Mini Shell
# Copyright 2011 OpenStack Foundation.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Time related utilities and helper functions.
"""
import calendar
import datetime
import functools
import logging
import time
import iso8601
try:
import zoneinfo
except ImportError:
# zoneinfo is available in Python >= 3.9
import pytz
zoneinfo = None
from oslo_utils import reflection
# ISO 8601 extended time format with microseconds
_ISO8601_TIME_FORMAT_SUBSECOND = '%Y-%m-%dT%H:%M:%S.%f'
_ISO8601_TIME_FORMAT = '%Y-%m-%dT%H:%M:%S'
PERFECT_TIME_FORMAT = _ISO8601_TIME_FORMAT_SUBSECOND
_MAX_DATETIME_SEC = 59
now = time.monotonic
def parse_isotime(timestr):
"""Parse time from ISO 8601 format."""
try:
return iso8601.parse_date(timestr)
except iso8601.ParseError as e:
raise ValueError(str(e))
except TypeError as e:
raise ValueError(str(e))
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 naive object."""
offset = timestamp.utcoffset()
if offset is None:
return timestamp
return timestamp.replace(tzinfo=None) - offset
def is_older_than(before, seconds):
"""Return True if before is older than seconds.
.. versionchanged:: 1.7
Accept datetime string with timezone information.
Fix comparison with timezone aware datetime.
"""
if isinstance(before, str):
before = parse_isotime(before)
before = normalize_time(before)
return utcnow() - before > datetime.timedelta(seconds=seconds)
def is_newer_than(after, seconds):
"""Return True if after is newer than seconds.
.. versionchanged:: 1.7
Accept datetime string with timezone information.
Fix comparison with timezone aware datetime.
"""
if isinstance(after, str):
after = parse_isotime(after)
after = normalize_time(after)
return after - utcnow() > datetime.timedelta(seconds=seconds)
def utcnow_ts(microsecond=False):
"""Timestamp version of our utcnow function.
See :py:class:`oslo_utils.fixture.TimeFixture`.
.. versionchanged:: 1.3
Added optional *microsecond* parameter.
"""
if utcnow.override_time is None:
# NOTE(kgriffs): This is several times faster
# than going through calendar.timegm(...)
timestamp = time.time()
if not microsecond:
timestamp = int(timestamp)
return timestamp
now = utcnow()
timestamp = calendar.timegm(now.timetuple())
if microsecond:
timestamp += float(now.microsecond) / 1000000
return timestamp
def utcnow(with_timezone=False):
"""Overridable version of utils.utcnow that can return a TZ-aware datetime.
See :py:class:`oslo_utils.fixture.TimeFixture`.
.. versionchanged:: 1.6
Added *with_timezone* parameter.
"""
if utcnow.override_time:
try:
return utcnow.override_time.pop(0)
except AttributeError:
return utcnow.override_time
if with_timezone:
return datetime.datetime.now(tz=iso8601.iso8601.UTC)
return datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
utcnow.override_time = None
def set_time_override(override_time=None):
"""Overrides utils.utcnow.
Make it return a constant time or a list thereof, one at a time.
See :py:class:`oslo_utils.fixture.TimeFixture`.
:param override_time: datetime instance or list thereof. If not
given, defaults to the current UTC time.
"""
utcnow.override_time = (
override_time or
datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None))
def advance_time_delta(timedelta):
"""Advance overridden time using a datetime.timedelta.
See :py:class:`oslo_utils.fixture.TimeFixture`.
"""
assert utcnow.override_time is not None # nosec
try:
for dt in utcnow.override_time:
dt += timedelta
except TypeError:
utcnow.override_time += timedelta
def advance_time_seconds(seconds):
"""Advance overridden time by seconds.
See :py:class:`oslo_utils.fixture.TimeFixture`.
"""
advance_time_delta(datetime.timedelta(0, seconds))
def clear_time_override():
"""Remove the overridden time.
See :py:class:`oslo_utils.fixture.TimeFixture`.
"""
utcnow.override_time = None
def marshall_now(now=None):
"""Make an rpc-safe datetime with microseconds.
