【微服务系列】eureka结合Ribbon进行负载均衡搭建

于 2019-01-23 01:02:05 发布
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分类专栏： java 文章标签： 微服务 SpringCloud
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本文链接：https://blog.youkuaiyun.com/qq_36313726/article/details/86599901
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【微服务系列】eruka结合Ribbon进行负载均衡

一、Eureka

  1. Eureka 是 Netflix 出品的用于实现服务注册和发现的工具。
  2. Eureka是一个基于REST(Representational State Transfer)的服务，主要用于AWS cloud， 提供服务定位(locating services)、负载均衡(load balancing)、故障转移(failover of middle-tier servers)。我们把它叫做Eureka Server.
  3. Eureka也提供了基于Java的客户端组件，Eureka Client,内置的负载均衡器可以实现基本的round-robin负载均衡能力。

二、Ribbon

  1. Ribbon是Netflix发布的负载均衡器，它有助于控制HTTP和TCP的客户端的行为。
  2. 在给Ribbon配置服务提供地址后，Ribbon就可基于某种负载均衡算法，自动地帮助服务消费者去请求
    eureka与ribbon结合进行负载均衡

三、SpringBoot集成eureka与Ribbon示例代码：

1、创建eureka注册中心：

创建eureka注册中心
目录结构
配置application.yml


server:
  port: 3333

eureka:
  instance:
    hostname: localhost

  server:
    enable-self-preservation: false #关闭自我保护
    #eviction-interval-timer-in-ms: 8000 #清理间隔（单位毫秒，默认是60*1000）
    # 此处不开启缓存
    use-read-only-response-cache: false

  #不要向注册中心注册自己
  client:
    #设置是否向注册中心注册，默认是true
    register-with-eureka: false
    #禁止检索服务
    fetch-registry: false
    service-url:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka

对启动类添加**@EnableEurekaServer**注解

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

新建一个listener包并在其内创建EurekaStateListener类(监听服务注册与下线)


package com.example.demo.listener;

import com.netflix.appinfo.InstanceInfo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.netflix.eureka.server.event.*;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
public class EurekaStateListener {

    private final static Logger logger = LoggerFactory.getLogger(EurekaStateListener.class);

    @EventListener
    public void listen(EurekaInstanceCanceledEvent event) {
        logger.info("服务{}已下线", event.getAppName());
        logger.info("server地址信息{}", event.getServerId());
    }

    @EventListener
    public void listen(EurekaInstanceRegisteredEvent event) {
        InstanceInfo instanceInfo = event.getInstanceInfo();
        logger.info("服务{}进行注册", instanceInfo.getAppName()+ instanceInfo.getHostName() +"  "+ instanceInfo.getIPAddr() +"  "+ instanceInfo.getPort());
    }

    @EventListener
    public void listen(EurekaInstanceRenewedEvent event) {
        logger.info("服务{}进行续约", event.getServerId() +"  "+ event.getAppName());
    }

    @EventListener
    public void listen(EurekaRegistryAvailableEvent event) {
        logger.info("注册中心启动,{}", System.currentTimeMillis());
    }

    @EventListener
    public void listen(EurekaServerStartedEvent event) {
        logger.info("注册中心服务端启动,{}", System.currentTimeMillis());
    }

}

2、创建ribbon

在这里插入图片描述
application.yml配置信息

eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:3333/eureka
    healthcheck:
      enabled: true
  instance:
    lease-expiration-duration-in-seconds: 90
    lease-renewal-interval-in-seconds: 30
    appname: ribbon-client


server:
  port: 8092
spring:
  application:
    name: ribbon-client
  #必须加下面，否则ribbon重试机制开启不了
  cloud:
    loadbalancer:
      retry:
        enabled: true

#重试机制
  ribbon:
    MaxAutoRetries: 1
    MaxAutoRetriesNextServer: 1
    OkToRetryOnAllOperations: true
    ConnectTimeout: 250
    ReadTimeout: 1000
#熔断
hystrix:
  command:
    default:
      execution:
        isolation:
          thread:
            timeoutInMilliseconds: 4500

pom.xml里面加入重试机制依赖：feign、retry、hystrix并且加入监控依赖：actuator
依赖信息

<!-- 引入Actuator监控依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!-- 重试机制 ，必须配，否则重试不生效 -->
        <dependency>
            <groupId>org.springframework.retry</groupId>
            <artifactId>spring-retry</artifactId>
        </dependency>

