5.使用Ribbon实现客户端侧负载均衡

                            Ribbon实现客户端侧负载均衡

5.1. Ribbon简介

           Ribbon是Netflix发布的开源项目，主要功能是提供客户端的软件负载均衡算法，将Netflix的中间层服务连接在一起。

          Ribbon客户端组件提供一系列完善的配置项如连接超时，重试等。简单的说，就是在配置文件中列出Load Balancer

          后面所有的机器，Ribbon会自动的帮助你基于某种规则（如简单轮询，随机连接等）去连接这些机器。我们也很容易

          使用Ribbon实现自定义的负载均衡算法。简单地说，Ribbon是一个客户端负载均衡器。

          Ribbon工作时分为两步：

               第一步先选择 Eureka Server, 它优先选择在同一个Zone且负载较少的Server；

               第二步再根据用户指定的策略，在从Server取到的服务注册列表中选择一个地址。其中Ribbon提供了多种策略，例如轮询、随机、根据响应时间加权等。

5.2. 为服务消费者整合Ribbon

 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>

    <artifactId>microservice-consumer-movie-ribbon</artifactId>
    <packaging>jar</packaging>

    <parent>
        <groupId>com.itmuch.cloud</groupId>
        <artifactId>microservice-spring-cloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.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-eureka</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>
</project>

实体类

package com.itmuch.cloud.entity;

import java.math.BigDecimal;

public class User {
  private Long id;

  private String username;

  private String name;

  private Short age;

  private BigDecimal balance;

  public Long getId() {
    return this.id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getUsername() {
    return this.username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getName() {
    return this.name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Short getAge() {
    return this.age;
  }

  public void setAge(Short age) {
    this.age = age;
  }

  public BigDecimal getBalance() {
    return this.balance;
  }

  public void setBalance(BigDecimal balance) {
    this.balance = balance;
  }

}

Controller类

package com.itmuch.cloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
 
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.itmuch.cloud.entity.User;

@RestController
public class MovieController {
  @Autowired
  private RestTemplate restTemplate;

  @GetMapping("/movie/{id}")
  public User findById(@PathVariable Long id) {
     
    return this.restTemplate.getForObject("http://microservice-provider-user/simple/" + id, User.class);
  }
 
}

启动类

package com.itmuch.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.client.RestTemplate;

 

@SpringBootApplication
@EnableEurekaClient
public class RibbonApplication {

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

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

配置文件

spring:
  application:
    name: microservice-consumer-movie-ribbon
server:
  port: 8010
eureka:
  client:
    healthcheck:
      enabled: true
    serviceUrl:
      defaultZone: http://user:password123@localhost:8761/eureka
  instance:
    prefer-ip-address: true

访问路径：

5.3. 使用Java代码自定义Ribbon配置

 Spring Cloud还允许通过使用@RibbonClient声明其他配置（位于RibbonClientConfiguration之上）来完全控制客户端。例：

启动类

package com.itmuch.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

import com.itmuch.config.TestConfiguration;

 

@SpringBootApplication
@EnableEurekaClient
@RibbonClient(name="microservice-provider-user",configuration=TestConfiguration.class)
public class RibbonApplication {

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

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

package com.itmuch.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.netflix.client.config.IClientConfig;
import com.netflix.loadbalancer.IRule;
import com.netflix.loadbalancer.RandomRule;

@Configuration
public class TestConfiguration {
     @Autowired
     IClientConfig config;
     @Bean
     public IRule ribbonRule(IClientConfig config) {
            return new RandomRule();
     }
}

图文：

111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7901:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7901:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7901:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7900:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2
111--->172.20.10.4:7901:microservice-provider-user
222--->172.20.10.4:7801:microservice-provider-user2
111--->172.20.10.4:7901:microservice-provider-user
222--->172.20.10.4:7800:microservice-provider-user2

5.4. 使用属性自定义Ribbon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>

    <artifactId>microservice-consumer-movie-ribbon-config</artifactId>
    <packaging>jar</packaging>

    <parent>
        <groupId>com.itmuch.cloud</groupId>
        <artifactId>microservice-spring-cloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.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-eureka</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>
</project>

配置文件

spring:
  application:
    name: microservice-consumer-movie-ribbon-config
server:
  port: 8010
eureka:
  client:
    healthcheck:
      enabled: true
    serviceUrl:
      defaultZone: http://user:password123@localhost:8761/eureka
  instance:
    prefer-ip-address: true
microservice-provider-user:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.WeightedResponseTimeRule
     

实体类

package com.itmuch.cloud.entity;

import java.math.BigDecimal;

public class User {
  private Long id;

  private String username;

  private String name;

  private Short age;

  private BigDecimal balance;

  public Long getId() {
    return this.id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getUsername() {
    return this.username;
  }

  public void setUsername(String username) {
    this.username = username;
  }

  public String getName() {
    return this.name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Short getAge() {
    return this.age;
  }

  public void setAge(Short age) {
    this.age = age;
  }

  public BigDecimal getBalance() {
    return this.balance;
  }

  public void setBalance(BigDecimal balance) {
    this.balance = balance;
  }

}

Controller类

package com.itmuch.cloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.itmuch.cloud.entity.User;

@RestController
public class MovieController {
  @Autowired
  private RestTemplate restTemplate;
  @Autowired
  private LoadBalancerClient  loadBalancerClient;
 
  @GetMapping("/movie/{id}")
  public User findById(@PathVariable Long id) {
     
    return this.restTemplate.getForObject("http://microservice-provider-user/simple/" + id, User.class);
  }
    @GetMapping("/test")
    public String test(){
    ServiceInstance     serviceInstance=this.loadBalancerClient.choose("microservice-provider-user");
    System.out.println("cyj:--->"+serviceInstance.getHost()+":"+serviceInstance.getPort()+":"+serviceInstance.getServiceId());
    
    ServiceInstance     serviceInstance2=this.loadBalancerClient.choose("microservice-provider-user2");
    System.out.println("lxq:--->"+serviceInstance2.getHost()+":"+serviceInstance2.getPort()+":"+serviceInstance2.getServiceId());
   
    return "1";
    }
}

图文

5.5. 脱离Eureka使用Ribbon

Eureka是一种方便的方式来抽象远程服务器的发现，因此您不必在客户端中对其URL进行硬编码，

但如果您不想使用它，Ribbon和Feign仍然是适用的。假设您已经为“商店”申请了@RibbonClient，

并且Eureka未被使用（甚至不在类路径上）。Ribbon客户端默认为已配置的服务器列表，

您可以提供这样的配置

stores:
  ribbon:
    listOfServers: example.com,google.com

在Ribbon中禁用Eureka使用

ribbon:
  eureka:
   enabled: false

设置属性ribbon.eureka.enabled = false将明确禁用在Ribbon中使用Eureka。

 

spring:
  application:
    name: microservice-consumer-movie-ribbon-config
server:
  port: 8010
eureka:
  client:
    healthcheck:
      enabled: true
    serviceUrl:
      defaultZone: http://user:password123@localhost:8761/eureka
  instance:
    prefer-ip-address: true
ribbon:
  eureka:
   enabled: false      
microservice-provider-user:
   ribbon:
     listOfServers: localhost:7800