【SpringCloud系列】开发环境下重写Loadbalancer实现自定义负载均衡_百度小程序

前言

spring-cloud-starter-netflix-ribbon已经不再更新了，最新版本是2.2.10.RELEASE，最后更新时间是2021年11月18日，详细信息可以看maven官方仓库：https://search.maven.org/artifact/org.springframework.cloud/spring-cloud-starter-netflix-ribbon，SpringCloud官方推荐使用spring-cloud-starter-loadbalancer进行负载均衡。我们在开发的时候，多人开发同一个微服务，都注册到同一个nacos，前端请求的时候，网关Gateway默认轮训请求注册中心的服务，OpenFeign也会轮询请求注册中心的服务，这样就会导致前端有时会无法请求到我们本地写的接口，而是请求到别人的服务中。所以我们可以重写Loadbalancer默认的负载均衡策略，实现自定义负载均衡策略，不管是Gateway还是OpenFeign都只能请求到我们自己本地的服务。

我的版本如下：

2.7.3

2021.0.4

2021.0.4.0

一、添加负载方式配置

1、定义负载均衡方式的枚举

public enum LoadBalancerTypeEnum {
    /**
     * 开发环境，获取自己的服务
     */
    DEV,
    /**
     * 网关，根据请求地址获取对应的服务
     */
    GATEWAY,
    /**
     * 轮循
     */
    ROUND_ROBIN,
    /**
     * 随机
     */
    RANDOM;
}

2、添加配置类，默认使用轮训方式

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
/**
 * 负载均衡配置项
 */
@Data
@ConfigurationProperties(prefix = "spring.cloud.loadbalancer")
public class LoadBalanceProperties {
    private LoadBalancerTypeEnum type = LoadBalancerTypeEnum.ROUND_ROBIN;
}

二、参考默认实现自定义

默认的负载均衡策略是这个类：

org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer

我们参考这个类实现自己的负载均衡策略即可，RoundRobinLoadBalancer实现了ReactorServiceInstanceLoadBalancer这个接口，实现了choose这个方法，如下图：

【SpringCloud系列】开发环境下重写Loadbalancer实现自定义负载均衡,第1张

在choose方法中调用了processInstanceResponse方法，processInstanceResponse方法中调用了getInstanceResponse方法，所以我们我们可以复制RoundRobinLoadBalancer整个类，只修改getInstanceResponse这个方法里的内容就可以实现自定义负载均衡策略。

在自定义的类中，我们实现了四种负载均衡策略

1、getRoundRobinInstance方法是直接复制的RoundRobinLoadBalancer类中的实现；

2、getRandomInstance方法参考org.springframework.cloud.loadbalancer.core.RandomLoadBalancer类中的实现；

