网站建设 网络科技公司,热点新闻事件素材,北京开网站建设公司,如何查询百度收录文章目录 SpringCloud Hystrix 熔断器、服务降级防止服务雪崩需求背景引入依赖启动类加Hystrix注解接口配置熔断常规配置超时断开错误率熔断请求数熔断限流 全局配置可配置项HystrixCommand.Setter参数Command Properties 服务降级 SpringCloud Hystrix 熔断器、服务降级防止服… 文章目录 SpringCloud Hystrix 熔断器、服务降级防止服务雪崩需求背景引入依赖启动类加Hystrix注解接口配置熔断常规配置超时断开错误率熔断请求数熔断限流 全局配置可配置项HystrixCommand.Setter参数Command Properties 服务降级 SpringCloud Hystrix 熔断器、服务降级防止服务雪崩 Hystrix英文意思是豪猪全身是刺刺是一种保护机制。Hystrix也是Netflflix公司的一款组件。
Hystrix是什么?
在分布式环境中许多服务依赖项中的部分服务必然有概率出现失败。Hystrix是一个库通过添加延迟和容错逻辑来帮助你控制这些分布式服务之间的交互。Hystrix通过隔离服务之间的访问点阻止级联失败通过提供回退选项来实现防止级联出错。提高了系统的整体弹性。与Ribbon并列也几乎存在于每个Spring Cloud构建的微服务和基础设施中。
Hystrix被设计的目标是
对通过第三方客户端库访问的依赖项通常是通过网络的延迟和故障进行保护和控制。
在复杂的分布式系统中阻止雪崩效应。
快速失败快速恢复。
回退尽可能优雅地降级。
需求背景
项目有慢接口多个渠道都需要这个接口一旦有突发大流量过来会导致这个接口变慢甚至超时。引发第三方重试不断调用我们接口这个接口又会调用其他接口在突发大流量时会引发雪崩且雪崩积攒的重试流量会把刚滚动启动的实例实例有探针发现持续两次不响应ping就会滚动重启实例起一个新的回收旧实例又打垮因此需要加入服务熔断、服务降级让系统将无法消化的流量直接熔断返回报错让服务不被阻塞住。
引入依赖
dependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-netflix-hystrix/artifactId
/dependency启动类加Hystrix注解
启动类加EnableHystrix 或EnableCircuitBreaker 注解都可以建议用EnableHystrix 因为后一个在后续版本被弃用EnableHystrix是包含了EnableCircuitBreaker的
Target(ElementType.TYPE)
Retention(RetentionPolicy.RUNTIME)
Documented
Inherited
EnableCircuitBreaker
public interface EnableHystrix {}SpringCloudApplication
EnableHystrix
public class ManageApplication{}接口配置熔断 熔断效果测试可以使用jmeter这样的工具来实现 https://jmeter.apache.org/download_jmeter.cgi 常规配置 配置的值自己根据自己需求去改这里是测试用设的值 HystrixCommand(commandProperties {// 隔离策略这个配置项默认是THREAD(线程)另外一个选项是SEMAPHORE信号量在信号量策略下无法使用超时时间设置。HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_STRATEGY, value THREAD),// 单实例vivo接口最大并发请求数150多处的直接拒绝HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_SEMAPHORE_MAX_CONCURRENT_REQUESTS, value 1),// 线程超时时间10秒HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value 100),//错误百分比条件达到熔断器最小请求数后错误率达到百分之多少后打开熔断器HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_ERROR_THRESHOLD_PERCENTAGE, value 10),//断容器最小请求数达到这个值过后才开始计算是否打开熔断器HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_REQUEST_VOLUME_THRESHOLD, value 3),// 默认5秒; 熔断器打开后多少秒后 熔断状态变成半熔断状态(对该微服务进行一次请求尝试不成功则状态改成熔断成功则关闭熔断器HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_SLEEP_WINDOW_IN_MILLISECONDS, value 5000)})EXECUTION_ISOLATION_STRATEGY隔离策略这个配置项默认是THREAD(线程)另外一个选项是SEMAPHORE信号量在信号量策略下无法使用超时时间设置。 超时断开 RequestMapping(testTimeout)HystrixCommand(commandProperties {// 线程超时时间10秒HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value 100)})public String testTimeout() throws InterruptedException {Thread.sleep(5000);return test;}
错误率熔断
请求报错率达到多少之后开启熔断 RequestMapping(test)HystrixCommand(groupKey vivoApi, commandProperties {//错误百分比条件达到熔断器最小请求数后错误率达到百分之多少后打开熔断器HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_ERROR_THRESHOLD_PERCENTAGE, value 10)})public String test() throws Exception {Thread.sleep(50);return test;}请求数熔断限流
处理调用的线程池核心线程一个任务队列长度为10超出的请求会被熔断打回在执行和队列里的请求没事正常执行。 HystrixCommand(groupKey vivoApi, threadPoolProperties {HystrixProperty(name HystrixPropertiesManager.CORE_SIZE, value 1),HystrixProperty(name HystrixPropertiesManager.MAX_QUEUE_SIZE, value 10)})public String test() throws Exception {Thread.sleep(50);return test;}全局配置 全局配置并非全局所有接口自动配置上熔断、超时等操作而是当你注解没有声明的配置会去读全局默认配置 例如下面配置了全局默认配置那接口里用的时候你可以直接只加HystrixCommand /*** author humorchen* date: 2024/4/7* description: 全局熔断配置**/
Configuration
