SpringCloud Hystrix 实战-编程知识

一、配置

1.引入jar包

单独使用hystrix ，不配合openFegin使用的话，单独使用hystrix,需要引入spring-cloud-starter-netflix-hystrix包。要使用的hystrix-dashboard 界面的话需要引入spring-boot-starter-actuator 包和spring-cloud-starter-netflix-hystrix-dashboard 包

  <!--不配合openfegin单独使用hystrix--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-hystrix</artifactId></dependency><!-- pom必须引入actuator，所有需要被监控的服务都要引入actuator--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency><!-- 引入 hystrix-dashboard--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId></dependency>

1.2 开启注解

要使用的熔断讲解功能需要开启@EnableHystrix注解，要开启HystrixDashboard 监控功能
需要@EnableHystrixDashboard 注解

配置HystrixDashboard 监控访问的 stream的监控流serverlet
/hystrix.stream

@SpringBootApplication
//开启Hystrix熔断，或者使用@EnableCircuitBreaker
@EnableHystrix
//开启HystrixDashboard
@EnableHystrixDashboard
public class AmasterReportServerApplication {public static void main(String[] args) {SpringApplication.run(AmasterReportServerApplication.class, args);}}@Beanpublic ServletRegistrationBean getServlet() {HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);registrationBean.setLoadOnStartup(1);registrationBean.addUrlMappings("/hystrix.stream");registrationBean.setName("HystrixMetricsStreamServlet");return registrationBean;}

由于springcloud的版本不同，有些版本在访问界面的时候不配置ServletRegistrationBean 会在打开hystrixdash的访问页面，输入监控的hystrix.stream地址，在进入hystrixdash的监控界面会，监控解密那上会显示 Unable to connect to Command Metric Stream。有些版本不需要配置ServletRegistrationBean

1.3 在调用方法上配置降级方法和熔断条件

@Slf4j
public class ReportServiceImpl {@Autowiredprivate RestTemplate restTemplate;@HystrixCommand( commandProperties = {@HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "10")},fallbackMethod = "ribbionAloneUseFallback")public List<String> ribbionAloneUse(String clientMark, String path) {String url  = String.format("http://%s%s",clientMark,path);ResponseEntity<List> entity = restTemplate.getForEntity(url, List.class);return  entity.getBody();}//ribbionAloneUse方法降级服务public List<String> ribbionAloneUseFallback(String clientMark,String path,Throwable e){log.error(e.getMessage(),e);String url  = String.format("http://%s%s",clientMark,path);return Arrays.asList("触发降级"+url) ;}
}

注意：在配置熔断方法的时候，目标方法的降级方法，入参和返回值类型要相同。要不然在调用ribbionAloneUse 的时候会报

hystrix回调方法报错：fallback method wasn‘t found

hystrix降级的fallback方法需要与原方法有相同的返回类型和参数列表,fallback方法可以在参数列表后加一个Throwable类型参数用于接收异常信息

1.4 配置文件，配置dashboard的访问代理允许许可

amaster-report-server的服务配置文件

spring:application:name: amaster-report-servercloud:load-balancer:
#            ribbon:
#                eager-load:
#                    enabled: true # 开启饥饿加载,这里为配合注册中心使用，因此关闭掉懒加载
#                    clients: # 指定饥饿加载的服务名称
#                        - amaster-work-server   # 用户服务
#                        - amaster-config-env # 仓库服务#开启重试机制，默认是关闭的retry:enabled: trueamaster-work-server:ribbon:#请求连接的超时时间ConnectTimeout: 250#请求处理的超时时间ReadTimeout: 1000#对所有操作请求都进行重试，默认false，只有GET请求会重试；这是防止POST等对数据有影响的请求在重试后因为接口未做幂等性导致数据异常，影响较大OkToRetryOnAllOperations: true#切换实例的重试次数MaxAutoRetriesNextServer: 2#对当前实例的重试次数MaxAutoRetries: 1# 服务的实例地址列表listOfServers: localhost:9005,localhost:9015#给某个微服务配置负载均衡规则NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
#配置运训访问的监控地址列表
hystrix:dashboard:# "127.0.0.1"proxy-stream-allow-list: "**"#hystrix:
#    dashboard:
#        # "127.0.0.1"
#        proxy-stream-allow-list: "localhost"# 暴漏监控信息
management:endpoints:web:exposure:include: hystrix.stream# 暴漏监控信息
#management:
#    endpoints:
#        web:
#            exposure:
#                include: "*"

