Track work item creation

Implement model level tracking of when a work item is creted.
Tracking issue creation at the same time is intentional

app/models/work_item.rb

@@ -7,4 +7,12 @@ class WorkItem < Issue
   def noteable_target_type_name
     'issue'
   end
+
+  private
+
+  def record_create_action
+    super
+
+    Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter.track_work_item_created_action(author: author)
+  end
 end

config/metrics/counts_28d/20220221210352_users_creating_work_items_monthly.yml

+---
+key_path: redis_hll_counters.work_items.users_creating_work_items_monthly
+description: Unique users creating work items
+product_category: team planning
+product_section: dev
+product_stage: plan
+product_group: group::project management
+value_type: number
+status: active
+milestone: '14.9'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81201
+time_frame: 28d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - users_creating_work_items
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate

config/metrics/counts_7d/20220221210026_users_creating_work_items_weekly.yml

+---
+key_path: redis_hll_counters.work_items.users_creating_work_items_weekly
+description: Unique users creating work items
+product_category: team planning
+product_section: dev
+product_stage: plan
+product_group: group::project management
+value_type: number
+status: active
+milestone: '14.9'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/81201
+time_frame: 7d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - users_creating_work_items
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate

lib/gitlab/usage_data_counters/known_events/work_items.yml

@@ -4,3 +4,8 @@
   redis_slot: users
   aggregation: weekly
   feature_flag: track_work_items_activity
+- name: users_creating_work_items
+  category: work_items
+  redis_slot: users
+  aggregation: weekly
+  feature_flag: track_work_items_activity

lib/gitlab/usage_data_counters/work_item_activity_unique_counter.rb

@@ -3,9 +3,14 @@
 module Gitlab
   module UsageDataCounters
     module WorkItemActivityUniqueCounter
+      WORK_ITEM_CREATED = 'users_creating_work_items'
       WORK_ITEM_TITLE_CHANGED = 'users_updating_work_item_title'
 
       class << self
+        def track_work_item_created_action(author:)
+          track_unique_action(WORK_ITEM_CREATED, author)
+        end
+
         def track_work_item_title_changed_action(author:)
           track_unique_action(WORK_ITEM_TITLE_CHANGED, author)
         end

spec/lib/gitlab/usage_data_counters/work_item_activity_unique_counter_spec.rb

@@ -17,16 +17,12 @@ RSpec.describe Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter, :clean_
     end
   end
 
-  describe '.track_work_item_title_changed_action' do
-    subject(:track_event) { described_class.track_work_item_title_changed_action(author: user) }
-
-    let(:event_name) { described_class::WORK_ITEM_TITLE_CHANGED }
-
+  shared_examples 'work item unique counter' do
     context 'when track_work_items_activity FF is enabled' do
       it 'tracks a unique event only once' do
         expect { 3.times { track_event } }.to change {
           Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(
-            event_names: described_class::WORK_ITEM_TITLE_CHANGED,
+            event_names: event_name,
             start_date: 2.weeks.ago,
             end_date: 2.weeks.from_now
           )
@@ -48,4 +44,20 @@ RSpec.describe Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter, :clean_
       it_behaves_like 'counter that does not track the event'
     end
   end
+
+  describe '.track_work_item_created_action' do
+    subject(:track_event) { described_class.track_work_item_created_action(author: user) }
+
+    let(:event_name) { described_class::WORK_ITEM_CREATED }
+
+    it_behaves_like 'work item unique counter'
+  end
+
+  describe '.track_work_item_title_changed_action' do
+    subject(:track_event) { described_class.track_work_item_title_changed_action(author: user) }
+
+    let(:event_name) { described_class::WORK_ITEM_TITLE_CHANGED }
+
+    it_behaves_like 'work item unique counter'
+  end
 end

spec/models/work_item_spec.rb

@@ -10,4 +10,16 @@ RSpec.describe WorkItem do
       expect(work_item.noteable_target_type_name).to eq('issue')
     end
   end
+
+  describe 'callbacks' do
+    describe 'record_create_action' do
+      it 'records the creation action after saving' do
+        expect(Gitlab::UsageDataCounters::WorkItemActivityUniqueCounter).to receive(:track_work_item_created_action)
+        # During the work item transition we also want to track work items as issues
+        expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).to receive(:track_issue_created_action)
+
+        create(:work_item)
+      end
+    end
+  end
 end