A code example referenced in our blog post: https://medium.com/expected-behavior/our-plan-for-zero-downtime-database-transitions-with-rails-part-2-3cc4c5d6051c

ex01-happy-path-after-commit.rb

def write_active_migrator_destination_model!
  if ActiveMigrator.config.enabled_checker.call(id)
    ActiveMigrator.config.metric_incrementer.call("active_migrator.#{active_migrator_source_klass.name}.write_active_migrator_destination_model")
    original_record = find_original_model
    if original_record
      active_migrator_destination_model = original_record.find_active_migrator_destination_model
      original_record.transformed_attributes_for_active_migrator.each do |name, value|
        active_migrator_destination_model.send(:write_attribute, name, value)
      end
      active_migrator_destination_model.save!
    else
      active_migrator_destination_model = find_active_migrator_destination_model
      active_migrator_destination_model.destroy unless active_migrator_destination_model.new_record?
    end
  end
end