Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.
This commit is contained in:
rembo10
2022-01-14 10:38:03 +05:30
parent 9a7006ad14
commit ab4dd18be4
813 changed files with 146338 additions and 65753 deletions

682
lib/tempora/__init__.py Normal file
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"Objects and routines pertaining to date and time (tempora)"
import datetime
import time
import re
import numbers
import functools
import warnings
import contextlib
from jaraco.functools import once
class Parser:
"""
*deprecated*
Datetime parser: parses a date-time string using multiple possible
formats.
>>> p = Parser(('%H%M', '%H:%M'))
>>> tuple(p.parse('1319'))
(1900, 1, 1, 13, 19, 0, 0, 1, -1)
>>> dateParser = Parser(('%m/%d/%Y', '%Y-%m-%d', '%d-%b-%Y'))
>>> tuple(dateParser.parse('2003-12-20'))
(2003, 12, 20, 0, 0, 0, 5, 354, -1)
>>> tuple(dateParser.parse('16-Dec-1994'))
(1994, 12, 16, 0, 0, 0, 4, 350, -1)
>>> tuple(dateParser.parse('5/19/2003'))
(2003, 5, 19, 0, 0, 0, 0, 139, -1)
>>> dtParser = Parser(('%Y-%m-%d %H:%M:%S', '%a %b %d %H:%M:%S %Y'))
>>> tuple(dtParser.parse('2003-12-20 19:13:26'))
(2003, 12, 20, 19, 13, 26, 5, 354, -1)
>>> tuple(dtParser.parse('Tue Jan 20 16:19:33 2004'))
(2004, 1, 20, 16, 19, 33, 1, 20, -1)
Be forewarned, a ValueError will be raised if more than one format
matches:
>>> Parser(('%H%M', '%H%M%S')).parse('732')
Traceback (most recent call last):
...
ValueError: More than one format string matched target 732.
>>> Parser(('%H',)).parse('22:21')
Traceback (most recent call last):
...
ValueError: No format strings matched the target 22:21.
"""
formats = ('%m/%d/%Y', '%m/%d/%y', '%Y-%m-%d', '%d-%b-%Y', '%d-%b-%y')
"some common default formats"
def __init__(self, formats=None):
warnings.warn("Use dateutil.parser", DeprecationWarning)
if formats:
self.formats = formats
def parse(self, target):
self.target = target
results = tuple(filter(None, map(self._parse, self.formats)))
del self.target
if not results:
tmpl = "No format strings matched the target {target}."
raise ValueError(tmpl.format(**locals()))
if not len(results) == 1:
tmpl = "More than one format string matched target {target}."
raise ValueError(tmpl.format(**locals()))
return results[0]
def _parse(self, format):
try:
result = time.strptime(self.target, format)
except ValueError:
result = False
return result
# some useful constants
osc_per_year = 290091329207984000
"""
mean vernal equinox year expressed in oscillations of atomic cesium at the
year 2000 (see http://webexhibits.org/calendars/timeline.html for more info).
"""
osc_per_second = 9192631770
seconds_per_second = 1
seconds_per_year = 31556940
seconds_per_minute = 60
minutes_per_hour = 60
hours_per_day = 24
seconds_per_hour = seconds_per_minute * minutes_per_hour
seconds_per_day = seconds_per_hour * hours_per_day
days_per_year = seconds_per_year / seconds_per_day
thirty_days = datetime.timedelta(days=30)
# these values provide useful averages
six_months = datetime.timedelta(days=days_per_year / 2)
seconds_per_month = seconds_per_year / 12
hours_per_month = hours_per_day * days_per_year / 12
@once
def _needs_year_help():
"""
Some versions of Python render %Y with only three characters :(
https://bugs.python.org/issue39103
"""
return len(datetime.date(900, 1, 1).strftime('%Y')) != 4
def ensure_datetime(ob):
"""
Given a datetime or date or time object from the ``datetime``
module, always return a datetime using default values.
"""
if isinstance(ob, datetime.datetime):
return ob
date = time = ob
if isinstance(ob, datetime.date):
time = datetime.time()
if isinstance(ob, datetime.time):
date = datetime.date(1900, 1, 1)
return datetime.datetime.combine(date, time)
def strftime(fmt, t):
"""
Portable strftime.
In the stdlib, strftime has `known portability problems
<https://bugs.python.org/issue13305>`_. This function
aims to smooth over those issues and provide a
consistent experience across the major platforms.
