auth.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-
from functools import wraps
from getpass import getpass
import sys
import pickle

from db import Users


Logged = False

def authenticate(username, password):
    try:
        global Users
        with open("database.db","r") as f:
            Users = pickle.load(f)
    except Exception:
        pass
    for user in Users:
        if user['username'] == username and user['password'] == password:
            return True
    return False


def login():
    global Logged
    if Logged:
        return
    print u"\nLogin necessário!\n"
    username = raw_input(u"Digite o usuário: ")
    password = getpass("Digite a senha: ")
    if authenticate(username, password):
        Logged = True
        print u"Usuário autenticado com sucesso!"
    else:
        print u"Falha na autenticação do usuário!"
        sys.exit(0)


def login_required(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        login()
        return func(*args, **kwargs)
    return wrapper

db.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-

Users = [
    {
        'name': 'Fábio Cerqueira',
        'username': 'fabio',
        'password': 'acens',
    }
]

main.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-
import sys
import pickle
import os.path

from auth import login_required
from screens import menu
from db import Users

@login_required
def create():
    new_name = raw_input(u"Digite o nome do admin a ser adicionado: ")
    new_user = raw_input(u"Digite o usuário do admin: ")
    new_password = raw_input("Digite a senha: ")
    Users.append({'name': new_name, 'username': new_user, 'password': new_password})
    print u"\nUsuário cadastrado com sucesso\n"
    with open("database.db", "w") as f:
        pickle.dump(Users, f)

@login_required
def update():
    update_user = raw_input(u"Digite o nome do usuário a ser modificado: ")
    for user in Users:
        if user['name'] == update_user:
            new_username = raw_input(u"Digite o novo usuário: ")
            new_password = raw_input("Digite a nova senha: ")
            new_user = {'username': new_username, 'password': new_password}
            user.update(new_user)
            print "\nSeus dados foram editados com sucesso\n"
            with open("database.db", "w") as f:
                pickle.dump(Users, f)
            return
    print u"Usuário não existe"

    
@login_required
def delete():
    delete_user = raw_input(u"Digite o nome do usuário a ser deletado: ")
    for user in Users:
        if user['name'] == delete_user:
            Users.remove(user)
            print u"\nUsuário deletado com sucesso\n"
            with open("database.db", "w") as f:
                pickle.dump(Users, f)
            return
        else:
            continue
    print u"Usuário não existe"

        
def show_users():
    i = 1
    for user in Users:
        print "-" * 3
        print "{i} - {user}".format(i = i, user = user['name'])
        print "-" * 3
        i += 1


def exit():
    print 'Bye bye!'
    sys.exit(0)


@login_required
def admin():
    menu_text = u"""
    Menu admin:
        1 - Criar usuário
        2 - Mostrar usuários
        3 - Editar usuário
        4 - Deletar usuário
        5 - Exit
    """
    options = {
        '1': create,
        '2': show_users,
        '3': update,
        '4': delete,
        '5': exit
    }
    menu(menu_text, options)


def home():
    menu_text = u"""
    Menu:
        1 - Mostrar usuários
        2 - Admin
        9 - Exit
    """
    options = {
        '1': show_users,
        '2': admin,
        '9': exit
    }
    menu(menu_text, options)


if __name__ == '__main__':
    try:
        global Users
        with open("database.db", "r") as f:
            Users = pickle.load(f)
    except Exception:
        with open("database.db", "w") as f:
            pass
    home()

screens.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-

def menu(menu_text, options):
    while True:
        print menu_text
        option = raw_input(u"Escolha uma opção: ")
        screen = options.get(option)
        if screen:
            screen()
        else:
            print u"Opção inválida!"