Resilience4j轻量级的容错组件
Resilience4j 是一个轻量级的容错组件,其灵感来自于 Hystrix,但主要为 Java 8 和函数式编程所设计。轻量级体现在其只用 Vavr 库(前身是 Javaslang),没有任何外部依赖。而 Hystrix 依赖了 Archaius ,Archaius 本身又依赖很多第三方包,例如 Guava、Apache Commons Configuration 等。
限速组件架构:
Resilience4j 提供了如下几款核心组件
resilience4j-circuitbreaker: Circuit breaking
resilience4j-ratelimiter: Rate limiting
resilience4j-bulkhead: Bulkheading
resilience4j-retry: Automatic retrying (sync and async)
resilience4j-cache: Response caching
附件组件包括:
resilience4j-reactor: Spring Reactor adapter
resilience4j-rxjava2: RxJava2 adapter
resilience4j-micrometer: Micrometer Metrics exporter
resilience4j-metrics: Dropwizard Metrics exporter
resilience4j-prometheus: Prometheus Metrics exporter
resilience4j-spring-boot: Spring Boot Starter
resilience4j-ratpack: Ratpack Starter
resilience4j-retrofit: Retrofit Call Adapter Factories
resilience4j-vertx: Vertx Future decorator
resilience4j-consumer: Circular Buffer Event consumer
使用示例:
使用 Resilience4j 实现请求调用频率限制的示例代码:
// Create a custom RateLimiter configuration RateLimiterConfig config = RateLimiterConfig.custom() .timeoutDuration(Duration.ofMillis(100)) .limitRefreshPeriod(Duration.ofSeconds(1)) .limitForPeriod(1) .build(); // Create a RateLimiter RateLimiter rateLimiter = RateLimiter.of("backendName", config); // Decorate your call to BackendService.doSomething() Supplier<String> restrictedSupplier = RateLimiter .decorateSupplier(rateLimiter, backendService::doSomething); // First call is successful Try<String> firstTry = Try.ofSupplier(restrictedSupplier); assertThat(firstTry.isSuccess()).isTrue(); // Second call fails, because the call was not permitted Try<String> secondTry = Try.of(restrictedSupplier); assertThat(secondTry.isFailure()).isTrue(); assertThat(secondTry.getCause()).isInstanceOf(RequestNotPermitted.class);