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, 88 insertions, 0 deletions

diff --git a/spec/workers/namespaces/root_statistics_worker_spec.rb b/spec/workers/namespaces/root_statistics_worker_spec.rb
new file mode 100644
index 00000000000..8dd74b96d49
--- /dev/null
+++ b/spec/workers/namespaces/root_statistics_worker_spec.rb
@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Namespaces::RootStatisticsWorker, '#perform' do
+  let(:group) { create(:group, :with_aggregation_schedule) }
+
+  subject(:worker) { described_class.new }
+
+  context 'with a namespace' do
+    it 'executes refresher service' do
+      expect_any_instance_of(Namespaces::StatisticsRefresherService)
+        .to receive(:execute)
+
+      worker.perform(group.id)
+    end
+
+    it 'deletes namespace aggregated schedule row' do
+      worker.perform(group.id)
+
+      expect(group.reload.aggregation_schedule).to be_nil
+    end
+
+    context 'when something goes wrong when updating' do
+      before do
+        allow_any_instance_of(Namespaces::StatisticsRefresherService)
+          .to receive(:execute)
+          .and_raise(Namespaces::StatisticsRefresherService::RefresherError, 'error')
+      end
+
+      it 'does not delete the aggregation schedule' do
+        worker.perform(group.id)
+
+        expect(group.reload.aggregation_schedule).to be_present
+      end
+
+      it 'logs the error' do
+        # A Namespace::RootStatisticsWorker is scheduled when
+        # a Namespace::AggregationSchedule is created, so having
+        # create(:group, :with_aggregation_schedule), will execute
+        # another worker
+        allow_any_instance_of(Namespace::AggregationSchedule)
+          .to receive(:schedule_root_storage_statistics).and_return(nil)
+
+        expect(Gitlab::SidekiqLogger).to receive(:error).once
+
+        worker.perform(group.id)
+      end
+    end
+  end
+
+  context 'with no namespace' do
+    before do
+      group.destroy
+    end
+
+    it 'does not execute the refresher service' do
+      expect_any_instance_of(Namespaces::StatisticsRefresherService)
+        .not_to receive(:execute)
+
+      worker.perform(group.id)
+    end
+  end
+
+  context 'with a namespace with no aggregation scheduled' do
+    before do
+      group.aggregation_schedule.destroy
+    end
+
+    it 'does not execute the refresher service' do
+      expect_any_instance_of(Namespaces::StatisticsRefresherService)
+        .not_to receive(:execute)
+
+      worker.perform(group.id)
+    end
+  end
+
+  context 'when update_statistics_namespace is off' do
+    it 'does not create a new one' do
+      stub_feature_flags(update_statistics_namespace: false, namespace: group)
+
+      expect_any_instance_of(Namespaces::StatisticsRefresherService)
+        .not_to receive(:execute)
+
+      worker.perform(group.id)
+    end
+  end
+end