Aggregate certain usage metrics for code review

MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/53553

config/feature_flags/development/usage_data_code_review_aggregation.yml

+---
+name: usage_data_code_review_aggregation
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/53553
+rollout_issue_url: 
+milestone: '13.9'
+type: development
+group: group::code review
+default_enabled: false

lib/gitlab/usage_data_counters/aggregated_metrics/code_review.yml

+# code_review_extension_category_monthly_active_users
+# This is only metrics related to the VS Code Extension for now.
+#
+# code_review_category_monthly_active_users
+# This is the user based metrics. These should only be user based metrics and only be related to the Code Review things inside of GitLab.
+#
+# code_review_group_monthly_active_users
+# This is an aggregation of both of the above aggregations. It's intended to represent all users who interact with our group across all of our categories.
+---
+- name: code_review_group_monthly_active_users
+  operator: OR
+  feature_flag: usage_data_code_review_aggregation
+  source: redis
+  events: [
+    'i_code_review_user_single_file_diffs',
+    'i_code_review_user_create_mr',
+    'i_code_review_user_close_mr',
+    'i_code_review_user_reopen_mr',
+    'i_code_review_user_resolve_thread',
+    'i_code_review_user_unresolve_thread',
+    'i_code_review_edit_mr_title',
+    'i_code_review_edit_mr_desc',
+    'i_code_review_user_merge_mr',
+    'i_code_review_user_create_mr_comment',
+    'i_code_review_user_edit_mr_comment',
+    'i_code_review_user_remove_mr_comment',
+    'i_code_review_user_create_review_note',
+    'i_code_review_user_publish_review',
+    'i_code_review_user_create_multiline_mr_comment',
+    'i_code_review_user_edit_multiline_mr_comment',
+    'i_code_review_user_remove_multiline_mr_comment',
+    'i_code_review_user_add_suggestion',
+    'i_code_review_user_apply_suggestion',
+    'i_code_review_user_assigned',
+    'i_code_review_user_review_requested',
+    'i_code_review_user_approve_mr',
+    'i_code_review_user_unapprove_mr',
+    'i_code_review_user_marked_as_draft',
+    'i_code_review_user_unmarked_as_draft',
+    'i_code_review_user_approval_rule_added',
+    'i_code_review_user_approval_rule_deleted',
+    'i_code_review_user_approval_rule_edited',
+    'i_code_review_user_vs_code_api_request',
+    'i_code_review_user_toggled_task_item_status',
+    'i_code_review_user_create_mr_from_issue'
+  ]
+- name: code_review_category_monthly_active_users
+  operator: OR
+  feature_flag: usage_data_code_review_aggregation
+  source: redis
+  events: [
+    'i_code_review_user_single_file_diffs',
+    'i_code_review_user_create_mr',
+    'i_code_review_user_close_mr',
+    'i_code_review_user_reopen_mr',
+    'i_code_review_user_resolve_thread',
+    'i_code_review_user_unresolve_thread',
+    'i_code_review_edit_mr_title',
+    'i_code_review_edit_mr_desc',
+    'i_code_review_user_merge_mr',
+    'i_code_review_user_create_mr_comment',
+    'i_code_review_user_edit_mr_comment',
+    'i_code_review_user_remove_mr_comment',
+    'i_code_review_user_create_review_note',
+    'i_code_review_user_publish_review',
+    'i_code_review_user_create_multiline_mr_comment',
+    'i_code_review_user_edit_multiline_mr_comment',
+    'i_code_review_user_remove_multiline_mr_comment',
+    'i_code_review_user_add_suggestion',
+    'i_code_review_user_apply_suggestion',
+    'i_code_review_user_assigned',
+    'i_code_review_user_review_requested',
+    'i_code_review_user_approve_mr',
+    'i_code_review_user_unapprove_mr',
+    'i_code_review_user_marked_as_draft',
+    'i_code_review_user_unmarked_as_draft',
+    'i_code_review_user_approval_rule_added',
+    'i_code_review_user_approval_rule_deleted',
+    'i_code_review_user_approval_rule_edited',
+    'i_code_review_user_toggled_task_item_status',
+    'i_code_review_user_create_mr_from_issue'
+  ]
+- name: code_review_extension_category_monthly_active_users
+  operator: OR
+  feature_flag: usage_data_code_review_aggregation
+  source: redis
+  events: [
+    'i_code_review_user_vs_code_api_request'
+  ]

spec/lib/gitlab/usage/metrics/aggregates/aggregate_spec.rb

@@ -223,7 +223,7 @@ RSpec.describe Gitlab::Usage::Metrics::Aggregates::Aggregate, :clean_gitlab_redi
     end
 
     it 'allows for YAML aliases in aggregated metrics configs' do
-      expect(YAML).to receive(:safe_load).with(kind_of(String), aliases: true)
+      expect(YAML).to receive(:safe_load).with(kind_of(String), aliases: true).at_least(:once)
 
       described_class.new(recorded_at)
     end

spec/lib/gitlab/usage_data_counters/code_review_events_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+# If this spec fails, we need to add the new code review event to the correct aggregated metric
+RSpec.describe 'Code review events' do
+  it 'the aggregated metrics contain all the code review metrics' do
+    wildcard = Gitlab::Usage::Metrics::Aggregates::AGGREGATED_METRICS_PATH
+    aggregated_events = Dir[wildcard].each_with_object([]) do |path, metrics|
+      metrics.push(*YAML.safe_load(File.read(path), aliases: true)&.map(&:with_indifferent_access))
+    end
+    code_review_aggregated_events = aggregated_events
+      .select { |event| event['name'].include?('code_review') }
+      .map { |event| event['events'] }
+      .flatten
+      .uniq
+
+    code_review_events = Gitlab::UsageDataCounters::HLLRedisCounter.events_for_category("code_review")
+
+    exceptions = %w[i_code_review_mr_diffs i_code_review_mr_single_file_diffs]
+    code_review_aggregated_events += exceptions
+
+    expect(code_review_events - code_review_aggregated_events).to be_empty
+  end
+end