<?php namespace Eesa\CoreBundle\DependencyInjection; use Symfony\Component\Config\Definition\Builder\TreeBuilder; use Symfony\Component\Config\Definition\ConfigurationInterface; class Configuration implements ConfigurationInterface { /** * {@inheritdoc} */ public function getConfigTreeBuilder() { $treeBuilder = new TreeBuilder(); $rootNode = $treeBuilder->root('eesa_core'); $rootNode ->children() ->scalarNode('mandrill_api_key')->isRequired()->end() ->end() ; return $treeBuilder; } }