CreatedByListener.php

<?php
  ....
  public function prePersist(LifecycleEventArgs $args)
  {
    $entity = $args->getEntity();
  
    if (method_exists($entity, 'setCreatedBy') {
      $user = $this->container->get('security.context')->getToken()->getUser();
      $entity->setCreatedBy($user);
    }
  }