SpringCloud微服务之hystrix(五)

短命女 2022-04-22 10:22 335阅读 0赞

## 前言 ##

本小节将学习一下Hystrix的Dashboard。Hystrix Dashboard是Hystrix的仪表盘组件，主要用来实时监控Hystrix的各项指标信息，通过界面反馈的信息可以快速发现系统中存在的问题，即服务节点实现Hystrix Metrics Stream，然后通过Hystrix Dashboard将stream的信息可视化。下面我们将通过案例来学习一下Hystrix-Dashboard。

## 案例 ##

*  Eureka Server端编写(参考前例)。  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70]
 *  Eureka Client端服务提供方编写。
    
     *  项目结构  
        ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 1]
     *  CoreCode
        
            <?xml version="1.0" encoding="UTF-8"?>
            <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
            	<modelVersion>4.0.0</modelVersion>
            
            	<artifactId>microservice-deal-broker-cloud-hystrix-dashboard</artifactId>
            	<packaging>jar</packaging>
            
            	<name>microservice-deal-broker-cloud-hystrix-dashboard</name>
            	<description>Demo project for Spring Boot</description>
            
            	<parent>
            		<groupId>com.example</groupId>
            		<artifactId>microservice-deal-parent</artifactId>
            		<version>0.0.1-SNAPSHOT</version>
            	</parent>
            
            	<dependencies>
            		
            		<dependency>
            			<groupId>org.springframework.cloud</groupId>
            			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            		</dependency>
            
            		
            		<dependency>
            			<groupId>org.springframework.cloud</groupId>
            			<artifactId>spring-cloud-starter-openfeign</artifactId>
            		</dependency>
            
            		
            		<dependency>
            			<groupId>org.springframework.cloud</groupId>
            			<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            		</dependency>
            		
            		
            		<dependency>
            			<groupId>org.springframework.cloud</groupId>
            			<artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
            		</dependency>
            		
            	</dependencies>
            
            </project>
        
            @SpringBootApplication
            @EnableDiscoveryClient
            @EnableFeignClients //开启FeignClient注解
            @EnableCircuitBreaker //开启Hystrix熔断机制
            @EnableHystrixDashboard
            public class MicroserviceDealBrokerHystrixDashBoardApplication {
            
            	public static void main(String[] args) {
            		SpringApplication.run(MicroserviceDealBrokerHystrixDashBoardApplication.class,
            				args);
            	}
            }
        
            /**
             * SpringCould 2.0+需要为HystrixMricsStreamServlet手动注入到ServletRegistrationBean中
             * @author Administrator
             *
             */
            @Component
            public class HystrtixStreamServlet {
            	
            	@Bean
            	public ServletRegistrationBean<Servlet> getSerlvet(){
            		HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
            		ServletRegistrationBean<Servlet> registrationBean =  new ServletRegistrationBean<>(streamServlet);
            		registrationBean.setLoadOnStartup(1);
            		registrationBean.addUrlMappings("/hystrix.stream");
            		//registrationBean.addUrlMappings("/hystrix");
            		registrationBean.setName("HystrixMricsStreamServlet");
            		return registrationBean;
            	}
            }
        
            @FeignClient(name = "microservice-deal-cloud",fallback = HystrixFallBackMethod.class)
            public interface FeignConfig {
            
            	//第一个坑：使用Feign的时候,如果参数中带有@PathVariable形式的参数,则要用value=""标明对应的参数,否则会抛出IllegalStateException异常
            	@GetMapping("/deal/{id}")
            	public Deal findById(@PathVariable(value="id") Long id);
            	
            	@GetMapping("/dealMock/{id}")
            	public Deal findByIdMock(@PathVariable(value="id") Long id);
            }
        
            @Component
            public class HystrixFallBackMethod implements FeignConfig {
            
            	@Override
            	public Deal findById(Long id) {
            		Deal deal = new Deal();
            		deal.setId(id.intValue());
            		deal.setName("Dustyone");
            		return deal;
            	}
            
            	@Override
            	public Deal findByIdMock(Long id) {
            		Deal deal = new Deal();
            		deal.setId(id.intValue());
            		deal.setName("Dustyone");
            		return deal;
            	}
            
