This is how to configure a Service in Symfony 2 with dynamic parameters. No magic, but still awesome.

DefaultController.php

<?
  //..
  //the following will return an Instance of InstagramAPI ... configured and ready to roll!
  $this->get('instagram');
  //..
?>

InstagramAPI.class.php

<?
  //...
  public function __construct($apiKey, $apiSecret, Request $request, Router $router) {

      if(empty($apiKey)){
          throw new \Exception("Error: __construct() - Configuration data is missing.");
      }

      $this->setApiKey($apiKey);
      $this->setApiSecret($apiSecret);
      $this->setApiCallbackFromSymfonyData($request, $router);
  }
  //...
?>

services.yml

parameters:
    client_id: xxxxx
    client_secret: yyyyy
    clops.instagram.api.class: Clops\InstagramBundle\InstagramAPI

services:
    instagram:
        scope: request
        class: "%clops.instagram.api.class%"
        arguments: ["%client_id%", "%client_secret%", @request, @router]

try this: http://jmsyst.com/bundles/JMSDiExtraBundle/master/annotations ;) it's awsome to write