[Predator] Add local cache for get command output.

appengine/findit/util_scripts/script_util.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This module contains util functions that local scripts can use."""
 
 import logging
 import os
 import subprocess
 import sys
 
+from lib.cache_decorator import Cached
+from local_cache import LocalCacher  # pylint: disable=W
+
 
 def SetUpSystemPaths():  # pragma: no cover
   """Sets system paths so as to import modules in findit, third_party and
   appengine."""
   findit_root_dir = os.path.join(os.path.dirname(__file__), os.path.pardir)
   third_party_dir = os.path.join(findit_root_dir, 'third_party')
   appengine_sdk_dir = os.path.join(findit_root_dir, os.path.pardir,
                                    os.path.pardir, os.path.pardir,
                                    'google_appengine')
 
   # Add App Engine SDK dir to sys.path.
   sys.path.insert(1, appengine_sdk_dir)
   sys.path.insert(1, third_party_dir)
   import dev_appserver
   dev_appserver.fix_sys_path()
 
   # Add Findit root dir to sys.path so that modules in Findit is available.
   sys.path.insert(1, findit_root_dir)
 
 
-# TODO(katesonia): Add local cache for this function.
-def GetCommandOutput(command):
+@Cached(namespace='Command-output', cacher=LocalCacher())
+def GetCommandOutput(command):  # pragma: no cover
   """Gets the output stream of executable command.
 
   Args:
     command (str): Command to execute to get output.
 
   Return:
     Output steam of the command.
   """
   p = subprocess.Popen(
       command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
   stdoutdata, stderrdata = p.communicate()
 
   if p.returncode != 0:
     logging.error('Error running command %s: %s', command, stderrdata)
     return None
 
   return stdoutdata