>>> strftime('%Y', datetime.datetime(1890, 1, 1))
'1890'
>>> strftime('%Y', datetime.datetime(900, 1, 1))
'0900'
Supports time.struct_time, tuples, and datetime.datetime objects.
>>> strftime('%Y-%m-%d', (1976, 5, 7))
'1976-05-07'
Also supports date objects
>>> strftime('%Y', datetime.date(1976, 5, 7))
'1976'
Also supports milliseconds using %s.
>>> strftime('%s', datetime.time(microsecond=20000))
'020'
Also supports microseconds (3 digits) using %µ
>>> strftime('%µ', datetime.time(microsecond=123456))
'456'
Historically, %u was used for microseconds, but now
it honors the value rendered by stdlib.
>>> strftime('%u', datetime.date(1976, 5, 7))
'5'
Also supports microseconds (6 digits) using %f
>>> strftime('%f', datetime.time(microsecond=23456))
'023456'
Even supports time values on date objects (discouraged):
>>> strftime('%f', datetime.date(1976, 1, 1))
'000000'
>>> strftime('%µ', datetime.date(1976, 1, 1))
'000'
>>> strftime('%s', datetime.date(1976, 1, 1))
'000'
And vice-versa:
>>> strftime('%Y', datetime.time())
'1900'
"""
if isinstance(t, (time.struct_time, tuple)):
t = datetime.datetime(*t[:6])
t = ensure_datetime(t)
subs = (
('%s', '%03d' % (t.microsecond // 1000)),
('%µ', '%03d' % (t.microsecond % 1000)),
)
if _needs_year_help(): # pragma: nocover
subs += (('%Y', '%04d' % t.year),)
def doSub(s, sub):
return s.replace(*sub)
def doSubs(s):
return functools.reduce(doSub, subs, s)
fmt = '%%'.join(map(doSubs, fmt.split('%%')))
return t.strftime(fmt)
def datetime_mod(dt, period, start=None):
"""
Find the time which is the specified date/time truncated to the time delta
relative to the start date/time.
By default, the start time is midnight of the same day as the specified
date/time.
>>> datetime_mod(datetime.datetime(2004, 1, 2, 3),
... datetime.timedelta(days = 1.5),
... start = datetime.datetime(2004, 1, 1))
datetime.datetime(2004, 1, 1, 0, 0)
>>> datetime_mod(datetime.datetime(2004, 1, 2, 13),
... datetime.timedelta(days = 1.5),
... start = datetime.datetime(2004, 1, 1))
datetime.datetime(2004, 1, 2, 12, 0)
>>> datetime_mod(datetime.datetime(2004, 1, 2, 13),
... datetime.timedelta(days = 7),
... start = datetime.datetime(2004, 1, 1))
datetime.datetime(2004, 1, 1, 0, 0)
>>> datetime_mod(datetime.datetime(2004, 1, 10, 13),
... datetime.timedelta(days = 7),
... start = datetime.datetime(2004, 1, 1))
datetime.datetime(2004, 1, 8, 0, 0)
"""
if start is None:
# use midnight of the same day
start = datetime.datetime.combine(dt.date(), datetime.time())
# calculate the difference between the specified time and the start date.
delta = dt - start
# now aggregate the delta and the period into microseconds
# Use microseconds because that's the highest precision of these time
# pieces. Also, using microseconds ensures perfect precision (no floating
# point errors).
def get_time_delta_microseconds(td):
return (td.days * seconds_per_day + td.seconds) * 1000000 + td.microseconds
delta, period = map(get_time_delta_microseconds, (delta, period))
offset = datetime.timedelta(microseconds=delta % period)
# the result is the original specified time minus the offset
result = dt - offset
return result
def datetime_round(dt, period, start=None):
"""
Find the nearest even period for the specified date/time.
>>> datetime_round(datetime.datetime(2004, 11, 13, 8, 11, 13),
... datetime.timedelta(hours = 1))
datetime.datetime(2004, 11, 13, 8, 0)
>>> datetime_round(datetime.datetime(2004, 11, 13, 8, 31, 13),
... datetime.timedelta(hours = 1))
datetime.datetime(2004, 11, 13, 9, 0)
>>> datetime_round(datetime.datetime(2004, 11, 13, 8, 30),
... datetime.timedelta(hours = 1))
datetime.datetime(2004, 11, 13, 9, 0)
"""
result = datetime_mod(dt, period, start)
if abs(dt - result) >= period // 2:
result += period
return result
def get_nearest_year_for_day(day):
"""
Returns the nearest year to now inferred from a Julian date.
