public function prepend(ContainerBuilder $container)
    {
        parent::prepend($container);

        // populated from cf's VCAP_SERVICES variable
        $services = getenv('VCAP_SERVICES');
        if (!empty($services)) {
            $services = json_decode($services, true);

            if (!isset($services['rabbitmq'][0]['credentials'])) {
                return false;
            }

            $creds = $services['rabbitmq'][0]['credentials'];
            $container->setParameter('rabbitmq.host', $creds['host']);
            $container->setParameter('rabbitmq.port', $creds['port']);
            $container->setParameter('rabbitmq.user', $creds['username']);
            $container->setParameter('rabbitmq.password', $creds['password']);
            $container->setParameter('rabbitmq.vhost', $creds['vhost']);
        } else {
            $container->setParameter('rabbitmq.host', $container->getParameter('graviton.rabbitmq.host'));
            $container->setParameter('rabbitmq.port', $container->getParameter('graviton.rabbitmq.port'));
            $container->setParameter('rabbitmq.user', $container->getParameter('graviton.rabbitmq.user'));
            $container->setParameter('rabbitmq.password', $container->getParameter('graviton.rabbitmq.password'));
            $container->setParameter('rabbitmq.vhost', $container->getParameter('graviton.rabbitmq.vhost'));
        }
    }