MediumRate LimitingPython 3

Notification Rate Limiter

Throttle noisy notification channels while deduping repeated webhook or automation events.

35m2 sample tests5 hidden tests

Implement NotificationLimiter, a per-channel notification throttle with dedupe keys.

Requirements

Constructor receives limit, window_seconds, and injected now.
allow(channel, dedupe_key) returns (allowed, retry_after_seconds).
A channel may send at most limit unique dedupe keys per rolling window.
Repeating the same dedupe key inside the window is blocked without consuming a new slot.
Expired records are removed on every call.
retry_after_seconds is 0 when allowed.

Example

python

clock = {"now": 0.0}
limiter = NotificationLimiter(2, 10.0, lambda: clock["now"])
assert limiter.allow("slack", "a") == (True, 0.0)
assert limiter.allow("slack", "a")[0] is False

Constraints

Use injected time. Keep tests free of sleeps.
Keep channels isolated.

Editor