.. versionchanged:: 1.6
Timezone information is now serialized instead of being stripped.
"""
if not now:
now = utcnow()
d = dict(day=now.day, month=now.month, year=now.year, hour=now.hour,
minute=now.minute, second=now.second,
microsecond=now.microsecond)
if now.tzinfo:
# Need to handle either iso8601 or python UTC format
tzname = now.tzinfo.tzname(None)
d['tzname'] = 'UTC' if tzname == 'UTC+00:00' else tzname
return d
def unmarshall_time(tyme):
"""Unmarshall a datetime dict.
.. versionchanged:: 1.5
Drop leap second.
.. versionchanged:: 1.6
Added support for timezone information.
"""
# NOTE(ihrachys): datetime does not support leap seconds,
# so the best thing we can do for now is dropping them
# http://bugs.python.org/issue23574
second = min(tyme['second'], _MAX_DATETIME_SEC)
dt = datetime.datetime(day=tyme['day'],
month=tyme['month'],
year=tyme['year'],
hour=tyme['hour'],
minute=tyme['minute'],
second=second,
microsecond=tyme['microsecond'])
tzname = tyme.get('tzname')
if tzname:
# Need to handle either iso8601 or python UTC format
tzname = 'UTC' if tzname == 'UTC+00:00' else tzname
if zoneinfo:
tzinfo = zoneinfo.ZoneInfo(tzname)
dt = dt.replace(tzinfo=tzinfo)
else:
tzinfo = pytz.timezone(tzname)
dt = tzinfo.localize(dt)
return dt
def delta_seconds(before, after):
"""Return the difference between two timing objects.
Compute the difference in seconds between two date, time, or
datetime objects (as a float, to microsecond resolution).
"""
delta = after - before
return delta.total_seconds()
def is_soon(dt, window):
"""Determines if time is going to happen in the next window seconds.
:param dt: the time
:param window: minimum seconds to remain to consider the time not soon
:return: True if expiration is within the given duration
"""
soon = (utcnow() + datetime.timedelta(seconds=window))
return normalize_time(dt) <= soon
class Split(object):
"""A *immutable* stopwatch split.
See: http://en.wikipedia.org/wiki/Stopwatch for what this is/represents.
.. versionadded:: 1.4
"""
__slots__ = ['_elapsed', '_length']
def __init__(self, elapsed, length):
self._elapsed = elapsed
self._length = length
@property
def elapsed(self):
"""Duration from stopwatch start."""
return self._elapsed
@property
def length(self):
"""Seconds from last split (or the elapsed time if no prior split)."""
return self._length
def __repr__(self):
r = reflection.get_class_name(self, fully_qualified=False)
r += "(elapsed=%s, length=%s)" % (self._elapsed, self._length)
return r
def time_it(logger, log_level=logging.DEBUG,
message="It took %(seconds).02f seconds to"
" run function '%(func_name)s'",
enabled=True, min_duration=0.01):
"""Decorator that will log how long its decorated function takes to run.
This does **not** output a log if the decorated function fails
with an exception.
:param logger: logger instance to use when logging elapsed time
:param log_level: logger logging level to use when logging elapsed time
:param message: customized message to use when logging elapsed time,
the message may use automatically provide values
``%(seconds)`` and ``%(func_name)`` if it finds those
values useful to record
:param enabled: whether to enable or disable this decorator (useful to
decorate a function with this decorator, and then easily
be able to switch that decoration off by some config or
other value)
:param min_duration: argument that determines if logging is triggered
or not, it is by default set to 0.01 seconds to avoid
logging when durations and/or elapsed function call
times are less than 0.01 seconds, to disable
any ``min_duration`` checks this value should be set
to less than or equal to zero or set to none
"""
def decorator(func):
if not enabled:
return func
@functools.wraps(func)
def wrapper(*args, **kwargs):
with StopWatch() as w:
result = func(*args, **kwargs)
time_taken = w.elapsed()
if min_duration is None or time_taken >= min_duration:
logger.log(log_level, message,
{'seconds': time_taken,
'func_name': reflection.get_callable_name(func)})
return result
return wrapper
return decorator
class StopWatch(object):
"""A simple timer/stopwatch helper class.
