how to add token auth to swagger + django rest framework?

I answer myself since I made it work.

Actually Swagger settings has an option for this, api_key ->

SWAGGER_SETTINGS = {
    "exclude_namespaces": [], # List URL namespaces to ignore
    "api_version": '0.1',  # Specify your API's version
    "api_path": "/",  # Specify the path to your API not a root level
    "enabled_methods": [  # Specify which methods to enable in Swagger UI
        'get',
        'post',
        'put',
        'patch',
        'delete'
    ],
    "api_key": '', # An API key
    "is_authenticated": False,  # Set to True to enforce user authentication,
    "is_superuser": False,  # Set to True to enforce admin only access
}

To me it wasn't that clear, but I've just input a valid token for testing user and it worked for the auth needed views :-)

If you're using token authentication, you might want to look at this question

Basically, you just need to add this to your settings.py:

SWAGGER_SETTINGS = {
    'SECURITY_DEFINITIONS': {
        'api_key': {
            'type': 'apiKey',
            'in': 'header',
            'name': 'Authorization'
        }
    },
}

In your Swagger UI page you should see an Authorize button. Click that and enter your Authorization value in the input text field.