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.falcon.logging.v1; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.methods.GetMethod; import org.apache.falcon.logging.DefaultTaskLogRetriever; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapred.DefaultJobHistoryParser; import org.apache.hadoop.mapred.JobHistory; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; /** * Hadoop v1 task log retriever based on job history */ public final class TaskLogRetrieverV1 extends DefaultTaskLogRetriever { private static final Logger LOG = LoggerFactory.getLogger(TaskLogRetrieverV1.class); @Override public String getFromHistory(String jobId) throws IOException { Configuration conf = getConf(); String file = getHistoryFile(conf, jobId); if (file == null) return null; JobHistory.JobInfo jobInfo = new JobHistory.JobInfo(jobId); DefaultJobHistoryParser.parseJobTasks(file, jobInfo, new Path(file).getFileSystem(conf)); LOG.info("History file: {}", file); LOG.debug("Number of tasks in the history file: {}", jobInfo.getAllTasks().size()); for (JobHistory.Task task : jobInfo.getAllTasks().values()) { if (task.get(JobHistory.Keys.TASK_TYPE).equals(JobHistory.Values.MAP.name()) && task.get(JobHistory.Keys.TASK_STATUS).equals(JobHistory.Values.SUCCESS.name())) { for (JobHistory.TaskAttempt attempt : task.getTaskAttempts().values()) { if (attempt.get(JobHistory.Keys.TASK_STATUS).equals(JobHistory.Values.SUCCESS.name())) { return JobHistory.getTaskLogsUrl(attempt); } } } } LOG.warn("Unable to find successful map task attempt"); return null; } private String getHistoryFile(Configuration conf, String jobId) throws IOException { String jtAddress = "scheme://" + conf.get("mapred.job.tracker"); String jtHttpAddr = "scheme://" + conf.get("mapred.job.tracker.http.address"); try { String host = new URI(jtAddress).getHost(); int port = new URI(jtHttpAddr).getPort(); HttpClient client = new HttpClient(); String jobUrl = "http://" + host + ":" + port + "/jobdetails.jsp"; GetMethod get = new GetMethod(jobUrl); get.setQueryString("jobid=" + jobId); get.setFollowRedirects(false); int status = client.executeMethod(get); String file = null; if (status == HttpStatus.SC_MOVED_PERMANENTLY || status == HttpStatus.SC_MOVED_TEMPORARILY) { file = get.getResponseHeader("Location").toString(); file = file.substring(file.lastIndexOf('=') + 1); file = JobHistory.JobInfo.decodeJobHistoryFileName(file); } else { LOG.warn("JobURL {} for id: {} returned {}", jobUrl, jobId, status); } return file; } catch (URISyntaxException e) { throw new IOException("JT Address: " + jtAddress + ", http Address: " + jtHttpAddr, e); } } }