为什么Resilience4j断路器不会启动新线程

Question

我正在尝试从Hystrix迁移到Resilience4j，并尝试了使用注释（https://resilience4j.readme.io/docs/getting-started-3）配置resilience4j的选项，该注释使用了resilience4j-spring-boot2依赖项。

当我使用它进行测试并分析日志时，即使使用@CircuitBreaker装饰的方法也在同一http-nio线程中运行：

带有CircuitBreaker批注的日志：

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2020-01-10 10：31：15,996 [ http-nio-8080-exec-1 ] INFO APP = test-app | ENV = LOCAL | REQUEST_ID = 1 | TRACE_ID = eb88d5c53ab97a40 | SPAN_ID = eb88d5c53ab97a40 | CLIENT_ID = 1 | CLIENT_VERSION = 1 | a.c.s.i.m.p.dependent.DependentApi-请求：http://example.api.com/api/customers/John

2020-01-10 10：31：15,997 [ http-nio-8080-exec-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = 1 | TRACE_ID = eb88d5c53ab97a40 | SPAN_ID = eb88d5c53ab97a40 | CLIENT_ID = 1 | CLIENT_VERSION = 1 | a.c.s.i.myservice.aop.LogingAspect-输入：au.com.suncorp.insurance.myservice.config.DependentApiRestOperation.getRestOperations（），参数为[s] = []

2020-01-10 10：31：15,999 [ http-nio-8080-exec-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = 1 | TRACE_ID = eb88d5c53ab97a40 | SPAN_ID = eb88d5c53ab97a40 | CLIENT_ID = 1 | CLIENT_VERSION = 1 | a.c.s.i.myservice.aop.LoggingAspect-退出：au.com.suncorp.insurance.myservice.config.DependentApiRestOperation.getRestOperations（），结果为org.springframework.web.client.RestTemplate@1f3111d1

2020-01-10 10：31：16,065 [ http-nio-8080-exec-1 ]错误APP = test-app | ENV = LOCAL | REQUEST_ID = 1 | TRACE_ID = eb88d5c53ab97a40 | SPAN_ID = eb88d5c53ab97a40 | CLIENT_ID = 1 | CLIENT_VERSION = 1 | a.c.s.i.myservice.aop.LoggingAspect

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相反，在那种情况下，当我从CircuitBreakerFactory创建CircuitBreaker时，当控件中的控件受断路器保护时，我可以看到新的断路器线程旋转起来。

CircuitBreakerFactory的日志：

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2020-01-10 10：50：04,178 [ hystrix-HystrixCircuitBreakerFactory-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | a.c.s.i.myservice.aop.LoggingAspect-输入：au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties.getAddress（），参数为[s] = []

2020-01-10 10：50：04,178 [ hystrix-HystrixCircuitBreakerFactory-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | acsimyservice.aop.LoggingAspect-退出：au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties.getAddress（），结果= au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties$Address@1928e7f3

2020-01-10 10：50：04,179 [ hystrix-HystrixCircuitBreakerFactory-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | a.c.s.i.myservice.aop.LoggingAspect-输入：au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties.getAddress（），参数为[s] = []

2020-01-10 10：50：04,179 [ hystrix-HystrixCircuitBreakerFactory-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | acsimyservice.aop.LoggingAspect-退出：au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties.getAddress（），结果= au.com.suncorp.insurance.myservice.config.properties.DependentApiProperties$Address@1928e7f3

2020-01-10 10：50：04,184 [ hystrix-HystrixCircuitBreakerFactory-1 ] INFO APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | a.c.s.i.m.p.dependent.DependentApi-请求：http://example.api.com/api/customers/John

2020-01-10 10：50：04,186 [ hystrix-HystrixCircuitBreakerFactory-1 ] DEBUG APP = test-app | ENV = LOCAL | REQUEST_ID = | TRACE_ID = bde6e74d65833730 | SPAN_ID = d5dc68689645201a | CLIENT_ID = | CLIENT_VERSION = | a.c.s.i.myservice.aop.LoggingAspect-输入：au.com.suncorp.insurance.myservice.config.DependentApiRestOperation.getRestOperations（），参数为[s] = []

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Answer 1

Resilience4j Spring Boot Starter和Spring Cloud CircuitBreaker是两个不同/分离的项目。

Spring Cloud CircuitBreaker在单独的线程池中运行方法。参见-> https://github.com/spring-cloud/spring-cloud-circuitbreaker/blob/master/spring-cloud-circuitbreaker-resilience4j/src/main/java/org/springframework/cloud/circuitbreaker/resilience4j/Resilience4JCircuitBreaker.java#L68

在Resilience4j和Spring Boot Starter中，CircuitBreaker和基于Threadpool的Bulkhead是两种不同的弹性模式，您可能需要结合或不结合。如果要合并它们，则必须对方法应用两个注释-> @CircuitBreaker和@Bulkhead(type = Type.THREADPOOL)。

看一下演示-> https://github.com/resilience4j/resilience4j-spring-boot2-demo