>>> freezer = getfixture('freezer')
>>> freezer.move_to('2019-05-20')
>>> get_nearest_year_for_day(20)
2019
>>> get_nearest_year_for_day(340)
2018
>>> freezer.move_to('2019-12-15')
>>> get_nearest_year_for_day(20)
2020
"""
now = time.gmtime()
result = now.tm_year
# if the day is far greater than today, it must be from last year
if day - now.tm_yday > 365 // 2:
result -= 1
# if the day is far less than today, it must be for next year.
if now.tm_yday - day > 365 // 2:
result += 1
return result
def gregorian_date(year, julian_day):
"""
Gregorian Date is defined as a year and a julian day (1-based
index into the days of the year).
>>> gregorian_date(2007, 15)
datetime.date(2007, 1, 15)
"""
result = datetime.date(year, 1, 1)
result += datetime.timedelta(days=julian_day - 1)
return result
def get_period_seconds(period):
"""
return the number of seconds in the specified period
>>> get_period_seconds('day')
86400
>>> get_period_seconds(86400)
86400
>>> get_period_seconds(datetime.timedelta(hours=24))
86400
>>> get_period_seconds('day + os.system("rm -Rf *")')
Traceback (most recent call last):
...
ValueError: period not in (second, minute, hour, day, month, year)
"""
if isinstance(period, str):
try:
name = 'seconds_per_' + period.lower()
result = globals()[name]
except KeyError:
msg = "period not in (second, minute, hour, day, month, year)"
raise ValueError(msg)
elif isinstance(period, numbers.Number):
result = period
elif isinstance(period, datetime.timedelta):
result = period.days * get_period_seconds('day') + period.seconds
else:
raise TypeError('period must be a string or integer')
return result
def get_date_format_string(period):
"""
For a given period (e.g. 'month', 'day', or some numeric interval
such as 3600 (in secs)), return the format string that can be
used with strftime to format that time to specify the times
across that interval, but no more detailed.
For example,
>>> get_date_format_string('month')
'%Y-%m'
>>> get_date_format_string(3600)
'%Y-%m-%d %H'
>>> get_date_format_string('hour')
'%Y-%m-%d %H'
>>> get_date_format_string(None)
Traceback (most recent call last):
...
TypeError: period must be a string or integer
>>> get_date_format_string('garbage')
Traceback (most recent call last):
...
ValueError: period not in (second, minute, hour, day, month, year)
"""
# handle the special case of 'month' which doesn't have
# a static interval in seconds
if isinstance(period, str) and period.lower() == 'month':
return '%Y-%m'
file_period_secs = get_period_seconds(period)
format_pieces = ('%Y', '-%m-%d', ' %H', '-%M', '-%S')
seconds_per_second = 1
intervals = (
seconds_per_year,
seconds_per_day,
seconds_per_hour,
seconds_per_minute,
seconds_per_second,
)
mods = list(map(lambda interval: file_period_secs % interval, intervals))
format_pieces = format_pieces[: mods.index(0) + 1]
return ''.join(format_pieces)
def divide_timedelta_float(td, divisor):
"""
Divide a timedelta by a float value
>>> one_day = datetime.timedelta(days=1)
>>> half_day = datetime.timedelta(days=.5)
>>> divide_timedelta_float(one_day, 2.0) == half_day
True
>>> divide_timedelta_float(one_day, 2) == half_day
True
"""
warnings.warn("Use native division", DeprecationWarning)
return td / divisor
def calculate_prorated_values():
"""
>>> monkeypatch = getfixture('monkeypatch')
>>> import builtins
>>> monkeypatch.setattr(builtins, 'input', lambda prompt: '3/hour')
>>> calculate_prorated_values()
per minute: 0.05
per hour: 3.0
per day: 72.0
per month: 2191.454166666667
per year: 26297.45
"""
rate = input("Enter the rate (3/hour, 50/month)> ")
for period, value in _prorated_values(rate):
print("per {period}: {value}".format(**locals()))
def _prorated_values(rate):
"""
Given a rate (a string in units per unit time), and return that same
rate for various time periods.
>>> for period, value in _prorated_values('20/hour'):
... print('{period}: {value:0.3f}'.format(**locals()))
minute: 0.333
hour: 20.000
day: 480.000
month: 14609.694
year: 175316.333
"""
res = re.match(r'(?P<value>[\d.]+)/(?P<period>\w+)$', rate).groupdict()
value = float(res['value'])
value_per_second = value / get_period_seconds(res['period'])
for period in ('minute', 'hour', 'day', 'month', 'year'):
period_value = value_per_second * get_period_seconds(period)
yield period, period_value
def parse_timedelta(str):
"""
Take a string representing a span of time and parse it to a time delta.
