完善 gateway 服务，支持 tag 过滤服务实例

yudao-gateway/src/main/java/cn/iocoder/yudao/gateway/util/EnvUtils.java

@@ -0,0 +1,39 @@
+package cn.iocoder.yudao.gateway.util;
+
+import cn.hutool.core.net.NetUtil;
+import cn.hutool.core.util.IdUtil;
+import cn.hutool.core.util.StrUtil;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.http.HttpHeaders;
+
+import java.util.Objects;
+
+/**
+ * 环境 Utils
+ *
+ * copy from yudao-spring-boot-starter-env 的 EnvUtils 类
+ *
+ * @author 芋道源码
+ */
+public class EnvUtils {
+
+    private static final String HEADER_TAG = "tag";
+
+    public static final String HOST_NAME_VALUE = "${HOSTNAME}";
+
+    public static String getTag(HttpHeaders headers) {
+        String tag = headers.getFirst(HEADER_TAG);
+        // 如果请求的是 "${HOSTNAME}"，则解析成对应的本地主机名
+        // 目的：特殊逻辑，解决 IDEA Rest Client 不支持环境变量的读取，所以就服务器来做
+        return Objects.equals(tag, HOST_NAME_VALUE) ? getHostName() : tag;
+    }
+
+    public static String getTag(ServiceInstance instance) {
+        return instance.getMetadata().get(HEADER_TAG);
+    }
+
+    public static String getHostName() {
+        return StrUtil.blankToDefault(NetUtil.getLocalHostName(), IdUtil.fastSimpleUUID());
+    }
+
+}

yudao-gateway/src/main/java/cn/iocoder/yudao/gateway/util/WebFrameworkUtils.java

@@ -26,9 +26,10 @@ import reactor.core.publisher.Mono;
 @Slf4j
 public class WebFrameworkUtils {
 
-    @SuppressWarnings("UastIncorrectHttpHeaderInspection")
     private static final String HEADER_TENANT_ID = "tenant-id";
 
+    private static final String HEADER_TAG = "tag";
+
     private WebFrameworkUtils() {}
 
     /**