class_docstr: Implementation of some common hadoop operations.
      
docstr: hdfs_file_open 
docstr_tok: ["hdfs_file_open"]
code: def open(self, filename, encoding="utf-8"):
      """hdfs_file_open"""
      cmd = self.hadoop_bin + " fs -D fs.default.name=" + self.fs_name
      cmd += " -D hadoop.job.ugi=" + self.fs_ugi
      cmd += " -cat " + filename
  
      p = Popen(cmd, shell=True, stdout=PIPE)
      p = io.TextIOWrapper(p.stdout, encoding=encoding, errors="ignore")
      return p
  
imports: import os
  import sys
  import numpy
  import json
  import io
  from subprocess import Popen, PIPE
label_desc: Use image node_id 3 for calling the HadoopUtil obj's underlying member method code with example usage: obj.open(filename, encoding) and returns: p