org.apache.hadoop.tools.GetGroupsBase 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.tools;
import java.io.IOException;
import java.io.PrintStream;
import java.net.InetSocketAddress;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.ipc.RPC;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.util.Tool;
/**
* Base class for the HDFS and MR implementations of tools which fetch and
* display the groups that users belong to.
*/
public abstract class GetGroupsBase extends Configured implements Tool {
private PrintStream out;
/**
* Create an instance of this tool using the given configuration.
* @param conf
*/
protected GetGroupsBase(Configuration conf) {
this(conf, System.out);
}
/**
* Used exclusively for testing.
*
* @param conf The configuration to use.
* @param out The PrintStream to write to, instead of System.out
*/
protected GetGroupsBase(Configuration conf, PrintStream out) {
super(conf);
this.out = out;
}
/**
* Get the groups for the users given and print formatted output to the
* {@link PrintStream} configured earlier.
*/
@Override
public int run(String[] args) throws Exception {
if (args.length == 0) {
args = new String[] { UserGroupInformation.getCurrentUser().getUserName() };
}
for (String username : args) {
StringBuilder sb = new StringBuilder();
sb.append(username + " :");
for (String group : getUgmProtocol().getGroupsForUser(username)) {
sb.append(" ")
.append(group);
}
out.println(sb);
}
return 0;
}
/**
* Must be overridden by subclasses to get the address where the
* {@link GetUserMappingsProtocol} implementation is running.
*
* @param conf The configuration to use.
* @return The address where the service is listening.
* @throws IOException
*/
protected abstract InetSocketAddress getProtocolAddress(Configuration conf)
throws IOException;
/**
* Get a client of the {@link GetUserMappingsProtocol}.
* @return A {@link GetUserMappingsProtocol} client proxy.
* @throws IOException
*/
protected GetUserMappingsProtocol getUgmProtocol() throws IOException {
GetUserMappingsProtocol userGroupMappingProtocol =
RPC.getProxy(GetUserMappingsProtocol.class,
GetUserMappingsProtocol.versionID,
getProtocolAddress(getConf()), UserGroupInformation.getCurrentUser(),
getConf(), NetUtils.getSocketFactory(getConf(),
GetUserMappingsProtocol.class));
return userGroupMappingProtocol;
}
}