Accepts any string of comma-separated numbers each with a unit indicator.
>>> parse_timedelta('1 day')
datetime.timedelta(days=1)
>>> parse_timedelta('1 day, 30 seconds')
datetime.timedelta(days=1, seconds=30)
>>> parse_timedelta('47.32 days, 20 minutes, 15.4 milliseconds')
datetime.timedelta(days=47, seconds=28848, microseconds=15400)
Supports weeks, months, years
>>> parse_timedelta('1 week')
datetime.timedelta(days=7)
>>> parse_timedelta('1 year, 1 month')
datetime.timedelta(days=395, seconds=58685)
Note that months and years strict intervals, not aligned
to a calendar:
>>> now = datetime.datetime.now()
>>> later = now + parse_timedelta('1 year')
>>> diff = later.replace(year=now.year) - now
>>> diff.seconds
20940
>>> parse_timedelta('14 seconds foo')
Traceback (most recent call last):
...
ValueError: Unexpected 'foo'
Supports abbreviations:
>>> parse_timedelta('1s')
datetime.timedelta(seconds=1)
>>> parse_timedelta('1sec')
datetime.timedelta(seconds=1)
>>> parse_timedelta('5min1sec')
datetime.timedelta(seconds=301)
>>> parse_timedelta('1 ms')
datetime.timedelta(microseconds=1000)
>>> parse_timedelta('1 µs')
datetime.timedelta(microseconds=1)
>>> parse_timedelta('1 us')
datetime.timedelta(microseconds=1)
And supports the common colon-separated duration:
>>> parse_timedelta('14:00:35.362')
datetime.timedelta(seconds=50435, microseconds=362000)
TODO: Should this be 14 hours or 14 minutes?
>>> parse_timedelta('14:00')
datetime.timedelta(seconds=50400)
>>> parse_timedelta('14:00 minutes')
Traceback (most recent call last):
...
ValueError: Cannot specify units with composite delta
Nanoseconds get rounded to the nearest microsecond:
>>> parse_timedelta('600 ns')
datetime.timedelta(microseconds=1)
>>> parse_timedelta('.002 µs, 499 ns')
datetime.timedelta(microseconds=1)
"""
return _parse_timedelta_nanos(str).resolve()
def _parse_timedelta_nanos(str):
parts = re.finditer(r'(?P<value>[\d.:]+)\s?(?P<unit>[^\W\d_]+)?', str)
chk_parts = _check_unmatched(parts, str)
deltas = map(_parse_timedelta_part, chk_parts)
return sum(deltas, _Saved_NS())
def _check_unmatched(matches, text):
"""
Ensure no words appear in unmatched text.
"""
def check_unmatched(unmatched):
found = re.search(r'\w+', unmatched)
if found:
raise ValueError(f"Unexpected {found.group(0)!r}")
pos = 0
for match in matches:
check_unmatched(text[pos : match.start()])
yield match
pos = match.end()
check_unmatched(text[match.end() :])
_unit_lookup = {
'µs': 'microsecond',
'µsec': 'microsecond',
'us': 'microsecond',
'usec': 'microsecond',
'micros': 'microsecond',
'ms': 'millisecond',
'msec': 'millisecond',
'millis': 'millisecond',
's': 'second',
'sec': 'second',
'h': 'hour',
'hr': 'hour',
'm': 'minute',
'min': 'minute',
'w': 'week',
'wk': 'week',
'd': 'day',
'ns': 'nanosecond',
'nsec': 'nanosecond',
'nanos': 'nanosecond',
}
def _resolve_unit(raw_match):
if raw_match is None:
return 'second'
text = raw_match.lower()
return _unit_lookup.get(text, text)
def _parse_timedelta_composite(raw_value, unit):
if unit != 'seconds':
raise ValueError("Cannot specify units with composite delta")
values = raw_value.split(':')
units = 'hours', 'minutes', 'seconds'
composed = ' '.join(f'{value} {unit}' for value, unit in zip(values, units))
return _parse_timedelta_nanos(composed)
def _parse_timedelta_part(match):
unit = _resolve_unit(match.group('unit'))
if not unit.endswith('s'):
unit += 's'
raw_value = match.group('value')
if ':' in raw_value:
return _parse_timedelta_composite(raw_value, unit)
value = float(raw_value)
if unit == 'months':
unit = 'years'
value = value / 12
if unit == 'years':
unit = 'days'
value = value * days_per_year
return _Saved_NS.derive(unit, value)
class _Saved_NS:
"""
Bundle a timedelta with nanoseconds.
