HDDS-96. Add an option in ozone script to generate a site file with minimally required ozone configs.

Contributed by Dinesh Chitlangia.

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/conf/OzoneConfiguration.java

@@ -137,7 +137,7 @@ public int compareTo(Property o) {
 
     @Override
     public String toString() {
-      return this.getName() + " " + this.getValue() + this.getTag();
+      return this.getName() + " " + this.getValue() + " " + this.getTag();
     }
 
     @Override
@@ -152,7 +152,7 @@ public boolean equals(Object obj) {
     }
   }
 
-  public static void activate(){
+  public static void activate() {
     // adds the default resources
     Configuration.addDefaultResource("hdfs-default.xml");
     Configuration.addDefaultResource("hdfs-site.xml");

hadoop-ozone/common/src/main/bin/ozone

@@ -47,6 +47,7 @@ function hadoop_usage
   hadoop_add_subcommand "scm" daemon "run the Storage Container Manager service"
   hadoop_add_subcommand "scmcli" client "run the CLI of the Storage Container Manager "
   hadoop_add_subcommand "version" client "print the version"
+  hadoop_add_subcommand "genconf" client "generate minimally required ozone configs and output to ozone-site.xml in specified path"
 
   hadoop_generate_usage "${HADOOP_SHELL_EXECNAME}" false
 }
@@ -118,6 +119,9 @@ function ozonecmd_case
     version)
       HADOOP_CLASSNAME=org.apache.hadoop.util.VersionInfo
     ;;
+    genconf)
+      HADOOP_CLASSNAME=org.apache.hadoop.ozone.genconf.GenerateOzoneRequiredConfigurations
+    ;;
     *)
       HADOOP_CLASSNAME="${subcmd}"
       if ! hadoop_validate_classname "${HADOOP_CLASSNAME}"; then

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/genconf/TestGenerateOzoneRequiredConfigurations.java

@@ -0,0 +1,100 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.hadoop.ozone.genconf;
+
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.junit.AfterClass;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.IOException;
+
+
+/**
+ * Tests GenerateOzoneRequiredConfigurations.
+ */
+public class TestGenerateOzoneRequiredConfigurations {
+  private static MiniOzoneCluster cluster;
+  private static OzoneConfiguration conf;
+
+  /**
+   * Create a MiniDFSCluster for testing.
+   * <p>
+   * Ozone is made active by setting OZONE_ENABLED = true and
+   * OZONE_HANDLER_TYPE_KEY = "distributed"
+   *
+   * @throws IOException
+   */
+  @BeforeClass
+  public static void init() throws Exception {
+    conf = new OzoneConfiguration();
+    cluster = MiniOzoneCluster.newBuilder(conf).setNumDatanodes(1).build();
+    cluster.waitForClusterToBeReady();
+  }
+
+  /**
+   * Shutdown MiniDFSCluster.
+   */
+  @AfterClass
+  public static void shutdown() {
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  /**
+   * Tests a valid path and generates ozone-site.xml.
+   * @throws Exception
+   */
+  @Test
+  public void generateConfigurationsSuccess() throws Exception {
+    String[] args = new String[]{"-output", "."};
+    GenerateOzoneRequiredConfigurations.main(args);
+
+    Assert.assertEquals("Path is valid",
+        true, GenerateOzoneRequiredConfigurations.isValidPath(args[1]));
+
+    Assert.assertEquals("Permission is valid",
+        true, GenerateOzoneRequiredConfigurations.canWrite(args[1]));
+
+    Assert.assertEquals("Config file generated",
+        0, GenerateOzoneRequiredConfigurations.generateConfigurations(args[1]));
+  }
+
+  /**
+   * Test to avoid generating ozone-site.xml when invalid permission.
+   * @throws Exception
+   */
+  @Test
+  public void generateConfigurationsFailure() throws Exception {
+    String[] args = new String[]{"-output", "/"};
+    GenerateOzoneRequiredConfigurations.main(args);
+
+    Assert.assertEquals("Path is valid",
+        true, GenerateOzoneRequiredConfigurations.isValidPath(args[1]));
+
+    Assert.assertEquals("Invalid permission",
+        false, GenerateOzoneRequiredConfigurations.canWrite(args[1]));
+
+    Assert.assertEquals("Config file not generated",
+        1, GenerateOzoneRequiredConfigurations.generateConfigurations(args[1]));
+  }
+}

hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/genconf/GenerateOzoneRequiredConfigurations.java

