library/library_app/controllers/main.py

from odoo import http

class Books(http.Controller):

    @http.route('/library/books', auth='user')
    def list(self, **kwargs):
        Book = http.request.env['library.book']
        books = Book.search([])
        return http.request.render(
            'library_app.book_list_template', {'books':books})