Add nova time util functions to timeutils

Fixes bug #1009410

1. Add the following functions from nova/utils.py
- strtime
- parse_strtime
- is_older_than
- utcnow_ts
- advance_time_delta
- advance_time_seconds

2. Write unittests in tests/unit/test_timeutils.py

Change-Id: Ie0bba90833e2ed31bb5ab867a7c1a76a9901cacb

1 files changed, 35 insertions, 0 deletions

diff --git a/openstack/common/timeutils.py b/openstack/common/timeutils.py
index 345f315..a7b2ce3 100644
--- a/openstack/common/timeutils.py
+++ b/openstack/common/timeutils.py
@@ -20,11 +20,13 @@ Time related utilities and helper functions.
 """
 
 import datetime
+import time
 
 import iso8601
 
 
 TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
+PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
 
 
 def isotime(at=None):
@@ -47,12 +49,34 @@ def parse_isotime(timestr):
         raise ValueError(e.message)
 
 
+def strtime(at=None, fmt=PERFECT_TIME_FORMAT):
+    """Returns formatted utcnow."""
+    if not at:
+        at = utcnow()
+    return at.strftime(fmt)
+
+
+def parse_strtime(timestr, fmt=PERFECT_TIME_FORMAT):
+    """Turn a formatted time back into a datetime."""
+    return datetime.datetime.strptime(timestr, fmt)
+
+
 def normalize_time(timestamp):
     """Normalize time in arbitrary timezone to UTC"""
     offset = timestamp.utcoffset()
     return timestamp.replace(tzinfo=None) - offset if offset else timestamp
 
 
+def is_older_than(before, seconds):
+    """Return True if before is older than seconds."""
+    return utcnow() - before > datetime.timedelta(seconds=seconds)
+
+
+def utcnow_ts():
+    """Timestamp version of our utcnow function."""
+    return time.mktime(utcnow().timetuple())
+
+
 def utcnow():
     """Overridable version of utils.utcnow."""
     if utcnow.override_time:
@@ -68,6 +92,17 @@ def set_time_override(override_time=datetime.datetime.utcnow()):
     utcnow.override_time = override_time
 
 
+def advance_time_delta(timedelta):
+    """Advance overriden time using a datetime.timedelta."""
+    assert(not utcnow.override_time is None)
+    utcnow.override_time += timedelta
+
+
+def advance_time_seconds(seconds):
+    """Advance overriden time by seconds."""
+    advance_time_delta(datetime.timedelta(0, seconds))
+
+
 def clear_time_override():
     """Remove the overridden time."""
     utcnow.override_time = None