public class GlobalHystrixPropertiesConfiguration {/*** 熔断器配置** return*/Beanpublic HystrixCommandProperties.Setter commandPropertiesConfig() {return HystrixCommandProperties.Setter()// 熔断器在整个统计时间内是否开启的阀值.withExecutionTimeoutInMilliseconds(3000).withExecutionTimeoutEnabled(true).withExecutionIsolationThreadInterruptOnTimeout(true)// 报错比例决定熔断器是否开启.withCircuitBreakerErrorThresholdPercentage(10)// 熔断器开启必须有超过多少个请求.withCircuitBreakerRequestVolumeThreshold(10);}/*** 线程池配置** return*/Beanpublic HystrixThreadPoolProperties.Setter threadPoolConfig() {return HystrixThreadPoolProperties.Setter().withCoreSize(1).withMaxQueueSize(10);}
}
可配置项 可配置项 官方文档 https://github.com/Netflix/Hystrix/wiki/Configuration 配置的中文翻译 Hystrix配置中文文档 关键配置类 HystrixCommandProperties.java、HystrixPropertiesManager.java HystrixCommand.Setter参数
HystrixCommandGroupKey区分一组服务一般以接口为粒度。 HystrixCommandKey区分一个方法一般以方法为粒度。 HystrixThreadPoolKey一个HystrixThreadPoolKey下的所有方法共用一个线程池。 HystrixCommandProperties基本配置
Command Properties
hystrix.command.default.execution.isolation.strategy 隔离策略默认是Thread,可选ThreadSemaphore。thread用于线程池的隔离一般适用于同步请求。semaphore是信号量模式适用于异步请求 hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds 命令执行超时时间默认1000ms hystrix.command.default.execution.timeout.enabled 执行是否启用超时默认启用true hystrix.command.default.execution.isolation.thread.interruptOnTimeout 发生超时是是否中断默认true hystrix.command.default.execution.isolation.semaphore.maxConcurrentRequests 最大并发请求数默认10该参数当使用ExecutionIsolationStrategy.SEMAPHORE策略时才有效。如果达到最大并发请求数请求会被拒绝。理论上选择semaphore size的原则和选择thread size一致但选用semaphore时每次执行的单元要比较小且执行速度快ms级别否则的话应该用thread。 hystrix.command.default.execution.isolation.thread.interruptOnCancel public abstract class HystrixCommandProperties {private static final Logger logger LoggerFactory.getLogger(HystrixCommandProperties.class);/* defaults *//* package */ static final Integer default_metricsRollingStatisticalWindow 10000;// default statisticalWindow: 10000 10 seconds (and default of 10 buckets so each bucket is 1 second)private static final Integer default_metricsRollingStatisticalWindowBuckets 10;// default statisticalWindowBuckets: 10 10 buckets in a 10 second window so each bucket is 1 secondprivate static final Integer default_circuitBreakerRequestVolumeThreshold 20;// default statisticalWindowVolumeThreshold: 20 requests in 10 seconds must occur before statistics matterprivate static final Integer default_circuitBreakerSleepWindowInMilliseconds 5000;// default sleepWindow: 5000 5 seconds that we will sleep before trying again after tripping the circuitprivate static final Integer default_circuitBreakerErrorThresholdPercentage 50;// default errorThresholdPercentage 50 if 50% of requests in 10 seconds are failures or latent then we will trip the circuitprivate static final Boolean default_circuitBreakerForceOpen false;// default forceCircuitOpen false (we want to allow traffic)/* package */ static final Boolean default_circuitBreakerForceClosed false;// default ignoreErrors false private static final Integer default_executionTimeoutInMilliseconds 1000; // default executionTimeoutInMilliseconds: 1000 1 secondprivate static final Boolean default_executionTimeoutEnabled true;private static final ExecutionIsolationStrategy default_executionIsolationStrategy ExecutionIsolationStrategy.THREAD;private static final Boolean default_executionIsolationThreadInterruptOnTimeout true;private static final Boolean default_executionIsolationThreadInterruptOnFutureCancel false;private static final Boolean default_metricsRollingPercentileEnabled true;private static final Boolean default_requestCacheEnabled true;private static final Integer default_fallbackIsolationSemaphoreMaxConcurrentRequests 10;private static final Boolean default_fallbackEnabled true;private static final Integer default_executionIsolationSemaphoreMaxConcurrentRequests 10;private static final Boolean default_requestLogEnabled true;private static final Boolean default_circuitBreakerEnabled true;private static