            }
        
            @RestController
            public class BrokerController {
            	
            	@Autowired
            	private FeignConfig feignConfig;
            	
            	@GetMapping("/deal/{id}")
            	public Deal findById(@PathVariable(value="id") Long id) {
            		return this.feignConfig.findById(id);
            	}
            	
            	@GetMapping("/dealMock/{id}")
            	public Deal findByIdMock(@PathVariable(value="id") Long id) {
            		return this.feignConfig.findByIdMock(id);
            	}
            }
        
            server:
              port: 8082
            spring:
              application:
                name: microservice-deal-broker-cloud-hystrix-dashboard
            eureka:
              client:
                serviceUrl:
                  defaultZone: http://localhost:8080/eureka/
              instance:
                prefer-ip-address: true
            
            
            #开放所有的监控节点
            management:
              endpoints:
                web:
                  exposure:
                    include: '*'
            
            #声明Feign中的Hystrix
            # 说明：请务必注意，从Spring Cloud Dalston开始，Feign默认是不开启Hystrix的。
            # 因此，如使用Dalston请务必额外设置属性：feign.hystrix.enabled=true，否则断路器不会生效。
            # 而，Spring Cloud Angel/Brixton/Camden中，Feign默认都是开启Hystrix的。无需设置该属性。
            feign:
              hystrix:
                enabled: true
            
            
            
            #使用Feign时必须添加以下两项配置
            ribbon:
              eureka:
                enabled: true
            
            #设置feign的hystrix响应超时时间(必须)
            hystrix:
              command:
                  default:
                    execution:
                      isolation:
                        thread:
                          timeoutInMilliseconds: 5000
 *  Eureka Client端服务提消费编写(单实例) (参考前例)。
 *  访问：[http://localhost:8082/hystrix][http_localhost_8082_hystrix]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 2]

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 3]

*  持续访问：[http://localhost:8082/deal/2、http://localhost:8082/dealMock/2，然后刷新Dashboard：][http_localhost_8082_deal_2_http_localhost_8082_dealMock_2_Dashboard]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 4]
 *  一段时间后：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 5]
 *  从Hystrix-Dashboard上我们可以看见:
    
     *  请求成功次数与占比率。
     *  请求失败次数与占比率。
     *  请求峰值图，一段时间内的请求次数总和。
     *  该服务节点处理请求频率。
     *  该服务节点的请求处理延迟率。
     *  该节点的断路器状态。
     *  服务提供者相关信息。
 *  手动shutdowm服务提供者：  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 6]
 *  持续访问：[http://localhost:8082/deal/2、http://localhost:8082/dealMock/2，然后刷新Dashboard：][http_localhost_8082_deal_2_http_localhost_8082_dealMock_2_Dashboard]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTI0Mzc3ODE_size_16_color_FFFFFF_t_70 7]  
    由此我们便达到了对某个微服务节点实时监控的目的。(实时监控非常消耗系统资源)。

## 小结 ##

*  Dashboard服务是个独立的结点，不需要配置eureka信息，需要Hystrix Dashboard 依赖包:spring-cloud-starter-netflix-hystrix-dashboard。
 *  启用Hystrix Dashboard只需在主类上开启注解：@EnableHystrixDashboard。
 *  要确保被监控的服务打开了Actuator，并开启了断路器（@EnableCircuitBreaker注解）。同时我们需要对Actuator做访问时需要对一些节点做声明，本案例中默认所有监控节点都可以被查看：  
    management: endpoints: web:exposure: include: ‘\*’。
 *  SpringCloud V2.0+之后需要手动声明HystrixMetricsStreamServlet，详情查看本小节HystrtixStreamServlet.java。
 *  本小节用到的案例：microservice-deal-eureka、microservice-deal-cloud、microservice-deal-broker-cloud-hystrix-dashboard。

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[http_localhost_8082_hystrix]: http://localhost:8082/hystrix
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[http_localhost_8082_deal_2_http_localhost_8082_dealMock_2_Dashboard]: http://localhost:8082/deal/2%E3%80%81http://localhost:8082/dealMock/2%EF%BC%8C%E7%84%B6%E5%90%8E%E5%88%B7%E6%96%B0Dashboard%EF%BC%9A
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