@@ -0,0 +1,174 @@
+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.hadoop.ozone.genconf;
+
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+import javax.xml.bind.Marshaller;
+import java.io.File;
+import java.net.URL;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * GenerateOzoneRequiredConfigurations - A tool to generate ozone-site.xml<br>
+ * This tool generates an ozone-site.xml with minimally required configs.
+ * This tool can be invoked as follows:<br>
+ * <ul>
+ * <li>ozone genconf -output <Path to output file></li>
+ * <li>ozone genconf -help</li>
+ * </ul>
+ */
+public final class GenerateOzoneRequiredConfigurations {
+
+  private static final String OUTPUT = "-output";
+  private static final String HELP = "-help";
+  private static final String USAGE = "Usage: \nozone genconf "
+      + OUTPUT + " <Path to output file> \n"
+      + "ozone genconf "
+      + HELP;
+  private static final int SUCCESS = 0;
+  private static final int FAILURE = 1;
+
+  private GenerateOzoneRequiredConfigurations() {
+
+  }
+  /**
+   * Entry point for using genconf tool.
+   *
+   * @param args
+   * @throws JAXBException
+   */
+  public static void main(String[] args) {
+
+    try {
+      if (args.length == 0) {
+        System.out.println(USAGE);
+        System.exit(1);
+      }
+
+      switch (args[0]) {
+      case OUTPUT:
+        if (args.length > 1) {
+          int result = generateConfigurations(args[1]);
+        } else {
+          System.out.println("Path to output file is mandatory");
+          System.out.println(USAGE);
+          System.exit(1);
+        }
+        break;
+
+      case HELP:
+        System.out.println(USAGE);
+        System.exit(0);
+        break;
+
+      default:
+        System.out.println(USAGE);
+        System.exit(1);
+      }
+
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  /**
+   * Check if the path is valid.
+   *
+   * @param path
+   * @return true, if path is valid, else return false
+   */
+  public static boolean isValidPath(String path) {
+    try {
+      Paths.get(path);
+    } catch (InvalidPathException | NullPointerException ex) {
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * Check if user has permission to write in the specified path.
+   *
+   * @param path
+   * @return true, if the user has permission to write, else returns false
+   */
+  public static boolean canWrite(String path) {
+    File file = new File(path);
+    return file.canWrite();
+  }
+
+  /**
+   * Generate ozone-site.xml at specified path.
+   *
+   * @param path
+   * @return SUCCESS(0) if file can be generated, else returns FAILURE(1)
+   * @throws JAXBException
+   */
+  public static int generateConfigurations(String path) throws JAXBException {
+
+    if (!isValidPath(path)) {
+      System.out.println("Invalid path or insufficient permission");
+      return FAILURE;
+    }
+
+    if (!canWrite(path)) {
+      System.out.println("Invalid path or insufficient permission");
+      return FAILURE;
+    }
+
+    OzoneConfiguration oc = new OzoneConfiguration();
+
+    ClassLoader cL = Thread.currentThread().getContextClassLoader();
+    if (cL == null) {
+      cL = OzoneConfiguration.class.getClassLoader();
+    }
+    URL url = cL.getResource("ozone-default.xml");
+
+    List<OzoneConfiguration.Property> allProperties =
+        oc.readPropertyFromXml(url);
+
+    List<OzoneConfiguration.Property> requiredProperties = new ArrayList<>();
+
+    for (OzoneConfiguration.Property p : allProperties) {
+      if (p.getTag() != null && p.getTag().contains("REQUIRED")) {
+        requiredProperties.add(p);
+      }
+    }
+
+    OzoneConfiguration.XMLConfiguration requiredConfig =
+        new OzoneConfiguration.XMLConfiguration();
+    requiredConfig.setProperties(requiredProperties);
+
+    JAXBContext context =
+        JAXBContext.newInstance(OzoneConfiguration.XMLConfiguration.class);
+    Marshaller m = context.createMarshaller();
+    m.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
+    m.marshal(requiredConfig, new File(path, "ozone-site.xml"));
+
+    System.out.println("ozone-site.xml has been generated at " + path);
+
+    return SUCCESS;
+  }
+}

hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/genconf/package-info.java

@@ -0,0 +1,24 @@
+/**
+ * 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.hadoop.ozone.genconf;
+
+/**
+ * Command line tool to generate required Ozone configs to an ozone-site.xml.
+ */
+