Symfony2: How to use twig templates in service container?

Question

symfony

It is necessary to send form data (field name + value) to email. But I can’t figure out how to connect twig templates in the service.
Mistake:

Attempted to call an undefined method named "render" of class "AppBundle\Helper\Notification".

//  SomeController.php
...
if ($form->isSubmitted()) {
   if ($form->isValid()) {
      $this->get('app.send.notification') 
           ->send('Заголовок', $form);
   }
}

// services.yml
services:
    app.send.notification:
        class: AppBundle\Helper\Notification
        arguments:
          service: ["@service_container"]

<?php
// AppBundle\Helper\Notification
namespace AppBundle\Helper;

use Symfony\Component\DependencyInjection\ContainerInterface as Container;

class Notification {
    
/**
 * admin email address
 */
const EMAIL_FROM = '[email protected]';
   
/**
 * my email address
 */
const EMAIL_TO = '[email protected]';
  
/*
 * @var array
 */
protected $dataMail = [];


/**
 * service container
 *
 * @var object
 */
protected $service;
 
/**
 * init service
 *
 * @param object $service
 * @return $this
 */
public function __construct($service) {
    $this->service = $service;
    return $this;
}

/**
 * Send notification
 *
 * @param string $subject
 * @param array $form
 */    
public function send($subject, $form) {
        
    $data_form = $form->all();
    array_pop($data_form);

    foreach ($data_form as $value) {
        $label = $value->getConfig()
                       ->getOption("label");
        $data = $value->getData();
        $res = ($data instanceof \DateTime) ? ($data->format('d.m.Y')) : $data;
        $this->dataMail[$label] = $res;

        try {
            $message = \Swift_Message::newInstance()
                    ->setSubject($subject)
                    ->setFrom(self::EMAIL_FROM)
                    ->setTo(self::EMAIL_TO)
                    ->setBody(
                        $this->render(
                            'Emails/request.html.twig', array('form' => $dataMail)
                        ), 'text/plain');
            
            $this->service->get('mailer')->send($message);
        } catch (Swift_TransportException $e) {
            return $e->getMessage();
        } catch (Exception $e) {
            return $e->getMessage();
        }
    }
}

// request.html.twig
{% for value in form %}
    {{ value }}
{% endfor %}

Answer 1

You need to pass a template engine to the service, i.e.

app.send.notification:
        class: AppBundle\Helper\Notification
        arguments:
          service: ["@templating"]

In service:

public function __construct($templating) { //Класс по-моему Twig_Engine, могу ошибаться
    $this->templating = $templating;
}

And use it accordingly like:
$this->templating->render(...);

Answer 2

$this->container->get('templating')->renderView($view, $parameters)