example_handlers_registry.py

import time
from handlers import handlers, invalid_command, Exit


def get_greeting():
    commands = ", ".join(handlers)
    return (
        f"available commands are: {commands}\n"
        "hit CTRL+C or type exit to exit"
    )


def receive_command():
    command, *arguments = input("$ ").split()
    return command, arguments


def process_command(command, arguments, context):
    command_function = handlers.get(command, invalid_command)
    return command_function(*arguments, **context)


def send(response):
    print(response)


def run_server():
    context = {
        "start_time": time.time(),
        "info": "this is some fake data just to pass as example kwarg",
    }

    send(get_greeting())
    while True:
        command, arguments = receive_command()
        response = process_command(command, arguments, context)
        send(response)


if __name__ == "__main__":
    try:
        run_server()
    except (Exit, KeyboardInterrupt):
        print("exit")

handlers.py

import time

handlers = {}


class Exit(Exception):
    pass


def register(name):
    def decorate(f):
        handlers[name] = f
        return f

    return decorate


@register("serverinfo")
def server_info(*args, info, **kwargs):
    return f"this is server info: {info}"


@register("uptime")
def uptime(*args, start_time, **kwargs):
    duration = time.time() - start_time
    return f"this is uptime: {duration}"


@register("newaccount")
def create_new_account(username, password, **kwargs):
    return f"new account registered: {username}"


@register("exit")
def exit(*_, **__):
    raise Exit()


def invalid_command(*args, **kwargs):
    return "invalid command"