>>> _Saved_NS.derive('microseconds', .001)
_Saved_NS(td=datetime.timedelta(0), nanoseconds=1)
"""
td = datetime.timedelta()
nanoseconds = 0
multiplier = dict(
seconds=1000000000,
milliseconds=1000000,
microseconds=1000,
)
def __init__(self, **kwargs):
vars(self).update(kwargs)
@classmethod
def derive(cls, unit, value):
if unit == 'nanoseconds':
return _Saved_NS(nanoseconds=value)
res = _Saved_NS(td=datetime.timedelta(**{unit: value}))
with contextlib.suppress(KeyError):
res.nanoseconds = int(value * cls.multiplier[unit]) % 1000
return res
def __add__(self, other):
return _Saved_NS(
td=self.td + other.td, nanoseconds=self.nanoseconds + other.nanoseconds
)
def resolve(self):
"""
Resolve any nanoseconds into the microseconds field,
discarding any nanosecond resolution (but honoring partial
microseconds).
"""
addl_micros = round(self.nanoseconds / 1000)
return self.td + datetime.timedelta(microseconds=addl_micros)
def __repr__(self):
return f'_Saved_NS(td={self.td!r}, nanoseconds={self.nanoseconds!r})'
def divide_timedelta(td1, td2):
"""
Get the ratio of two timedeltas
>>> one_day = datetime.timedelta(days=1)
>>> one_hour = datetime.timedelta(hours=1)
>>> divide_timedelta(one_hour, one_day) == 1 / 24
True
"""
warnings.warn("Use native division", DeprecationWarning)
return td1 / td2
def date_range(start=None, stop=None, step=None):
"""
Much like the built-in function range, but works with dates
>>> range_items = date_range(
... datetime.datetime(2005,12,21),
... datetime.datetime(2005,12,25),
... )
>>> my_range = tuple(range_items)
>>> datetime.datetime(2005,12,21) in my_range
True
>>> datetime.datetime(2005,12,22) in my_range
True
>>> datetime.datetime(2005,12,25) in my_range
False
>>> from_now = date_range(stop=datetime.datetime(2099, 12, 31))
>>> next(from_now)
datetime.datetime(...)
"""
if step is None:
step = datetime.timedelta(days=1)
if start is None:
start = datetime.datetime.now()
while start < stop:
yield start
start += step

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"""
Classes for calling functions a schedule. Has time zone support.
For example, to run a job at 08:00 every morning in 'Asia/Calcutta':
>>> job = lambda: print("time is now", datetime.datetime())
>>> time = datetime.time(8, tzinfo=pytz.timezone('Asia/Calcutta'))
>>> cmd = PeriodicCommandFixedDelay.daily_at(time, job)
>>> sched = InvokeScheduler()
>>> sched.add(cmd)
>>> while True: # doctest: +SKIP
... sched.run_pending()
... time.sleep(.1)
"""
import datetime
import numbers
import abc
import bisect
import pytz
def now():
"""
Provide the current timezone-aware datetime.
A client may override this function to change the default behavior,
such as to use local time or timezone-naïve times.
"""
return datetime.datetime.utcnow().replace(tzinfo=pytz.utc)
def from_timestamp(ts):
"""
Convert a numeric timestamp to a timezone-aware datetime.
A client may override this function to change the default behavior,
such as to use local time or timezone-naïve times.
"""
return datetime.datetime.utcfromtimestamp(ts).replace(tzinfo=pytz.utc)
class DelayedCommand(datetime.datetime):
"""
A command to be executed after some delay (seconds or timedelta).
"""
@classmethod
def from_datetime(cls, other):
return cls(
other.year,
other.month,
other.day,
other.hour,
other.minute,
other.second,
other.microsecond,
other.tzinfo,
)
@classmethod
def after(cls, delay, target):
if not isinstance(delay, datetime.timedelta):
delay = datetime.timedelta(seconds=delay)
due_time = now() + delay
cmd = cls.from_datetime(due_time)
cmd.delay = delay
cmd.target = target
return cmd
@staticmethod
def _from_timestamp(input):
"""
If input is a real number, interpret it as a Unix timestamp
(seconds sinc Epoch in UTC) and return a timezone-aware
datetime object. Otherwise return input unchanged.
"""
if not isinstance(input, numbers.Real):
return input
return from_timestamp(input)
@classmethod
def at_time(cls, at, target):
"""
Construct a DelayedCommand to come due at `at`, where `at` may be
a datetime or timestamp.
