Track related epics added on usage ping

Record related epics added on usage ping
usins Redis HLL counters.

Changelog: other
EE: true

app/services/issuable_links/create_service.rb

@@ -67,7 +67,9 @@ module IssuableLinks
       target_issuables.map do |referenced_object|
         link = relate_issuables(referenced_object)
 
-        unless link.valid?
+        if link.valid?
+          after_create_for(link)
+        else
           @errors << _("%{ref} cannot be added: %{error}") % {
             ref: referenced_object.to_reference,
             error: link.errors.messages.values.flatten.to_sentence
@@ -143,9 +145,17 @@ module IssuableLinks
       # no-op
     end
 
+    # Override on child classes to perform
+    # actions when the service is executed.
     def track_event
       # no-op
     end
+
+    # Override on child classes to
+    # perform actions for each object created.
+    def after_create_for(_link)
+      # no-op
+    end
   end
 end
 

ee/app/services/epics/related_epic_links/create_service.rb

@@ -14,6 +14,12 @@ module Epics::RelatedEpicLinks
 
     private
 
+    def after_create_for(link)
+      if link.link_type == link.class::TYPE_RELATES_TO
+        ::Gitlab::UsageDataCounters::EpicActivityUniqueCounter.track_epic_related_added(author: current_user)
+      end
+    end
+
     def references(extractor)
       extractor.epics
     end

ee/config/metrics/counts_28d/20210318183733_epics_usage_total_unique_counts_monthly.yml

@@ -44,6 +44,7 @@ options:
     - g_project_management_epic_destroyed
     - g_project_management_epic_cross_referenced
     - g_project_management_users_epic_issue_added_from_epic
+    - g_project_management_epic_related_added
 distribution:
 - ee
 tier:

ee/config/metrics/counts_28d/20220321185831_g_project_management_epic_related_added_monthly.yml

+---
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_related_added_monthly
+description: Count of MAU adding related epics
+product_section: dev
+product_stage: plan
+product_group: group::product planning
+product_category: epics_usage
+value_type: number
+status: active
+milestone: "14.10"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/83323
+time_frame: 28d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - g_project_management_epic_related_added
+distribution:
+- ee
+tier:
+- ultimate

ee/config/metrics/counts_7d/20210318183220_epics_usage_total_unique_counts_weekly.yml

@@ -44,6 +44,7 @@ options:
     - g_project_management_epic_destroyed
     - g_project_management_epic_cross_referenced
     - g_project_management_users_epic_issue_added_from_epic
+    - g_project_management_epic_related_added
 distribution:
 - ee
 tier:

ee/config/metrics/counts_7d/20220321184021_g_project_management_epic_related_added_weekly.yml

+---
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_related_added_weekly
+description: Count of WAU adding related epics
+product_section: dev
+product_stage: plan
+product_group: group::product planning
+product_category: epics_usage
+value_type: number
+status: active
+milestone: "14.10"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/83323
+time_frame: 7d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - g_project_management_epic_related_added
+distribution:
+- ee
+tier:
+- ultimate

ee/lib/gitlab/usage_data_counters/epic_activity_unique_counter.rb

@@ -35,6 +35,7 @@ module Gitlab
       EPIC_TASK_CHECKED = 'project_management_users_checking_epic_task'
       EPIC_TASK_UNCHECKED = 'project_management_users_unchecking_epic_task'
       EPIC_CROSS_REFERENCED = 'g_project_management_epic_cross_referenced'
+      EPIC_RELATED_ADDED = 'g_project_management_epic_related_added'
 
       class << self
         def track_epic_created_action(author:)
@@ -149,6 +150,10 @@ module Gitlab
           track_unique_action(EPIC_CROSS_REFERENCED, author)
         end
 
+        def track_epic_related_added(author:)
+          track_unique_action(EPIC_RELATED_ADDED, author)
+        end
+
         private
 
         def track_unique_action(action, author)

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

@@ -337,4 +337,16 @@ RSpec.describe Gitlab::UsageDataCounters::EpicActivityUniqueCounter, :clean_gitl
 
     it_behaves_like 'does not track when feature flag is disabled', :track_epics_activity
   end
+
+  context 'for related epic added' do
+    def track_action(params)
+      described_class.track_epic_related_added(**params)
+    end
+
+    it_behaves_like 'a daily tracked issuable event' do
+      let(:action) { described_class::EPIC_RELATED_ADDED }
+    end
+
+    it_behaves_like 'does not track when feature flag is disabled', :track_epics_activity
+  end
 end

ee/spec/services/epics/related_epic_links/create_service_spec.rb

@@ -52,5 +52,20 @@ RSpec.describe Epics::RelatedEpicLinks::CreateService do
         expect(issuable_link_class.find_by!(target: issuable3)).to have_attributes(source: issuable, link_type: 'relates_to')
       end
     end
+
+    context 'event tracking' do
+      context 'for related link type' do
+        it 'records event for each link created' do
+          params = {
+            link_type: IssuableLink::TYPE_RELATES_TO,
+            issuable_references: [issuable_a, issuable3].map { |epic| epic.to_reference(issuable.group, full: true) }
+          }
+
+          expect(Gitlab::UsageDataCounters::EpicActivityUniqueCounter).to receive(:track_epic_related_added).with(author: user).twice
+
+          described_class.new(issuable, user, params).execute
+        end
+      end
+    end
   end
 end

lib/gitlab/usage_data_counters/known_events/epic_events.yml

@@ -188,3 +188,9 @@
   redis_slot: project_management
   aggregation: daily
   feature_flag: track_epics_activity
+
+- name: g_project_management_epic_related_added
+  category: epics_usage
+  redis_slot: project_management
+  aggregation: daily
+  feature_flag: track_epics_activity