Add Collected Data Categories Service Ping metric

With metrics categorization being enrolled, we need to pass information
about which categories was included in given period, in order to
properly process it in downsteam systems.

Changelog: added

config/metrics/objects_schemas/collected_data_categories_schema.json

+{
+  "type": "array",
+  "items": {
+    "type": ["string", "null"],
+    "enum": ["Standard", "Subscription", "Operational", "Optional"]
+  }
+}

config/metrics/settings/20210702140138_collected_data_categories.yml

+---
+key_path: settings.collected_data_categories
+name: collected_data_categories
+description: List of collected data categories corresponding to instance settings
+product_section: growth
+product_stage: growth
+product_group: group::product intelligence
+product_category: collection
+value_type: object
+status: implemented
+milestone: "14.1"
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/65336
+time_frame: none
+data_source: system
+data_category: Standard
+distribution:
+- ce
+- ee
+tier:
+- free
+- premium
+- ultimate
+value_json_schema: 'config/metrics/objects_schemas/collected_data_categories_schema.json'

doc/development/usage_ping/dictionary.md

@@ -18316,6 +18316,22 @@ Status: `data_available`
 
 Tiers: `free`, `premium`, `ultimate`
 
+### `settings.collected_data_categories`
+
+List of collected data categories corresponding to instance settings
+
+[Object JSON schema](https://gitlab.com/gitlab-org/gitlab/-/blob/master/config/metrics/objects_schemas/collected_data_categories_schema.json)
+
+[YAML definition](https://gitlab.com/gitlab-org/gitlab/-/blob/master/config/metrics/settings/20210702140138_collected_data_categories.yml)
+
+Group: `group::product intelligence`
+
+Data Category: `Standard`
+
+Status: `implemented`
+
+Tiers: `free`, `premium`, `ultimate`
+
 ### `settings.gitaly_apdex`
 
 Gitaly application performance

lib/gitlab/usage/metrics/instrumentations/collected_data_categories_metric.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Usage
+    module Metrics
+      module Instrumentations
+        class CollectedDataCategoriesMetric < GenericMetric
+          def value
+            ::ServicePing::PermitDataCategoriesService.new.execute
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/usage_data.rb

@@ -256,7 +256,8 @@ module Gitlab
           settings: {
             ldap_encrypted_secrets_enabled: alt_usage_data(fallback: nil) { Gitlab::Auth::Ldap::Config.encrypted_secrets.active? },
             operating_system: alt_usage_data(fallback: nil) { operating_system },
-            gitaly_apdex: alt_usage_data { gitaly_apdex }
+            gitaly_apdex: alt_usage_data { gitaly_apdex },
+            collected_data_categories: alt_usage_data(fallback: []) { Gitlab::Usage::Metrics::Instrumentations::CollectedDataCategoriesMetric.new(time_frame: 'none').value }
           }
         }
       end

spec/lib/gitlab/usage/metrics/instrumentations/collected_data_categories_metric_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Usage::Metrics::Instrumentations::CollectedDataCategoriesMetric do
+  it_behaves_like 'a correct instrumented metric value', {} do
+    let(:expected_value) { %w[Standard Subscription Operational Optional] }
+
+    before do
+      allow_next_instance_of(ServicePing::PermitDataCategoriesService) do |instance|
+        expect(instance).to receive(:execute).and_return(expected_value)
+      end
+    end
+  end
+end

spec/lib/gitlab/usage_data_spec.rb

@@ -1078,6 +1078,16 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
       it 'gathers gitaly apdex', :aggregate_failures do
         expect(subject[:settings][:gitaly_apdex]).to be_within(0.001).of(0.95)
       end
+
+      it 'reports collected data categories' do
+        expected_value = %w[Standard Subscription Operational Optional]
+
+        allow_next_instance_of(ServicePing::PermitDataCategoriesService) do |instance|
+          expect(instance).to receive(:execute).and_return(expected_value)
+        end
+
+        expect(subject[:settings][:collected_data_categories]).to eq(expected_value)
+      end
     end
   end