SpringBoot集成hystrix

hystrix有什么用

• 资源隔离：包括线程池隔离和信号量隔离，限制调用分布式服务的资源使用，某一个调用的服务出现问题不会影响其他服务调用。
• 降级机制：超时降级、资源不足时(线程或信号量)降级，降级后可以配合降级接口返回托底数据。
• 融断：当失败率达到阀值自动触发降级(如因网络故障/超时造成的失败率高)，熔断器触发的快速失败会进行快速恢复。
• 缓存：提供了请求缓存、请求合并实现。

在SpringBoot项目中集成

引入依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

启用hystrix

@EnableCircuitBreaker

使用示例

@Component
@RestController
public class HelloService {
    @RequestMapping("/hi")
    @HystrixCommand(fallbackMethod = "hiFail")
    public String hi(String name){
//        try {
//            Thread.sleep(5000);
//        } catch (InterruptedException e) {
//            e.printStackTrace();
//        }
//        throw new RuntimeException("test");
        return "hi "+name;
    }


    public String hiFail(String name){
        return "hiFail "+name;
    }
}

通过注解@HystrixCommand标记方法调用失败或超时时，跳转的fallbackMethod方法

配置监控路径

@Bean
public ServletRegistrationBean getServlet(){
    HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
    ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
    registrationBean.setLoadOnStartup(1);  //系统启动时加载顺序
    registrationBean.addUrlMappings("/actuator/hystrix.stream");//路径
    registrationBean.setName("HystrixMetricsStreamServlet");
    return registrationBean;
}

更多配置示例

配置线程池

@Component
@RestController
public class Hello2Service {
    @RequestMapping("/hello2")
    @HystrixCommand(fallbackMethod = "hiFail", commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "500")
    },
            threadPoolProperties = {
                    @HystrixProperty(name = "coreSize", value = "10"),
                    @HystrixProperty(name = "maxQueueSize", value = "20"),
                    @HystrixProperty(name = "keepAliveTimeMinutes", value = "0"),
                    @HystrixProperty(name = "queueSizeRejectionThreshold", value = "15"),
                    @HystrixProperty(name = "metrics.rollingStats.numBuckets", value = "12"),
                    @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds", value = "1440")
            })
    public String hi(String name) {
        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "hi " + name;
    }


    public String hiFail(String name, Throwable e) {
        if (e != null) {
            e.printStackTrace();
        }
        return "hiFail " + name;
    }
}

配置信号量

@Component
@RestController
public class Hello3Service {
    @RequestMapping("/hello3")
    @HystrixCommand(fallbackMethod = "hiFail", commandProperties = {
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "500"),
            @HystrixProperty(name = "execution.isolation.semaphore.maxConcurrentRequests", value = "9"),
            @HystrixProperty(name = "fallback.isolation.semaphore.maxConcurrentRequests", value = "20"),
            @HystrixProperty(name = "execution.isolation.strategy", value ="SEMAPHORE")
    })
    public String hi(String name) {
        try {
            Thread.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return "hi " + name;
    }


    public String hiFail(String name, Throwable e) {
        if (e != null) {
            e.printStackTrace();
        }
        return "hiFail " + name;
    }
}

配合feignClient使用

引入依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

在application.properties里面添加配置

feign.hystrix.enabled=true

创建feignClient接口，并指定fallback类，fallback类必须实现该接口

@FeignClient(name ="hystrix-consumer", path = "",url = "http://127.0.0.1:8080/",fallback = IHelloFailback.class)
public interface IHelloClient {
    @RequestMapping("/hi")
    public String hi(@RequestParam("name") String name);
}

@Component
public class IHelloFailback implements IHelloClient {
    @Override
    public String hi(String name) {
        return "Hi，服务异常";
    }
}

启用FeignClient，在启动类添加注解

@EnableFeignClients(basePackages = {"com.example.hj.springcloudhystrixprovider.client"})

默认参数

final class Default implements SetterFactory {

@Override
public HystrixCommand.Setter create(Target<?> target, Method method) {
  String groupKey = target.name();
  String commandKey = Feign.configKey(target.type(), method);
  return HystrixCommand.Setter
      .withGroupKey(HystrixCommandGroupKey.Factory.asKey(groupKey))
      .andCommandKey(HystrixCommandKey.Factory.asKey(commandKey));
}
}

自定义参数

@Bean
public Feign.Builder feignHystrixBuilder() {
    return HystrixFeign.builder().setterFactory(new SetterFactory() {
        @Override
        public HystrixCommand.Setter create(Target<?> target, Method method) {
            return HystrixCommand.Setter
                    .withGroupKey(HystrixCommandGroupKey.Factory.asKey(RemoteProductService.class.getSimpleName()))// 控制 RemoteProductService 下,所有方法的Hystrix Configuration
                    .andCommandPropertiesDefaults(
                            HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(10000) // 超时配置
                    );
        }
    });
}

