def describe_step(jobflow_id, step_id)
      params = {
        :operation => 'DescribeStep',
        :cluster_id => jobflow_id,
        :step_id => step_id
      }
      aws_result = @aws_request.submit(params)
      yield aws_result if block_given?
      JSON.parse(aws_result)
    end
def describe_step(jobflow_id, step_id)
      params = {
        :operation => 'DescribeStep',
        :cluster_id => jobflow_id,
        :step_id => step_id
      }
      aws_result = @aws_request.submit(params)
      yield aws_result if block_given?
      JSON.parse(aws_result)
    end
Provides details about the specified step within an existing jobflow

   emr.describe_step('j-123', 'step-456')

 http://docs.aws.amazon.com/ElasticMapReduce/latest/API/API_DescribeStep.html