476 lines
14 KiB
Python
476 lines
14 KiB
Python
# Copyright 2011 OpenStack Foundation.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Time related utilities and helper functions.
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"""
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import calendar
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import datetime
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import time
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from debtcollector import removals
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import iso8601
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from monotonic import monotonic as now # noqa
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from pytz import timezone
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import six
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from oslo_utils import reflection
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# ISO 8601 extended time format with microseconds
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_ISO8601_TIME_FORMAT_SUBSECOND = '%Y-%m-%dT%H:%M:%S.%f'
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_ISO8601_TIME_FORMAT = '%Y-%m-%dT%H:%M:%S'
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PERFECT_TIME_FORMAT = _ISO8601_TIME_FORMAT_SUBSECOND
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_MAX_DATETIME_SEC = 59
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@removals.remove(
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message="use datetime.datetime.isoformat()",
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version="1.6",
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removal_version="?",
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)
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def isotime(at=None, subsecond=False):
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"""Stringify time in ISO 8601 format.
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.. deprecated:: > 1.5.0
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Use :func:`utcnow` and :func:`datetime.datetime.isoformat` instead.
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"""
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if not at:
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at = utcnow()
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st = at.strftime(_ISO8601_TIME_FORMAT
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if not subsecond
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else _ISO8601_TIME_FORMAT_SUBSECOND)
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tz = at.tzinfo.tzname(None) if at.tzinfo else 'UTC'
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st += ('Z' if tz == 'UTC' else tz)
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return st
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def parse_isotime(timestr):
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"""Parse time from ISO 8601 format."""
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try:
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return iso8601.parse_date(timestr)
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except iso8601.ParseError as e:
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raise ValueError(six.text_type(e))
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except TypeError as e:
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raise ValueError(six.text_type(e))
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@removals.remove(
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message="use either datetime.datetime.isoformat() "
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"or datetime.datetime.strftime() instead",
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version="1.6",
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removal_version="?",
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)
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def strtime(at=None, fmt=PERFECT_TIME_FORMAT):
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"""Returns formatted utcnow.
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.. deprecated:: > 1.5.0
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Use :func:`utcnow()`, :func:`datetime.datetime.isoformat`
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or :func:`datetime.strftime` instead.
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strtime() => utcnow().isoformat()
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strtime(fmt=...) => utcnow().strftime(fmt)
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strtime(at) => at.isoformat()
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strtime(at, fmt) => at.strftime(fmt)
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"""
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if not at:
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at = utcnow()
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return at.strftime(fmt)
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def parse_strtime(timestr, fmt=PERFECT_TIME_FORMAT):
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"""Turn a formatted time back into a datetime."""
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return datetime.datetime.strptime(timestr, fmt)
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def normalize_time(timestamp):
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"""Normalize time in arbitrary timezone to UTC naive object."""
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offset = timestamp.utcoffset()
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if offset is None:
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return timestamp
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return timestamp.replace(tzinfo=None) - offset
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def is_older_than(before, seconds):
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"""Return True if before is older than seconds."""
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if isinstance(before, six.string_types):
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before = parse_isotime(before)
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before = normalize_time(before)
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return utcnow() - before > datetime.timedelta(seconds=seconds)
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def is_newer_than(after, seconds):
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"""Return True if after is newer than seconds."""
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if isinstance(after, six.string_types):
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after = parse_isotime(after)
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after = normalize_time(after)
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return after - utcnow() > datetime.timedelta(seconds=seconds)
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def utcnow_ts(microsecond=False):
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"""Timestamp version of our utcnow function.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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"""
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if utcnow.override_time is None:
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# NOTE(kgriffs): This is several times faster
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# than going through calendar.timegm(...)
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timestamp = time.time()
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if not microsecond:
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timestamp = int(timestamp)
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return timestamp
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now = utcnow()
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timestamp = calendar.timegm(now.timetuple())
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if microsecond:
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timestamp += float(now.microsecond) / 1000000
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return timestamp
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def utcnow(with_timezone=False):
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"""Overridable version of utils.utcnow that can return a TZ-aware datetime.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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"""
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if utcnow.override_time:
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try:
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return utcnow.override_time.pop(0)
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except AttributeError:
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return utcnow.override_time
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if with_timezone:
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return datetime.datetime.now(tz=iso8601.iso8601.UTC)
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return datetime.datetime.utcnow()
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@removals.remove(
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message="use datetime.datetime.utcfromtimestamp().isoformat()",
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version="1.6",
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removal_version="?",
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)
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def iso8601_from_timestamp(timestamp, microsecond=False):
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"""Returns an iso8601 formatted date from timestamp.
