Struct Quota 

pub struct Quota { /* private fields */ }

A rate-limiting quota.

Quotas are expressed in a positive number of “cells” (the maximum number of positive decisions / allowed items until the rate limiter needs to replenish) and the amount of time for the rate limiter to replenish a single cell.

Neither the number of cells nor the replenishment unit of time may be zero.

Burst Sizes

There are multiple ways of expressing the same quota: a quota given as Quota::per_second(1) allows, on average, the same number of cells through as a quota given as Quota::per_minute(60). The quota of Quota::per_minute(60) has a burst size of 60 cells, meaning it is possible to accommodate 60 cells in one go, after which the equivalent of a minute of inactivity is required for the burst allowance to be fully restored.

Burst size gets really important when you construct a rate limiter that should allow multiple elements through at one time (using RateLimiter.check_n and its related functions): Only at most as many cells can be let through in one call as are given as the burst size.

In other words, the burst size is the maximum number of cells that the rate limiter will ever allow through without replenishing them.

Implementations

impl Quota

Constructors for Quotas

pub const fn per_second(max_burst: NonZeroU32) -> Option<Self>

Constructs a quota for a number of cells per second. The given number of cells is also assumed to be the maximum burst size.

Returns None if max_burst is so large that the replenish interval rounds to zero nanoseconds (i.e. max_burst > 1_000_000_000).

pub const fn per_minute(max_burst: NonZeroU32) -> Self

Constructs a quota for a number of cells per 60-second period. The given number of cells is also assumed to be the maximum burst size.

pub const fn per_hour(max_burst: NonZeroU32) -> Self

Constructs a quota for a number of cells per 60-minute period. The given number of cells is also assumed to be the maximum burst size.

pub const fn with_period(replenish_1_per: Duration) -> Option<Self>

Constructs a quota that replenishes one cell in a given interval.

If the time interval is zero, returns None.

pub const fn allow_burst(self, max_burst: NonZeroU32) -> Self

Adjusts the maximum burst size for a quota to construct a rate limiter with a capacity for at most the given number of cells.

impl Quota

Retrieving information about a quota

pub const fn replenish_interval(&self) -> Duration

The time it takes for a rate limiter with an exhausted burst budget to replenish a single element.

pub const fn burst_size(&self) -> NonZeroU32

The maximum number of cells that can be allowed in one burst.

pub const fn burst_size_replenished_in(&self) -> Duration

The time it takes to replenish the entire maximum burst size.

Saturates at Duration::MAX if the full duration cannot be represented.

Trait Implementations

impl Clone for Quota

fn clone(&self) -> Quota

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Quota

impl Debug for Quota

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

Formats the value using the given formatter.

impl Eq for Quota

impl PartialEq for Quota

fn eq(&self, other: &Quota) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Quota