[GitHub] [incubator-dolphinscheduler] CalvinKirs commented on a change in pull request #2924: In the case of multiple network cards, a valid host is returned

[GitBox <gi...@apache.org>]

CalvinKirs commented on a change in pull request #2924:
URL: https://github.com/apache/incubator-dolphinscheduler/pull/2924#discussion_r440593109



##########
File path: dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/NetUtils.java
##########
@@ -0,0 +1,196 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.dolphinscheduler.common.utils;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.net.*;
+import java.util.Enumeration;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
+import java.util.regex.Pattern;
+
+import static java.util.Collections.emptyList;
+
+/**
+ * NetUtils
+ */
+public class NetUtils {
+
+    private static Logger logger = LoggerFactory.getLogger(NetUtils.class);
+
+
+    private static final Pattern ADDRESS_PATTERN = Pattern.compile("^\\d{1,3}(\\.\\d{1,3}){3}\\:\\d{1,5}$");
+
+    private static final Pattern LOCAL_IP_PATTERN = Pattern.compile("127(\\.\\d{1,3}){3}$");
+
+    private static final Pattern IP_PATTERN = Pattern.compile("\\d{1,3}(\\.\\d{1,3}){3,5}$");
+
+    private static String ANY_HOST_VALUE = "0.0.0.0";
+
+    private static String LOCALHOST_KEY = "localhost";
+
+    private static String LOCALHOST_VALUE = "127.0.0.1";
+
+    private static  InetAddress LOCAL_ADDRESS = null;
+
+    private static volatile String HOST_ADDRESS;
+
+    public static String getHost() {
+        if (HOST_ADDRESS != null) {
+            return HOST_ADDRESS;
+        }
+
+        InetAddress address = getLocalAddress();
+        if (address != null) {
+            return HOST_ADDRESS = address.getHostAddress();
+        }
+        return LOCALHOST_VALUE;
+    }
+
+    /**
+     * Find first valid IP from local network card
+     *
+     * @return first valid local IP
+     */
+    public static synchronized InetAddress getLocalAddress() {
+
+        if (null != LOCAL_ADDRESS) {
+            return LOCAL_ADDRESS;

Review comment:
       > what's purpose of this variable LOCAL_ADDRESS ? never assigned a value
   
   Sorry, this is my oversight, I have completed the change, please review it




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