gistfile1.py

# With a callback
def test():
    def handle_user(username, first_name, last_name, exception=None):
        if exception:
            # Blow up
            return

        print username, first_name, last_name

    get_user_id(10, handle_user)

# With tornado.gen interface
@gen.async
def test2():
    username, first_name, last_name, exception = yield gen.Task(get_user_id, 10)

    if exception:
        # Blow up
        return

    print username, first_name, last_name


# User module
def get_user_id(user_id, callback):
    async.run(da.read_user, callback, user_id)


# DA module
def read_user(user_id):
    # Synchronous call here
    user = User.objects.get(user_id)
    if user is None:
        raise Exception("Missing user")

    return user.username, user.first_name, user.last_name