1、Spring Cloud Gateway配置文件

gateway:userId-limit: 1000
agent-bff:ribbon:NFLoadBalancerRuleClassName: com.anlitech.gateway.gray.GrayRule
operator-bff:ribbon:NFLoadBalancerRuleClassName: com.anlitech.gateway.gray.GrayRule
spring:cloud:gateway:locator:enabled: trueroutes:- id: operator-bffuri: lb://operator-bffpredicates:- Path=/operatorPortal/**- id: agent-bffuri: lb://agent-bffpredicates:- Path=/agentPortal/**

2、Spring Cloud Gateway配置类

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;@Data
@Component
@RefreshScope
@ConfigurationProperties("gateway")
public class GatewayConfigProperties {/*** 用户id灰度阈值*/private Long userIdLimit;}

3、Spring Cloud Gateway的Ribbon请求上下文持有器

import com.alibaba.ttl.TransmittableThreadLocal;
import lombok.experimental.UtilityClass;import java.util.HashMap;
import java.util.Map;/*** @author ronshi* @date 2025/3/17 14:38*/
@UtilityClass
public class RibbonRequestContextHolder {private final ThreadLocal<Map<String, String>> CONTEXT_HOLDER = new TransmittableThreadLocal<Map<String, String>>() {@Overrideprotected Map<String, String> initialValue() {return new HashMap<>(16);}};/*** 获取当前线程的上下文Map*/public Map<String, String> getCurrentContext() {return CONTEXT_HOLDER.get();}/*** 向当前上下文添加键值*/public void put(String key, String value) {getCurrentContext().put(key, value);}/*** 从当前上下文获取值*/public static String get(String key) {return getCurrentContext().get(key);}/*** 清理当前线程上下文（防止内存泄漏）*/public void clear() {CONTEXT_HOLDER.remove();}
}

4、Spring Cloud Gateway的用户ID拦截器

import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;@Slf4j
@Component
@RequiredArgsConstructor
public class CommonGlobalFilter implements GlobalFilter, Ordered {@Overridepublic Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {ServerHttpRequest request = exchange.getRequest();String idStr = request.getQueryParams().getFirst("userId");RibbonRequestContextHolder.put("traffic-userId", idStr);return chain.filter(exchange).doFinally(signal -> RibbonRequestContextHolder.clear());}@Overridepublic int getOrder() {return -300;}}

5、Spring Cloud Gateway自定义 Ribbon 灰度规则

import com.alibaba.cloud.nacos.ribbon.NacosServer;
import com.netflix.loadbalancer.BaseLoadBalancer;
import com.netflix.loadbalancer.RoundRobinRule;
import com.netflix.loadbalancer.Server;
import com.anlitech.gateway.config.GatewayConfigProperties;
import org.springframework.beans.factory.annotation.Autowired;import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;/*** @author ronshi* @date 2025/3/18 14:24*/
public class GrayRule extends RoundRobinRule {@Autowiredprivate GatewayConfigProperties gatewayConfigProperties;@Overridepublic Server choose(Object key) {Long userIdLimit= gatewayConfigProperties.getUserIdLimit();String userId = RibbonRequestContextHolder.get("traffic-userId");String grayTag = userId == null || Long.parseLong(userId) < userIdLimit ? "gray" : "normal";List<Server> servers = getLoadBalancer().getReachableServers();List<Server> matchedServers = servers.stream().filter(server -> {Map<String, String> metadata = ((NacosServer) server).getInstance().getMetadata();return metadata.getOrDefault("traffic-group", "normal").equals(grayTag);}).collect(Collectors.toList());// 处理空列表情况：回退到原始负载均衡器if (matchedServers.isEmpty()) {//return super.choose(getLoadBalancer(), key);}// 创建临时负载均衡器，仅包含匹配的服务器BaseLoadBalancer loadBalancer = new BaseLoadBalancer();loadBalancer.addServers(matchedServers);return super.choose(loadBalancer, key);}
}

6、BFF服务增加nacos元数据的灰度标识

spring:application:# 服务名name: @artifactId@cloud:# nacos注册和配置中心相关配置nacos:discovery:server-addr: localhost:8848metadata:traffic-group: gray

上述方案即可实现根据用户ID进入灰度。ID不存在或者ID<1000进入灰度服务，否则进入普通服务。确保agent-bff和operator-bff的Ribbon客户端配置独立，避免共享实例列表。