Inspired by: apache-commons-lang java stopwatch.
Not thread-safe (when a single watch is mutated by multiple threads at
the same time). Thread-safe when used by a single thread (not shared) or
when operations are performed in a thread-safe manner on these objects by
wrapping those operations with locks.
.. versionadded:: 1.4
"""
_STARTED = 'STARTED'
_STOPPED = 'STOPPED'
def __init__(self, duration=None):
if duration is not None and duration < 0:
raise ValueError("Duration must be greater or equal to"
" zero and not %s" % duration)
self._duration = duration
self._started_at = None
self._stopped_at = None
self._state = None
self._splits = ()
def start(self):
"""Starts the watch (if not already started).
NOTE(harlowja): resets any splits previously captured (if any).
"""
if self._state == self._STARTED:
return self
self._started_at = now()
self._stopped_at = None
self._state = self._STARTED
self._splits = ()
return self
@property
def splits(self):
"""Accessor to all/any splits that have been captured."""
return self._splits
def split(self):
"""Captures a split/elapsed since start time (and doesn't stop)."""
if self._state == self._STARTED:
elapsed = self.elapsed()
if self._splits:
length = self._delta_seconds(self._splits[-1].elapsed, elapsed)
else:
length = elapsed
self._splits = self._splits + (Split(elapsed, length),)
return self._splits[-1]
else:
raise RuntimeError("Can not create a split time of a stopwatch"
" if it has not been started or if it has been"
" stopped")
def restart(self):
"""Restarts the watch from a started/stopped state."""
if self._state == self._STARTED:
self.stop()
self.start()
return self
@staticmethod
def _delta_seconds(earlier, later):
# Uses max to avoid the delta/time going backwards (and thus negative).
return max(0.0, later - earlier)
def elapsed(self, maximum=None):
"""Returns how many seconds have elapsed."""
if self._state not in (self._STARTED, self._STOPPED):
raise RuntimeError("Can not get the elapsed time of a stopwatch"
" if it has not been started/stopped")
if self._state == self._STOPPED:
elapsed = self._delta_seconds(self._started_at, self._stopped_at)
else:
elapsed = self._delta_seconds(self._started_at, now())
if maximum is not None and elapsed > maximum:
elapsed = max(0.0, maximum)
return elapsed
def __enter__(self):
"""Starts the watch."""
self.start()
return self
def __exit__(self, type, value, traceback):
"""Stops the watch (ignoring errors if stop fails)."""
try:
self.stop()
except RuntimeError: # nosec: errors are meant to be ignored
pass
def leftover(self, return_none=False):
"""Returns how many seconds are left until the watch expires.
:param return_none: when ``True`` instead of raising a ``RuntimeError``
when no duration has been set this call will
return ``None`` instead.
:type return_none: boolean
"""
if self._state != self._STARTED:
raise RuntimeError("Can not get the leftover time of a stopwatch"
" that has not been started")
if self._duration is None:
if not return_none:
raise RuntimeError("Can not get the leftover time of a watch"
" that has no duration")
return None
return max(0.0, self._duration - self.elapsed())
def expired(self):
"""Returns if the watch has expired (ie, duration provided elapsed)."""
if self._state not in (self._STARTED, self._STOPPED):
raise RuntimeError("Can not check if a stopwatch has expired"
" if it has not been started/stopped")
if self._duration is None:
return False
return self.elapsed() > self._duration
def has_started(self):
"""Returns True if the watch is in a started state."""
return self._state == self._STARTED
def has_stopped(self):
"""Returns True if the watch is in a stopped state."""
return self._state == self._STOPPED
def resume(self):
"""Resumes the watch from a stopped state."""
if self._state == self._STOPPED:
self._state = self._STARTED
return self
else:
raise RuntimeError("Can not resume a stopwatch that has not been"
" stopped")
def stop(self):
"""Stops the watch."""
if self._state == self._STOPPED:
return self
if self._state != self._STARTED:
raise RuntimeError("Can not stop a stopwatch that has not been"
" started")
self._stopped_at = now()
self._state = self._STOPPED
return self
Zerion Mini Shell 1.0