Add usage_data_api feature

config/feature_flags/development/usage_data_api.yml

+---
+name: usage_data_api
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/41301
+rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/235459
+group: group::telemetry
+type: development
+default_enabled: true

lib/api/usage_data.rb

@@ -14,6 +14,10 @@ module API
     end
 
     namespace 'usage_data' do
+      before do
+        not_found! unless Feature.enabled?(:usage_data_api, default_enabled: true)
+      end
+
       desc 'Track usage data events' do
         detail 'This feature was introduced in GitLab 13.4.'
       end
@@ -22,6 +26,7 @@ module API
         requires :name, type: String, desc: 'The event name it should be tracked'
         requires :values, type: Array, desc: 'The values counted'
       end
+
       post 'increment_unique_values' do
         event_name = params[:name]
         values = params[:values]

spec/requests/api/usage_data_spec.rb

@@ -10,6 +10,16 @@ RSpec.describe API::UsageData do
     let(:known_event) { 'g_compliance_dashboard' }
     let(:unknown_event) { 'unknown' }
 
+    context 'usage_data_api feature not enabled' do
+      it 'retruns not_found' do
+        stub_feature_flags(usage_data_api: false)
+
+        post api(endpoint, user), params: { values: [user.id] }
+
+        expect(response).to have_gitlab_http_status(:not_found)
+      end
+    end
+
     context 'without authentication' do
       it 'returns 401 response' do
         post api(endpoint), params: { values: [user.id] }
@@ -18,7 +28,11 @@ RSpec.describe API::UsageData do
       end
     end
 
-    context 'without authentication' do
+    context 'with authentication' do
+      before do
+        stub_feature_flags(usage_data_api: true)
+      end
+
       context 'when name is missing from params' do
         it 'returns bad request' do
           post api(endpoint, user), params: { values: [user.id] }