[CHUKWA-581] Demux do not support user custom reducer package name.

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.4.0, 0.5.0, 0.6.0
• Fix Version/s: 0.6.0
• Component/s: MR Data Processors
• Labels: patch

Environment

Ubuntu 10.0.4,Hadoop 0.20

• Tags: CustomReducer
• Assignee: Ivy Tang
• Reporter: Yingzhong Xu
• Created: 23/Feb/11 02:46
• Updated: 18/Aug/13 18:52
• Resolved: 18/Aug/13 18:02

Description

In ReduceProcessorFactory.java,
it only gets

{reduceType}

.class from this package,as following:

String path = "org.apache.hadoop.chukwa.extraction.demux.processor.reducer." + reduceType;

So our custom reducer could only be placed in that package.
Thus, When we add our

{demux}

.jar to Hadoop classpath, since the Hadoop framework will not be able to merge the class files from multiple jar files with the same package name, custom reduce class can not be found.
I get a way to overcome this defect.Put custom reducer into a package named with "org.apache.hadoop.chukwa.extraction.demux.processor.reducer."+

{custom}
Here,{custom}

is a part of package name.Then in parser,we can write like this:

Key.setReducerType("{custom}.YourReducer")

In this way, Hadoop framework could be able to find our reduce class in this partial user defined new package.
But I think it will be better to fix chukwa to remove the default package name and fully support custom package name for reducer.

Thanks for Eric Yang's help.