eZ Publish 5 - Legacy module with a Symfony controller

AdminController.php

<?php
/**
 * AcmeTestBundle/Controller/AdminController.php
 */
namespace Acme\TestBundle\Controller;

use eZ\Bundle\EzPublishCoreBundle\Controller;

/**
 * Here is your Symfony controller, defined as a service (see service definition below)
 **/
class AdminController extends Controller
{
    public function myAdminAction( $myParam = null )
    {
        return $this->render(
           'AcmeTestBundle::my_admin_action.html.twig',
            array(
                'some_var' => $myParam
            )
        );
    }
}

my_admin_action.html.twig

{# AcmeTestBundle/Resources/views/my_admin_action.html.twig #}
<h1>We did it with a Symfony controller !</h1>

<h2>{{ some_var }}</h2>

services.yml

# AcmeTestBundle/Resources/config/services.yml
parameters:
    my.admin.controller.class: Acme\TestBundle\Controller\AdminController

services:
    # Defining this controller as a service so it can be called from the container
    # in the legacy module
    my.admin.controller:
        class: %my.admin.controller.class%
        calls:
            # This setter is mandatory to be able to use all shorthand methods
            - [setContainer, [@service_container]]

sftest.php

<?php
/**
 * ezpublish_legacy/extension/myextension/modules/mymodule/sftest.php
 * 
 * Simple module test to use Symfony
 * This is your legacy module view
 */

$Module = $Params['Module'];
$Result = array();

$container = ezpKernel::instance()->getServiceContainer();
/** @var \Acme\TestBundle\Controller\AdminController $controller */
$controller = $container->get( 'my.admin.controller' );
$Result['content'] = $controller->myAdminAction( 'blabla' )->getContent();