How to pass configurations from hive script to UDF

Question

In pig, you can pass a configuration from your pig script to pig UDF via UDFContext. For example,

// in pig script
SET my.conf dummy-conf

// in UDF java code
Configuration conf = UDFContext.getUDFContext().getJobConf();
String myConf = conf.get("my.conf");

So, is there a similar way to pass configuration from a hive script to a hive UDF? For example, if I have set MY_CONF='foobar' in a hive script, how can I retrieve that in a java UDF, which needs to consume the value of MY_CONF?

Answer 1

Instead of extending UDF class, you can try subclassing GenericUDF. This class has the following method you can override:

/**
 * Additionally setup GenericUDF with MapredContext before initializing.
 * This is only called in runtime of MapRedTask.
 *
 * @param context context
 */
public void configure(MapredContext context) {
}

MapredContext has a method just like UDFContext from Pig to retrieve the Job configuration. So you could just do the following:

@Override
public void configure(MapredContext context) {
    Configuration conf = context.getJobConf();  
}