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.. deprecated:: > 1.5.0
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Use :func:`datetime.datetime.utcfromtimestamp` and
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:func:`datetime.datetime.isoformat` instead.
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"""
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return isotime(datetime.datetime.utcfromtimestamp(timestamp), microsecond)
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utcnow.override_time = None
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def set_time_override(override_time=None):
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"""Overrides utils.utcnow.
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Make it return a constant time or a list thereof, one at a time.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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:param override_time: datetime instance or list thereof. If not
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given, defaults to the current UTC time.
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"""
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utcnow.override_time = override_time or datetime.datetime.utcnow()
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def advance_time_delta(timedelta):
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"""Advance overridden time using a datetime.timedelta.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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"""
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assert utcnow.override_time is not None
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try:
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for dt in utcnow.override_time:
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dt += timedelta
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except TypeError:
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utcnow.override_time += timedelta
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def advance_time_seconds(seconds):
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"""Advance overridden time by seconds.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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"""
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advance_time_delta(datetime.timedelta(0, seconds))
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def clear_time_override():
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"""Remove the overridden time.
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See :py:class:`oslo_utils.fixture.TimeFixture`.
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"""
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utcnow.override_time = None
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def marshall_now(now=None):
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"""Make an rpc-safe datetime with microseconds."""
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if not now:
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now = utcnow()
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d = dict(day=now.day, month=now.month, year=now.year, hour=now.hour,
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minute=now.minute, second=now.second,
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microsecond=now.microsecond)
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if now.tzinfo:
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d['tzname'] = now.tzinfo.tzname(None)
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return d
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def unmarshall_time(tyme):
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"""Unmarshall a datetime dict."""
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# NOTE(ihrachys): datetime does not support leap seconds,
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# so the best thing we can do for now is dropping them
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# http://bugs.python.org/issue23574
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second = min(tyme['second'], _MAX_DATETIME_SEC)
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dt = datetime.datetime(day=tyme['day'],
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month=tyme['month'],
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year=tyme['year'],
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hour=tyme['hour'],
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minute=tyme['minute'],
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second=second,
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microsecond=tyme['microsecond'])
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tzname = tyme.get('tzname')
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if tzname:
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tzinfo = timezone(tzname)
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dt = tzinfo.localize(dt)
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return dt
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def delta_seconds(before, after):
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"""Return the difference between two timing objects.
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Compute the difference in seconds between two date, time, or
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datetime objects (as a float, to microsecond resolution).
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"""
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delta = after - before
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return total_seconds(delta)
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def total_seconds(delta):
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"""Return the total seconds of datetime.timedelta object.
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Compute total seconds of datetime.timedelta, datetime.timedelta
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doesn't have method total_seconds in Python2.6, calculate it manually.
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"""
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try:
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return delta.total_seconds()
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except AttributeError:
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return ((delta.days * 24 * 3600) + delta.seconds +
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float(delta.microseconds) / (10 ** 6))
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def is_soon(dt, window):
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"""Determines if time is going to happen in the next window seconds.
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:param dt: the time
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:param window: minimum seconds to remain to consider the time not soon
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:return: True if expiration is within the given duration
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"""
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soon = (utcnow() + datetime.timedelta(seconds=window))
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return normalize_time(dt) <= soon
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class Split(object):
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"""A *immutable* stopwatch split.
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See: http://en.wikipedia.org/wiki/Stopwatch for what this is/represents.
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"""
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__slots__ = ['_elapsed', '_length']
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def __init__(self, elapsed, length):
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self._elapsed = elapsed
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self._length = length
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@property
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def elapsed(self):
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"""Duration from stopwatch start."""
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return self._elapsed
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@property
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def length(self):
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"""Seconds from last split (or the elapsed time if no prior split)."""
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return self._length
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def __repr__(self):
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r = reflection.get_class_name(self, fully_qualified=False)
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r += "(elapsed=%s, length=%s)" % (self._elapsed, self._length)
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return r
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class StopWatch(object):
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"""A simple timer/stopwatch helper class.
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Inspired by: apache-commons-lang java stopwatch.
