[Findit] Add skeleton code for delta test script.

appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py

Index: appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py
diff --git a/appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py b/appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py
new file mode 100644
index 0000000000000000000000000000000000000000..7816d2558e2abab34acdc543fae3f1381ce48214
--- /dev/null
+++ b/appengine/findit/util_scripts/crash_queries/delta_test/delta_util.py
@@ -0,0 +1,101 @@
+# 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.
+
+"""Util functions for git repository processing."""
+
+import base64
+import hashlib
+import json
+import logging
+import os
+import pickle
+import re
+import subprocess
+import traceback
+import urllib2
+
+import dev_appserver
+dev_appserver.fix_sys_path()
+
+from common import appengine_util
+
+# TODO(katesonia): move host to azalea host after migration.
+_FEEDBACK_URL_TEMPLATE = 'host/crash/fracas-result-feedback?key=%s'
+GIT_HASH_PATTERN = re.compile(r'^[0-9a-fA-F]{40}$')
+
+
+def GenerateFileName(*args):
+  """Encodes args and returns the generated result file."""
+  return hashlib.md5(pickle.dumps(args)).hexdigest()
+
+
+def IsGitHash(revision):
+  return GIT_HASH_PATTERN.match(str(revision)) or revision.lower() == 'master'
+
+
+def ParseGitHash(revision):
+  """Gets git hash of a revision."""
+  if IsGitHash(revision):
+    return revision
+
+  try:
+    # Can parse revision like 'HEAD', 'HEAD~3'.
+    return subprocess.check_output(
+        ['git', 'rev-parse', revision]).replace('\n', '')
+  except: # pylint: disable=W
+    logging.error('Failed to parse git hash for %s\nStacktrace:\n%s',
+                  revision, traceback.format_exc())
+    return None
+
+
+def EnsureDirExists(path):
+  directory = os.path.dirname(path)
+  if os.path.exists(directory):
+    return
+
+  os.makedirs(directory)
+
+
+def FlushResult(result, result_path):
+  logging.info('\nFlushing results to %s', result_path)
+  EnsureDirExists(result_path)
+  with open(result_path, 'wb') as f:
+    pickle.dump(result, f)
+
+
+def PrintDelta(deltas, crash_num):
+  logging.info(('\n+++++++++++++++++++++'
+                '\nDelta on %d crashes '
+                '\n+++++++++++++++++++++'), crash_num)
+
+  if not deltas:
+    logging.info('Two sets of results are the same.')
+    return
+
+  for crash_id, delta in deltas.iteritems():
+    logging.info('\nCrash: %s\n%s\n',
+                 _FEEDBACK_URL_TEMPLATE % crash_id,
+                 str(delta))
+
+
+def WriteDeltaToCSV(deltas, crash_num, git_hash1, git_hash2, file_path):
+  EnsureDirExists(file_path)
+  def _EncodeStr(string):
+    return string.replace('\"', '\'') if string else ''
+
+  logging.info('Writing delta diff to %s\n', file_path)
+  with open(file_path, 'wb') as f:
+    f.write('Delta between githash1 %s and githash2 %s on %d crashes\n' % (
+        git_hash1, git_hash2, crash_num))
+    f.write('project, components, cls, regression_range\n')
+    for crash_id, delta in deltas.iteritems():
+      delta_str_dict = delta.delta_str_dict
+      feedback_url = _FEEDBACK_URL_TEMPLATE % crash_id
+      f.write('%s, "%s", "%s", "%s", "%s"\n' % (
+          feedback_url,
+          _EncodeStr(delta_str_dict.get('project', '')),
+          _EncodeStr(delta_str_dict.get('components', '')),
+          _EncodeStr(delta_str_dict.get('cls', '')),
+          _EncodeStr(delta_str_dict.get('regression_range', ''))
+      ))