Symfony2注销代码的位置，我在哪里放置无效代码

新Symfony用户在这里…

Symfony文档中的示例实际上没有任何关于如何正确注销的示例。这是我的security.yml

security:
    encoders: 
        Symfony'Component'Security'Core'User'User: plaintext
        AppBundle'Entity'User: bcrypt
    role_hierarchy:
        ROLE_ADMIN: [ROLE_USER]
    providers:
        chain_provider: 
            chain:
                providers: [in_memory, user_db]
        in_memory:
            memory:
                users: 
                    admin: { password: adminpass, roles: ROLE_ADMIN }
        user_db:
            entity: { class: AppBundle:User, property: username }
    firewalls:
        main: 
            pattern: /.*
            form_login:
                login_path: /login
                check_path: /login_check
                default_target_path: /
            logout:
                path: /logout
                target: /
                invalidate_session:   true
                delete_cookies:
                    name:
                    path: null
                    domain: null
            security: true
            anonymous: true
    access_control:
        - { path: /login, roles: IS_AUTHENTICATED_ANONYMOUSLY }
        - { path: /cms/user, roles: ROLE_ADMIN }
        - { path: /.*, roles: IS_AUTHENTICATED_ANONYMOUSLY }

我对这些设置的印象是，只要点击/logout路由，会话就会被破坏，用户将被重定向到登录页面。然而，在尝试这样做时，我得到一个no route found错误。

我发现这段代码在这里的堆栈溢出…

$this->get('security.token_storage')->setToken(null);
$this->get('request')->getSession()->invalidate();

很好，但是我对Symfony太陌生了，我不知道把它放在哪里。Stack上的所有示例都给出了该代码，但没有说明如何实现它。我要这样写一个注销操作吗?

    /**
     * @Route("/logout")
     */
    public function logoutAction() {
        $this->get('security.token_storage')->setToken(null);
        $this->get('request')->getSession()->invalidate();
        //if this works how do I redirect to another route, 
        //specifically back to /login
        return $this->render(
            //do i need a template?
            //do i need the array here?
            );
    }