Make smart futures avoid polling.

[python_utils.git] / argparse_utils.py

diff --git a/argparse_utils.py b/argparse_utils.py
index 0ee2be9f8017093caeff732962ad9b4d10a993e7..e8c2f5699bea4bceb67d22127a923099d0d143e5 100644 (file)
--- a/argparse_utils.py
+++ b/argparse_utils.py
@@ -6,6 +6,9 @@ import logging
 import os
 from typing import Any
 
+from overrides import overrides
+
+
 # This module is commonly used by others in here and should avoid
 # taking any unnecessary dependencies back on them.
 
@@ -47,6 +50,7 @@ class ActionNoYes(argparse.Action):
             help=help
         )
 
+    @overrides
     def __call__(self, parser, namespace, values, option_strings=None):
         if (
                 option_strings.startswith('--no-') or
@@ -232,6 +236,28 @@ def valid_datetime(txt: str) -> datetime.datetime:
     raise argparse.ArgumentTypeError(msg)
 
 
+def valid_duration(txt: str) -> datetime.timedelta:
+    """If the string is a valid time duration, return a
+    datetime.timedelta representing the period of time.  Otherwise
+    maybe raise an ArgumentTypeError or potentially just treat the
+    time window as zero in length.
+
+    >>> valid_duration('3m')
+    datetime.timedelta(seconds=180)
+
+    >>> valid_duration('your mom')
+    datetime.timedelta(0)
+
+    """
+    from datetime_utils import parse_duration
+    try:
+        secs = parse_duration(txt)
+    except Exception as e:
+        raise argparse.ArgumentTypeError(e)
+    finally:
+        return datetime.timedelta(seconds=secs)
+
+
 if __name__ == '__main__':
     import doctest
     doctest.ELLIPSIS_MARKER = '-ANYTHING-'