如果不开启开启允许hystrixDashboard 的监控流代理地址，在通过监控首页输入监控服务地址hystrx.stream的访问监控地址的时候会报如下错

2024-04-27 00:00:29.767  WARN 15572 --- [nio-9007-exec-5] ashboardConfiguration$ProxyStreamServlet : Origin parameter: http://127.0.0.1:9007/amaster-report-server/actuator/hystrix is not in the allowed list of proxy host names.  If it should be allowed add it to hystrix.dashboard.proxyStreamAllowList.
2024-04-27 00:00:29.767  WARN 15572 --- [io-9007-exec-10] ashboardConfiguration$ProxyStreamServlet : Origin parameter: http://127.0.0.1:9007/amaster-report-server/actuator/hystrix is not in the allowed list of proxy host names.  If it should be allowed add it to hystrix.dashboard.proxyStreamAllowList.
2024-04-27 00:01:13.625  WARN 15572 --- [nio-9007-exec-8] ashboardConfiguration$ProxyStreamServlet : Origin parameter: http://127.0.0.1:9007/amaster-report-server/actuator/hystrix is not in the allowed list of proxy host names.  If it should be allowed add it to hystrix.dashboard.proxyStreamAllowList.
2024-04-27 00:01:13.625  WARN 15572 --- [nio-9007-exec-7] ashboardConfiguration$ProxyStreamServlet : Origin parameter: http://127.0.0.1:9007/amaster-report-server/actuator/hystrix is not in the allowed list of proxy host names.  If it should be allowed add it to hystrix.dashboard.proxyStreamAllowList.

1.5 测试

开启两个服务amaster-work-server 的两个服务
amaster-work-server 9015 和amaster-work-server 9005

在这里插入图片描述

amaster-report 服务未注册到中心，调用amaster-work-serve 的两个服务通过ribbion的listOfServers 进行配置调用。可以看到两个服务被随机轮询调用；
当调用接口http://127.0.0.1:9007/amaster-report-server/env/get/report/ribbion/alone/use/v1 调用的时候会打印

2024-04-26 22:01:07.576  INFO 12804 --- [rtServiceImpl-1] c.netflix.loadbalancer.BaseLoadBalancer  : Client: amaster-work-server instantiated a LoadBalancer: DynamicServerListLoadBalancer:{NFLoadBalancer:name=amaster-work-server,current list of Servers=[],Load balancer stats=Zone stats: {},Server stats: []}ServerList:null
2024-04-26 22:01:07.585  INFO 12804 --- [rtServiceImpl-1] c.n.l.DynamicServerListLoadBalancer      : Using serverListUpdater PollingServerListUpdater
2024-04-26 22:01:07.613  INFO 12804 --- [rtServiceImpl-1] c.n.l.DynamicServerListLoadBalancer      : DynamicServerListLoadBalancer for client amaster-work-server initialized: DynamicServerListLoadBalancer:{NFLoadBalancer:name=amaster-work-server,current list of Servers=[localhost:9005, localhost:9015],Load balancer stats=Zone stats: {unknown=[Zone:unknown;	Instance count:2;	Active connections count: 0;	Circuit breaker tripped count: 0;	Active connections per server: 0.0;]
},Server stats: [[Server:localhost:9015;	Zone:UNKNOWN;	Total Requests:0;	Successive connection failure:0;	Total blackout seconds:0;	Last connection made:Thu Jan 01 08:00:00 CST 1970;	First connection made: Thu Jan 01 08:00:00 CST 1970;	Active Connections:0;	total failure count in last (1000) msecs:0;	average resp time:0.0;	90 percentile resp time:0.0;	95 percentile resp time:0.0;	min resp time:0.0;	max resp time:0.0;	stddev resp time:0.0]
, [Server:localhost:9005;	Zone:UNKNOWN;	Total Requests:0;	Successive connection failure:0;	Total blackout seconds:0;	Last connection made:Thu Jan 01 08:00:00 CST 1970;	First connection made: Thu Jan 01 08:00:00 CST 1970;	Active Connections:0;	total failure count in last (1000) msecs:0;	average resp time:0.0;	90 percentile resp time:0.0;	95 percentile resp time:0.0;	min resp time:0.0;	max resp time:0.0;	stddev resp time:0.0]
]}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@36eda38c

在这里插入图片描述
如果其中一个方不正常在调用的时候，在轮询调用到不正常的服务的时候就走，快速失败的方法

在这里插入图片描述

}ServerList:com.netflix.loadbalancer.ConfigurationBasedServerList@5d209707
2024-04-26 23:33:32.223 ERROR 1076 --- [ HystrixTimer-5] c.z.b.a.r.service.ReportServiceImpl      : nullcom.netflix.hystrix.exception.HystrixTimeoutException: nullat com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator$1.run(AbstractCommand.java:1142) ~[hystrix-core-1.5.18.jar:1.5.18]at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable$1.call(HystrixContextRunnable.java:41) ~[hystrix-core-1.5.18.jar:1.5.18]at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable$1.call(HystrixContextRunnable.java:37) ~[hystrix-core-1.5.18.jar:1.5.18]at com.netflix.hystrix.strategy.concurrency.HystrixContextRunnable.run(HystrixContextRunnable.java:57) ~[hystrix-core-1.5.18.jar:1.5.18]at com.netflix.hystrix.AbstractCommand$HystrixObservableTimeoutOperator$2.tick(AbstractCommand.java:1159) [hystrix-core-1.5.18.jar:1.5.18]at com.netflix.hystrix.util.HystrixTimer$1.run(HystrixTimer.java:99) [hystrix-core-1.5.18.jar:1.5.18]at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_401]at java.util.concurrent.FutureTask.runAndReset$$$capture(FutureTask.java:308) [na:1.8.0_401]at java.util.concurrent.FutureTask.runAndReset(FutureTask.java) [na:1.8.0_401]at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_401]at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_401]at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_401]at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_401]at java.lang.Thread.run(Thread.java:750) [na:1.8.0_401]