Struct RateLimiter 

pub struct RateLimiter { /* private fields */ }

Per-subject rate limiting.

Cheap to clone into an axum layer: the counters are behind an Arc, and two clones are one table rather than two.

Implementations

impl RateLimiter

pub fn new(policy: RateLimit) -> Self

A limiter applying policy, holding DEFAULT_CAPACITY subjects.

pub fn with_capacity(policy: RateLimit, capacity: usize) -> Self

A limiter holding at most capacity subjects before it sweeps.

capacity is never read as zero: a table that cannot hold a subject would clear itself on every request and limit nobody.

pub const fn policy(&self) -> &RateLimit

The policy this limiter applies.

pub fn check(&self, subject: &str) -> Verdict

Counts one request from subject and says whether it may proceed.

The clock is read here rather than passed in so a caller cannot accidentally supply a stale Instant; check_at is the same function with the clock supplied, and exists for tests.

pub fn check_at(&self, subject: &str, now: Instant) -> Verdict

check with the observation time supplied.

Public because a test that has to sleep for a wall-clock window is a test that is skipped in CI.

pub fn tracked(&self) -> usize

How many subjects are currently tracked.

Public so a test can assert the bound is actually a bound.

Trait Implementations

impl Clone for RateLimiter

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RateLimiter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.