Includes logic to persist namespace statistics

- Add two new ActiveRecord models:
  - RootNamespaceStoragestatistics will persist root namespace statistics
  - NamespaceAggregationSchedule will save information when a new update
to the namespace statistics needs to be scheduled
- Inject into UpdateProjectStatistics concern a new callback that will
call an async job to insert a new row onto NamespaceAggregationSchedule
table
- When a new row is inserted a new job is scheduled. This job will
update call an specific service to update the statistics and after that
it will delete thee aggregated scheduled row
- The RefresherServices makes heavy use of arel to build composable
queries to update Namespace::RootStorageStatistics attributes.
- Add an extra worker to traverse pending rows on
NAmespace::AggregationSchedule table and schedule a worker for each one
of this rows.
- Add an extra worker to traverse pending rows on
NAmespace::AggregationSchedule table and schedule a worker for each one
of this rows

1 files changed, 22 insertions, 0 deletions

diff --git a/app/services/namespaces/statistics_refresher_service.rb b/app/services/namespaces/statistics_refresher_service.rb
new file mode 100644
index 00000000000..c07b302839b
--- /dev/null
+++ b/app/services/namespaces/statistics_refresher_service.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+module Namespaces
+  class StatisticsRefresherService
+    RefresherError = Class.new(StandardError)
+
+    def execute(root_namespace)
+      root_storage_statistics = find_or_create_root_storage_statistics(root_namespace.id)
+
+      root_storage_statistics.recalculate!
+    rescue ActiveRecord::ActiveRecordError => e
+      raise RefresherError.new(e.message)
+    end
+
+    private
+
+    def find_or_create_root_storage_statistics(root_namespace_id)
+      Namespace::RootStorageStatistics
+        .safe_find_or_create_by!(namespace_id: root_namespace_id)
+    end
+  end
+end