symfony2 DI how to compile only doctrine bundle

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<?php

namespace Foo;

//use Doctrine\ORM\Configuration;
use Doctrine\ORM\EntityManager;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Bundle\DoctrineBundle\DependencyInjection\DoctrineExtension;
use Symfony\Component\DependencyInjection\Dumper\PhpDumper;
use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;

class FooClass
{
    public static function get()
    {
        $parameterBag = new ParameterBag(array(
            'kernel.debug' => true,
            'kernel.root_dir' => '/path/to/root/dir',
            'kernel.cache_dir' => sys_get_temp_dir(),
            'kernel.environment' => 'test',
            'kernel.bundles' => array(),
            ));
        
        $doctrineExtenstion = new DoctrineExtension();
        
        $container = new ContainerBuilder($parameterBag);
        $container->registerExtension($doctrineExtenstion);
        $container->loadFromExtension($doctrineExtenstion->getAlias(), array(
            'dbal' => array(
                'default_connection' => 'default',
                'connections' => array(
                    'default' => array(
                        'driver' => 'pdo_sqlite',
                        'path'   => ':memory:'
                     ),
                ),
            ),
            'orm' => array(
                'auto_generate_proxy_classes'   => true,
                'proxy_namespace' => 'Proxies',
                'proxy_dir' => sys_get_temp_dir(),
                'default_entity_manager' => 'default',
                'entity_managers' => array(
                    'default' => array(
                        'connection' => 'default',
                        'mappings' => array(),
                        'class_metadata_factory_name' => 'Doctrine\ORM\Mapping\ClassMetadataFactory',
                        'metadata_cache_driver' => 'array',
                        'query_cache_driver' => 'array',
                    ),
                ),
            
            ),
        ));
        
        $container->compile();
        
        // cache the container
        $dumper = new PhpDumper($container);
        $content = $dumper->dump(array('class' => 'FooContainer', 'base_class' => 'Container'));       
        
        $filePath = tempnam(sys_get_temp_dir(), 'foo');
        file_put_contents($filePath, $content);
        
        require_once $filePath;
        
        return new \FooContainer();
    }
}