Add a block argument in track_redis_hll_event

Add specs for the change

app/controllers/concerns/redis_tracking.rb

@@ -10,26 +10,31 @@
 # track_redis_hll_event :index, :show, name: 'i_analytics_dev_ops_score'
 #
 # You can also pass custom conditions using `if:`, using the same format as with Rails callbacks.
+# You can also pass an optional block that calculates and returns a custom id to track.
 module RedisTracking
   extend ActiveSupport::Concern
 
   class_methods do
-    def track_redis_hll_event(*controller_actions, name:, if: nil)
+    def track_redis_hll_event(*controller_actions, name:, if: nil, &block)
       custom_conditions = Array.wrap(binding.local_variable_get('if'))
       conditions = [:trackable_request?, *custom_conditions]
 
       after_action only: controller_actions, if: conditions do
-        track_unique_redis_hll_event(name)
+        track_unique_redis_hll_event(name, &block)
       end
     end
   end
 
   private
 
-  def track_unique_redis_hll_event(event_name)
-    return unless visitor_id
+  def track_unique_redis_hll_event(event_name, &block)
+    custom_id = block_given? ? yield(self) : nil
 
-    Gitlab::UsageDataCounters::HLLRedisCounter.track_event(event_name, values: visitor_id)
+    unique_id = custom_id || visitor_id
+
+    return unless unique_id
+
+    Gitlab::UsageDataCounters::HLLRedisCounter.track_event(event_name, values: unique_id)
   end
 
   def trackable_request?

doc/development/usage_ping/index.md

@@ -502,13 +502,14 @@ Implemented using Redis methods [PFADD](https://redis.io/commands/pfadd) and [PF
 
 Use one of the following methods to track events:
 
-1. Track event in controller using `RedisTracking` module with `track_redis_hll_event(*controller_actions, name:, if: nil)`.
+1. Track event in controller using `RedisTracking` module with `track_redis_hll_event(*controller_actions, name:, if: nil, &block)`.
 
    Arguments:
 
    - `controller_actions`: controller actions we want to track.
    - `name`: event name.
    - `if`: optional custom conditions, using the same format as with Rails callbacks.
+   - `&block`: optional block that computes and returns the `custom_id` that we want to track. This will override the `visitor_id`.
 
    Example usage:
 

spec/controllers/concerns/redis_tracking_spec.rb

@@ -9,8 +9,8 @@ RSpec.describe RedisTracking do
     include RedisTracking
 
     skip_before_action :authenticate_user!, only: :show
-    track_redis_hll_event :index, :show, name: 'g_compliance_approval_rules',
-      if: [:custom_condition_one?, :custom_condition_two?]
+    track_redis_hll_event(:index, :show, name: 'g_compliance_approval_rules',
+      if: [:custom_condition_one?, :custom_condition_two?]) { |controller| controller.get_custom_id }
 
     def index
       render html: 'index'
@@ -24,6 +24,10 @@ RSpec.describe RedisTracking do
       render html: 'show'
     end
 
+    def get_custom_id
+      'some_custom_id'
+    end
+
     private
 
     def custom_condition_one?
@@ -92,19 +96,15 @@ RSpec.describe RedisTracking do
     end
   end
 
-  context 'when user is not logged in and there is a visitor_id' do
+  context 'when user is not logged in' do
     let(:visitor_id) { SecureRandom.uuid }
 
-    before do
-      routes.draw { get 'show' => 'anonymous#show' }
-    end
-
-    it 'tracks the event' do
+    it 'tracks the event when there is a visitor id' do
       cookies[:visitor_id] = { value: visitor_id, expires: 24.months }
 
       expect_tracking
 
-      get :show
+      get :show, params: { id: 1 }
     end
   end
 
@@ -114,5 +114,19 @@ RSpec.describe RedisTracking do
 
       get :index
     end
+
+    it 'tracks the event when there is custom id' do
+      expect_tracking
+
+      get :show, params: { id: 1 }
+    end
+
+    it 'does not track the event when there is no custom id' do
+      expect(controller).to receive(:get_custom_id).and_return(nil)
+
+      expect_no_tracking
+
+      get :show, params: { id: 2 }
+    end
   end
 end