/**
* Copyright 2005 The Apache Software Foundation
*
* Licensed 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.mapred.jobcontrol;
import org.apache.hadoop.mapred.JobClient;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RunningJob;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.util.StringUtils;
import java.util.ArrayList;
import java.io.IOException;
/** This class encapsulates a MapReduce job and its dependency. It monitors
* the states of the depending jobs and updates the state of this job.
* A job stats in the WAITING state. If it does not have any deoending jobs, or
* all of the depending jobs are in SUCCESS state, then the job state will become
* READY. If any depending jobs fail, the job will fail too.
* When in READY state, the job can be submitted to Hadoop for execution, with
* the state changing into RUNNING state. From RUNNING state, the job can get into
* SUCCESS or FAILED state, depending the status of the jon execution.
*
*/
public class Job {
// A job will be in one of the following states
final public static int SUCCESS = 0;
final public static int WAITING = 1;
final public static int RUNNING = 2;
final public static int READY = 3;
final public static int FAILED = 4;
final public static int DEPENDENT_FAILED = 5;
private JobConf theJobConf;
private int state;
private String jobID; // assigned and used by JobControl class
private String mapredJobID; // the job ID assigned by map/reduce
private String jobName; // external name, assigned/used by client app
private String message; // some info for human consumption,
// e.g. the reason why the job failed
private ArrayList dependingJobs; // the jobs the current job depends on
private JobClient jc = null; // the map reduce job client
/**
* Construct a job.
* @param jobConf a mapred job configuration representing a job to be executed.
* @param dependingJobs an array of jobs the current job depends on
*/
public Job(JobConf jobConf, ArrayList dependingJobs) throws IOException {
this.theJobConf = jobConf;
this.dependingJobs = dependingJobs;
this.state = Job.WAITING;
this.jobID = "unassigned";
this.mapredJobID = "unassigned";
this.jobName = "unassigned";
this.message = "just initialized";
this.jc = new JobClient(jobConf);
}
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("job name:\t").append(this.jobName).append("\n");
sb.append("job id:\t").append(this.jobID).append("\n");
sb.append("job state:\t").append(this.state).append("\n");
sb.append("job mapred id:\t").append(this.mapredJobID).append("\n");
sb.append("job message:\t").append(this.message).append("\n");
if (this.dependingJobs == null) {
sb.append("job has no depending job:\t").append("\n");
} else {
sb.append("job has ").append(this.dependingJobs.size()).append(" dependeng jobs:\n");
for (int i = 0; i < this.dependingJobs.size(); i++) {
sb.append("\t depending job ").append(i).append(":\t");
sb.append(((Job) this.dependingJobs.get(i)).getJobName()).append("\n");
}
}
return sb.toString();
}
/**
* @return the job name of this job
*/
public String getJobName() {
return this.jobName;
}
/**
* Set the job name for this job.
* @param jobName the job name
*/
public void setJobName(String jobName) {
this.jobName = jobName;
}
/**
* @return the job ID of this job
*/
public String getJobID() {
return this.jobID;
}
/**
* Set the job ID for this job.
* @param id the job ID
*/
public void setJobID(String id) {
this.jobID = id;
}
/**
* @return the mapred ID of this job
*/
public String getMapredJobID() {
return this.mapredJobID;
}
/**
* Set the mapred ID for this job.
* @param mapredJobID the mapred job ID for this job.
*/
public void setMapredJobID(String mapredJobID) {
this.jobID = mapredJobID;
}
/**
* @return the mapred job conf of this job
*/
public JobConf getJobConf() {
return this.theJobConf;
}
/**
* Set the mapred job conf for this job.
* @param jobConf the mapred job conf for this job.
*/
public void setJobConf(JobConf jobConf) {
this.theJobConf = jobConf;
}
/**
* @return the state of this job
*/
public int getState() {
return this.state;
}
/**
* Set the state for this job.
* @param state the new state for this job.
*/
public void setState(int state) {
this.state = state;
}
/**
* @return the message of this job
*/
public String getMessage() {
return this.message;
}
/**
* Set the message for this job.
* @param message the message for this job.
*/
public void setMessage(String message) {
this.message = message;
}
/**
* @return the depending jobs of this job
*/
public ArrayList getDependingJobs() {
return this.dependingJobs;
}
/**
* @return true if this job is in a complete state
*/
public boolean isCompleted() {
return this.state == Job.FAILED ||
this.state == Job.DEPENDENT_FAILED ||
this.state == Job.SUCCESS;
}
/**
* @return true if this job is in READY state
*/
public boolean isReady() {
return this.state == Job.READY;
}
/**
* Check the state of this running job. The state may
* remain the same, become SUCCESS or FAILED.
*/
private void checkRunningState() {
RunningJob running = null;
try {
running = jc.getJob(this.mapredJobID);
if (running.isComplete()) {
if (running.isSuccessful()) {
this.state = Job.SUCCESS;
} else {
this.state = Job.FAILED;
this.message = "Job failed!";
try {
running.killJob();
} catch (IOException e1) {
}
try {
this.jc.close();
} catch (IOException e2) {
}
}
}
} catch (IOException ioe) {
this.state = Job.FAILED;
this.message = StringUtils.stringifyException(ioe);
try {
running.killJob();
} catch (IOException e1) {
}
try {
this.jc.close();
} catch (IOException e1) {
}
}
}
/**
* Check and update the state of this job. The state changes
* depending on its current state and the states of the depending jobs.
*/
public int checkState() {
if (this.state == Job.RUNNING) {
checkRunningState();
}
if (this.state != Job.WAITING) {
return this.state;
}
if (this.dependingJobs == null || this.dependingJobs.size() == 0) {
this.state = Job.READY;
return this.state;
}
Job pred = null;
int n = this.dependingJobs.size();
for (int i = 0; i < n; i++) {
pred = (Job) this.dependingJobs.get(i);
int s = pred.checkState();
if (s == Job.WAITING || s == Job.READY || s == Job.RUNNING) {
break; // a pred is still not completed, continue in WAITING
// state
}
if (s == Job.FAILED || s == Job.DEPENDENT_FAILED) {
this.state = Job.DEPENDENT_FAILED;
this.message = "depending job " + i + " with jobID "
+ pred.getJobID() + " failed. " + pred.getMessage();
break;
}
// pred must be in success state
if (i == n - 1) {
this.state = Job.READY;
}
}
return this.state;
}
/**
* Submit this job to mapred. The state becomes RUNNING if submission
* is successful, FAILED otherwise.
*/
public void submit() {
try {
if (theJobConf.getBoolean("create.empty.dir.if.nonexist", false)) {
FileSystem fs = FileSystem.get(theJobConf);
Path inputPaths[] = theJobConf.getInputPaths();
for (int i = 0; i < inputPaths.length; i++) {
if (!fs.exists(inputPaths[i])) {
try {
fs.mkdirs(inputPaths[i]);
} catch (IOException e) {
}
}
}
}
RunningJob running = jc.submitJob(theJobConf);
this.mapredJobID = running.getJobID();
this.state = Job.RUNNING;
} catch (IOException ioe) {
this.state = Job.FAILED;
this.message = StringUtils.stringifyException(ioe);
}
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
}
}