[Culprit-Finder] Add generator cache decorator.

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 atexit
 import functools
 import os
 import Queue
@@ skipping 107 matching lines @@
   # Push task to task queue for execution.
   for task in tasks:
     TASK_QUEUE.put((task['function'], task.get('args', []),
                     task.get('kwargs', {}), result_semaphore))
 
   # Wait until all tasks to be executed.
   for _ in tasks:
     result_semaphore.acquire()
 
 
-@Cached(namespace='Command-output', cache=LocalCache())
+@Cached(LocalCache(), namespace='Command-output')
 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:
     raise Exception('Error running command %s: %s' % (command, stderrdata))
 
   return stdoutdata
 
 
 def GetLockedMethod(cls, method_name, lock):  # pragma: no cover
   """Returns a class/object method serialized with lock."""
   method = getattr(cls, method_name)
 
   def LockedMethod(cls, *args, **kwargs):  # pylint: disable=W
     with lock:
       return method(*args, **kwargs)
 
   return functools.partial(LockedMethod, cls)