datafu.hourglass.jobs

Class AbstractJob

java.lang.Object

org.apache.hadoop.conf.Configured

datafu.hourglass.jobs.AbstractJob

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable

Direct Known Subclasses:

TimeBasedJob

public abstract class AbstractJob
extends org.apache.hadoop.conf.Configured

Base class for Hadoop jobs.

This class defines a set of common methods and configuration shared by Hadoop jobs. Jobs can be configured either by providing properties or by calling setters. Each property has a corresponding setter.

This class recognizes the following properties:

• input.path - Input path job will read from
• output.path - Output path job will write to
• temp.path - Temporary path under which intermediate files are stored
• retention.count - Number of days to retain in output directory
• num.reducers - Number of reducers to use
• use.combiner - Whether to use a combiner or not
• counters.path - Path to store job counters in

The input.path property may be a comma-separated list of paths. When there is more than one it implies a join is to be performed. Alternatively the paths may be listed separately. For example, input.path.first and input.path.second define two separate input paths.

The num.reducers fixes the number of reducers. When not set the number of reducers is computed based on the input size.

The temp.path property defines the parent directory for temporary paths, not the temporary path itself. Temporary paths are created under this directory with an hourglass- prefix followed by a GUID.

The input and output paths are the only required parameters. The rest are optional.

Hadoop configuration may be provided by setting a property with the prefix hadoop-conf.. For example, mapred.min.split.size can be configured by setting property hadoop-conf.mapred.min.split.size to the desired value.

Constructor Summary

Constructors

Constructor and Description
AbstractJob() Initializes the job.
AbstractJob(java.lang.String name, java.util.Properties props) Initializes the job with a job name and properties.

Method Summary

Modifier and Type	Method and Description
void	config(org.apache.hadoop.conf.Configuration conf) Overridden to provide custom configuration before the job starts.
protected org.apache.hadoop.fs.Path	createRandomTempPath() Creates a random temporary path within the file system.
protected org.apache.hadoop.fs.Path	ensurePath(org.apache.hadoop.fs.Path path) Creates a path, if it does not already exist.
org.apache.hadoop.fs.Path	getCountersParentPath() Gets the path where counters will be stored.
protected org.apache.hadoop.fs.FileSystem	getFileSystem() Gets the file system.
java.util.List<org.apache.hadoop.fs.Path>	getInputPaths() Gets the input paths.
java.lang.String	getName() Gets the job name
java.lang.Integer	getNumReducers() Gets the number of reducers to use.
org.apache.hadoop.fs.Path	getOutputPath() Gets the output path.
java.util.Properties	getProperties() Gets the configuration properties.
java.lang.Integer	getRetentionCount() Gets the number of days of data which will be retained in the output path.
org.apache.hadoop.fs.Path	getTempPath() Gets the temporary path under which intermediate files will be stored.
protected void	initialize() Initialization required before running job.
boolean	isUseCombiner() Gets whether the combiner should be used.
protected org.apache.hadoop.fs.Path	randomTempPath() Generates a random temporary path within the file system.
abstract void	run() Run the job.
void	setCountersParentPath(org.apache.hadoop.fs.Path countersParentPath) Sets the path where counters will be stored.
void	setInputPaths(java.util.List<org.apache.hadoop.fs.Path> inputPaths) Sets the input paths.
void	setName(java.lang.String name) Sets the job name
void	setNumReducers(java.lang.Integer numReducers) Sets the number of reducers to use.
void	setOutputPath(org.apache.hadoop.fs.Path outputPath) Sets the output path.
void	setProperties(java.util.Properties props) Sets the configuration properties.
void	setRetentionCount(java.lang.Integer retentionCount) Sets the number of days of data which will be retained in the output path.
void	setTempPath(org.apache.hadoop.fs.Path tempPath) Sets the temporary path where intermediate files will be stored.
void	setUseCombiner(boolean useCombiner) Sets whether the combiner should be used.
protected void	validate() Validation required before running job.

Methods inherited from class org.apache.hadoop.conf.Configured

getConf, setConf

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractJob

public AbstractJob()

Initializes the job.

AbstractJob

public AbstractJob(java.lang.String name,
                   java.util.Properties props)

Initializes the job with a job name and properties.

