Spring Cloud Hystrix熔断与调用隔离组件

谁践踏了优雅 2022-03-17 11:40 162阅读 0赞

微服务框架(Spring Cloud,Dubbo)中将业务划分为许多微业务模块进行管理，这样会导致微服务间相互调用，彼此依赖，如果某一个环节的微服务出现问题，整个调用链条都会出现问题，会阻塞所有调用此服务的线程。Netflix为解决此问题根据断路器模式设计了Hystrix库，"断路器"是电气设备中的一种开关装置，当某个服务出现故障后，通过断路器的故障监控，向调用线程返回一个符号预期可处理的备选响应(Fallback),从而避免线程长时间等待或者抛出异常，这样保证了服务调用线程不会被长时间被占用，从而避免故障在微服务系统中的蔓延，乃至雪崩。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70]

假设：一个服务依赖30个微服务,每个微服务99.99%可用。  
99.99%的30次方 ≈ 99.7%  
0.3% 意味着一千次请求 会有 3次失败  
按照时间换算大约每月有2个小时时间服务出现问题。  
如果服务依赖数量继续增加，服务不稳定导致的后果更加严重。

## Hystrix如何进行熔断与调用隔离 ##

Hystrix使用命令模式HystrixCommand(Command)包装依赖调用逻辑，每个命令在单独线程中/信号授权下执行。  
可配置依赖调用超时时间,超时时间一般设为比99.5%平均时间略高即可.当调用超时时，直接返回或执行fallback逻辑。  
为每个依赖提供一个小的线程池（或信号），如果线程池已满调用将被立即拒绝，默认不采用排队.加速失败判定时间。  
依赖调用结果分:成功，失败（抛出异常），超时，线程拒绝，短路。 请求失败(异常，拒绝，超时，短路)时执行fallback(降级)逻辑。  
提供熔断器组件,可以自动运行或手动调用,停止当前依赖一段时间(10秒)，熔断器默认错误率阈值为50%,超过将自动运行。  
提供近实时依赖的统计和监控。

## Hystrix容错机制 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 1]

## 设计Eureka注册中心 ##

POM.xml

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.test</groupId>
      <artifactId>eureka-server</artifactId>
      <packaging>war</packaging>
      <version>0.0.1-SNAPSHOT</version>
      <name>eureka-server Maven Webapp</name>
      <url>http://maven.apache.org</url>
    	
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.2.RELEASE</version>
    	</parent>
    
    	<properties>
    	  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	</properties>
    
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Dalston.SR1</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    
    	<dependencies>
    	  <dependency>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-test</artifactId>
    		<scope>test</scope>
    	  </dependency>
    	  
    	  <dependency>
    		<groupId>org.springframework.cloud</groupId>
    		<artifactId>spring-cloud-starter-eureka-server</artifactId>
    	  </dependency>
    	  
    	  
    		<dependency> 
    			<groupId>org.springframework.boot</groupId> 
    			<artifactId>spring-boot-starter-security</artifactId> 	
    		</dependency> 
    	</dependencies>
    
    	
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

application.properties

server.port=8110
    eureka.instance.hostname=localhost
    eureka.client.register-with-eureka=false
    eureka.client.fetch-registry=false
    eureka.client.serviceUrl.defaultZone=http://localhost:8110/eureka/
    
    security.user.name=chenqx
    security.user.password=123

EureKaServer启动类

package com.test.eureka_server;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    
    @EnableEurekaServer
    @SpringBootApplication
    public class EureKaServer 
    {
        public static void main( String[] args )
        {
            SpringApplication.run(EureKaServer.class, args);
        }
    }

## 设计微服务提供者 ##

POM.xml

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.test</groupId>
      <artifactId>eureka-service-order</artifactId>
      <packaging>war</packaging>
      <version>0.0.1-SNAPSHOT</version>
      <name>eureka-service-order Maven Webapp</name>
      <url>http://maven.apache.org</url>
    	
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.2.RELEASE</version>
    	</parent>
    	
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-eureka</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-hystrix</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-actuator</artifactId>
    		</dependency>
    	</dependencies>
      
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Dalston.SR1</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	
    	
