Track blocking epics added on usage ping

Record blocking epic added on usage ping
and use RedisHLL for data aggregation.

Changelog: added
EE: true

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

@@ -46,6 +46,7 @@ options:
     - g_project_management_users_epic_issue_added_from_epic
     - g_project_management_epic_related_added
     - g_project_management_epic_related_removed
+    - g_project_management_epic_blocking_added
 distribution:
 - ee
 tier:

ee/config/metrics/counts_28d/20220404201348_g_project_management_epic_blocking_added_monthly.yml

+---
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_blocking_added_monthly
+description: Count of MAU adding blocking 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/84400
+time_frame: 28d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - g_project_management_epic_blocking_added
+distribution:
+- ee
+tier:
+- ultimate

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

@@ -46,6 +46,7 @@ options:
     - g_project_management_users_epic_issue_added_from_epic
     - g_project_management_epic_related_added
     - g_project_management_epic_related_removed
+    - g_project_management_epic_blocking_added
 distribution:
 - ee
 tier:

ee/config/metrics/counts_7d/20220404201112_g_project_management_epic_blocking_added_weekly.yml

+---
+key_path: redis_hll_counters.epics_usage.g_project_management_epic_blocking_added_weekly
+description: Count of WAU adding blocking 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/84400
+time_frame: 7d
+data_source: redis_hll
+data_category: optional
+instrumentation_class: RedisHLLMetric
+options:
+  events:
+    - g_project_management_epic_blocking_added
+distribution:
+- ee
+tier:
+- ultimate

ee/lib/gitlab/usage_data_counters/epic_activity_unique_counter.rb

@@ -37,6 +37,7 @@ module Gitlab
       EPIC_CROSS_REFERENCED = 'g_project_management_epic_cross_referenced'
       EPIC_RELATED_ADDED = 'g_project_management_epic_related_added'
       EPIC_RELATED_REMOVED = 'g_project_management_epic_related_removed'
+      EPIC_BLOCKING_ADDED = 'g_project_management_epic_blocking_added'
 
       class << self
         def track_epic_created_action(author:)
@@ -160,6 +161,7 @@ module Gitlab
         end
 
         def track_linked_epic_with_type_blocks_added(author:)
+          track_unique_action(EPIC_BLOCKING_ADDED, author)
         end
 
         def track_linked_epic_with_type_blocks_removed(author:)

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

@@ -361,4 +361,16 @@ RSpec.describe Gitlab::UsageDataCounters::EpicActivityUniqueCounter, :clean_gitl
 
     it_behaves_like 'does not track when feature flag is disabled', :track_epics_activity
   end
+
+  context 'for blocking epic added' do
+    def track_action(params)
+      described_class.track_linked_epic_with_type_blocks_added(**params)
+    end
+
+    it_behaves_like 'a daily tracked issuable event' do
+      let(:action) { described_class::EPIC_BLOCKING_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

@@ -54,18 +54,32 @@ RSpec.describe Epics::RelatedEpicLinks::CreateService do
     end
 
     context 'event tracking' do
-      context 'for relates_to link type' do
+      shared_examples 'a recorded event' do
         it 'records event for each link created' do
           params = {
-            link_type: IssuableLink::TYPE_RELATES_TO,
+            link_type: link_type,
             issuable_references: [issuable_a, issuable3].map { |epic| epic.to_reference(issuable.group, full: true) }
           }
 
-          expect(Gitlab::UsageDataCounters::EpicActivityUniqueCounter).to receive(:track_linked_epic_with_type_relates_to_added).with(author: user).twice
+          expect(Gitlab::UsageDataCounters::EpicActivityUniqueCounter).to receive(tracking_method_name).with(author: user).twice
 
           described_class.new(issuable, user, params).execute
         end
       end
+
+      context 'for relates_to link type' do
+        let(:link_type) { IssuableLink::TYPE_RELATES_TO }
+        let(:tracking_method_name) { :track_linked_epic_with_type_relates_to_added }
+
+        it_behaves_like 'a recorded event'
+      end
+
+      context 'for blocks link_type' do
+        let(:link_type) { IssuableLink::TYPE_BLOCKS }
+        let(:tracking_method_name) { :track_linked_epic_with_type_blocks_added }
+
+        it_behaves_like 'a recorded event'
+      end
     end
   end
 end

lib/gitlab/usage_data_counters/known_events/epic_events.yml

@@ -200,3 +200,9 @@
   redis_slot: project_management
   aggregation: daily
   feature_flag: track_epics_activity
+
+- name: g_project_management_epic_blocking_added
+  category: epics_usage
+  redis_slot: project_management
+  aggregation: daily
+  feature_flag: track_epics_activity