基本配置

参考官方配置

配置项	默认值	说明
hystrix.command.default.execution.isolation.strategy	THREAD	隔离策略，THREAD, SEMAPHORE
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds	1000	线程超时时间
hystrix.command.default.execution.timeout.enabled	true	启用超时设置
hystrix.command.default.execution.isolation.thread.interruptOnTimeout	true	线程超时时，是否可被中断
hystrix.command.default.execution.isolation.thread.interruptOnCancel	false	线程取消时，是否可被中断
hystrix.command.default.execution.isolation.semaphore.maxConcurrentRequests	10	最大并发信号量
hystrix.command.default.fallback.isolation.semaphore.maxConcurrentRequests	10	最大并发备用信号量
hystrix.command.default.fallback.enabled	true	启用fallback
hystrix.command.default.circuitBreaker.enabled	true	启用断路器
hystrix.command.default.circuitBreaker.requestVolumeThreshold	20	在一个时间窗口内触发断路器的最小请求量
hystrix.command.default.circuitBreaker.sleepWindowInMilliseconds	5000	触发断路器时，服务休眠时间
hystrix.command.default.circuitBreaker.errorThresholdPercentage	50	触发断路器时，最小错误比率
hystrix.command.default.circuitBreaker.forceOpen	false	强制打开断路器
hystrix.command.default.circuitBreaker.forceClosed	false	强制关闭断路器
hystrix.command.default.metrics.rollingStats.timeInMilliseconds	10000	数据采集时间段
hystrix.command.default.metrics.rollingStats.numBuckets	10	采集数据份，必须能被timeInMilliseconds整除
hystrix.command.default.metrics.rollingPercentile.enabled	true	开启采集滚动百分比
hystrix.command.default.metrics.rollingPercentile.timeInMilliseconds	60000	滚动百分收集时间段
hystrix.command.default.metrics.rollingPercentile.numBuckets	6	滚动百分比收集份数，必须能被timeInMilliseconds整除
hystrix.command.default.metrics.rollingPercentile.bucketSize	100	每份数据的最大统计请求量
hystrix.command.default.metrics.healthSnapshot.intervalInMilliseconds	500	健康检查间隔时间
hystrix.command.default.requestCache.enabled	true	开启请求缓存，HystrixRequestCache
hystrix.command.default.requestLog.enabled	true	开启请求日志，记录在HystrixRequestLog
hystrix.collapser.default.maxRequestsInBatch	Integer.MAX_VALUE	单批次最大请求量
hystrix.collapser.default.timerDelayInMilliseconds	10	批次请求延迟启动时间
hystrix.collapser.default.requestCache.enabled	true	开启批次请求缓存, HystrixCollapser.execute(), HystrixCollapser.queue()
hystrix.threadpool.default.coreSize	10	核心线程数
hystrix.threadpool.default.maximumSize	10	最大线程数
hystrix.threadpool.default.maxQueueSize	-1	最大阻塞线程队列
hystrix.threadpool.default.queueSizeRejectionThreshold	5	队列上限，超过会拒绝请求
hystrix.threadpool.default.keepAliveTimeMinutes	1	线程保持活跃时间（分钟）
hystrix.threadpool.default.allowMaximumSizeToDivergeFromCoreSize	false	启用maximumSize参数
hystrix.threadpool.default.metrics.rollingStats.timeInMilliseconds	10000	线程池数据采集时间段
hystrix.threadpool.default.metrics.rollingStats.numBuckets	10	线程池数据采集份数

可视化组件

视图hystrix-dashboard

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>

@EnableTurbine
@EnableHystrixDashboard

启动工程后，访问路径：http://localhost:9001/hystrix

在打开的页面输入需要监控的链接，如：http://localhost:8081/actuator/hystrix.stream

汇总监控turbine

能够使用turbine的前提条件时，所有的服务必须在同一个服务注册中心（同一个eureka），每个待监控的服务都必须有监控路径（/actuator/hystrix.stream）

添加依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-turbine</artifactId>
</dependency>

配置需要监控的服务

在application.properties中添加配置，配置每个需要监控的服务名称

turbine.app-config=turbine,hystrix-provider,hystrix-consumer

启动工程，在打开的页面输入汇总监控链接，如：http://localhost:9001/turbine.stream

参考

• https://www.cnblogs.com/lexiaofei/p/7761982.html
• https://github.com/Netflix/Hystrix/wiki