"""
at = cls._from_timestamp(at)
cmd = cls.from_datetime(at)
cmd.delay = at - now()
cmd.target = target
return cmd
def due(self):
return now() >= self
class PeriodicCommand(DelayedCommand):
"""
Like a delayed command, but expect this command to run every delay
seconds.
"""
def _next_time(self):
"""
Add delay to self, localized
"""
return self._localize(self + self.delay)
@staticmethod
def _localize(dt):
"""
Rely on pytz.localize to ensure new result honors DST.
"""
try:
tz = dt.tzinfo
return tz.localize(dt.replace(tzinfo=None))
except AttributeError:
return dt
def next(self):
cmd = self.__class__.from_datetime(self._next_time())
cmd.delay = self.delay
cmd.target = self.target
return cmd
def __setattr__(self, key, value):
if key == 'delay' and not value > datetime.timedelta():
raise ValueError(
"A PeriodicCommand must have a positive, " "non-zero delay."
)
super(PeriodicCommand, self).__setattr__(key, value)
class PeriodicCommandFixedDelay(PeriodicCommand):
"""
Like a periodic command, but don't calculate the delay based on
the current time. Instead use a fixed delay following the initial
run.
"""
@classmethod
def at_time(cls, at, delay, target):
"""
>>> cmd = PeriodicCommandFixedDelay.at_time(0, 30, None)
>>> cmd.delay.total_seconds()
30.0
"""
at = cls._from_timestamp(at)
cmd = cls.from_datetime(at)
if isinstance(delay, numbers.Number):
delay = datetime.timedelta(seconds=delay)
cmd.delay = delay
cmd.target = target
return cmd
@classmethod
def daily_at(cls, at, target):
"""
Schedule a command to run at a specific time each day.
>>> from tempora import utc
>>> noon = utc.time(12, 0)
>>> cmd = PeriodicCommandFixedDelay.daily_at(noon, None)
>>> cmd.delay.total_seconds()
86400.0
"""
daily = datetime.timedelta(days=1)
# convert when to the next datetime matching this time
when = datetime.datetime.combine(datetime.date.today(), at)
when -= daily
while when < now():
when += daily
return cls.at_time(cls._localize(when), daily, target)
class Scheduler:
"""
A rudimentary abstract scheduler accepting DelayedCommands
and dispatching them on schedule.
"""
def __init__(self):
self.queue = []
def add(self, command):
assert isinstance(command, DelayedCommand)
bisect.insort(self.queue, command)
def run_pending(self):
while self.queue:
command = self.queue[0]
if not command.due():
break
self.run(command)
if isinstance(command, PeriodicCommand):
self.add(command.next())
del self.queue[0]
@abc.abstractmethod
def run(self, command):
"""
Run the command
"""
class InvokeScheduler(Scheduler):
"""
Command targets are functions to be invoked on schedule.
"""
def run(self, command):
command.target()
class CallbackScheduler(Scheduler):
"""
Command targets are passed to a dispatch callable on schedule.
"""
def __init__(self, dispatch):
super().__init__()
self.dispatch = dispatch
def run(self, command):
self.dispatch(command.target)

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import time
import random
import datetime
from unittest import mock
import pytest
import pytz
import freezegun
from tempora import schedule
do_nothing = type(None)
def test_delayed_command_order():
"""
delayed commands should be sorted by delay time
"""
delays = [random.randint(0, 99) for x in range(5)]
cmds = sorted(
[schedule.DelayedCommand.after(delay, do_nothing) for delay in delays]
)
assert [c.delay.seconds for c in cmds] == sorted(delays)
def test_periodic_command_delay():
"A PeriodicCommand must have a positive, non-zero delay."
with pytest.raises(ValueError) as exc_info:
schedule.PeriodicCommand.after(0, None)
assert str(exc_info.value) == test_periodic_command_delay.__doc__
def test_periodic_command_fixed_delay():
"""
Test that we can construct a periodic command with a fixed initial
delay.
"""
fd = schedule.PeriodicCommandFixedDelay.at_time(
at=schedule.now(), delay=datetime.timedelta(seconds=2), target=lambda: None
)
assert fd.due() is True
assert fd.next().due() is False
class TestCommands:
def test_delayed_command_from_timestamp(self):
"""
Ensure a delayed command can be constructed from a timestamp.
"""
t = time.time()
schedule.DelayedCommand.at_time(t, do_nothing)
def test_command_at_noon(self):
"""
Create a periodic command that's run at noon every day.
