Add new metric definition for on-call notifications

changelogs/unreleased/sy-on-call-usage-ping.yml

+---
+title: Add count of unique users to receive on-call notification to usage ping
+merge_request: 58606
+author:
+type: changed

config/feature_flags/development/usage_data_i_incident_management_oncall_notification_sent.yml

+---
+name: usage_data_i_incident_management_oncall_notification_sent
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58606
+rollout_issue_url:
+milestone: '13.11'
+type: development
+group: group::monitor
+default_enabled: true

doc/development/usage_ping/dictionary.md

@@ -10340,6 +10340,30 @@ Status: `data_available`
 
 Tiers:
 
+### `redis_hll_counters.incident_management.i_incident_management_oncall_notification_sent_monthly`
+
+Count of unique users to receive a notification while on-call
+
+[YAML definition](https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/config/metrics/counts_28d/20210405222005_i_incident_management_oncall_notification_sent_monthly.yml)
+
+Group: `group::monitor`
+
+Status: `implemented`
+
+Tiers: `premium`, `ultimate`
+
+### `redis_hll_counters.incident_management.i_incident_management_oncall_notification_sent_weekly`
+
+Count of unique users to receive a notification while on-call
+
+[YAML definition](https://gitlab.com/gitlab-org/gitlab/-/blob/master/ee/config/metrics/counts_7d/20210405220139_i_incident_management_oncall_notification_sent_weekly.yml)
+
+Group: `group::monitor`
+
+Status: `implemented`
+
+Tiers: `premium`, `ultimate`
+
 ### `redis_hll_counters.incident_management.incident_management_alert_assigned_monthly`
 
 Missing description

ee/app/services/ee/notification_service.rb

@@ -2,6 +2,8 @@
 
 module EE
   module NotificationService
+    include ::Gitlab::Utils::UsageData
+
     # When we add approvers to a merge request we should send an email to:
     #
     #  * the new approvers
@@ -67,6 +69,8 @@ module EE
     end
 
     def notify_oncall_users_of_alert(users, alert)
+      track_usage_event(:i_incident_management_oncall_notification_sent, users.map(&:id))
+
       users.each do |user|
         mailer.prometheus_alert_fired_email(alert.project, user, alert).deliver_later
       end

ee/config/metrics/counts_28d/20210405222005_i_incident_management_oncall_notification_sent_monthly.yml

+---
+key_path: redis_hll_counters.incident_management.i_incident_management_oncall_notification_sent_monthly
+description: Count of unique users to receive a notification while on-call
+product_section: ops
+product_stage: monitor
+product_group: group::monitor
+product_category: incident_management
+value_type: number
+status: implemented
+milestone: "13.11"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58606
+time_frame: 28d
+data_source: redis_hll
+distribution:
+- ee
+tier:
+- premium
+- ultimate

ee/config/metrics/counts_7d/20210405220139_i_incident_management_oncall_notification_sent_weekly.yml

+---
+key_path: redis_hll_counters.incident_management.i_incident_management_oncall_notification_sent_weekly
+description: Count of unique users to receive a notification while on-call
+product_section: ops
+product_stage: monitor
+product_group: group::monitor
+product_category: incident_management
+value_type: number
+status: implemented
+milestone: "13.11"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/58606
+time_frame: 7d
+data_source: redis_hll
+distribution:
+- ee
+tier:
+- premium
+- ultimate

ee/spec/services/ee/notification_service_spec.rb

@@ -899,12 +899,25 @@ RSpec.describe EE::NotificationService, :mailer do
       let_it_be(:user) { create(:user) }
       let_it_be(:alert) { create(:alert_management_alert) }
       let_it_be(:project) { alert.project }
+      let(:tracking_params) do
+        {
+          event_names: 'i_incident_management_oncall_notification_sent',
+          start_date: 1.week.ago,
+          end_date: 1.week.from_now
+        }
+      end
 
       it 'sends an email to the specified users' do
         expect(Notify).to receive(:prometheus_alert_fired_email).with(project, user, alert).and_call_original
 
         subject.notify_oncall_users_of_alert([user], alert)
       end
+
+      it 'tracks a count of unique recipients', :clean_gitlab_redis_shared_state do
+        expect { subject.notify_oncall_users_of_alert([user], alert) }
+          .to change { Gitlab::UsageDataCounters::HLLRedisCounter.unique_events(**tracking_params) }
+          .by 1
+      end
     end
   end
 end

lib/gitlab/usage_data_counters/known_events/common.yml

@@ -247,6 +247,12 @@
   category: incident_management_alerts
   aggregation: weekly
   feature_flag: usage_data_incident_management_alert_create_incident
+# Incident management on-call
+- name: i_incident_management_oncall_notification_sent
+  redis_slot: incident_management
+  category: incident_management_oncall
+  aggregation: weekly
+  feature_flag: usage_data_i_incident_management_oncall_notification_sent
 # Testing category
 - name: i_testing_test_case_parsed
   category: testing

spec/lib/gitlab/usage_data_counters/hll_redis_counter_spec.rb

@@ -34,6 +34,7 @@ RSpec.describe Gitlab::UsageDataCounters::HLLRedisCounter, :clean_gitlab_redis_s
         'source_code',
         'incident_management',
         'incident_management_alerts',
+        'incident_management_oncall',
         'testing',
         'issues_edit',
         'ci_secrets_management',

spec/lib/gitlab/usage_data_spec.rb

@@ -1362,7 +1362,7 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
 
     let(:categories) { ::Gitlab::UsageDataCounters::HLLRedisCounter.categories }
     let(:ineligible_total_categories) do
-      %w[source_code ci_secrets_management incident_management_alerts snippets terraform]
+      %w[source_code ci_secrets_management incident_management_alerts snippets terraform incident_management_oncall]
     end
 
     context 'with redis_hll_tracking feature enabled' do