Adds event tracker helper for controllers

Adds controller concern to track events
inside controller.
Allows to call #track_event() to track
arbitrary events.

app/controllers/application_controller.rb

@@ -13,6 +13,7 @@ class ApplicationController < ActionController::Base
   include WithPerformanceBar
   include SessionlessAuthentication
   include ConfirmEmailWarning
+  include Gitlab::Tracking::ControllerConcern
 
   before_action :authenticate_user!
   before_action :enforce_terms!, if: :should_enforce_terms?

lib/gitlab/tracking.rb

@@ -6,6 +6,17 @@ module Gitlab
   module Tracking
     SNOWPLOW_NAMESPACE = 'gl'
 
+    module ControllerConcern
+      extend ActiveSupport::Concern
+
+      protected
+
+      def track_event(action = action_name, **args)
+        category = args.delete(:category) || self.class.name
+        Gitlab::Tracking.event(category, action.to_s, **args)
+      end
+    end
+
     class << self
       def enabled?
         Gitlab::CurrentSettings.snowplow_enabled?

spec/controllers/application_controller_spec.rb

@@ -56,6 +56,8 @@ describe ApplicationController do
     end
   end
 
+  it_behaves_like 'a Trackable Controller'
+
   describe '#add_gon_variables' do
     before do
       Gon.clear

spec/support/shared_examples/trackable_shared_examples.rb

+# frozen_string_literal: true
+
+shared_examples 'a Trackable Controller' do
+  describe '#track_event' do
+    before do
+      sign_in user
+    end
+
+    context 'with no params' do
+      controller(described_class) do
+        def index
+          track_event
+          head :ok
+        end
+      end
+
+      it 'tracks the action name' do
+        expect(Gitlab::Tracking).to receive(:event).with('AnonymousController', 'index', {})
+        get :index
+      end
+    end
+
+    context 'with params' do
+      controller(described_class) do
+        def index
+          track_event('some_event', category: 'SomeCategory', label: 'errorlabel')
+          head :ok
+        end
+      end
+
+      it 'tracks with the specified param' do
+        expect(Gitlab::Tracking).to receive(:event).with('SomeCategory', 'some_event', label: 'errorlabel')
+        get :index
+      end
+    end
+  end
+end