211 lines
6.2 KiB
Python
211 lines
6.2 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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import iso8601
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import six
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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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def isotime(at=None, subsecond=False):
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"""Stringify time in ISO 8601 format."""
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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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def strtime(at=None, fmt=PERFECT_TIME_FORMAT):
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"""Returns formatted utcnow."""
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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_strtime(before).replace(tzinfo=None)
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else:
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before = before.replace(tzinfo=None)
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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_strtime(after).replace(tzinfo=None)
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else:
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after = after.replace(tzinfo=None)
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return after - utcnow() > datetime.timedelta(seconds=seconds)
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def utcnow_ts():
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"""Timestamp version of our utcnow function."""
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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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return int(time.time())
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return calendar.timegm(utcnow().timetuple())
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def utcnow():
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"""Overridable version of utils.utcnow."""
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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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return datetime.datetime.utcnow()
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def iso8601_from_timestamp(timestamp):
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"""Returns an iso8601 formatted date from timestamp."""
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return isotime(datetime.datetime.utcfromtimestamp(timestamp))
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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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: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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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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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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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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Note: tzinfo is stripped, but not required for relative times.
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"""
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if not now:
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now = utcnow()
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return 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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def unmarshall_time(tyme):
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"""Unmarshall a datetime dict."""
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return 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=tyme['second'],
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microsecond=tyme['microsecond'])
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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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