/*
* Copyright 2010-2012 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.elasticmapreduce.util;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.amazonaws.services.elasticmapreduce.model.HadoopJarStepConfig;
/**
* Class that makes it easy to define Hadoop Streaming steps.
* <p>
* See also: <a href="http://hadoop.apache.org/common/docs/r0.20.2/streaming.html">Hadoop Streaming</a>
*
* <pre>
* AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
* AmazonElasticMapReduce emr = new AmazonElasticMapReduceClient(credentials);
*
* HadoopJarStepConfig config = new StreamingStep()
* .withInputs("s3://elasticmapreduce/samples/wordcount/input")
* .withOutput("s3://my-bucket/output/")
* .withMapper("s3://elasticmapreduce/samples/wordcount/wordSplitter.py")
* .withReducer("aggregate")
* .toHadoopJarStepConfig();
*
* StepConfig wordCount = new StepConfig()
* .withName("Word Count")
* .withActionOnFailure("TERMINATE_JOB_FLOW")
* .withHadoopJarStep(config);
*
* RunJobFlowRequest request = new RunJobFlowRequest()
* .withName("Word Count")
* .withSteps(wordCount)
* .withLogUri("s3://log-bucket/")
* .withInstances(new JobFlowInstancesConfig()
* .withEc2KeyName("keypairt")
* .withHadoopVersion("0.20")
* .withInstanceCount(5)
* .withKeepJobFlowAliveWhenNoSteps(true)
* .withMasterInstanceType("m1.small")
* .withSlaveInstanceType("m1.small"));
*
* RunJobFlowResult result = emr.runJobFlow(request);
* </pre>
*/
public class StreamingStep {
private List<String> inputs = new ArrayList<String>();
private String output;
private String mapper;
private String reducer;
private Map<String, String> hadoopConfig = new HashMap<String, String>();
/**
* Creates a new default StreamingStep.
*/
public StreamingStep() {
}
/**
* Get list of step input paths.
* @return List of step inputs
*/
public List<String> getInputs() {
return inputs;
}
/**
* Set the list of step input paths.
* @param inputs List of step inputs.
*/
public void setInputs(Collection<String> inputs) {
List<String> newInputs = new ArrayList<String>();
if (inputs != null) {
newInputs.addAll(inputs);
}
this.inputs = newInputs;
}
/**
* Add more input paths to this step.
* @param inputs A list of inputs to this step.
* @return A reference to this updated object so that method calls can be chained
* together.
*/
public StreamingStep withInputs(String ... inputs) {
for (String input : inputs) {
this.inputs.add(input);
}
return this;
}
/**
* Get output path.
* @return Output path.
*/
public String getOutput() {
return output;
}
/**
* Set the output path for this step.
* @param output Output path.
*/
public void setOutput(String output) {
this.output = output;
}
/**
* Set the output path for this step.
* @param output Output path
* @return A reference to this updated object so that method calls can be chained
* together.
*/
public StreamingStep withOutput(String output) {
this.output = output;
return this;
}
/**
* Get the mapper.
* @return Mapper.
*/
public String getMapper() {
return mapper;
}
/**
* Set the mapper.
* @param mapper Mapper
*/
public void setMapper(String mapper) {
this.mapper = mapper;
}
/**
* Set the mapper
* @param mapper Mapper
* @return A reference to this updated object so that method calls can be chained
* together.
*/
public StreamingStep withMapper(String mapper) {
this.mapper = mapper;
return this;
}
/**
* Get the reducer
* @return Reducer
*/
public String getReducer() {
return reducer;
}
/**
* Set the reducer
* @param reducer Reducer
*/
public void setReducer(String reducer) {
this.reducer = reducer;
}
/**
* Set the reducer
* @param reducer Reducer
* @return A reference to this updated object so that method calls can be chained
* together.
*/
public StreamingStep withReducer(String reducer) {
this.reducer = reducer;
return this;
}
/**
* Get the Hadoop config overrides (-D values).
* @return Hadoop config.
*/
public Map<String, String> getHadoopConfig() {
return hadoopConfig;
}
/**
* Set the Hadoop config overrides (-D values).
* @param hadoopConfig Hadoop config.
*/
public void setHadoopConfig(Map<String, String> hadoopConfig) {
this.hadoopConfig = hadoopConfig;
}
/**
* Add a Hadoop config override (-D value).
* @param key Hadoop configuration key.
* @param value Configuration value.
* @return A reference to this updated object so that method calls can be chained
* together.
*/
public StreamingStep withHadoopConfig(String key, String value) {
hadoopConfig.put(key, value);
return this;
}
/**
* Creates the final HadoopJarStepConfig once you are done configuring the step. You can use
* this as you would any other HadoopJarStepConfig.
* @return HadoopJarStepConfig representing this streaming step.
*/
public HadoopJarStepConfig toHadoopJarStepConfig() {
List<String> args = new ArrayList<String>();
if (reducer == null) {
hadoopConfig.put("mapred.reduce.tasks", "0");
}
for (Map.Entry<String, String> entry : hadoopConfig.entrySet()) {
args.add("-D");
args.add(entry.getKey() + "=" + entry.getValue());
}
for (String input : inputs) {
args.add("-input");
args.add(input);
}
if (output != null) {
args.add("-output");
args.add(output);
}
if (mapper != null) {
args.add("-mapper");
args.add(mapper);
}
if (reducer != null) {
args.add("-reducer");
args.add(reducer);
}
return new HadoopJarStepConfig()
.withJar("/home/hadoop/contrib/streaming/hadoop-streaming.jar")
.withArgs(args);
}
}