src/CoreBundle/DependencyInjection/Configuration.php
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode    = $treeBuilder->root('metamodels');

        $rootNode
            ->children()
                ->booleanNode('enable_cache')
                    ->defaultValue(!$this->debug)
                ->end()
                ->scalarNode('cache_dir')
                    ->defaultValue('%kernel.cache_dir%' . DIRECTORY_SEPARATOR . 'metamodels')
                ->end()
                ->scalarNode('assets_dir')
                    ->cannotBeEmpty()
                    ->defaultValue($this->resolvePath($this->rootDir . '/assets/metamodels'))
                    ->validate()
                        ->always(function ($value) {
                            return $this->resolvePath($value);
                        })
                    ->end()
                ->end()
                ->scalarNode('assets_web')
                    ->cannotBeEmpty()
                    ->defaultValue('assets/metamodels')
                ->end()
            ->end();

        return $treeBuilder;
    }
public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode    = $treeBuilder->root('metamodels');

        $rootNode
            ->children()
                ->booleanNode('enable_cache')
                    ->defaultValue(!$this->debug)
                ->end()
                ->scalarNode('cache_dir')
                    ->defaultValue('%kernel.cache_dir%' . DIRECTORY_SEPARATOR . 'metamodels')
                ->end()
                ->scalarNode('assets_dir')
                    ->cannotBeEmpty()
                    ->defaultValue($this->resolvePath($this->rootDir . '/assets/metamodels'))
                    ->validate()
                        ->always(function ($value) {
                            return $this->resolvePath($value);
                        })
                    ->end()
                ->end()
                ->scalarNode('assets_web')
                    ->cannotBeEmpty()
                    ->defaultValue('assets/metamodels')
                ->end()
            ->end();

        return $treeBuilder;
    }
Generates the configuration tree builder.

@return TreeBuilder