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

application.properties

server.port=9100
    spring.application.name=service-order
    eureka.client.service-url.defaultZone=http://chenqx:123@localhost:8110/eureka
    eureka.client.register-with-eureka=true
    eureka.client.registry-fetch-interval-seconds=10
    eureka.client.fetch-registry=true

实体类

package com.test.eureka_service_order;
    
    import java.io.Serializable;
    import java.sql.Date;
    
    public class OrderInfo implements Serializable {
        private static final long serialVersionUID = -7233238826463139634L;
        private Long id;
        private String name;
        private String prdtName;
        private Integer count;
        private Integer amount;
        private Date createDt = new Date(System.currentTimeMillis());
        private String userId = null;
        
     
        public OrderInfo() {
        }
     
        public OrderInfo(String name,String prdtName,Integer count,Integer amount,Date createDt,String userId) {
            this.name = name;
            this.prdtName = prdtName;
            this.count = count;
            this.amount = amount;
            this.createDt = createDt;
            this.userId = userId;
        }
     
     
        public Long getId() {
    		return id;
    	}
    
    	public void setId(Long id) {
    		this.id = id;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public String getPrdtName() {
    		return prdtName;
    	}
    
    	public void setPrdtName(String prdtName) {
    		this.prdtName = prdtName;
    	}
    
    	public Integer getCount() {
    		return count;
    	}
    
    	public void setCount(Integer count) {
    		this.count = count;
    	}
    
    	public Integer getAmount() {
    		return amount;
    	}
    
    	public void setAmount(Integer amount) {
    		this.amount = amount;
    	}
    
    	public Date getCreateDt() {
    		return createDt;
    	}
    
    	public void setCreateDt(Date createDt) {
    		this.createDt = createDt;
    	}
    
    	public String getUserId() {
    		return userId;
    	}
    
    	public void setUserId(String userId) {
    		this.userId = userId;
    	}
    
    	@Override
        public String toString() {
            return "User{" +
                    "name='" + name + '\'' +
                    ",prdtName=" + prdtName +
                    ",count=" + count +
                    ",amount=" + amount +
                    '}';
        }
    }

服务类

package com.test.eureka_service_order;
    
    import java.io.UnsupportedEncodingException;
    import java.net.URLDecoder;
    import java.sql.Date;
    
    import org.springframework.web.bind.annotation.RequestBody;
    import org.springframework.web.bind.annotation.RequestHeader;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class OrderServiceApiImpl{
    
    	@RequestMapping(value = "/hello1", method = RequestMethod.GET)
    	public String hello(@RequestParam("name") String name) {
    		System.out.println("name="+name);
    		return "hello " + name;
    	}
    
    	@RequestMapping(value = "/hello2", method = RequestMethod.GET)
        public OrderInfo hello(@RequestHeader("name") String name,
        		@RequestHeader("prdtName") String prdtName,
        		@RequestHeader("count") Integer count,
        		@RequestHeader("amount") Integer amount,
        		@RequestHeader("createDt") Date createDt,
        		@RequestHeader("userId") String userId) {
            try {
                name= URLDecoder.decode(name,"UTF-8");
                prdtName= URLDecoder.decode(prdtName,"UTF-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            return new OrderInfo(name, prdtName,count,amount,createDt,userId);
        }
     
    	@RequestMapping(value = "/hello3", method = RequestMethod.GET)
        public String hello(@RequestBody OrderInfo order) {
            if (order == null) {
                return "未知";
            }
            return order.toString();
        }
    
    }

启动类

package com.test.eureka_service_order;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    
    @EnableDiscoveryClient
    @SpringBootApplication
    public class OrderServer 
    {
        public static void main( String[] args )
        {
        	SpringApplication.run(OrderServer.class, args);
        }
    }

## 设计服务消费者 ##

POM.xml

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
    	
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.2.RELEASE</version>
    	</parent>
    
      <groupId>com.test</groupId>
      <artifactId>eureka-service-web</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <packaging>jar</packaging>
    
      <name>eureka-service-web</name>
      <url>http://maven.apache.org</url>
    
      <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      </properties>
    
      <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-eureka</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-feign</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-hystrix</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
      </dependencies>
      
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Dalston.SR1</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	
    	
