Java tutorial
/** * 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.oozie.action.hadoop; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapreduce.MRJobConfig; import org.apache.hadoop.mapreduce.security.TokenCache; import org.apache.hadoop.security.Credentials; import org.apache.hadoop.security.UserGroupInformation; import org.apache.hadoop.security.token.Token; import org.apache.oozie.ErrorCode; import org.apache.oozie.action.ActionExecutor; import org.apache.oozie.service.HadoopAccessorException; import org.apache.oozie.service.Services; import org.apache.oozie.service.UserGroupInformationService; import org.apache.oozie.util.XLog; import java.io.IOException; import java.net.URISyntaxException; import java.security.PrivilegedExceptionAction; public class HDFSCredentials implements CredentialsProvider { protected XLog LOG = XLog.getLog(getClass()); /** * Add an HDFS_DELEGATION_TOKEN to the {@link Credentials} provided. * This is also important to ensure that log aggregation works correctly from the NM * * @param credentials the credentials object which is updated * @param config launcher AM configuration * @param props properties for getting credential token or certificate * @param context workflow context * @throws Exception thrown if failed */ @Override public void updateCredentials(Credentials credentials, Configuration config, CredentialsProperties props, ActionExecutor.Context context) throws Exception { final String jobNameNodes[] = config.getStrings(MRJobConfig.JOB_NAMENODES); if (jobNameNodes != null) { final Path[] paths = new Path[jobNameNodes.length]; for (int i = 0; i != jobNameNodes.length; ++i) { paths[i] = new Path(jobNameNodes[i]); } final UserGroupInformation ugi = Services.get().get(UserGroupInformationService.class) .getProxyUser(context.getWorkflow().getUser()); obtainTokensForNamenodes(credentials, config, ugi, paths); } else { obtainTokenForAppFileSystemNameNode(credentials, config, context); } } private void obtainTokenForAppFileSystemNameNode(final Credentials credentials, final Configuration config, final ActionExecutor.Context context) throws IOException, CredentialException, HadoopAccessorException, URISyntaxException { try (FileSystem fileSystem = context.getAppFileSystem()) { final String renewer = new HadoopTokenHelper().getServerPrincipal(config); LOG.debug("Server principal present, getting HDFS delegation token. [renewer={0}]", renewer); final Token hdfsDelegationToken = fileSystem.getDelegationToken(renewer); if (hdfsDelegationToken == null) { throw new CredentialException(ErrorCode.E0511, renewer); } LOG.info("Got HDFS delegation token, setting credentials. [hdfsDelegationToken={0}]", hdfsDelegationToken); credentials.addToken(hdfsDelegationToken.getService(), hdfsDelegationToken); } catch (Exception e) { LOG.debug("exception in updateCredentials", e); throw e; } } private void obtainTokensForNamenodes(final Credentials credentials, final Configuration config, final UserGroupInformation ugi, final Path[] paths) throws IOException, InterruptedException { LOG.info(String.format("\"%s\" is present in workflow configuration. Obtaining tokens for NameNode(s) [%s]", MRJobConfig.JOB_NAMENODES, config.get(MRJobConfig.JOB_NAMENODES))); ugi.doAs(new PrivilegedExceptionAction<Void>() { @Override public Void run() throws Exception { TokenCache.obtainTokensForNamenodes(credentials, paths, config); return null; } }); } }