final Integer default_metricsRollingPercentileWindow 60000; // default to 1 minute for RollingPercentile private static final Integer default_metricsRollingPercentileWindowBuckets 6; // default to 6 buckets (10 seconds each in 60 second window)private static final Integer default_metricsRollingPercentileBucketSize 100; // default to 100 values max per bucketprivate static final Integer default_metricsHealthSnapshotIntervalInMilliseconds 500; // default to 500ms as max frequency between allowing snapshots of health (error percentage etc)SuppressWarnings(unused) private final HystrixCommandKey key;private final HystrixPropertyInteger circuitBreakerRequestVolumeThreshold; // number of requests that must be made within a statisticalWindow before open/close decisions are made using statsprivate final HystrixPropertyInteger circuitBreakerSleepWindowInMilliseconds; // milliseconds after tripping circuit before allowing retryprivate final HystrixPropertyBoolean circuitBreakerEnabled; // Whether circuit breaker should be enabled.private final HystrixPropertyInteger circuitBreakerErrorThresholdPercentage; // % of marks that must be failed to trip the circuitprivate final HystrixPropertyBoolean circuitBreakerForceOpen; // a property to allow forcing the circuit open (stopping all requests)private final HystrixPropertyBoolean circuitBreakerForceClosed; // a property to allow ignoring errors and therefore never trip open (ie. allow all traffic through)private final HystrixPropertyExecutionIsolationStrategy executionIsolationStrategy; // Whether a command should be executed in a separate thread or not.private final HystrixPropertyInteger executionTimeoutInMilliseconds; // Timeout value in milliseconds for a commandprivate final HystrixPropertyBoolean executionTimeoutEnabled; //Whether timeout should be triggeredprivate final HystrixPropertyString executionIsolationThreadPoolKeyOverride; // What thread-pool this command should run in (if running on a separate thread).private final HystrixPropertyInteger executionIsolationSemaphoreMaxConcurrentRequests; // Number of permits for execution semaphoreprivate final HystrixPropertyInteger fallbackIsolationSemaphoreMaxConcurrentRequests; // Number of permits for fallback semaphoreprivate final HystrixPropertyBoolean fallbackEnabled; // Whether fallback should be attempted.private final HystrixPropertyBoolean executionIsolationThreadInterruptOnTimeout; // Whether an underlying Future/Thread (when runInSeparateThread true) should be interrupted after a timeoutprivate final HystrixPropertyBoolean executionIsolationThreadInterruptOnFutureCancel; // Whether canceling an underlying Future/Thread (when runInSeparateThread true) should interrupt the execution threadprivate final HystrixPropertyInteger metricsRollingStatisticalWindowInMilliseconds; // milliseconds back that will be trackedprivate final HystrixPropertyInteger metricsRollingStatisticalWindowBuckets; // number of buckets in the statisticalWindowprivate final HystrixPropertyBoolean metricsRollingPercentileEnabled; // Whether monitoring should be enabled (SLA and Tracers).private final HystrixPropertyInteger metricsRollingPercentileWindowInMilliseconds; // number of milliseconds that will be tracked in RollingPercentileprivate final HystrixPropertyInteger metricsRollingPercentileWindowBuckets; // number of buckets percentileWindow will be divided intoprivate final HystrixPropertyInteger metricsRollingPercentileBucketSize; // how many values will be stored in each percentileWindowBucketprivate final HystrixPropertyInteger metricsHealthSnapshotIntervalInMilliseconds; // time between health snapshotsprivate final HystrixPropertyBoolean requestLogEnabled; // whether command request logging is enabled.private final HystrixPropertyBoolean requestCacheEnabled; // Whether request caching is enabled./*** Isolation strategy to use when executing a {link HystrixCommand}.