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Not thread-safe (when a single watch is mutated by multiple threads at
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the same time). Thread-safe when used by a single thread (not shared) or
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when operations are performed in a thread-safe manner on these objects by
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wrapping those operations with locks.
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It will try to use ``time.monotonic`` and then attempt to use the
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`monotonic`_ pypi library and then fallback to using the non-monotonic
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``time.time``.
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.. _monotonic: https://pypi.python.org/pypi/monotonic/
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"""
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_STARTED = 'STARTED'
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_STOPPED = 'STOPPED'
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def __init__(self, duration=None):
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if duration is not None and duration < 0:
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raise ValueError("Duration must be greater or equal to"
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" zero and not %s" % duration)
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self._duration = duration
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self._started_at = None
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self._stopped_at = None
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self._state = None
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self._splits = []
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def start(self):
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"""Starts the watch (if not already started).
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NOTE(harlowja): resets any splits previously captured (if any).
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"""
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if self._state == self._STARTED:
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return self
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self._started_at = now()
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self._stopped_at = None
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self._state = self._STARTED
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self._splits = []
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return self
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@property
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def splits(self):
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"""Accessor to all/any splits that have been captured."""
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return tuple(self._splits)
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def split(self):
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"""Captures a split/elapsed since start time (and doesn't stop)."""
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if self._state == self._STARTED:
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elapsed = self.elapsed()
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if self._splits:
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length = self._delta_seconds(self._splits[-1].elapsed, elapsed)
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else:
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length = elapsed
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self._splits.append(Split(elapsed, length))
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return self._splits[-1]
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else:
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raise RuntimeError("Can not create a split time of a stopwatch"
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" if it has not been started or if it has been"
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" stopped")
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def restart(self):
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"""Restarts the watch from a started/stopped state."""
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if self._state == self._STARTED:
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self.stop()
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self.start()
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return self
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@staticmethod
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def _delta_seconds(earlier, later):
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# Uses max to avoid the delta/time going backwards (and thus negative).
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return max(0.0, later - earlier)
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def elapsed(self, maximum=None):
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"""Returns how many seconds have elapsed."""
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if self._state not in (self._STARTED, self._STOPPED):
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raise RuntimeError("Can not get the elapsed time of a stopwatch"
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" if it has not been started/stopped")
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if self._state == self._STOPPED:
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elapsed = self._delta_seconds(self._started_at, self._stopped_at)
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else:
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elapsed = self._delta_seconds(self._started_at, now())
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if maximum is not None and elapsed > maximum:
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elapsed = max(0.0, maximum)
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return elapsed
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def __enter__(self):
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"""Starts the watch."""
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self.start()
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return self
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def __exit__(self, type, value, traceback):
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"""Stops the watch (ignoring errors if stop fails)."""
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try:
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self.stop()
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except RuntimeError:
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pass
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def leftover(self, return_none=False):
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"""Returns how many seconds are left until the watch expires.
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:param return_none: when ``True`` instead of raising a ``RuntimeError``
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when no duration has been set this call will
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return ``None`` instead.
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:type return_none: boolean
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"""
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if self._state != self._STARTED:
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raise RuntimeError("Can not get the leftover time of a stopwatch"
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" that has not been started")
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if self._duration is None:
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if not return_none:
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raise RuntimeError("Can not get the leftover time of a watch"
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" that has no duration")
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return None
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return max(0.0, self._duration - self.elapsed())
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def expired(self):
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"""Returns if the watch has expired (ie, duration provided elapsed)."""
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if self._state not in (self._STARTED, self._STOPPED):
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raise RuntimeError("Can not check if a stopwatch has expired"
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" if it has not been started/stopped")
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if self._duration is None:
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return False
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return self.elapsed() > self._duration
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def has_started(self):
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return self._state == self._STARTED
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def has_stopped(self):
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return self._state == self._STOPPED
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def resume(self):
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"""Resumes the watch from a stopped state."""
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if self._state == self._STOPPED:
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self._state = self._STARTED
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return self
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else:
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raise RuntimeError("Can not resume a stopwatch that has not been"
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" stopped")
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def stop(self):
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"""Stops the watch."""
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if self._state == self._STOPPED:
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return self
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if self._state != self._STARTED:
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raise RuntimeError("Can not stop a stopwatch that has not been"
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" started")
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self._stopped_at = now()
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self._state = self._STOPPED
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return self
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