Struct CircuitBreaker 

pub struct CircuitBreaker { /* private fields */ }

A CircuitBreaker throttler rejects retry attempts if the success rate is too low.

This struct implements the gRPC throttler algorithm. The throttler works by tracking the number of available “tokens” for a retry attempt. If this number goes below a threshold all retry attempts are throttled.

Retry failures decrement the number of tokens by a given cost. Completed requests (successfully or not) increase the tokens by 1.

Note: the number of tokens may go below the throttling threshold as multiple concurrent requests may fail and decrease the token count.

Note: throttling only applies to retry attempts, the initial requests is never throttled. This may increases the token count even if all retry attempts are throttled.

Examples

let tokens = 1000;
let min_tokens = 250;
let error_cost = 10;
let throttler = CircuitBreaker::new(tokens, min_tokens, error_cost)?;

Implementations

impl CircuitBreaker

pub fn new(tokens: u64, min_tokens: u64, error_cost: u64) -> Result<Self, Error>

Creates a new instance.

Parameters

• tokens - the initial number of tokens. This is decreased by error_cost on each retry failure, and increased by 1 when a request succeeds.
• min_tokens - stops accepting retry attempts when the number of tokens is at or below this value.
• error_cost - decrease the token count by this value on failed request attempts.

Example

let throttler = CircuitBreaker::new(1000, 250, 10)?;

pub fn clamp(tokens: u64, min_tokens: u64, error_cost: u64) -> Self

Creates a new instance, adjusting min_tokens if needed.

Parameters

• tokens - the initial number of tokens. This is decreased by error_cost on each retry failure, and increased by 1 when a request succeeds.
• min_tokens - stops accepting retry attempts when the number of tokens is at or below this value. Clamped to be <= tokens.
• error_cost - decrease the token count by this value on failed request attempts.

Example

let throttler = CircuitBreaker::clamp(1000, 250, 10);

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 Debug for CircuitBreaker

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

Formats the value using the given formatter.

impl Default for CircuitBreaker

fn default() -> Self

Initialize a CircuitBreaker configured with recommended values.

Example

let throttler = CircuitBreaker::default();

impl RetryThrottler for CircuitBreaker