Add logdog_helper script.

build/android/pylib/utils/python_utils.py

Index: build/android/pylib/utils/python_utils.py
diff --git a/build/android/pylib/utils/python_utils.py b/build/android/pylib/utils/python_utils.py
new file mode 100644
index 0000000000000000000000000000000000000000..1ba208ec067aab75bd85f07d4b392a45d610cc49
--- /dev/null
+++ b/build/android/pylib/utils/python_utils.py
@@ -0,0 +1,44 @@
+# Copyright 2017 The Chromium Authors. All rights reserved.

[jbudorick, 2017/01/31 16:11:53]

python_utils doesn't really say anything as a name.

+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import functools
+import logging
+
+
+def Memoize(f):

[jbudorick, 2017/01/31 16:11:53]

I could've sworn that we had this somewhere, but I don't see it any more.

[mikecase (-- gone --), 2017/01/31 23:08:25]

A slightly different implementation of this existed in pylib/constants.py. It
was used to cache something like CHROMIUM_SRC_DIR or soemthing

Its gone now though.

+  """Decorator to cache return values of function."""
+
+  memoize_dict = {}
+  @functools.wraps(f)
+  def wrapper(*args, **kwargs):
+      key = repr((args, kwargs))

[jbudorick, 2017/01/31 16:11:53]

4 space indents...? Did you lift this from somewhere else?

[mikecase (-- gone --), 2017/01/31 23:08:25]

...

+      if key not in memoize_dict:
+          try:
+              memoize_dict[key] = f(*args, **kwargs)
+          except Exception as e:  # pylint: disable=broad-except
+              memoize_dict[key] = e
+              raise
+      return_value = memoize_dict[key]
+      if isinstance(return_value, Exception):
+          raise return_value
+      return return_value
+  return wrapper
+
+
+def NoRaiseException(default_return_value=None):
+  """Returns decorator that catches and logs uncaught Exceptions.
+
+  Args:
+    default_return_value: Value to return in the case of uncaught Exception.
+  """
+  def decorator(f):
+    @functools.wraps(f)
+    def wrapper(*args, **kwargs):
+      try:
+        return f(*args, **kwargs)
+      except Exception:  # pylint: disable=broad-except
+        logging.exception('message')

[jbudorick, 2017/01/31 16:11:53]

You're just going to log 'message'?

[mikecase (-- gone --), 2017/01/31 23:08:25]

I mean, logging.exception will log the exception. But it requires at least 1
arg. Maybe there is a cleaner way to just log the exception if I dont care about
having an accompanying message.

[jbudorick, 2017/01/31 23:15:12]

Can it be an additional argument to NoRaiseException?

+        return default_return_value
+    return wrapper
+  return decorator