Spring Cloud - 5 (Spring Cloud Netflix Hystrix)

深碍√TFBOYSˉ_ 2021-11-29 10:56 265阅读 0赞

# Spring Cloud Netflix Hystrix) #

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## 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][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][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<String>{
    
            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<String> 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);
        }
    
    }

[https_github.com_Netflix_Hystrix]: https://github.com/Netflix/Hystrix
[https_github.com_Netflix_Hystrix_wiki_Configuration]: http://https//github.com/Netflix/Hystrix/wiki/Configuration