Cache-Aside Pattern in Python: Per-Service Mock

class ServiceCache:
    def __init__(self):
        self.database = {"user:1": "Alice", "user:2": "Bob", "user:3": "Charlie"}
        self.cache = {}

    def get_user(self, user_id):
        cache_key = f"user:{user_id}"
        if cache_key in self.cache:
            print(f"CACHE HIT: {cache_key}")
            return self.cache[cache_key]

        print(f"CACHE MISS: {cache_key}, loading from database")
        user = self.database.get(cache_key)
        if user:
            self.cache[cache_key] = user
        return user

    def update_user(self, user_id, new_name):
        cache_key = f"user:{user_id}"
        self.database[cache_key] = new_name
        self.cache.pop(cache_key, None)
        print(f"UPDATED {cache_key}, invalidated cache")


if __name__ == "__main__":
    service = ServiceCache()

    print("First read (cache miss):", service.get_user(1))
    print("Second read (cache hit):", service.get_user(1))
    print("Third read (cache hit):", service.get_user(1))

    service.update_user(1, "Alice Smith")
    print("After update (cache miss):", service.get_user(1))
    print("After update (cache hit):", service.get_user(1))