"""
when = datetime.time(12, 0, tzinfo=pytz.utc)
cmd = schedule.PeriodicCommandFixedDelay.daily_at(when, target=None)
assert cmd.due() is False
next_cmd = cmd.next()
daily = datetime.timedelta(days=1)
day_from_now = schedule.now() + daily
two_days_from_now = day_from_now + daily
assert day_from_now < next_cmd < two_days_from_now
@pytest.mark.parametrize("hour", range(10, 14))
@pytest.mark.parametrize("tz_offset", (14, -14))
def test_command_at_noon_distant_local(self, hour, tz_offset):
"""
Run test_command_at_noon, but with the local timezone
more than 12 hours away from UTC.
"""
with freezegun.freeze_time(f"2020-01-10 {hour:02}:01", tz_offset=tz_offset):
self.test_command_at_noon()
class TestTimezones:
def test_alternate_timezone_west(self):
target_tz = pytz.timezone('US/Pacific')
target = schedule.now().astimezone(target_tz)
cmd = schedule.DelayedCommand.at_time(target, target=None)
assert cmd.due()
def test_alternate_timezone_east(self):
target_tz = pytz.timezone('Europe/Amsterdam')
target = schedule.now().astimezone(target_tz)
cmd = schedule.DelayedCommand.at_time(target, target=None)
assert cmd.due()
def test_daylight_savings(self):
"""
A command at 9am should always be 9am regardless of
a DST boundary.
"""
with freezegun.freeze_time('2018-03-10 08:00:00'):
target_tz = pytz.timezone('US/Eastern')
target_time = datetime.time(9, tzinfo=target_tz)
cmd = schedule.PeriodicCommandFixedDelay.daily_at(
target_time, target=lambda: None
)
def naive(dt):
return dt.replace(tzinfo=None)
assert naive(cmd) == datetime.datetime(2018, 3, 10, 9, 0, 0)
next_ = cmd.next()
assert naive(next_) == datetime.datetime(2018, 3, 11, 9, 0, 0)
assert next_ - cmd == datetime.timedelta(hours=23)
class TestScheduler:
def test_invoke_scheduler(self):
sched = schedule.InvokeScheduler()
target = mock.MagicMock()
cmd = schedule.DelayedCommand.after(0, target)
sched.add(cmd)
sched.run_pending()
target.assert_called_once()
assert not sched.queue
def test_callback_scheduler(self):
callback = mock.MagicMock()
sched = schedule.CallbackScheduler(callback)
target = mock.MagicMock()
cmd = schedule.DelayedCommand.after(0, target)
sched.add(cmd)
sched.run_pending()
callback.assert_called_once_with(target)
def test_periodic_command(self):
sched = schedule.InvokeScheduler()
target = mock.MagicMock()
before = datetime.datetime.utcnow()
cmd = schedule.PeriodicCommand.after(10, target)
sched.add(cmd)
sched.run_pending()
target.assert_not_called()
with freezegun.freeze_time(before + datetime.timedelta(seconds=15)):
sched.run_pending()
assert sched.queue
target.assert_called_once()
with freezegun.freeze_time(before + datetime.timedelta(seconds=25)):
sched.run_pending()
assert target.call_count == 2

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import datetime
import time
import contextlib
import os
from unittest import mock
import pytest
from tempora import timing
def test_IntervalGovernor():
"""
IntervalGovernor should prevent a function from being called more than
once per interval.
"""
func_under_test = mock.MagicMock()
# to look like a function, it needs a __name__ attribute
func_under_test.__name__ = 'func_under_test'
interval = datetime.timedelta(seconds=1)
governed = timing.IntervalGovernor(interval)(func_under_test)
governed('a')
governed('b')
governed(3, 'sir')
func_under_test.assert_called_once_with('a')
@pytest.fixture
def alt_tz(monkeypatch):
hasattr(time, 'tzset') or pytest.skip("tzset not available")
@contextlib.contextmanager
def change():
val = 'AEST-10AEDT-11,M10.5.0,M3.5.0'
with monkeypatch.context() as ctx:
ctx.setitem(os.environ, 'TZ', val)
time.tzset()
yield
time.tzset()
return change()
def test_Stopwatch_timezone_change(alt_tz):
"""
The stopwatch should provide a consistent duration even
if the timezone changes.
"""
watch = timing.Stopwatch()
with alt_tz:
assert abs(watch.split().total_seconds()) < 0.1

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lib/tempora/timing.py Normal file
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import datetime
import functools
import numbers
import time
import collections.abc
import contextlib
import jaraco.functools
class Stopwatch:
"""
A simple stopwatch which starts automatically.
