Use PortChecker to help settle on port

Author: idodeclare

dev/checkstyle/suppressions.xml

@@ -19,7 +19,7 @@ information: Portions Copyright [yyyy] [name of copyright owner]
 CDDL HEADER END
 
 Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
-Portions Copyright (c) 2018-2019, Chris Fraire <[email protected]>.
+Portions Copyright (c) 2018-2020, Chris Fraire <[email protected]>.
 
 -->
 
@@ -33,7 +33,7 @@ Portions Copyright (c) 2018-2019, Chris Fraire <[email protected]>.
         |Summary\.java|OGKUnifiedHighlighter\.java|ResponseHeaderFilter\.java|BoundedBlockingObjectPool\.java|
         |ObjectPool\.java|ObjectValidator\.java|ObjectFactory\.java|AbstractObjectPool\.java|
         |BlockingObjectPool\.java|OGKTextVecField\.java|OGKTextField\.java|
-        |LazilyInstantiate\.java" />
+        |LazilyInstantiate\.java|PortChecker\.java" />
 
     <suppress checks="ParameterNumber" files="CtagsReader\.java|Definitions\.java|
         |JFlexXrefUtils\.java|FileAnalyzerFactory\.java|SearchController\.java|

opengrok-indexer/src/main/java/org/opengrok/indexer/util/PortChecker.java

@@ -0,0 +1,75 @@
+/*
+ *  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.opengrok.indexer.util;
+
+import java.io.IOException;
+import java.net.DatagramSocket;
+import java.net.ServerSocket;
+
+/**
+ * Represents a helper for checking a network port, borrowed from Apache
+ * Usergrid's AvailablePortFinder.java.
+ */
+public class PortChecker {
+    /** The minimum number of server port number. */
+    public static final int MIN_PORT_NUMBER = 1;
+
+    /** The maximum number of server port number. */
+    public static final int MAX_PORT_NUMBER = 65535;
+
+    /**
+     * Checks to see if a specific port is available.
+     *
+     * @param port the port to check for availability
+     */
+    public static boolean available(int port) {
+        if (port < MIN_PORT_NUMBER || port > MAX_PORT_NUMBER) {
+            throw new IllegalArgumentException("Port out of valid range: " + port);
+        }
+
+        ServerSocket ss = null;
+        DatagramSocket ds = null;
+        try {
+            ss = new ServerSocket(port);
+            ss.setReuseAddress(true);
+            ds = new DatagramSocket(port);
+            ds.setReuseAddress(true);
+            return true;
+        } catch (IOException e) {
+            return false;
+        } finally {
+            if (ds != null) {
+                ds.close();
+            }
+
+            if (ss != null) {
+                try {
+                    ss.close();
+                } catch (IOException e) {
+                    /* should not be thrown */
+                }
+            }
+        }
+    }
+
+    /* private to enforce static */
+    private PortChecker() {
+    }
+}

opengrok-web/src/test/java/org/opengrok/web/api/v1/controller/OGKJerseyTest.java

@@ -26,6 +26,7 @@
 import org.glassfish.jersey.test.JerseyTest;
 import org.glassfish.jersey.test.TestProperties;
 import org.junit.Before;
+import org.opengrok.indexer.util.PortChecker;
 
 import java.util.Random;
 
@@ -39,6 +40,8 @@ public abstract class OGKJerseyTest extends JerseyTest {
     /** Random.nextInt() will be at most one less than this -- but OK */
     private static final int DYNAMIC_OR_PRIVATE_PORT_RANGE = 16383;
 
+    private static final int MAX_PORT_TRIES = 20;
+
     private final Random rand = new Random();
 
     /**
@@ -47,9 +50,20 @@ public abstract class OGKJerseyTest extends JerseyTest {
      */
     @Before
     public void setUp() throws Exception {
-        int jerseyPort = BASE_DYNAMIC_OR_PRIVATE_PORT +
-                rand.nextInt(DYNAMIC_OR_PRIVATE_PORT_RANGE);
-        forceSet(TestProperties.CONTAINER_PORT, String.valueOf(jerseyPort));
+
+        int triesCount = 0;
+        while (true) {
+            int jerseyPort = BASE_DYNAMIC_OR_PRIVATE_PORT +
+                    rand.nextInt(DYNAMIC_OR_PRIVATE_PORT_RANGE);
+            if (PortChecker.available(jerseyPort)) {
+                forceSet(TestProperties.CONTAINER_PORT, String.valueOf(jerseyPort));
+                break;
+            }
+            if (++triesCount > MAX_PORT_TRIES) {
+                throw new RuntimeException("Could not find an available port after " +
+                        MAX_PORT_TRIES + " tries");
+            }
+        }
 
         super.setUp();
     }