org.apache.hadoop.hdfs.tools.AdminHelper Maven / Gradle / Ivy
/**
* 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 com.google.common.base.Preconditions;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hdfs.DFSUtil;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.protocol.CachePoolInfo;
import org.apache.hadoop.tools.TableListing;
import java.io.IOException;
import java.net.URI;
import java.util.List;
/**
* Helper methods for CacheAdmin/CryptoAdmin/StoragePolicyAdmin
*/
public class AdminHelper {
/**
* Maximum length for printed lines
*/
static final int MAX_LINE_WIDTH = 80;
static final String HELP_COMMAND_NAME = "-help";
static DistributedFileSystem getDFS(Configuration conf)
throws IOException {
FileSystem fs = FileSystem.get(conf);
if (!(fs instanceof DistributedFileSystem)) {
throw new IllegalArgumentException("FileSystem " + fs.getUri() +
" is not an HDFS file system");
}
return (DistributedFileSystem)fs;
}
static DistributedFileSystem getDFS(URI uri, Configuration conf)
throws IOException {
FileSystem fs = FileSystem.get(uri, conf);
if (!(fs instanceof DistributedFileSystem)) {
throw new IllegalArgumentException("FileSystem " + fs.getUri()
+ " is not an HDFS file system");
}
return (DistributedFileSystem) fs;
}
/**
* NN exceptions contain the stack trace as part of the exception message.
* When it's a known error, pretty-print the error and squish the stack trace.
*/
static String prettifyException(Exception e) {
if (e.getLocalizedMessage() != null) {
return e.getClass().getSimpleName() + ": "
+ e.getLocalizedMessage().split("\n")[0];
} else if (e.getStackTrace() != null && e.getStackTrace().length > 0) {
return e.getClass().getSimpleName() + " at " + e.getStackTrace()[0];
} else {
return e.getClass().getSimpleName();
}
}
static TableListing getOptionDescriptionListing() {
return new TableListing.Builder()
.addField("").addField("", true)
.wrapWidth(MAX_LINE_WIDTH).hideHeaders().build();
}
/**
* Parses a time-to-live value from a string
* @return The ttl in milliseconds
* @throws IOException if it could not be parsed
*/
static Long parseTtlString(String maxTtlString) throws IOException {
Long maxTtl = null;
if (maxTtlString != null) {
if (maxTtlString.equalsIgnoreCase("never")) {
maxTtl = CachePoolInfo.RELATIVE_EXPIRY_NEVER;
} else {
maxTtl = DFSUtil.parseRelativeTime(maxTtlString);
}
}
return maxTtl;
}
static Long parseLimitString(String limitString) {
Long limit = null;
if (limitString != null) {
if (limitString.equalsIgnoreCase("unlimited")) {
limit = CachePoolInfo.LIMIT_UNLIMITED;
} else {
limit = Long.parseLong(limitString);
}
}
return limit;
}
static Command determineCommand(String commandName, Command[] commands) {
Preconditions.checkNotNull(commands);
if (HELP_COMMAND_NAME.equals(commandName)) {
return new HelpCommand(commands);
}
for (Command command : commands) {
if (command.getName().equals(commandName)) {
return command;
}
}
return null;
}
static void printUsage(boolean longUsage, String toolName,
Command[] commands) {
Preconditions.checkNotNull(commands);
System.err.println("Usage: bin/hdfs " + toolName + " [COMMAND]");
final HelpCommand helpCommand = new HelpCommand(commands);
for (AdminHelper.Command command : commands) {
if (longUsage) {
System.err.print(command.getLongUsage());
} else {
System.err.print(" " + command.getShortUsage());
}
}
System.err.print(longUsage ? helpCommand.getLongUsage() :
(" " + helpCommand.getShortUsage()));
System.err.println();
}
interface Command {
String getName();
String getShortUsage();
String getLongUsage();
int run(Configuration conf, List args) throws IOException;
}
static class HelpCommand implements Command {
private final Command[] commands;
public HelpCommand(Command[] commands) {
Preconditions.checkNotNull(commands, "commands cannot be null.");
this.commands = commands;
}
@Override
public String getName() {
return HELP_COMMAND_NAME;
}
@Override
public String getShortUsage() {
return "[-help ]\n";
}
@Override
public String getLongUsage() {
final TableListing listing = AdminHelper.getOptionDescriptionListing();
listing.addRow("", "The command for which to get " +
"detailed help. If no command is specified, print detailed help for " +
"all commands");
return getShortUsage() + "\n" +
"Get detailed help about a command.\n\n" +
listing.toString();
}
@Override
public int run(Configuration conf, List args) throws IOException {
if (args.size() == 0) {
for (AdminHelper.Command command : commands) {
System.err.println(command.getLongUsage());
}
return 1;
}
if (args.size() != 1) {
System.err.println("You must give exactly one argument to -help.");
return 1;
}
final String commandName = args.get(0);
// prepend a dash to match against the command names
final AdminHelper.Command command = AdminHelper
.determineCommand("-" + commandName, commands);
if (command == null) {
System.err.print("Unknown command '" + commandName + "'.\n");
System.err.print("Valid help command names are:\n");
String separator = "";
for (AdminHelper.Command c : commands) {
System.err.print(separator + c.getName().substring(1));
separator = ", ";
}
System.err.print("\n");
return 1;
}
System.err.print(command.getLongUsage());
return 0;
}
}
}