[Predator] Add local cache for get command output.

appengine/findit/common/repo_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.
 
 import json
 import logging
 import re
 import subprocess
 import urllib2
 
+from common import cache_decorator
+
 CODE_REVIEW_URL_PATTERN = re.compile(
     '^(?:Review URL|Review-Url): (.*\d+).*$', re.IGNORECASE)
 COMMIT_POSITION_PATTERN = re.compile(
     '^Cr-Commit-Position: refs/heads/master@{#(\d+)}$', re.IGNORECASE)
 REVERTED_REVISION_PATTERN = re.compile(
     '^> Committed: https://.+/([0-9a-fA-F]{40})$', re.IGNORECASE)
 COMMIT_POSITION_CODE_REVIEW_URL_PARSING_START_LINE = -5
 
 
 def ExtractCommitPositionAndCodeReviewUrl(message):
@@ skipping 48 matching lines @@
   if not lines[0].lower().startswith('revert'):
     return None
 
   for line in reversed(lines):  # pragma: no cover
     # TODO: Handle cases where no reverted_revision in reverting message.
     reverted_revision_match = REVERTED_REVISION_PATTERN.match(line)
     if reverted_revision_match:
       return reverted_revision_match.group(1)
 
 
-# TODO(katesonia): Add local cache for this function.
+@cache_decorator.Cached('Command-output', cacher=cache_decorator.LocalCacher())

[Martin Barbella, 2016/10/26 23:21:20]

Is the format used here for the namespace consistent with the other uses of
Cached? I don't particularly like this format, but I'm fine with it so long as
it's consistent with the rest of the usage.

[Sharu Jiang, 2016/10/27 21:59:05]

The other 2 are 'Gitiles-json-view' for SendRequestForJsonResponse and
'Gitiles-text-view' for SendRequestForTextResponse. I think they are consistent
or do you have any better name?

 def GetCommandOutput(command):
   """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