protected function addEndpointsSection(ArrayNodeDefinition $node)
    {
        $node->children()
            ->arrayNode('endpoints')
                ->info('Solr Search Engine endpoint configuration')
                ->useAttributeAsKey('endpoint_name')
                ->performNoDeepMerging()
                ->prototype('array')
                    ->children()
                        // To support Symfony 3 env() variables we don't parse the dsn setting here but in Endpoint ctor
                        ->scalarNode('dsn')
                            ->defaultNull()
                        ->end()
                        ->scalarNode('scheme')
                            ->defaultValue($this->defaultEndpointValues['scheme'])
                        ->end()
                        ->scalarNode('host')
                            ->defaultValue($this->defaultEndpointValues['host'])
                        ->end()
                        ->scalarNode('port')
                            ->defaultValue($this->defaultEndpointValues['port'])
                        ->end()
                        ->scalarNode('user')
                            ->defaultValue($this->defaultEndpointValues['user'])
                        ->end()
                        ->scalarNode('pass')
                            ->defaultValue($this->defaultEndpointValues['pass'])
                        ->end()
                        ->scalarNode('path')
                            ->defaultValue($this->defaultEndpointValues['path'])
                        ->end()
                        ->scalarNode('core')
                            ->isRequired()
                        ->end()
                    ->end()
                ->end()
            ->end()
        ->end();
    }