Implement Danger Telemetry Review

.gitlab/CODEOWNERS

@@ -48,3 +48,11 @@ Dangerfile @gl-quality/eng-prod
 
 # Delivery owner files
 /.gitlab/ci/releases.gitlab-ci.yml @gitlab-org/delivery
+
+# Telemetry owner files
+/ee/lib/gitlab/usage_data_counters/ @gitlab-org/growth/telemetry
+/ee/lib/ee/gitlab/usage_data.rb @gitlab-org/growth/telemetry
+/lib/gitlab/grafana_embed_usage_data.rb @gitlab-org/growth/telemetry
+/lib/gitlab/usage_data.rb @gitlab-org/growth/telemetry
+/lib/gitlab/cycle_analytics/usage_data.rb @gitlab-org/growth/telemetry
+/lib/gitlab/usage_data_counters/ @gitlab-org/growth/telemetry

danger/telemetry/Dangerfile

+# frozen_string_literal: true
+
+TELEMETRY_CHANGED_FILES_MESSAGE = <<~MSG
+This merge request adds or changes files that require a
+review from the Data team and Telemetry team @gitlab-org/growth/telemetry.
+The specific group is mentioned in order to send a notification to team members.
+MSG
+
+usage_data_changed_files = git.modified_files.grep(%r{usage_data})
+
+if usage_data_changed_files.any?
+  warn format(TELEMETRY_CHANGED_FILES_MESSAGE)
+
+  USAGE_DATA_FILES_MESSAGE = <<~MSG
+  The following files require a review from the [Data team and Telemetry team](https://gitlab.com/groups/gitlab-org/growth/telemetry/-/group_members?with_inherited_permissions=exclude):
+  MSG
+
+  markdown(USAGE_DATA_FILES_MESSAGE + helper.markdown_list(usage_data_changed_files))
+end

lib/gitlab_danger.rb

@@ -11,6 +11,7 @@ class GitlabDanger
     karma
     database
     commit_messages
+    telemetry
   ].freeze
 
   CI_ONLY_RULES ||= %w[

spec/lib/gitlab_danger_spec.rb

@@ -9,7 +9,7 @@ describe GitlabDanger do
 
   describe '.local_warning_message' do
     it 'returns an informational message with rules that can run' do
-      expect(described_class.local_warning_message).to eq('==> Only the following Danger rules can be run locally: changes_size, documentation, frozen_string, duplicate_yarn_dependencies, prettier, eslint, karma, database, commit_messages')
+      expect(described_class.local_warning_message).to eq('==> Only the following Danger rules can be run locally: changes_size, documentation, frozen_string, duplicate_yarn_dependencies, prettier, eslint, karma, database, commit_messages, telemetry')
     end
   end