetricsController < Projects::ApplicationController
+      before_action :authorize_read_project!
+      before_action :require_prometheus_metrics!
+
+      def active
+        respond_to do |format|
+          format.json do
+            matched_metrics = project.prometheus_service.matched_metrics || {}
+
+            if matched_metrics.any?
+              render json: matched_metrics
+            else
+              head :no_content
+            end
+          end
+        end
+      end
+
+      private
+
+      def require_prometheus_metrics!
+        render_404 unless project.prometheus_service.present?
+      end
+    end
+  end
+end

app/views/projects/services/prometheus/_show.html.haml

@@ -10,7 +10,7 @@
       = link_to s_('PrometheusService|More information'), help_page_path('user/project/integrations/prometheus')
 
   .col-lg-9
-    .panel.panel-default.js-panel-monitored-metrics{ data: { "active-metrics" => "#{project_prometheus_active_metrics_path(@project, :json)}" } }
+    .panel.panel-default.js-panel-monitored-metrics{ data: { "active-metrics" => "#{active_namespace_project_prometheus_metrics_path(@project, :json)}" } }
       .panel-heading
         %h3.panel-title
           = s_('PrometheusService|Monitored')

config/routes/project.rb

@@ -74,9 +74,10 @@ constraints(ProjectUrlConstrainer.new) do
 
       namespace :prometheus do
         resources :metrics, constraints: { id: /[^\/]+/ }, only: [:index, :show, :edit, :update, :destroy] do
-          post :validate_query
-          get :active
+          post :validate_query, on: :collection
+          get :active, on: :collection
         end
+
         get :active_metrics
       end
 

spec/controllers/projects/prometheus_controller_spec.rb → spec/controllers/projects/prometheus/metrics_controller_spec.rb

 require('spec_helper')
 
-describe Projects::PrometheusController do
+describe Projects::Prometheus::MetricsController do
   let(:user) { create(:user) }
   let!(:project) { create(:project) }
 
@@ -14,7 +14,7 @@ describe Projects::PrometheusController do
     sign_in(user)
   end
 
-  describe 'GET #active_metrics' do
+  describe 'GET #active' do
     context 'when prometheus metrics are enabled' do
       context 'when data is not present' do
         before do
@@ -22,7 +22,7 @@ describe Projects::PrometheusController do
         end
 
         it 'returns no content response' do
-          get :active_metrics, project_params(format: :json)
+          get :active, project_params(format: :json)
 
           expect(response).to have_gitlab_http_status(204)
         end
@@ -36,7 +36,7 @@ describe Projects::PrometheusController do
         end
 
         it 'returns no content response' do
-          get :active_metrics, project_params(format: :json)
+          get :active, project_params(format: :json)
 
           expect(response).to have_gitlab_http_status(200)
           expect(json_response).to eq(sample_response.deep_stringify_keys)
@@ -45,7 +45,7 @@ describe Projects::PrometheusController do
 
       context 'when requesting non json response' do
         it 'returns not found response' do
-          get :active_metrics, project_params
+          get :active, project_params
 
           expect(response).to have_gitlab_http_status(404)
         end