完整的配置pom.xml

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.RC2</spring-cloud.version>
    </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-netflix-eureka-server</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-ribbon</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!-- 引入Actuator监控依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <!-- 重试机制 ，必须配，否则重试不生效 -->
        <dependency>
            <groupId>org.springframework.retry</groupId>
            <artifactId>spring-retry</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>

</project>

创建config包，并且创建RibbonConfig类

package com.example.demo.config;

import com.netflix.loadbalancer.BestAvailableRule;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RoundRobinRule;
import feign.Retryer;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.web.client.RestTemplate;

@Configuration
public class RibbonConfig {
    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

    @Primary
    @Bean(name="lbcRestTemplate")
    RestTemplate lbcRestTemplate() {
        return new RestTemplate();
    }


    /**自定义配置ribbon负载均衡算法
     * @return
     */
    @Bean
    public IRule myRule(){
        return new RoundRobinRule();//轮询
        //return new RetryRule();//重试
        //return new RandomRule(); //随机负载
        //return new BestAvailableRule();//选择一个最小的并发请求的server
    }
}

创建controller包并创建HelloController类

package com.example.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.net.URI;

@RestController
public class HelloController {
    @Autowired
    @Qualifier(value = "restTemplate")
    private RestTemplate restTemplate;

    @Autowired
    @Qualifier(value = "lbcRestTemplate")
    private RestTemplate lbcRestTemplate;

    @Autowired
    private LoadBalancerClient loadBalancerClient;
    @CrossOrigin
    @RequestMapping(value = "/hello" ,method = RequestMethod.GET)
    public String hello(){
        String url="http://hello/hello";
        ServiceInstance instance = this.loadBalancerClient.choose("hello");
        URI helloUri = URI.create(String.format("http://%s:%s/hello", instance.getHost(), instance.getPort()));
        System.out.println("Target service uri =  "+helloUri.toString());
        return restTemplate.getForObject(url,String.class);
    }
}

3、创建服务提供者Hello

Hello的配置
在pom.xml添加actuator依赖

 <!-- 引入Actuator监控依赖 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

即完整的pom.xml

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.RC2</spring-cloud.version>
    </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-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- 引入Actuator监控依赖 -->
        <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>${spring-cloud.version}</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>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>

</project>

创建controller包并创建HelloController类

package com.example.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class HelloController {
    @ResponseBody
    @RequestMapping(value = "hello")
    public Object hello()
    {
        return "HelloWorld";
    }
    
}

编写application.yml内容

spring:
  application:
    name: hello
server:
  port: 8089
eureka:
  client:                                                   #客户端注册进eureka服务列表内
    service-url:
      defaultZone: http://127.0.0.1:3333/eureka
    healthcheck:
      enabled: true #开启健康检查（需要spring-boot-starter-actuator依赖）

  instance:
    lease-expiration-duration-in-seconds: 90 #服务过期时间配置,超过这个时间没有接收到心跳EurekaServer就会将这个实例剔除
    lease-renewal-interval-in-seconds: 30 #服务刷新时间配置，每隔这个时间会主动心跳一次
    appname: hello

management:
  endpoints:
    web:
      exposure:
        include: "*"
  server:
    port: 8089
    servlet:
      context-path: /
    ssl:
      enabled: false
  endpoint:
    health:
      show-details: always
  shutdown:
    enabled: true
    #禁用密码验证
    sensitive: false

访问http://localhost:3333出现eureka的界面(hello应用中只有一个url有效，另外一个是我一开始没设置应用名后来添加，eureka还没进行刷新的原因)
在这里插入图片描述
访问http://localhost:8092/hello
在这里插入图片描述
附上三个demo的目录
在这里插入图片描述
完整项目下载地址：https://download.youkuaiyun.com/download/qq_36313726/10933212

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