How to Implement a Sliding Window Log Rate Limiter in Python

from collections import deque
from datetime import datetime, timedelta
from time import sleep


class SlidingWindowLog:
    def __init__(self, window_seconds: int, max_requests: int):
        self.window_seconds = window_seconds
        self.max_requests = max_requests
        self.timestamps = deque()

    def allow_request(self) -> bool:
        now = datetime.utcnow()
        cutoff = now - timedelta(seconds=self.window_seconds)

        while self.timestamps and self.timestamps[0] < cutoff:
            self.timestamps.popleft()

        if len(self.timestamps) < self.max_requests:
            self.timestamps.append(now)
            return True
        return False

    def get_timestamps(self) -> list:
        return list(self.timestamps)


if __name__ == "__main__":
    log = SlidingWindowLog(window_seconds=3, max_requests=2)

    print(log.allow_request())   # True
    sleep(0.1)
    print(log.allow_request())   # True
    sleep(0.1)
    print(log.allow_request())   # False (window full)

    sleep(3.5)                   # wait for window to expire

    print(log.allow_request())   # True (old timestamps evicted)
    print(log.get_timestamps())  # show current window contents