1 files changed, 47 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/populate_namespace_statistics.rb b/lib/gitlab/background_migration/populate_namespace_statistics.rb
new file mode 100644
index 00000000000..97927ef48c2
--- /dev/null
+++ b/lib/gitlab/background_migration/populate_namespace_statistics.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # This class creates/updates those namespace statistics
+    # that haven't been created nor initialized.
+    # It also updates the related namespace statistics
+    class PopulateNamespaceStatistics
+      def perform(group_ids, statistics)
+        # Updating group statistics might involve calling Gitaly.
+        # For example, when calculating `wiki_size`, we will need
+        # to perform the request to check if the repo exists and
+        # also the repository size.
+        #
+        # The `allow_n_plus_1_calls` method is only intended for
+        # dev and test. It won't be raised in prod.
+        ::Gitlab::GitalyClient.allow_n_plus_1_calls do
+          relation(group_ids).each do |group|
+            upsert_namespace_statistics(group, statistics)
+          end
+        end
+      end
+
+      private
+
+      def upsert_namespace_statistics(group, statistics)
+        response = ::Groups::UpdateStatisticsService.new(group, statistics: statistics).execute
+
+        error_message("#{response.message} group: #{group.id}") if response.error?
+      end
+
+      def logger
+        @logger ||= ::Gitlab::BackgroundMigration::Logger.build
+      end
+
+      def error_message(message)
+        logger.error(message: "Namespace Statistics Migration: #{message}")
+      end
+
+      def relation(group_ids)
+        Group.includes(:namespace_statistics).where(id: group_ids)
+      end
+    end
+  end
+end
+
+Gitlab::BackgroundMigration::PopulateNamespaceStatistics.prepend_mod_with('Gitlab::BackgroundMigration::PopulateNamespaceStatistics')