6 changed files with 159 additions and 20 deletions
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package com.zdxt.gateway.webserver.config; |
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import lombok.extern.slf4j.Slf4j; |
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import org.springframework.beans.factory.ObjectProvider; |
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import org.springframework.cloud.client.ServiceInstance; |
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import org.springframework.cloud.client.loadbalancer.DefaultResponse; |
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import org.springframework.cloud.client.loadbalancer.EmptyResponse; |
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import org.springframework.cloud.client.loadbalancer.Request; |
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import org.springframework.cloud.client.loadbalancer.Response; |
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import org.springframework.cloud.loadbalancer.core.NoopServiceInstanceListSupplier; |
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import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer; |
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import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier; |
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import reactor.core.publisher.Mono; |
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import java.util.List; |
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/** |
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* 优先级负载均衡器 - 首选优先策略 |
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* <p> |
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* 根据配置文件中实例的声明顺序确定优先级， |
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* 始终选择优先级最高的健康实例。 |
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* <p> |
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* 健康检查并发执行后返回结果顺序不确定， |
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* 因此通过 preferredOrder 显式匹配配置中的优先级顺序。 |
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* |
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* @author zdxt |
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*/ |
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@Slf4j |
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public class PreferredFirstLoadBalancer implements ReactorServiceInstanceLoadBalancer { |
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private final String serviceId; |
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private final ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider; |
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/** 配置中声明的实例顺序（host:port），索引越小优先级越高 */ |
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private final List<String> preferredOrder; |
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public PreferredFirstLoadBalancer( |
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ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, |
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String serviceId, |
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List<String> preferredOrder) { |
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this.serviceId = serviceId; |
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this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider; |
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this.preferredOrder = preferredOrder; |
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log.info("[{}] 优先级顺序: {}", serviceId, preferredOrder); |
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} |
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@Override |
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public Mono<Response<ServiceInstance>> choose(Request request) { |
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ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider |
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.getIfAvailable(NoopServiceInstanceListSupplier::new); |
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return supplier.get(request) |
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.next() |
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.map(this::selectInstance); |
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} |
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private Response<ServiceInstance> selectInstance(List<ServiceInstance> instances) { |
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if (instances.isEmpty()) { |
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log.warn("[{}] 无可用服务实例", serviceId); |
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return new EmptyResponse(); |
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} |
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// 按配置优先级顺序遍历，找到第一个在健康列表中的实例
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for (String preferred : preferredOrder) { |
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for (ServiceInstance instance : instances) { |
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String key = instance.getHost() + ":" + instance.getPort(); |
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if (preferred.equals(key)) { |
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log.debug("[{}] 选择优先实例: {}, 健康实例数: {}", |
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serviceId, key, instances.size()); |
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return new DefaultResponse(instance); |
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} |
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} |
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} |
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// 如果配置顺序中的实例都不在健康列表中（不应发生），取健康列表第一个
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ServiceInstance fallback = instances.get(0); |
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log.warn("[{}] 未匹配到配置优先级实例，回退使用: {}:{}", |
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serviceId, fallback.getHost(), fallback.getPort()); |
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return new DefaultResponse(fallback); |
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} |
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} |
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