3、getDevelopmentInstance方法是返回所有服务中和当前机器ip一致的服务，如果没有，则轮训返回；

4、getGatewayDevelopmentInstance方法是返回所有服务中和网关请求头中ip一致的服务。

import cn.hutool.core.convert.Convert;
import cn.hutool.core.lang.TypeReference;
import com.ruoyi.common.core.utils.StringUtils;
import com.ruoyi.common.core.utils.ip.IpUtils;
import com.ruoyi.common.loadbalance.config.LoadBalancerTypeEnum;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.DefaultRequest;
import org.springframework.cloud.client.loadbalancer.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.Request;
import org.springframework.cloud.client.loadbalancer.RequestData;
import org.springframework.cloud.client.loadbalancer.RequestDataContext;
import org.springframework.cloud.client.loadbalancer.Response;
import org.springframework.cloud.loadbalancer.core.NoopServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.SelectedInstanceCallback;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.http.HttpHeaders;
import reactor.core.publisher.Mono;
import java.util.List;
import java.util.Objects;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;
/**
 * 自定义 SpringCloud 负载均衡算法
 * 负载均衡算法的默认实现是 {@link org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer}
 *
 */
@Slf4j
public class CustomSpringCloudLoadBalancer implements ReactorServiceInstanceLoadBalancer {
    private final String serviceId;
    private final AtomicInteger position;
    private final LoadBalancerTypeEnum type;
    private final ObjectProvider serviceInstanceListSupplierProvider;
    public CustomSpringCloudLoadBalancer(String serviceId,
                                         LoadBalancerTypeEnum type,
                                         ObjectProvider serviceInstanceListSupplierProvider) {
        this(serviceId, new Random().nextInt(1000), type, serviceInstanceListSupplierProvider);
    }
    public CustomSpringCloudLoadBalancer(String serviceId,
                                         int seedPosition,
                                         LoadBalancerTypeEnum type,
                                         ObjectProvider serviceInstanceListSupplierProvider) {
        this.serviceId = serviceId;
        this.position = new AtomicInteger(seedPosition);
        this.type = type;
        this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
    }
    @Override
    public Mono> choose(Request request) {
        ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider.getIfAvailable(NoopServiceInstanceListSupplier::new);
        return supplier.get(request).next().map(serviceInstances -> processInstanceResponse(request, supplier, serviceInstances));
    }
    private Response processInstanceResponse(Request request,
               ServiceInstanceListSupplier supplier,
               List serviceInstances) {
        Response serviceInstanceResponse = getInstanceResponse(request, serviceInstances);
        if (supplier instanceof SelectedInstanceCallback && serviceInstanceResponse.hasServer()) {
            ((SelectedInstanceCallback) supplier).selectedServiceInstance(serviceInstanceResponse.getServer());
        }
        return serviceInstanceResponse;
    }
    private Response getInstanceResponse(Request request, List instances) {
        if (instances.isEmpty()) {
            if (log.isWarnEnabled()) {
                log.warn("No servers available for service: " + serviceId);
            }
            return new EmptyResponse();
        }
        if (Objects.equals(type, LoadBalancerTypeEnum.ROUND_ROBIN)){
            return this.getRoundRobinInstance(instances);
        }else if (Objects.equals(type, LoadBalancerTypeEnum.RANDOM)){
            return this.getRandomInstance(instances);
        }else if (Objects.equals(type, LoadBalancerTypeEnum.DEV)){
            return this.getDevelopmentInstance(instances);
        }else if (Objects.equals(type, LoadBalancerTypeEnum.GATEWAY)){
            return this.getGatewayDevelopmentInstance(request, instances);
        }
        return this.getRoundRobinInstance(instances);
    }
    /**
     * 获取网关本机实例
     *
     * @param instances 实例
     * @return {@link Response }<{@link ServiceInstance }>
     * @author : lwq
     * @date : 2022-12-15 14:22:13
     */
    private Response getGatewayDevelopmentInstance(Request request, List instances) {
        //把request转为默认的DefaultRequest，从request中拿到请求的ip信息，再选择ip一样的微服务
        DefaultRequest defaultRequest = Convert.convert(new TypeReference>() {}, request);
        RequestDataContext context = defaultRequest.getContext();
        RequestData clientRequest = context.getClientRequest();
        HttpHeaders headers = clientRequest.getHeaders();
        String requestIp = IpUtils.getIpAddressFromHttpHeaders(headers);
        log.debug("客户端请求gateway的ip:{}", requestIp);
        //先取得和本地ip一样的服务，如果没有则按默认来取
        for (ServiceInstance instance : instances) {
            String currentServiceId = instance.getServiceId();
            String host = instance.getHost();
            log.debug("注册服务：{}，ip：{}", currentServiceId, host);
            if (StringUtils.isNotEmpty(host) && StringUtils.equals(requestIp, host)) {
                return new DefaultResponse(instance);
            }
        }
        return getRoundRobinInstance(instances);
    }
    /**
     * 获取本机实例
     *
     * @param instances 实例
     * @return {@link Response }<{@link ServiceInstance }>
     * @author : lwq
     * @date : 2022-12-15 14:22:13
     */
    private Response getDevelopmentInstance(List instances) {
        //获取本机ip
        String hostIp = IpUtils.getHostIp();
        log.debug("本机Ip:{}", hostIp);
        //先取得和本地ip一样的服务，如果没有则按默认来取
        for (ServiceInstance instance : instances) {
            String currentServiceId = instance.getServiceId();
            String host = instance.getHost();
            log.debug("注册服务：{}，ip：{}", currentServiceId, host);
            if (StringUtils.isNotEmpty(host) && StringUtils.equals(hostIp, host)) {
                return new DefaultResponse(instance);
            }
        }
        return getRoundRobinInstance(instances);
    }
    /**
     * 使用随机算法
     * 参考{link {@link org.springframework.cloud.loadbalancer.core.RandomLoadBalancer}}
     *
     * @param instances 实例
     * @return {@link Response }<{@link ServiceInstance }>
     * @author : lwq
     * @date : 2022-12-15 13:32:11
     */
    private Response getRandomInstance(List instances) {
        int index = ThreadLocalRandom.current().nextInt(instances.size());
        ServiceInstance instance = instances.get(index);
        return new DefaultResponse(instance);
    }
    /**
     * 使用RoundRobin机制获取节点
     *
     * @param instances 实例
     * @return {@link Response }<{@link ServiceInstance }>
     * @author : lwq
     * @date : 2022-12-15 13:28:31
     */
    private Response getRoundRobinInstance(List instances) {
        // 每一次计数器都自动+1，实现轮询的效果
        int pos = this.position.incrementAndGet() & Integer.MAX_VALUE;
        ServiceInstance instance = instances.get(pos % instances.size());
        return new DefaultResponse(instance);
    }
}