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

实体类与服务提供者中的相同  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 2]  
定义Feign接口

package com.test.eureka_service_web;
    
    import java.sql.Date;
    
    import org.springframework.cloud.netflix.feign.FeignClient;
    import org.springframework.web.bind.annotation.RequestBody;
    import org.springframework.web.bind.annotation.RequestHeader;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    
    @FeignClient(value = "service-order",fallback=OrderFallBackImpl.class)
    public interface OrderBackgroundService{
    	
    	@RequestMapping(value = "/hello1", method = RequestMethod.GET)
    	public String hello(@RequestParam("name") String name);
    	
    	@RequestMapping(value = "/hello2", method = RequestMethod.GET)
        public OrderInfo hello(@RequestHeader("name") String name,
        		@RequestHeader("prdtName") String prdtName,
        		@RequestHeader("count") Integer count,
        		@RequestHeader("amount") Integer amount,
        		@RequestHeader("createDt") Date createDt,
        		@RequestHeader("userId") String userId);
        
    	@RequestMapping(value = "/hello3", method = RequestMethod.GET)
    	public String hello(@RequestBody OrderInfo order);
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 3]  
设计OrderFallBackImpl

package com.test.eureka_service_web;
    
    import java.io.UnsupportedEncodingException;
    import java.net.URLDecoder;
    import java.sql.Date;
    
    import org.springframework.stereotype.Component;
    import org.springframework.web.bind.annotation.RequestBody;
    import org.springframework.web.bind.annotation.RequestHeader;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    
    @Component
    public class OrderFallBackImpl implements OrderBackgroundService{
    
    	public String hello(@RequestParam("name") String name) {
    		return "返回Fallback.hello";
    	}
    
        public OrderInfo hello(@RequestHeader("name") String name,
        		@RequestHeader("prdtName") String prdtName,
        		@RequestHeader("count") Integer count,
        		@RequestHeader("amount") Integer amount,
        		@RequestHeader("createDt") Date createDt,
        		@RequestHeader("userId") String userId) {
        	name= "Fallback Name";
            prdtName= "Fallback PrdtName";
            return new OrderInfo(name, prdtName,count,amount,createDt,userId);
        }
    
        public String hello(@RequestBody OrderInfo order) {
        	return "返回Fallback.hello3";
        }
    
    }

消费者Controller

package com.gf.eureka_order_client;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class OrderController {
    	@Autowired
    	private OrderBackgroundService service;
    	
        @RequestMapping("/hello1")
        public String hello1(){
        	return service.hello("Java");
        }
    }

启动类

package com.test.eureka_service_web;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.netflix.feign.EnableFeignClients;
    import org.springframework.context.annotation.Bean;
    
    import feign.Logger;
    
    @EnableCircuitBreaker
    @EnableFeignClients
    @EnableDiscoveryClient
    @SpringBootApplication
    public class OrderClient 
    {
        @Bean
        Logger.Level feginLoggerLevel(){
            return Logger.Level.FULL;
        }
     
        public static void main(String[] args) {
            SpringApplication.run(OrderClient.class, args);
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 4]  
application.properties

server.port=8887
    spring.application.name=order-service-web
    eureka.instance.hostname=localhost
    eureka.instance.server.port=8110
    eureka.client.serviceUrl.defaultZone=http://chenqx:123@${eureka.instance.hostname}:${eureka.instance.server.port}/eureka/
     
    feign.hystrix.enabled=true

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 5]

## 测试效果 ##

分别启动EurekaServer注册中心，服务和消费者  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 6]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 7]  
停止SERVICE-ORDER服务后，再次请求http://localhost:8887/hello1  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 8]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70]: /images/20220317/2af1b06e8be04f8ebf0dc9806353183f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 1]: /images/20220317/28e57dd9e26e44a0a35ccf182b1da23b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 2]: /images/20220317/e94f4c5573bc4615992d1ff4b351073e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 3]: /images/20220317/cd33d197d5fc4d0580e61acf3c46dda6.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 4]: /images/20220317/c4fe5ae211e44e0e9747903c1857a007.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 5]: /images/20220317/785df6482049400289e197c3f6bcf151.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 6]: /images/20220317/b67757c822514a949c164a7d4b03a6fe.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 7]: /images/20220317/dea9c9a28ab84eccbf59c12fa5b4af8f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FpeGlhbmdfY2hlbg_size_16_color_FFFFFF_t_70 8]: /images/20220317/6009688e7cbb4039aceefba597820777.png