Add infra_libs as a bootstrap dependency.

infra_libs/time_functions/zulu.py

-# Copyright 2015 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.
-
-
-"""Provides functions for parsing and outputting Zulu time."""
-
-import datetime
-import pytz
-
-from infra_libs.time_functions import timestamp
-
-
-def parse_zulu_time(string):
-  """Parses a Zulu time string, returning None if unparseable."""
-
-  # Ugh https://bugs.python.org/issue19475.
-  zulu_format = "%Y-%m-%dT%H:%M:%S"
-  if '.' in string:
-    zulu_format += ".%f"
-  zulu_format += "Z"
-  try:
-    return datetime.datetime.strptime(string, zulu_format)
-  except ValueError:
-    return None
-
-
-def parse_zulu_ts(string):
-  """Parses Zulu time and converts into a timestamp or None."""
-  zuluparse = parse_zulu_time(string)
-  if zuluparse is None:
-    return None
-  return timestamp.utctimestamp(zuluparse)
-
-
-def to_zulu_string(dt):
-  """Returns a Zulu time string from a datetime.
-
-  Assumes naive datetime objects are in UTC.
-  Ensures the output always has a floating-point number of seconds.
-  """
-
-  # Assume non-tz-aware datetimes are in UTC.
-  if dt.tzinfo is None or dt.tzinfo.utcoffset(dt) is None:
-    dt = dt.replace(tzinfo=pytz.UTC)
-
-  # Convert datetime into UTC.
-  isodate = dt.astimezone(pytz.UTC).isoformat().split('+')[0]
-
-  # Add fractional seconds if not present.
-  if '.' not in isodate:
-    isodate += '.0'
-
-  return isodate + 'Z'