Programatically define Menu links

Question

I want to show Login link in the Menu navigation, only for guest User.

clinical_trial.login:
  title: Login
  description: 'Login'
  parent: main
  menu_name: main
  route_name: user.login

This is my Custom Menu links code.

What to add?

Answer 1

If you are creating a menu link from a custom module, you can check this

https://www.drupal.org/docs/8/api/routing-system/structure-of-routes

Quoting the documentation:

requirements (required): Determines what must be met in order to grant access to the route. 
    _role: A specific Drupal role, eg. 'anonymous'. 

Alternatively you can use this module: https://www.drupal.org/project/menu_item_visibility "It exposes configurable and extendable visibility settings for menu links."