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| 1 | +//! Exponential backoff implementation for Pyth Lazer client. |
| 2 | +//! |
| 3 | +//! This module provides a wrapper around the [`backoff`] crate's exponential backoff functionality, |
| 4 | +//! offering a simplified interface tailored for Pyth Lazer client operations. |
| 5 | +
|
| 6 | +use std::time::Duration; |
| 7 | + |
| 8 | +use backoff::{ |
| 9 | + default::{INITIAL_INTERVAL_MILLIS, MAX_INTERVAL_MILLIS, MULTIPLIER, RANDOMIZATION_FACTOR}, |
| 10 | + ExponentialBackoff, ExponentialBackoffBuilder, |
| 11 | +}; |
| 12 | + |
| 13 | +/// A wrapper around the backoff crate's exponential backoff configuration. |
| 14 | +/// |
| 15 | +/// This struct encapsulates the parameters needed to configure exponential backoff |
| 16 | +/// behavior and can be converted into the backoff crate's [`ExponentialBackoff`] type. |
| 17 | +#[derive(Debug)] |
| 18 | +pub struct HermesExponentialBackoff { |
| 19 | + /// The initial retry interval. |
| 20 | + initial_interval: Duration, |
| 21 | + /// The randomization factor to use for creating a range around the retry interval. |
| 22 | + /// |
| 23 | + /// A randomization factor of 0.5 results in a random period ranging between 50% below and 50% |
| 24 | + /// above the retry interval. |
| 25 | + randomization_factor: f64, |
| 26 | + /// The value to multiply the current interval with for each retry attempt. |
| 27 | + multiplier: f64, |
| 28 | + /// The maximum value of the back off period. Once the retry interval reaches this |
| 29 | + /// value it stops increasing. |
| 30 | + max_interval: Duration, |
| 31 | +} |
| 32 | + |
| 33 | +impl From<HermesExponentialBackoff> for ExponentialBackoff { |
| 34 | + fn from(val: HermesExponentialBackoff) -> Self { |
| 35 | + ExponentialBackoffBuilder::default() |
| 36 | + .with_initial_interval(val.initial_interval) |
| 37 | + .with_randomization_factor(val.randomization_factor) |
| 38 | + .with_multiplier(val.multiplier) |
| 39 | + .with_max_interval(val.max_interval) |
| 40 | + .with_max_elapsed_time(None) |
| 41 | + .build() |
| 42 | + } |
| 43 | +} |
| 44 | + |
| 45 | +/// Builder for [`PythLazerExponentialBackoff`]. |
| 46 | +/// |
| 47 | +/// Provides a fluent interface for configuring exponential backoff parameters |
| 48 | +/// with sensible defaults from the backoff crate. |
| 49 | +#[derive(Debug)] |
| 50 | +pub struct HermesExponentialBackoffBuilder { |
| 51 | + initial_interval: Duration, |
| 52 | + randomization_factor: f64, |
| 53 | + multiplier: f64, |
| 54 | + max_interval: Duration, |
| 55 | +} |
| 56 | + |
| 57 | +impl Default for HermesExponentialBackoffBuilder { |
| 58 | + fn default() -> Self { |
| 59 | + Self { |
| 60 | + initial_interval: Duration::from_millis(INITIAL_INTERVAL_MILLIS), |
| 61 | + randomization_factor: RANDOMIZATION_FACTOR, |
| 62 | + multiplier: MULTIPLIER, |
| 63 | + max_interval: Duration::from_millis(MAX_INTERVAL_MILLIS), |
| 64 | + } |
| 65 | + } |
| 66 | +} |
| 67 | + |
| 68 | +impl HermesExponentialBackoffBuilder { |
| 69 | + /// Creates a new builder with default values. |
| 70 | + pub fn new() -> Self { |
| 71 | + Default::default() |
| 72 | + } |
| 73 | + |
| 74 | + /// Sets the initial retry interval. |
| 75 | + /// |
| 76 | + /// This is the starting interval for the first retry attempt. |
| 77 | + pub fn with_initial_interval(&mut self, initial_interval: Duration) -> &mut Self { |
| 78 | + self.initial_interval = initial_interval; |
| 79 | + self |
| 80 | + } |
| 81 | + |
| 82 | + /// Sets the randomization factor to use for creating a range around the retry interval. |
| 83 | + /// |
| 84 | + /// A randomization factor of 0.5 results in a random period ranging between 50% below and 50% |
| 85 | + /// above the retry interval. This helps avoid the "thundering herd" problem when multiple |
| 86 | + /// clients retry at the same time. |
| 87 | + pub fn with_randomization_factor(&mut self, randomization_factor: f64) -> &mut Self { |
| 88 | + self.randomization_factor = randomization_factor; |
| 89 | + self |
| 90 | + } |
| 91 | + |
| 92 | + /// Sets the value to multiply the current interval with for each retry attempt. |
| 93 | + /// |
| 94 | + /// A multiplier of 2.0 means each retry interval will be double the previous one. |
| 95 | + pub fn with_multiplier(&mut self, multiplier: f64) -> &mut Self { |
| 96 | + self.multiplier = multiplier; |
| 97 | + self |
| 98 | + } |
| 99 | + |
| 100 | + /// Sets the maximum value of the back off period. |
| 101 | + /// |
| 102 | + /// Once the retry interval reaches this value it stops increasing, providing |
| 103 | + /// an upper bound on the wait time between retries. |
| 104 | + pub fn with_max_interval(&mut self, max_interval: Duration) -> &mut Self { |
| 105 | + self.max_interval = max_interval; |
| 106 | + self |
| 107 | + } |
| 108 | + |
| 109 | + /// Builds the [`PythLazerExponentialBackoff`] configuration. |
| 110 | + pub fn build(&self) -> HermesExponentialBackoff { |
| 111 | + HermesExponentialBackoff { |
| 112 | + initial_interval: self.initial_interval, |
| 113 | + randomization_factor: self.randomization_factor, |
| 114 | + multiplier: self.multiplier, |
| 115 | + max_interval: self.max_interval, |
| 116 | + } |
| 117 | + } |
| 118 | +} |
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