Failsafe

一种用于检测故障并封装防止故障持续发生的逻辑的实现，这发生在维护期间、临时外部系统故障或意外系统困难时。

• https://martinfowler.com.cn/bliki/CircuitBreaker.html
• 阅读文档

特性

• 与 Fn() -> Result 和 Future （通过默认的 futures-support 功能可选）一起工作。
• 退避策略：constant、exponential、equal_jittered、full_jittered
• 故障检测策略：consecutive_failures、success_rate_over_time_window
• 最低 Rust 版本：1.59

使用方法

将此添加到您的 Cargo.toml 中

failsafe = "1.3.0"

示例

使用默认退避策略和故障累积策略。

use failsafe::{Config, CircuitBreaker, Error};

// A function that sometimes failed.
fn dangerous_call() -> Result<(), ()> {
  if thread_rng().gen_range(0, 2) == 0 {
    return Err(())
  }
  Ok(())
}

// Create a circuit breaker which configured by reasonable default backoff and
// failure accrual policy.
let circuit_breaker = Config::new().build();

// Call the function in a loop, after some iterations the circuit breaker will
// be in a open state and reject next calls.
for n in 0..100 {
  match circuit_breaker.call(|| dangerous_call()) {
    Err(Error::Inner(_)) => {
      eprintln!("{}: fail", n);
    },
    Err(Error::Rejected) => {
       eprintln!("{}: rejected", n);
       break;
    },
    _ => {}
  }
}

或配置自定义退避和策略

use std::time::Duration;
use failsafe::{backoff, failure_policy, CircuitBreaker};

// Create an exponential growth backoff which starts from 10s and ends with 60s.
let backoff = backoff::exponential(Duration::from_secs(10), Duration::from_secs(60));

// Create a policy which failed when three consecutive failures were made.
let policy = failure_policy::consecutive_failures(3, backoff);

// Creates a circuit breaker with given policy.
let circuit_breaker = Config::new()
  .failure_policy(policy)
  .build();