Parameters:

name - Job name

props - Configuration properties

Method Detail

getName

public java.lang.String getName()

Gets the job name

Returns:

Job name

setName

public void setName(java.lang.String name)

Sets the job name

Parameters:

name - Job name

getProperties

public java.util.Properties getProperties()

Gets the configuration properties.

Returns:

Configuration properties

setProperties

public void setProperties(java.util.Properties props)

Sets the configuration properties.

Parameters:

props - Properties

config

public void config(org.apache.hadoop.conf.Configuration conf)

Overridden to provide custom configuration before the job starts.

Parameters:

conf - configuration

getNumReducers

public java.lang.Integer getNumReducers()

Gets the number of reducers to use.

Returns:

Number of reducers

setNumReducers

public void setNumReducers(java.lang.Integer numReducers)

Sets the number of reducers to use. Can also be set with num.reducers property.

Parameters:

numReducers - Number of reducers to use

isUseCombiner

public boolean isUseCombiner()

Gets whether the combiner should be used.

Returns:

True if combiner should be used, otherwise false.

setUseCombiner

public void setUseCombiner(boolean useCombiner)

Sets whether the combiner should be used. Can also be set with use.combiner.

Parameters:

useCombiner - True if a combiner should be used, otherwise false.

getCountersParentPath

public org.apache.hadoop.fs.Path getCountersParentPath()

Gets the path where counters will be stored.

Returns:

Counters path

setCountersParentPath

public void setCountersParentPath(org.apache.hadoop.fs.Path countersParentPath)

Sets the path where counters will be stored. Can also be set with counters.path.

Parameters:

countersParentPath - Counters path

getRetentionCount

public java.lang.Integer getRetentionCount()

Gets the number of days of data which will be retained in the output path. Only the latest will be kept. Older paths will be removed.

Returns:

retention count

setRetentionCount

public void setRetentionCount(java.lang.Integer retentionCount)

Sets the number of days of data which will be retained in the output path. Only the latest will be kept. Older paths will be removed. Can also be set with retention.count.

Parameters:

retentionCount - retention count

getInputPaths

public java.util.List<org.apache.hadoop.fs.Path> getInputPaths()

Gets the input paths. Multiple input paths imply a join is to be performed.

Returns:

input paths

setInputPaths

public void setInputPaths(java.util.List<org.apache.hadoop.fs.Path> inputPaths)

Sets the input paths. Multiple input paths imply a join is to be performed. Can also be set with input.path or several properties starting with input.path..

Parameters:

inputPaths - input paths

getOutputPath

public org.apache.hadoop.fs.Path getOutputPath()

Gets the output path.

Returns:

output path

setOutputPath

public void setOutputPath(org.apache.hadoop.fs.Path outputPath)

Sets the output path. Can also be set with output.path.

Parameters:

outputPath - output path

getTempPath

public org.apache.hadoop.fs.Path getTempPath()

Gets the temporary path under which intermediate files will be stored. Defaults to /tmp.

Returns:

Temporary path

setTempPath

public void setTempPath(org.apache.hadoop.fs.Path tempPath)

Sets the temporary path where intermediate files will be stored. Defaults to /tmp.

Parameters:

tempPath - Temporary path

getFileSystem

protected org.apache.hadoop.fs.FileSystem getFileSystem()

Gets the file system.

Returns:

File system

randomTempPath

protected org.apache.hadoop.fs.Path randomTempPath()

Generates a random temporary path within the file system. This does not create the path.

Returns:

Random temporary path

createRandomTempPath

protected org.apache.hadoop.fs.Path createRandomTempPath()
                                                  throws java.io.IOException

Creates a random temporary path within the file system.

Returns:

Random temporary path

Throws:

java.io.IOException - IOException

ensurePath

protected org.apache.hadoop.fs.Path ensurePath(org.apache.hadoop.fs.Path path)
                                        throws java.io.IOException

Creates a path, if it does not already exist.

Parameters:

path - Path to create

Returns:

The same path that was provided

Throws:

java.io.IOException - IOException

validate

protected void validate()

Validation required before running job.

initialize

protected void initialize()

Initialization required before running job.

run

public abstract void run()
                  throws java.io.IOException,
                         java.lang.InterruptedException,
                         java.lang.ClassNotFoundException

Run the job.

Throws:

java.io.IOException - IOException

java.lang.InterruptedException - InterruptedException

java.lang.ClassNotFoundException - ClassNotFoundException