config.yml

FooNamespace\FooClass:
  FooNamespace\BarClass:
    setting1: value
    setting2: value

FooService.php

<?php

class FooService
{
  protected $container;
  
  public function __construct(Symfony\Component\DependencyInjection\Container $container)
  {
    $this->container = $container;
  }
  
  public function createFooObject(\stdClass $obj1)
  {
    $config = $this->container->getParameter('foo_service.config');
    
    if(!is_array($config) || !array_key_exists(get_class($obj1), $config)){
      throw new \Exception('Config for class ' . get_class($obj1) . ' not found');
    }
  }
}

What if you want to use FooNamespace\MegaBarClass instead. That extends functionality of FooNamespace\BarClass ? You need to update config???

In that case yes, because the classes are in fact entities and I persist them. All is about entities. I'm trying to be able to configure my bundle to manage the relation between 2 entities

<?php

interface ConfigurableEntity
{
    public function getEntityName();
}

class ConfigurableBarEntity implements ConfigurableEntity
{
    public function getEntityName()
    {
        return 'bar';
    }
}

class FooService
{ 
  public function createFooObject(ConfigurableEntity $entity)
  {
    $config = $this->container->getParameter('foo_service.config');

    if(!is_array($config) || !array_key_exists($entity->getConfigKey(), $config)){
      throw new \Exception('Config for entity ' . $entity->getEntityName() . ' not found');
    }
  }
}

foo:
  bar:
    setting1: value
    setting2: value

You rocks! Thanks for show me the way :)