Add post migration to backfill projects updated at after repository move

In https://gitlab.com/gitlab-data/analytics/-/issues/7868 we discovered
that, after a repository was moved to a different storage, the
container's updated_at column of that repository wasn't updated.

This made some syncing scripts to Sisense to fail because they
couldn't detect the containers were updated.

In this commit, we add a post_migration to update those projects'
updated_at column that hasn't been updated after the repository was
moved.

changelogs/unreleased/fj-backfill-project-updated_at-after-repository-move.yml

+---
+title: Add post migration to backfill projects updated at after repository move
+merge_request: 53845
+author:
+type: fixed

db/post_migrate/20210210093901_backfill_updated_at_after_repository_storage_move.rb

+# frozen_string_literal: true
+
+class BackfillUpdatedAtAfterRepositoryStorageMove < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 10_000
+  INTERVAL = 2.minutes
+  MIGRATION_CLASS = 'BackfillProjectUpdatedAtAfterRepositoryStorageMove'
+
+  disable_ddl_transaction!
+
+  class ProjectRepositoryStorageMove < ActiveRecord::Base
+    include EachBatch
+
+    self.table_name = 'project_repository_storage_moves'
+  end
+
+  def up
+    ProjectRepositoryStorageMove.reset_column_information
+
+    ProjectRepositoryStorageMove.select(:project_id).distinct.each_batch(of: BATCH_SIZE, column: :project_id) do |batch, index|
+      migrate_in(
+        INTERVAL * index,
+        MIGRATION_CLASS,
+        batch.pluck(:project_id)
+      )
+    end
+  end
+
+  def down
+    # No-op
+  end
+end

db/schema_migrations/20210210093901

+961c147e9c8e35eac5b8dd33f879582e173b7f6e31659b2d00989bc38afc6f5a
\ No newline at end of file

lib/gitlab/background_migration/backfill_project_updated_at_after_repository_storage_move.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    # Update existent project update_at column after their repository storage was moved
+    class BackfillProjectUpdatedAtAfterRepositoryStorageMove
+      def perform(*project_ids)
+        updated_repository_storages = ProjectRepositoryStorageMove.select("project_id, MAX(updated_at) as updated_at").where(project_id: project_ids).group(:project_id)
+
+        Project.connection.execute <<-SQL
+          WITH repository_storage_cte as (
+            #{updated_repository_storages.to_sql}
+          )
+          UPDATE projects
+          SET updated_at = (repository_storage_cte.updated_at + interval '1 second')
+          FROM repository_storage_cte
+          WHERE projects.id = repository_storage_cte.project_id AND projects.updated_at <= repository_storage_cte.updated_at
+        SQL
+      end
+    end
+  end
+end

spec/lib/gitlab/background_migration/backfill_project_updated_at_after_repository_storage_move_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::BackgroundMigration::BackfillProjectUpdatedAtAfterRepositoryStorageMove, :migration, schema: 20210210093901 do
+  let(:projects) { table(:projects) }
+  let(:project_repository_storage_moves) { table(:project_repository_storage_moves) }
+  let(:namespace) { table(:namespaces).create!(name: 'user', path: 'user') }
+
+  subject { described_class.new }
+
+  describe '#perform' do
+    it 'updates project updated_at column if they were moved to a different repository storage' do
+      freeze_time do
+        project_1 = projects.create!(id: 1, namespace_id: namespace.id, updated_at: 1.day.ago)
+        project_2 = projects.create!(id: 2, namespace_id: namespace.id, updated_at: Time.current)
+        original_project_3_updated_at = 2.minutes.from_now
+        project_3 = projects.create!(id: 3, namespace_id: namespace.id, updated_at: original_project_3_updated_at)
+        original_project_4_updated_at = 10.days.ago
+        project_4 = projects.create!(id: 4, namespace_id: namespace.id, updated_at: original_project_4_updated_at)
+
+        repository_storage_move_1 = project_repository_storage_moves.create!(project_id: project_1.id, updated_at: 2.hours.ago, source_storage_name: 'default', destination_storage_name: 'default')
+        repository_storage_move_2 = project_repository_storage_moves.create!(project_id: project_2.id, updated_at: Time.current, source_storage_name: 'default', destination_storage_name: 'default')
+        project_repository_storage_moves.create!(project_id: project_3.id, updated_at: Time.current, source_storage_name: 'default', destination_storage_name: 'default')
+
+        subject.perform([1, 2, 3, 4, non_existing_record_id])
+
+        expect(project_1.reload.updated_at).to eq(repository_storage_move_1.updated_at + 1.second)
+        expect(project_2.reload.updated_at).to eq(repository_storage_move_2.updated_at + 1.second)
+        expect(project_3.reload.updated_at).to eq(original_project_3_updated_at)
+        expect(project_4.reload.updated_at).to eq(original_project_4_updated_at)
+      end
+    end
+  end
+end

spec/migrations/20210210093901_backfill_updated_at_after_repository_storage_move_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20210210093901_backfill_updated_at_after_repository_storage_move.rb')
+
+RSpec.describe BackfillUpdatedAtAfterRepositoryStorageMove, :sidekiq do
+  let_it_be(:projects) { table(:projects) }
+  let_it_be(:project_repository_storage_moves) { table(:project_repository_storage_moves) }
+  let_it_be(:namespace) { table(:namespaces).create!(name: 'user', path: 'user') }
+
+  describe '#up' do
+    it 'schedules background jobs for all distinct projects in batches' do
+      stub_const("#{described_class}::BATCH_SIZE", 3)
+
+      project_1 = projects.create!(id: 1, namespace_id: namespace.id)
+      project_2 = projects.create!(id: 2, namespace_id: namespace.id)
+      project_3 = projects.create!(id: 3, namespace_id: namespace.id)
+      project_4 = projects.create!(id: 4, namespace_id: namespace.id)
+      project_5 = projects.create!(id: 5, namespace_id: namespace.id)
+      project_6 = projects.create!(id: 6, namespace_id: namespace.id)
+      project_7 = projects.create!(id: 7, namespace_id: namespace.id)
+      projects.create!(id: 8, namespace_id: namespace.id)
+
+      project_repository_storage_moves.create!(id: 1, project_id: project_1.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 2, project_id: project_1.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 3, project_id: project_2.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 4, project_id: project_3.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 5, project_id: project_3.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 6, project_id: project_4.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 7, project_id: project_4.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 8, project_id: project_5.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 9, project_id: project_6.id, source_storage_name: 'default', destination_storage_name: 'default')
+      project_repository_storage_moves.create!(id: 10, project_id: project_7.id, source_storage_name: 'default', destination_storage_name: 'default')
+
+      Sidekiq::Testing.fake! do
+        freeze_time do
+          migrate!
+
+          expect(BackgroundMigrationWorker.jobs.size).to eq(3)
+          expect(described_class::MIGRATION_CLASS).to be_scheduled_delayed_migration(2.minutes, 1, 2, 3)
+          expect(described_class::MIGRATION_CLASS).to be_scheduled_delayed_migration(4.minutes, 4, 5, 6)
+          expect(described_class::MIGRATION_CLASS).to be_scheduled_delayed_migration(6.minutes, 7)
+        end
+      end
+    end
+  end
+end