Spring Cloud - 5 (Spring Cloud Netflix Hystrix)
Spring Cloud Netflix Hystrix)
服务短路（CircuitBreaker）
- QPS：Query Per Second
- TPS：Transaction Per Second
- QPS：经过全链路压测，计算单机极限QPS，集群QPS=单机PQS*集群机器数量*可靠性比率
- 全链路压测，除了压极限QPS，还有错误数量
- 全链路：一个完整的业务流程操作
- JMeter：可调整型比较灵活
Spring Cloud Hystrix Client
官网：https://github.com/Netflix/Hystrix
Reactive Java框架：
- java9 Flow API
- Reactor
- RxJava（Reactive X）
激活Hystrix
通过@EnableHystrix激活
配置信息wiki：https//github.com/Netflix/Hystrix/wiki/Configuration
Hystrix
1. 注解方式
@HystrixCommand(defaultFallback= "errorContent",commandProperties =
{@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value= "100")})
@GetMapping("/user/count")
public String userCount() throws InterruptedException {
Random random = new Random();
int nextInt = random.nextInt(200);
System.out.println("random time > "+nextInt);
Thread.sleep(nextInt);
return userService.userCount();
}
public String errorContent() {
System.out.println("超时了");
return "-1";
}
2. 编程方式
@GetMapping("/user/count2")
public String userCount2() {
return new MyHystrixCommand().execute();
}
private class MyHystrixCommand extends com.netflix.hystrix.HystrixCommand{
protected MyHystrixCommand() {
super(HystrixCommandGroupKey.Factory.asKey(""), 100);
}
@Override
protected String run() throws Exception {
Random random = new Random();
int nextInt = random.nextInt(200);
System.out.println("random time > "+nextInt);
Thread.sleep(nextInt);
return "OK";
}
@Override
protected String getFallback() {
return UserServiceProviderRestApiController.this.errorContent();
}
}
对比其他Java执行方式：
Feature
public class FutrueDemo {
public static void main(String[] args) {
Random random = new Random();
ExecutorService service = Executors.newFixedThreadPool(1);
Future futrue = service.submit(() -> {
int value = random.nextInt(200);
System.out.print("睡眠"+value+"ms.");
Thread.sleep(value);
return "OK";
});
try {
futrue.get(100,TimeUnit.MILLISECONDS);
}catch (Exception e) {
System.out.println("超时保护...");
}
service.shutdown();
}
}
Health Endpoint (/actuator/health)
{
"status": "UP",
"details": {
"diskSpace": {
"status": "UP",
"details": {
"total": 140382552064,
"free": 7376781312,
"threshold": 10485760
}
},
"refreshScope": {
"status": "UP"
},
"discoveryComposite": {
"status": "UP",
"details": {
"discoveryClient": {
"status": "UP",
"details": {
"services": ["user-service-consumer", "user-service-provider", "eureka-server"]
}
},
"eureka": {
"description": "Remote status from Eureka server",
"status": "UP",
"details": {
"applications": {
"USER-SERVICE-CONSUMER": 1,
"EUREKA-SERVER": 2,
"USER-SERVICE-PROVIDER": 2
}
}
}
}
},
"hystrix": {
"status": "UP"
}
}
}
激活熔断保护
@EnableCircuitBreaker 激活：@EnableHystrix + Spring Cloud功能
@EnableHystrix 激活，没有一些Spring Cloud功能，如 /hystrix.stream
hystrix Endpoint(/actuator/hystrix.stream)
data: {
"type": "HystrixCommand",
"name": "MyHystrixCommand",
"group": "",
"currentTime": 1563720628038,
"isCircuitBreakerOpen": false,
"errorPercentage": 50,
"errorCount": 2,
"requestCount": 4,
"rollingCountBadRequests": 0,
"rollingCountCollapsedRequests": 0,
"rollingCountEmit": 0,
"rollingCountExceptionsThrown": 0,
"rollingCountFailure": 0,
"rollingCountFallbackEmit": 0,
"rollingCountFallbackFailure": 0,
"rollingCountFallbackMissing": 0,
"rollingCountFallbackRejection": 0,
"rollingCountFallbackSuccess": 1,
"rollingCountResponsesFromCache": 0,
"rollingCountSemaphoreRejected": 0,
"rollingCountShortCircuited": 0,
"rollingCountSuccess": 2,
"rollingCountThreadPoolRejected": 0,
"rollingCountTimeout": 1,
"currentConcurrentExecutionCount": 0,
"rollingMaxConcurrentExecutionCount": 1,
"latencyExecute_mean": 0,
"latencyExecute": {
"0": 0,
"25": 0,
"50": 0,
"75": 0,
"90": 0,
"95": 0,
"99": 0,
"99.5": 0,
"100": 0
},
"latencyTotal_mean": 0,
"latencyTotal": {
"0": 0,
"25": 0,
"50": 0,
"75": 0,
"90": 0,
"95": 0,
"99": 0,
"99.5": 0,
"100": 0
},
"propertyValue_circuitBreakerRequestVolumeThreshold": 20,
"propertyValue_circuitBreakerSleepWindowInMilliseconds": 5000,
"propertyValue_circuitBreakerErrorThresholdPercentage": 50,
"propertyValue_circuitBreakerForceOpen": false,
"propertyValue_circuitBreakerForceClosed": false,
"propertyValue_circuitBreakerEnabled": true,
"propertyValue_executionIsolationStrategy": "THREAD",
"propertyValue_executionIsolationThreadTimeoutInMilliseconds": 100,
"propertyValue_executionTimeoutInMilliseconds": 100,
"propertyValue_executionIsolationThreadInterruptOnTimeout": true,
"propertyValue_executionIsolationThreadPoolKeyOverride": null,
"propertyValue_executionIsolationSemaphoreMaxConcurrentRequests": 10,
"propertyValue_fallbackIsolationSemaphoreMaxConcurrentRequests": 10,
"propertyValue_metricsRollingStatisticalWindowInMilliseconds": 10000,
"propertyValue_requestCacheEnabled": true,
"propertyValue_requestLogEnabled": true,
"reportingHosts": 1,
"threadPool": ""
}
Spring Cloud Hystrix Dashboard
使用@EnableHystrixDashboard激活
@SpringBootApplication
@EnableHystrixDashboard
public class SpringCloudHystrixDashboardApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCloudHystrixDashboardApplication.class, args);
}
}