其中的工具类如下：

import java.net.InetAddress;
import java.net.URL;
import java.net.UnknownHostException;
import java.util.List;
import java.util.Objects;
import javax.servlet.http.HttpServletRequest;
import cn.hutool.core.collection.CollectionUtil;
import cn.hutool.core.util.URLUtil;
import org.springframework.http.HttpHeaders;
/**
 * 获取IP方法
 */
public class IpUtils{
    /**
     * 获取IP地址
     *
     * @return 本地IP地址
     */
    public static String getHostIp(){
        try{
            return InetAddress.getLocalHost().getHostAddress();
        }catch (UnknownHostException e){
        }
        return "127.0.0.1";
    }
    /**
     * 获取客户端IP
     *
     * @param httpHeaders 请求头
     * @return IP地址
     */
    public static String getIpAddressFromHttpHeaders(HttpHeaders httpHeaders){
        if (httpHeaders == null){
            return "unknown";
        }
        //前端请求自定义请求头，转发到哪个服务
        List ipList = httpHeaders.get("forward-to");
        String ip = CollectionUtil.get(ipList, 0);
        //请求自带的请求头
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            ipList = httpHeaders.get("x-forwarded-for");
            ip = CollectionUtil.get(ipList, 0);
        }
        //从referer获取请求的ip地址
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            //从referer中获取请求的ip地址
            List refererList = httpHeaders.get("referer");
            String referer = CollectionUtil.get(refererList, 0);
            URL url = URLUtil.url(referer);
            if (Objects.nonNull(url)){
                ip = url.getHost();
            }else {
                ip = "unknown";
            }
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            ipList = httpHeaders.get("Proxy-Client-IP");
            ip = CollectionUtil.get(ipList, 0);
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            ipList = httpHeaders.get("X-Forwarded-For");
            ip = CollectionUtil.get(ipList, 0);
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            ipList = httpHeaders.get("WL-Proxy-Client-IP");
            ip = CollectionUtil.get(ipList, 0);
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)){
            ipList = httpHeaders.get("X-Real-IP");
            ip = CollectionUtil.get(ipList, 0);
        }
        return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : getMultistageReverseProxyIp(ip);
    }
}

getIpAddressFromHttpHeaders方法中，是从请求头总拿到了自定义的请求头forward-to，要想实现此功能，就需要前端发送请求的时候携带这个请求头，例如

在若依的request.js中可以这么写： config.headers['forward-to'] = '192.168.0.145'

【SpringCloud系列】开发环境下重写Loadbalancer实现自定义负载均衡,第2张

三、配置负载均衡策略

默认的配置在这里：

org.springframework.cloud.loadbalancer.annotation.LoadBalancerClientConfiguration

我们参考这个配置，实现自己的配置。启用上面写好的配置类LoadBalanceProperties，然后传到自定义的负载均衡策略类CustomSpringCloudLoadBalancer，其他的复制就可以。

import com.ruoyi.common.loadbalance.core.CustomSpringCloudLoadBalancer;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.loadbalancer.core.ReactorLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
/**
 * 自定义负载均衡客户端配置
 *
 */
@SuppressWarnings("all")
@Configuration(proxyBeanMethods = false)
@EnableConfigurationProperties(LoadBalanceProperties.class)
public class CustomLoadBalanceClientConfiguration {
    @Bean
    @ConditionalOnBean(LoadBalancerClientFactory.class)
    public ReactorLoadBalancer customLoadBalancer(LoadBalanceProperties loadBalanceProperties,
                    Environment environment,
                    LoadBalancerClientFactory loadBalancerClientFactory) {
        String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);
        return new CustomSpringCloudLoadBalancer(name, loadBalanceProperties.getType(),
                loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class));
    }
}

然后使用LoadBalancerClients注解加载一下配置

import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;
/**
 * 自定义负载均衡自动配置
 *
 */
@LoadBalancerClients(defaultConfiguration = CustomLoadBalanceClientConfiguration.class)
public class CustomLoadBalanceAutoConfiguration {
}

四、使用

将以上代码独立成一个模块，然后再其他微服务中的pom文件中引入，然后添加对应的配置就可以实现自定义负载均衡了

1、在微服务中配置如下即可实现调用其他服务时，调用自己本地开发环境的微服务

spring.cloud.loadbalancer.type=dev

2、在网关中配置如下即可实现调用固定某个服务

spring.cloud.loadbalancer.type=gateway

写在最后的话

最开始只有想法，但是不知道怎么实现，百度也没找到合适的方案。所以就开始看源码，研究了一下，然后照着源码写，测试了一下真的就实现了。所以，多看看源码还是有好处的。

深圳专业做网站多少钱软文营销案例网站建设平台价格常用网站推广方法广告网站策划方案关键词热度分析工具

上一篇：docker安装RabbitMQ教程(2023年最详细)

下一篇：postgresql统计数据库大小(表、行数等)