112 lines
4.5 KiB
Markdown
112 lines
4.5 KiB
Markdown
- [Spring Cloud Circuit Breaker](#spring-cloud-circuit-breaker)
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- [配置Resilience4J Circuit Breakers](#配置resilience4j-circuit-breakers)
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- [关闭自动装配](#关闭自动装配)
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- [默认配置](#默认配置)
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- [自定义ExecutorService](#自定义executorservice)
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- [指定Circuit Breaker 配置](#指定circuit-breaker-配置)
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- [Circuit Breaker属性配置](#circuit-breaker属性配置)
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- [全局默认](#全局默认)
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- [Configs Properties Configuration](#configs-properties-configuration)
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- [实例属性设置](#实例属性设置)
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# Spring Cloud Circuit Breaker
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Spring Cloud Circuit Breaker项目包含Resilience4J实现和Spring Retry实现。
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## 配置Resilience4J Circuit Breakers
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关于resilience4J Circuit Breakers实现，拥有如下两个启动器，一个用于响应式项目，另一个用于非响应式项目：
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- `org.springframework.cloud:spring-cloud-starter-circuitbreaker-resilience4j`
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- `org.springframework.cloud:spring-cloud-starter-circuitbreaker-reactor-resilience4j`
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### 关闭自动装配
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可以通过设置`spring.cloud.circuitbreaker.resilience4j.enabled`为false来关闭Resilience4J的自动装配
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### 默认配置
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如果想要为所有的circuit breaker提供默认配置，可以创建一个`Customizer` bean对象，该bean对象接收一个`Resilience4JCircuitBreakerFactory`类型参数。configureDefault方法可以用于提供默认的配置：
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```java
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@Bean
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public Customizer<Resilience4JCircuitBreakerFactory> defaultCustomizer() {
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return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
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.timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofSeconds(4)).build())
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.circuitBreakerConfig(CircuitBreakerConfig.ofDefaults())
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.build());
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}
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```
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### 自定义ExecutorService
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如果想要自定义执行circuit breaker的`ExecutorService`，可以通过Resilience4JCircuitBreakerFactor来指定。
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例如，想要指定一个context aware ExecutorService，可以按如下所示：
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```java
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@Bean
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public Customizer<ReactiveResilience4JCircuitBreakerFactory> defaultCustomizer() {
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return factory -> {
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ContextAwareScheduledThreadPoolExecutor executor = ContextAwareScheduledThreadPoolExecutor.newScheduledThreadPool().corePoolSize(5)
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.build();
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factory.configureExecutorService(executor);
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};
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}
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```
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### 指定Circuit Breaker 配置
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类似为所有Circuit Breakers指定默认配置，也能以如下方式为特定Circuit Breaker指定配置：
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```java
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@Bean
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public Customizer<Resilience4JCircuitBreakerFactory> slowCustomizer() {
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return factory -> factory.configure(builder -> builder.circuitBreakerConfig(CircuitBreakerConfig.ofDefaults())
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.timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofSeconds(2)).build()), "slow");
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}
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```
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### Circuit Breaker属性配置
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可以在配置文件中指定`CircuitBreaker`和`TimeLimiter`配置，配置文件中指定的配置比Customizer中指定的配置优先级更高。
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优先级从上到下递减：
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- 方法级别(id)配置 - 针对指定的方法或操作
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- service级别（group）配置 - 针对指定应用的service或操作
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- 全局默认配置
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#### 全局默认
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```yml
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resilience4j.circuitbreaker:
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configs:
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default:
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registerHealthIndicator: true
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slidingWindowSize: 50
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resilience4j.timelimiter:
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configs:
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default:
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timeoutDuration: 5s
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cancelRunningFuture: true
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```
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#### Configs Properties Configuration
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```yml
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resilience4j.circuitbreaker:
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configs:
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groupA:
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registerHealthIndicator: true
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slidingWindowSize: 200
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resilience4j.timelimiter:
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configs:
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groupC:
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timeoutDuration: 3s
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cancelRunningFuture: true
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```
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#### 实例属性设置
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```yml
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resilience4j.circuitbreaker:
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instances:
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backendA:
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registerHealthIndicator: true
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slidingWindowSize: 100
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backendB:
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registerHealthIndicator: true
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slidingWindowSize: 10
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permittedNumberOfCallsInHalfOpenState: 3
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slidingWindowType: TIME_BASED
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recordFailurePredicate: io.github.robwin.exception.RecordFailurePredicate
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resilience4j.timelimiter:
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instances:
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backendA:
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timeoutDuration: 2s
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cancelRunningFuture: true
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backendB:
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timeoutDuration: 1s
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cancelRunningFuture: false
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``` |