nacos规则设置

zdxt-web-server/zdxt-gateway-web-server/src/main/java/com/zdxt/gateway/webserver/filter/PreferredRoleFilter.java

@@ -0,0 +1,56 @@
+package com.zdxt.gateway.webserver.filter;
+
+import com.zdxt.gateway.webserver.config.PreferredFirstLoadBalancer;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.cloud.gateway.filter.GatewayFilterChain;
+import org.springframework.cloud.gateway.filter.GlobalFilter;
+import org.springframework.cloud.gateway.route.Route;
+import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
+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;
+
+/**
+ * 优先角色注入过滤器
+ * <p>
+ * 从命中的路由 metadata 中读取 role-order（逗号分隔的角色优先级列表），
+ * 复制为请求头 {@link PreferredFirstLoadBalancer#HEADER_ROLE_ORDER}，
+ * 供 {@link PreferredFirstLoadBalancer} 在负载均衡阶段读取。
+ * <p>
+ * Order 必须早于 Spring Cloud Gateway 的 ReactiveLoadBalancerClientFilter(默认 10150)，
+ * 否则 LoadBalancer choose 时拿不到 header。
+ *
+ * @author zdxt
+ */
+@Slf4j
+@Component
+public class PreferredRoleFilter implements GlobalFilter, Ordered {
+
+    /** 路由 metadata 中约定的 key */
+    public static final String ROUTE_METADATA_ROLE_ORDER = "role-order";
+
+    @Override
+    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
+        Route route = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);
+        if (route != null) {
+            Object roleOrder = route.getMetadata().get(ROUTE_METADATA_ROLE_ORDER);
+            if (roleOrder != null && !roleOrder.toString().isBlank()) {
+                log.debug("[{}] 路由 {} 注入角色优先级: {}",
+                        route.getId(), route.getUri(), roleOrder);
+                ServerHttpRequest mutated = exchange.getRequest().mutate()
+                        .header(PreferredFirstLoadBalancer.HEADER_ROLE_ORDER, roleOrder.toString())
+                        .build();
+                return chain.filter(exchange.mutate().request(mutated).build());
+            }
+        }
+        return chain.filter(exchange);
+    }
+
+    @Override
+    public int getOrder() {
+        // 早于 ReactiveLoadBalancerClientFilter(10150),晚于 AccessLogFilter(HIGHEST_PRECEDENCE)
+        return 10000;
+    }
+}