Struct http_rate::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). However, 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

pub fn per_second<B>(max_burst: B) -> Self

where B: TryInto<NonZeroU32>, B::Error: Debug,

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

Panics

• When max_burst is zero.

pub fn per_minute<B>(max_burst: B) -> Self

where B: TryInto<NonZeroU32>, B::Error: Debug,

Construct 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.

Panics

• When max_burst is zero.

pub fn per_hour<B>(max_burst: B) -> Self

where B: TryInto<NonZeroU32>, B::Error: Debug,

Construct a quota for a number of cells per 60-minute (3600-second) period. The given number of cells is also assumed to be the maximum burst size.

Panics

• When max_burst is zero.

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

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

This constructor is meant to replace ::new, in cases where a longer refresh period than 1 cell/hour is necessary.

If the time interval is zero, returns None.

pub fn allow_burst<B>(self, max_burst: B) -> Self

where B: TryInto<NonZeroU32>, B::Error: Debug,

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

Panics

• When max_burst is zero.

Trait Implementations

impl Clone for Quota

fn clone(&self) -> Quota

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Quota

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

Formats the value using the given formatter.

impl PartialEq for Quota

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Quota

impl Eq for Quota

impl StructuralEq for Quota

impl StructuralPartialEq for Quota