pubsub.py

from collections import defaultdict
from typing import Callable


REGISTRY: defaultdict = defaultdict(list)


def channel_handler(channel: str) -> Callable:
    def decorator(func: Callable) -> Callable:
        REGISTRY[channel].append(func)
        return func
    
    return decorator


def run_handlers(notify: Notify) -> None:
    handlers = REGISTRY.get(notify.channel, [])
    
    if not handlers:
        return
    
    for handler in handlers:
        handler(payload=notify.payload)
    

@channel_handler('top_score')
def notify_customers(payload: dict) -> None:
    ...