/**
* 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.hdfs.tools;
import java.io.IOException;
import java.io.PrintStream;
import java.net.InetSocketAddress;
import java.security.PrivilegedExceptionAction;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
/**
* Tool for getting configuration information from a configuration file.
*
* Adding more options:
* <ul>
* <li>
* If adding a simple option to get a value corresponding to a key in the
* configuration, use regular {@link GetConf.CommandHandler}.
* See {@link GetConf.Command#EXCLUDE_FILE} example.
* </li>
* <li>
* If adding an option that is does not return a value for a key, add
* a subclass of {@link GetConf.CommandHandler} and set it up in
* {@link GetConf.Command}.
*
* See {@link GetConf.Command#NAMENODE} for example.
*
* Add for the new option added, a map entry with the corresponding
* {@link GetConf.CommandHandler}.
* </ul>
*/
public class GetConf extends Configured implements Tool {
private static final String DESCRIPTION = "hdfs getconf is utility for "
+ "getting configuration information from the config file.\n";
enum Command {
NAMENODE("-namenodes", "gets list of namenodes in the cluster."),
SECONDARY("-secondaryNameNodes",
"gets list of secondary namenodes in the cluster."),
BACKUP("-backupNodes", "gets list of backup nodes in the cluster."),
INCLUDE_FILE("-includeFile",
"gets the include file path that defines the datanodes " +
"that can join the cluster."),
EXCLUDE_FILE("-excludeFile",
"gets the exclude file path that defines the datanodes " +
"that need to decommissioned."),
NNRPCADDRESSES("-nnRpcAddresses", "gets the namenode rpc addresses");
private static Map<String, CommandHandler> map;
static {
map = new HashMap<String, CommandHandler>();
map.put(NAMENODE.getName().toLowerCase(),
new NameNodesCommandHandler());
map.put(SECONDARY.getName().toLowerCase(),
new SecondaryNameNodesCommandHandler());
map.put(BACKUP.getName().toLowerCase(),
new BackupNodesCommandHandler());
map.put(INCLUDE_FILE.getName().toLowerCase(),
new CommandHandler("DFSConfigKeys.DFS_HOSTS"));
map.put(EXCLUDE_FILE.getName().toLowerCase(),
new CommandHandler("DFSConfigKeys.DFS_HOSTS_EXCLUDE"));
map.put(NNRPCADDRESSES.getName().toLowerCase(),
new NNRpcAddressesCommandHandler());
}
private final String cmd;
private final String description;
Command(String cmd, String description) {
this.cmd = cmd;
this.description = description;
}
public String getName() {
return cmd;
}
public String getDescription() {
return description;
}
public static CommandHandler getHandler(String name) {
return map.get(name.toLowerCase());
}
}
static final String USAGE;
static {
HdfsConfiguration.init();
/* Initialize USAGE based on Command values */
StringBuilder usage = new StringBuilder(DESCRIPTION);
usage.append("\nhadoop getconf \n");
for (Command cmd : Command.values()) {
usage.append("\t[" + cmd.getName() + "]\t\t\t" + cmd.getDescription()
+ "\n");
}
USAGE = usage.toString();
}
/**
* Handler to return value for key corresponding to the {@link Command}
*/
static class CommandHandler {
final String key; // Configuration key to lookup
CommandHandler() {
this(null);
}
CommandHandler(String key) {
this.key = key;
}
final int doWork(GetConf tool) {
try {
return doWorkInternal(tool);
} catch (Exception e) {
tool.printError(e.getMessage());
}
return -1;
}
/** Method to be overridden by sub classes for specific behavior */
int doWorkInternal(GetConf tool) throws Exception {
String value = tool.getConf().get(key);
if (value != null) {
tool.printOut(value);
return 0;
}
tool.printError("Configuration " + key + " is missing.");
return -1;
}
}
/**
* Handler for {@link Command#NAMENODE}
*/
static class NameNodesCommandHandler extends CommandHandler {
@Override
int doWorkInternal(GetConf tool) throws IOException {
tool.printList(DFSUtil.getNNServiceRpcAddresses(tool.getConf()));
return 0;
}
}
/**
* Handler for {@link Command#BACKUP}
*/
static class BackupNodesCommandHandler extends CommandHandler {
@Override
public int doWorkInternal(GetConf tool) throws IOException {
tool.printList(DFSUtil.getBackupNodeAddresses(tool.getConf()));
return 0;
}
}
/**
* Handler for {@link Command#SECONDARY}
*/
static class SecondaryNameNodesCommandHandler extends CommandHandler {
@Override
public int doWorkInternal(GetConf tool) throws IOException {
tool.printList(DFSUtil.getSecondaryNameNodeAddresses(tool.getConf()));
return 0;
}
}
/**
* Handler for {@link Command#NNRPCADDRESSES}
* If rpc addresses are defined in configuration, we return them. Otherwise,
* return empty string.
*/
static class NNRpcAddressesCommandHandler extends CommandHandler {
@Override
public int doWorkInternal(GetConf tool) throws IOException {
Configuration config = tool.getConf();
List<InetSocketAddress> rpclist = DFSUtil.getNNServiceRpcAddresses(config);
if (rpclist != null) {
for (InetSocketAddress rpc : rpclist) {
tool.printOut(rpc.getHostName()+":"+rpc.getPort());
}
return 0;
}
tool.printError("Did not get namenode service rpc addresses.");
return -1;
}
}
private final PrintStream out; // Stream for printing command output
private final PrintStream err; // Stream for printing error
GetConf(Configuration conf) {
this(conf, System.out, System.err);
}
GetConf(Configuration conf, PrintStream out, PrintStream err) {
super(conf);
this.out = out;
this.err = err;
}
void printError(String message) {
err.println(message);
}
void printOut(String message) {
out.println(message);
}
void printList(List<InetSocketAddress> list) {
StringBuilder buffer = new StringBuilder();
for (InetSocketAddress address : list) {
if (buffer.length() > 0) {
buffer.append(" ");
}
buffer.append(address.getHostName());
}
printOut(buffer.toString());
}
private void printUsage() {
printError(USAGE);
}
/**
* Main method that runs the tool for given arguments.
* @param args arguments
* @return return status of the command
*/
private int doWork(String[] args) {
if (args.length == 1) {
CommandHandler handler = Command.getHandler(args[0]);
if (handler != null) {
return handler.doWork(this);
}
}
printUsage();
return -1;
}
@Override
public int run(final String[] args) throws Exception {
try {
return UserGroupInformation.getCurrentUser().doAs(
new PrivilegedExceptionAction<Integer>() {
@Override
public Integer run() throws Exception {
return doWork(args);
}
});
} catch (InterruptedException e) {
throw new IOException(e);
}
}
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new GetConf(new HdfsConfiguration()), args);
System.exit(res);
}
}