How to read the parameter value in mapper code passed from oozie workflow?

[#1]

Hi,

I am running my oozie workflow through command prompt.

I assigning value to a parameter "var" in my my workflow.

       <property>
              <name>var</name>
              <value>2</value>
       </property>

Now how can i access the variable value in my java Mapper Program.

Will the below metioned work for me:

protected void setup(Context context) throws IOException,InterruptedException {

Configuration conf = context.getConfiguration();

var_val = conf.get("var");

}

[#2 · Accepted solution]

Yes, that will work if you use a map-reduce action type to define that
configuration property. If you are using a java action type instead, you
will also need to load the configuration in the driver explicitly:
http://archive.cloudera.com/cdh5/cdh/5/oozie/WorkflowFunctionalSpec.html#a3.2.7_Java_Action

"""

A java action can create a Hadoop configuration for interacting with a
cluster (e.g. launching a map-reduce job). Oozie prepares a Hadoop
configuration file which includes the environments site configuration files
(e.g. hdfs-site.xml, mapred-site.xml, etc) plus the properties added
to the section
of the java action. The Hadoop configuration file is made available as a
local file to the Java application in its running directory. It can be
added to the java actions Hadoop configuration by referencing the system
property: oozie-action.conf.xml . For example:

// loading action conf prepared by Oozie
Configuration actionConf = new Configuration(false);
actionConf.addResource(new Path("file:///",
System.getProperty("oozie.action.conf.xml")));

If oozie.action.conf.xml is not added then the job will pick up the
mapred-default properties and this may result in unexpected behaviour. For
repeated configuration properties later values override earlier ones.
"""

[#3]

Hi Harsh,

The information provided for Java Action is clear to me. But I have doubt regarding MapReduce action.

I am using only Mapreduce action for my workflow and I am placing only my Mapper class & Reducer Class in the .jar file. I want to pass all the properties and parameters through Oozie workflow.

Now can I get the value of the "var" variable, i.e. "2", in my Mapper using the below code in my mapper class.

protected void setup(Context context) throws IOException,InterruptedException {

Configuration conf = context.getConfiguration();

var_val = conf.get("var");

}

[#4]

Yes, do you not see it working?

You'll need to pass the XML property via the workflow.xml under the
action's configuration section.