Track epic destroy event on usage ping

Record epic destroy event on usage ping

app/services/issuable/destroy_service.rb

@@ -4,18 +4,26 @@ module Issuable
   class DestroyService < IssuableBaseService
     def execute(issuable)
       if issuable.destroy
-        delete_todos(issuable)
-        issuable.update_project_counter_caches
-        issuable.assignees.each(&:invalidate_cache_counts)
+        after_destroy(issuable)
       end
     end
 
     private
 
+    def after_destroy(issuable)
+      delete_todos(issuable)
+      issuable.update_project_counter_caches
+      issuable.assignees.each(&:invalidate_cache_counts)
+    end
+
+    def group_for(issuable)
+      issuable.resource_parent
+    end
+
     def delete_todos(issuable)
-      actor = issuable.is_a?(Epic) ? issuable.resource_parent : issuable.resource_parent.group
+      group = group_for(issuable)
 
-      if Feature.enabled?(:destroy_issuable_todos_async, actor, default_enabled: :yaml)
+      if Feature.enabled?(:destroy_issuable_todos_async, group, default_enabled: :yaml)
         TodosDestroyer::DestroyedIssuableWorker
           .perform_async(issuable.id, issuable.class.name)
       else
@@ -26,3 +34,5 @@ module Issuable
     end
   end
 end
+
+Issuable::DestroyService.prepend_if_ee('EE::Issuable::DestroyService')

doc/development/usage_ping/dictionary.md

@@ -9872,6 +9872,30 @@ Status: `data_available`
 
 Tiers: `premium`, `ultimate`
 
+### `redis_hll_counters.epics_usage.g_project_management_epic_destroyed_monthly`
+
+Count of MAU destroying epics
+
+[YAML definition](https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/config/metrics/counts_28d/20210413174710_g_project_management_epic_destroyed_monthly.yml)
+
+Group: `group::product planning`
+
+Status: `implemented`
+
+Tiers: `premium`, `ultimate`
+
+### `redis_hll_counters.epics_usage.g_project_management_epic_destroyed_weekly`
+
+Count of WAU destroying epics
+
+[YAML definition](https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/config/metrics/counts_7d/20210413174449_g_project_management_epic_destroyed_weekly.yml)
+
+Group: `group::product planning`
+
+Status: `implemented`
+
+Tiers: `premium`, `ultimate`
+
 ### `redis_hll_counters.epics_usage.g_project_management_epic_issue_added_monthly`
 
 Count of MAU adding issues to epics

ee/app/services/ee/issuable/destroy_service.rb

+# frozen_string_literal: true
+
+module EE
+  module Issuable
+    module DestroyService
+      extend ::Gitlab::Utils::Override
+
+      private
+
+      override :after_destroy
+      def after_destroy(issuable)
+        track_usage_ping_epic_destroyed if issuable.is_a?(Epic)
+
+        super
+      end
+
+      override :group_for
+      def group_for(issuable)
+        return issuable.resource_parent if issuable.is_a?(Epic)
+
+        super
+      end
+
+      def track_usage_ping_epic_destroyed
+        ::Gitlab::UsageDataCounters::EpicActivityUniqueCounter.track_epic_destroyed(author: current_user)
+      end
+    end
+  end
+end

ee/changelogs/unreleased/issue_292253-track_epic_destroyed.yml

+---
+title: Track epic destroyed action on usage ping
+merge_request: 59185
+author:
+type: other

ee/config/metrics/counts_28d/20210413174710_g_project_management_epic_destroyed_monthly.yml

+---
+# Name of this metric contains g_project_management prefix
+# because we are using the same slot from issue_tracking to
+# allow data aggregation.
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_destroyed_monthly
+description: Count of MAU destroying epics
+product_section: dev
+product_stage: plan
+product_group: group::product planning
+product_category: epics_usage
+value_type: number
+status: implemented
+milestone: "13.11"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/59185
+time_frame: 28d
+data_source: redis_hll
+distribution:
+- ee
+tier:
+- premium
+- ultimate

ee/config/metrics/counts_7d/20210413174449_g_project_management_epic_destroyed_weekly.yml

+---
+# Name of this metric contains g_project_management prefix
+# because we are using the same slot from issue_tracking to
+# allow data aggregation.
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_destroyed_weekly
+description: Count of WAU destroying epics
+product_section: dev
+product_stage: plan
+product_group: group::product planning
+product_category: epics_usage
+value_type: number
+status: implemented
+milestone: "13.11"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/59185
+time_frame: 7d
+data_source: redis_hll
+distribution:
+- ee
+tier:
+- premium
+- ultimate
+

ee/lib/gitlab/usage_data_counters/epic_activity_unique_counter.rb

@@ -28,6 +28,7 @@ module Gitlab
       EPIC_CONFIDENTIAL = 'g_project_management_users_setting_epic_confidential'
       EPIC_VISIBLE = 'g_project_management_users_setting_epic_visible'
       EPIC_LABELS = 'g_project_management_epic_users_changing_labels'
+      EPIC_DESTROYED = 'g_project_management_epic_destroyed'
 
       class << self
         def track_epic_created_action(author:)
@@ -114,6 +115,10 @@ module Gitlab
           track_unique_action(EPIC_LABELS, author)
         end
 
+        def track_epic_destroyed(author:)
+          track_unique_action(EPIC_DESTROYED, author)
+        end
+
         private
 
         def track_unique_action(action, author)

ee/spec/lib/gitlab/usage_data_counters/epic_activity_unique_counter_spec.rb

@@ -257,4 +257,16 @@ RSpec.describe Gitlab::UsageDataCounters::EpicActivityUniqueCounter, :clean_gitl
 
     it_behaves_like 'does not track when feature flag is disabled', :track_epics_activity
   end
+
+  context 'for destroying epic' do
+    def track_action(params)
+      described_class.track_epic_destroyed(**params)
+    end
+
+    it_behaves_like 'a daily tracked issuable event' do
+      let(:action) { described_class::ISSUE_EPIC_DESTROYED }
+    end
+
+    it_behaves_like 'does not track when feature flag is disabled', :track_epics_activity
+  end
 end

ee/spec/services/ee/issuable/destroy_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Issuable::DestroyService do
+  let_it_be(:user) { create(:user) }
+
+  subject(:service) { described_class.new(nil, user) }
+
+  describe '#execute' do
+    context 'when destroying an epic' do
+      let(:issuable) { create(:epic) }
+
+      it 'records usage ping epic destroy event' do
+        expect(Gitlab::UsageDataCounters::EpicActivityUniqueCounter).to receive(:track_epic_destroyed).with(author: user)
+
+        subject.execute(issuable)
+      end
+    end
+
+    context 'when destroying other issuable type' do
+      let(:issuable) { create(:issue) }
+
+      it 'does not track usage ping epic destroy event' do
+        expect(Gitlab::UsageDataCounters::EpicActivityUniqueCounter).not_to receive(:track_epic_destroyed)
+
+        subject.execute(issuable)
+      end
+    end
+  end
+end

lib/gitlab/usage_data_counters/known_events/epic_events.yml

@@ -134,3 +134,9 @@
   redis_slot: project_management
   aggregation: daily
   feature_flag: track_epics_activity
+
+- name: g_project_management_epic_destroyed
+  category: epics_usage
+  redis_slot: project_management
+  aggregation: daily
+  feature_flag: track_epics_activity