* p* ul* liTHREAD: Execute the {link HystrixCommand#run()} method on a separate thread and restrict concurrent executions using the thread-pool size./li* liSEMAPHORE: Execute the {link HystrixCommand#run()} method on the calling thread and restrict concurrent executions using the semaphore permit count./li* /ul*/public static enum ExecutionIsolationStrategy {THREAD, SEMAPHORE}服务降级 简单来说也就是在HystrixCommand注解上配置fallbackMethod参数指定降级后调用的方法名即可。当接口不可用、超时、错误率高于阈值时自动调用fallbackMethod指定的方法处理请求称为服务降级fallbackMethod方法可以直接返回错误或者提供带缓存的高性能的实现等如果fallbackMethod也不可用会发生熔断报错返回。 RestController
RequestMapping(hystrix)
public class HystrixController {Autowiredprivate HystrixService hystrixService;// 熔断降级GetMapping({num})HystrixCommand(fallbackMethodcircuitBreakerFallback, commandProperties {HystrixProperty(nameHystrixPropertiesManager.CIRCUIT_BREAKER_ENABLED, value true),// 是否开启熔断器HystrixProperty(nameHystrixPropertiesManager.CIRCUIT_BREAKER_REQUEST_VOLUME_THRESHOLD,value 20), // 统计时间窗内请求次数HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_ERROR_THRESHOLD_PERCENTAGE, value 50),// 在统计时间窗内失败率达到50%进入熔断状态HystrixProperty(name HystrixPropertiesManager.CIRCUIT_BREAKER_SLEEP_WINDOW_IN_MILLISECONDS, value 5000), // 休眠时间窗口HystrixProperty(name HystrixPropertiesManager.METRICS_ROLLING_STATS_TIME_IN_MILLISECONDS, value 10000) // 统计时间窗})public String testCircuitBreaker(PathVariable Integer num, RequestParam String name) {if (num % 2 0) {return 请求成功;} else {throw RunTimeException();}}// fallback方法的参数个数、参数类型、返回值类型要与原方法对应fallback方法的参数多加个Throwablepublic String circuitBreakerFallback(Integer num, String name) {return 请求失败请稍后重试;}// 超时降级GetMappingHystrixCommand(fallbackMethod timeoutFallback, commandProperties {HystrixProperty(name HystrixPropertiesManager.EXECUTION_TIMEOUT_ENABLED, value true),// 是否开启超时降级HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_THREAD_TIMEOUT_IN_MILLISECONDS, value 10000),// 请求的超时时间默认10000HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_THREAD_INTERRUPT_ON_TIMEOUT, value true)// 当请求超时时是否中断线程默认true})public String testTimeout(RequestParam String name) throws InterruptedException{Thread.sleep(200)return success;}public String timeoutFallback(String name) {return 请求超时请稍后重试;}// 资源隔离线程池触发降级GetMapping(isolation/threadpool)HystrixCommand(fallbackMethod isolationFallback,commandProperties {HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_STRATEGY, value THREAD)},threadPoolProperties {HystrixProperty(name HystrixPropertiesManager.CORE_SIZE, value 10),HystrixProperty(name HystrixPropertiesManager.MAX_QUEUE_SIZE, value -1),HystrixProperty(name HystrixPropertiesManager.QUEUE_SIZE_REJECTION_THRESHOLD, value 2),HystrixProperty(name HystrixPropertiesManager.KEEP_ALIVE_TIME_MINUTES, value 1),})public String testThreadPoolIsolation(RequestParam String name) throws InterruptedException {Thread.sleep(200)return success;}public String isolationFallback(String name) {return 资源隔离拒绝请稍后重试;}// 信号量资源隔离GetMapping(isolation/semaphore)HystrixCommand(fallbackMethod isolationFallback,commandProperties {HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_STRATEGY, value SEMAPHORE),HystrixProperty(name HystrixPropertiesManager.EXECUTION_ISOLATION_SEMAPHORE_MAX_CONCURRENT_REQUESTS, value 2)})public String testSemaphoreIsolation(RequestParam String name) throws InterruptedException {Thread.sleep(200)return success;}public String isolationFallback(String name) {return 资源隔离拒绝请稍后重试;}}
