Decisions

Admission calls (inc and absolute is_allowed) return RateLimitDecision. Provider changes where state lives, but decision model stays same.

Allowed

Allowed means the request should proceed.

You will see this:

• below the limit in absolute mode
• below the limit in suppressed mode
• sometimes above the nominal limit in suppressed mode when the probabilistic check still admits the request

Rejected

Rejected is used by the absolute strategy.

It means the limiter hit a hard boundary and the request should not proceed. The decision can also include best-effort hints such as:

• window_size: WindowSize: configured duration of sliding window.
• retry_after: Duration: standard-library duration until oldest live bucket expires.
• remaining_after_waiting: u64: capacity released when that bucket expires.

retry_after is time until oldest live bucket expires. remaining_after_waiting is capacity that bucket releases, not usage remaining afterward. These are operational hints, not exact future admission promises.

For example, if oldest bucket contains 3 and next bucket contains 7, remaining_after_waiting is 3. See Configuration Types for WindowSize and other validated settings.

Suppressed

Suppressed is used by the suppressed strategy. It carries:

• is_allowed
• suppression_factor

The important rule is simple: always check is_allowed.

If is_allowed is true, the request may proceed. If it is false, the request should be dropped or degraded.

When each decision shape appears

RateLimitDecision variants are exhaustive. Fields inside Rejected and Suppressed are non-exhaustive, so match them with { .. }.

What this means for application code

• Absolute mode is easiest when your app wants a hard yes/no answer.
• Suppressed mode is better when your app wants controlled load shedding instead of a cliff-edge cutoff.