Merge branch '9032-geo-pruneorphanedgeoevents-is-running-on-a-secondary' into 'master'

Geo - Ensure DB is writable before pruning Geo orphaned events

Closes #9032

See merge request gitlab-org/gitlab-ee!13983

ee/db/post_migrate/20180618193715_schedule_prune_orphaned_geo_events.rb

@@ -12,6 +12,7 @@ class SchedulePruneOrphanedGeoEvents < ActiveRecord::Migration[4.2]
 
   def up
     return unless Gitlab::Database.postgresql?
+    return if Gitlab::Database.read_only?
 
     BackgroundMigrationWorker.perform_async('PruneOrphanedGeoEvents')
   end

ee/lib/gitlab/background_migration/prune_orphaned_geo_events.rb

@@ -56,9 +56,10 @@ module Gitlab
       end
 
       def perform(table_name = EVENT_TABLES.first)
-        deleted = prune_orphaned_rows(table_name)
+        return if Gitlab::Database.read_only?
 
-        table_name = next_table(table_name) if deleted.zero?
+        deleted_rows = prune_orphaned_rows(table_name)
+        table_name   = next_table(table_name) if deleted_rows.zero?
 
         BackgroundMigrationWorker.perform_in(RESCHEDULE_DELAY, self.class.name, table_name) if table_name
       end

ee/spec/lib/gitlab/background_migration/prune_orphaned_geo_events_spec.rb

@@ -48,6 +48,12 @@ describe Gitlab::BackgroundMigration::PruneOrphanedGeoEvents, :migration, :postg
                                  tags_affected: 0)
     end
 
+    it 'does nothing if the database is read-only' do
+      allow(Gitlab::Database).to receive(:read_only?).and_return(true)
+
+      expect { background_migration.perform(event_table_name) }.not_to change { Geo::RepositoryUpdatedEvent.count }
+    end
+
     it 'takes the first table if no table is specified' do
       expect(subject).to receive(:prune_orphaned_rows).with(described_class::EVENT_TABLES.first).and_call_original
 

ee/spec/migrations/schedule_prune_orphaned_geo_events_spec.rb

@@ -4,8 +4,24 @@ require 'spec_helper'
 require Rails.root.join('ee', 'db', 'post_migrate', '20180618193715_schedule_prune_orphaned_geo_events.rb')
 
 describe SchedulePruneOrphanedGeoEvents, :migration, geo: false, schema: 20180615152524 do
-  describe '#up' do
-    it 'delegates work to Gitlab::BackgroundMigration::PruneOrphanedGeoEvents', :postgresql do
+  describe '#up', :postgresql do
+    it 'does nothing if it is not running on PostgreSQL' do
+      allow(Gitlab::Database).to receive(:postgresql?).and_return(false)
+
+      expect(BackgroundMigrationWorker).not_to receive(:perform_async).with('PruneOrphanedGeoEvents')
+
+      migrate!
+    end
+
+    it 'does nothing if the database is read-only' do
+      allow(Gitlab::Database).to receive(:read_only?).and_return(true)
+
+      expect(BackgroundMigrationWorker).not_to receive(:perform_async).with('PruneOrphanedGeoEvents')
+
+      migrate!
+    end
+
+    it 'delegates work to Gitlab::BackgroundMigration::PruneOrphanedGeoEvents' do
       expect(BackgroundMigrationWorker).to receive(:perform_async).with('PruneOrphanedGeoEvents')
 
       migrate!