Struct governor::DirectRateLimiter

pub struct DirectRateLimiter<C: Clock = DefaultClock> { /* fields omitted */ }

An in-memory rate limiter that makes direct (un-keyed) rate-limiting decisions. Direct rate limiters can be used to e.g. regulate the transmission of packets on a single connection, or to ensure that an API client stays within a service's rate limit.

Methods

impl<C: Clock<Instant = Instant>> DirectRateLimiter<C>

pub async fn until_ready<'_>(&'_ self)

Returns a future that resolves as soon as the rate limiter allows it.

impl DirectRateLimiter<DefaultClock>

pub fn new(quota: Quota) -> Self

Construct a new direct rate limiter for a quota with the default clock.

impl<C: Clock> DirectRateLimiter<C>

pub fn check(&self) -> Result<(), NotUntil<C::Instant>>

Allow a single cell through the rate limiter.

If the rate limit is reached, check returns information about the earliest time that a cell might be allowed through again.

pub fn check_all(
    &self,
    n: NonZeroU32
) -> Result<(), NegativeMultiDecision<NotUntil<C::Instant>>>

Allow only all n cells through the rate limiter.

This method can succeed in only one way and fail in two ways:

• Success: If all n cells can be accommodated, it returns Ok(()).
• Failure (but ok): Not all cells can make it through at the current time. The result is Err(NegativeMultiDecision::BatchNonConforming(NotUntil)), which can be interrogated about when the batch might next conform.
• Failure (the batch can never go through): The rate limit is too low for the given number of cells.

Performance

This method diverges a little from the GCRA algorithm, using multiplication to determine the next theoretical arrival time, and so is not as fast as checking a single cell.

pub fn new_with_clock(quota: Quota, clock: &C) -> DirectRateLimiter<C>

Construct a new direct rate limiter with a custom clock.

Trait Implementations

impl<C: Debug + Clock> Debug for DirectRateLimiter<C> where
    C::Instant: Debug, 

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

Formats the value using the given formatter.