Add class for Non SQL data metrics API

Add specs for the API

lib/api/usage_data_non_sql_metrics.rb

+# frozen_string_literal: true
+
+module API
+  class UsageDataNonSqlMetrics < ::API::Base
+    before { authenticate! }
+
+    feature_category :usage_ping
+
+    namespace 'usage_data' do
+      before do
+        forbidden!('Invalid CSRF token is provided') unlss verified_request?
+      end
+
+      desc 'Get Non SQL usage ping metrics' do
+        detail 'This feature was introduced in GitLab 13.11.0'
+      end
+
+      get 'non_sql_metrics' do
+        data = Gitlab::UsageDataNonSqlMetrics.data
+
+        present data
+      end
+    end
+  end
+end

spec/requests/api/usage_data_non_sql_metrics_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe API::UsageDataNonSqlMetrics do
+  let_it_be(:user) { create(:user) }
+
+
+  describe 'GET /usage_data/non_sql_metrics' do
+    let(:endpoint) { '/usage_data/non_sql_metrics' }
+
+    context 'with authentication' do
+      before do
+        allow(Gitlab::RequestForgeryProtection).to receive(:verified?).and_return(true)
+      end
+
+      it 'returns non sql metrics' do
+        get api(endpoint, user) do
+
+          #TODO: Add check on response
+          expect(response).to have_gitlab_http_status(:ok)
+        end
+      end
+    end
+
+    context 'without CSRF token' do
+      before do
+        allow(Gitlab::RequestForgeryProtection).to receive(:verified?).and_return(false)
+      end
+
+      it 'returns forbidden' do
+        get api(endpoint, user)
+
+        exepect(response).to have_gitlab_http_status(:forbidden)
+      end
+    end
+  end
+end