Struct CircuitBreaker 

pub struct CircuitBreaker {
    pub threshold: u32,
    pub cool_off: Duration,
    pub scope: BreakerScope,
}

Holding back deliveries to a destination that keeps failing, rather than sending each one to fail in turn, as a Stoplight with its default strategies does.

After threshold failures in a row a destination’s breaker opens (red), and deliveries to it are held — retried as failures, without a request — until cool_off has passed since the failure that opened it. Then it is half-open (yellow): one delivery at a time is let through as a probe, and the others are held while it is under way. A probe that succeeds closes the breaker; one that fails opens it for another cool_off. A probe that never reports back stops being one after cool_off, and the next delivery probes instead.

A failure is what may pass: a 5xx, 408, 429, or no answer. An answer that will not change is the server working. A success while the breaker is closed starts its count of failures again; one that was sent before the breaker opened and answers after does not close it, as only a probe does.

It is kept in memory, for each deliverer, unless the application gives the deliverer a BreakerStore of its own: deliverers in several processes sharing one store count their failures together, and let one probe through between them.

Fields

threshold: u32

Failures in a row that open it.

cool_off: Duration

How long it stays open before a probe is let through, and how long a probe is waited for.

scope: BreakerScope

What one breaker is kept for.

Trait Implementations

impl Clone for CircuitBreaker

fn clone(&self) -> CircuitBreaker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CircuitBreaker

impl Debug for CircuitBreaker

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

Formats the value using the given formatter.

impl Default for CircuitBreaker

fn default() -> Self

Ten failures in a row and a minute’s cool-off, as Mastodon’s, but for each host, where Mastodon keeps one for each inbox.

impl Eq for CircuitBreaker

impl PartialEq for CircuitBreaker

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for CircuitBreaker