Cascading

Thanks for using Cascading.

General Information:

Project and contact information: http://www.cascading.org/

This distribution includes six Cascading jar files:

• cascading-x.y.z.jar - all relevant Cascading class files and libraries, with a 'lib' folder
• cascading-core-x.y.z.jar - all Cascading Core class files
• cascading-local-x.y.z.jar - all Cascading Local mode class files
• cascading-hadoop-x.y.z.jar - all Cascading Hadoop mode class files
• cascading-xml-x.y.z.jar - all Cascading XML operations class files
• cascading-test-x.y.z.jar - all Cascading tests and test utilities

These jars are all available via www.conjars.org.

Hadoop mode is where the Cascading application should run on a Hadoop cluster.

Local mode is where the Cascading application will run locally in memory without any Hadoop dependenices.

Building:

To build Cascading, run the following in the shell:

> git clone https://github.com/cwensel/cascading.git
> cd cascading
> gradle build

Cascading currently requires Gradle 1.0-milestone-3 to build.

To use an IDE like IntelliJ, run the following to get all jar dependencies:

> gradle ideLibs

Using with Apache Hadoop:

To use Cascading with Hadoop, we suggest stuffing cascading-core, cascading-hadoop, (optionally) cascading-xml jarfiles and all third-party libs (optionally retrieved by calling gradle ideLibs) into the lib folder of your job jar and executing your job via $HADOOP_HOME/bin/hadoop jar your.jar <your args>.

Note you do not need to put the lib/hadoop jars in your jar as they are already present in your cluster.

For example, your job jar would look like this (via: jar -t your.jar)

/<all your class and resource files>
/lib/cascading-core-x.y.z.jar
/lib/cascading-hadoop-x.y.z.jar
/lib/cascading-xml-x.y.z.jar
/lib/<cascading third-party jar files>

Hadoop will unpack the jar locally and remotely (in the cluster) and add any libraries in lib to the classpath. This is a feature specific to Hadoop.

The cascading-x.y.z.jar file is typically used with scripting languages and is completely self contained, but it cannot be added to a jar lib folder as Hadoop will not recursively unjar jars.