Struct RateLimiter 

pub struct RateLimiter { /* private fields */ }

A cheap-to-clone async handle around a shared TokenBucket: clones share the same budget.

Two ways to consume it:

• RateLimiter::acquire waits until the budget allows (pacing);
• RateLimiter::try_acquire never waits and reports when to retry (rejecting, e.g. a 429 path).

Time is tracked against a per-limiter epoch taken at construction, using tokio’s clock (so paused-time tests work as expected).

There is no FIFO fairness guarantee between concurrent waiters.

Implementations

impl RateLimiter

pub fn new(rate: Rate, burst: u64) -> RateLimiter

Available on crate features grpc and http and std only.

Create a new RateLimiter with the given Rate and burst capacity, starting full.

Panics

Panics if burst is zero.

pub fn from_rate(rate: Rate) -> RateLimiter

Available on crate features grpc and http and std only.

Create a new RateLimiter with a burst capacity of one period worth of units (rate.units()): a plain smooth rate.

pub fn rate(&self) -> Rate

Available on crate features grpc and http and std only.

The configured Rate.

pub fn burst(&self) -> u64

Available on crate features grpc and http and std only.

The configured burst capacity.

pub fn try_acquire(&self, n: u64) -> Acquire

Available on crate features grpc and http and std only.

Try to spend n units without waiting.

See TokenBucket::try_acquire; the Acquire::RetryAt instant is in this limiter’s clock and can be turned into a deadline with RateLimiter::deadline.

pub async fn acquire(&self, n: u64)

Available on crate features grpc and http and std only.

Spend n units, waiting until the budget allows it.

Requests larger than the burst capacity are acquired in burst-sized chunks, so this never fails: it paces.

pub fn refund(&self, n: u64)

Available on crate features grpc and http and std only.

Give back up to n previously spent units, saturating at the burst capacity.

pub fn deadline(&self, retry_at_nanos: u64) -> Instant

Available on crate features grpc and http and std only.

Turn an Acquire::RetryAt instant into a timer deadline, for poll-based callers.

Trait Implementations

impl Clone for RateLimiter

fn clone(&self) -> RateLimiter

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<(), Error>

Formats the value using the given formatter.