>>> w = Stopwatch()
>>> _1_sec = datetime.timedelta(seconds=1)
>>> w.split() < _1_sec
True
>>> import time
>>> time.sleep(1.0)
>>> w.split() >= _1_sec
True
>>> w.stop() >= _1_sec
True
>>> w.reset()
>>> w.start()
>>> w.split() < _1_sec
True
It should be possible to launch the Stopwatch in a context:
>>> with Stopwatch() as watch:
... assert isinstance(watch.split(), datetime.timedelta)
In that case, the watch is stopped when the context is exited,
so to read the elapsed time:
>>> watch.elapsed
datetime.timedelta(...)
>>> watch.elapsed.seconds
0
"""
def __init__(self):
self.reset()
self.start()
def reset(self):
self.elapsed = datetime.timedelta(0)
with contextlib.suppress(AttributeError):
del self.start_time
def start(self):
self.start_time = datetime.datetime.utcnow()
def stop(self):
stop_time = datetime.datetime.utcnow()
self.elapsed += stop_time - self.start_time
del self.start_time
return self.elapsed
def split(self):
local_duration = datetime.datetime.utcnow() - self.start_time
return self.elapsed + local_duration
# context manager support
def __enter__(self):
self.start()
return self
def __exit__(self, exc_type, exc_value, traceback):
self.stop()
class IntervalGovernor:
"""
Decorate a function to only allow it to be called once per
min_interval. Otherwise, it returns None.
>>> gov = IntervalGovernor(30)
>>> gov.min_interval.total_seconds()
30.0
"""
def __init__(self, min_interval):
if isinstance(min_interval, numbers.Number):
min_interval = datetime.timedelta(seconds=min_interval)
self.min_interval = min_interval
self.last_call = None
def decorate(self, func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
allow = not self.last_call or self.last_call.split() > self.min_interval
if allow:
self.last_call = Stopwatch()
return func(*args, **kwargs)
return wrapper
__call__ = decorate
class Timer(Stopwatch):
"""
Watch for a target elapsed time.
>>> t = Timer(0.1)
>>> t.expired()
False
>>> __import__('time').sleep(0.15)
>>> t.expired()
True
"""
def __init__(self, target=float('Inf')):
self.target = self._accept(target)
super(Timer, self).__init__()
@staticmethod
def _accept(target):
"""
Accept None or ∞ or datetime or numeric for target
>>> Timer._accept(datetime.timedelta(seconds=30))
30.0
>>> Timer._accept(None)
inf
"""
if isinstance(target, datetime.timedelta):
target = target.total_seconds()
if target is None:
# treat None as infinite target
target = float('Inf')
return target
def expired(self):
return self.split().total_seconds() > self.target
class BackoffDelay(collections.abc.Iterator):
"""
Exponential backoff delay.
Useful for defining delays between retries. Consider for use
with ``jaraco.functools.retry_call`` as the cleanup.
Default behavior has no effect; a delay or jitter must
be supplied for the call to be non-degenerate.
>>> bd = BackoffDelay()
>>> bd()
>>> bd()
The following instance will delay 10ms for the first call,
20ms for the second, etc.
>>> bd = BackoffDelay(delay=0.01, factor=2)
>>> bd()
>>> bd()
Inspect and adjust the state of the delay anytime.
>>> bd.delay
0.04
>>> bd.delay = 0.01
Set limit to prevent the delay from exceeding bounds.
>>> bd = BackoffDelay(delay=0.01, factor=2, limit=0.015)
>>> bd()
>>> bd.delay
0.015
To reset the backoff, simply call ``.reset()``:
>>> bd.reset()
>>> bd.delay
0.01
Iterate on the object to retrieve/advance the delay values.
>>> next(bd)
0.01
>>> next(bd)
0.015
>>> import itertools
>>> tuple(itertools.islice(bd, 3))
(0.015, 0.015, 0.015)
Limit may be a callable taking a number and returning
the limited number.
>>> at_least_one = lambda n: max(n, 1)
>>> bd = BackoffDelay(delay=0.01, factor=2, limit=at_least_one)
>>> next(bd)
0.01
>>> next(bd)
1
Pass a jitter to add or subtract seconds to the delay.
>>> bd = BackoffDelay(jitter=0.01)
>>> next(bd)
0
>>> next(bd)
0.01
Jitter may be a callable. To supply a non-deterministic jitter
between -0.5 and 0.5, consider:
>>> import random
>>> jitter=functools.partial(random.uniform, -0.5, 0.5)
>>> bd = BackoffDelay(jitter=jitter)
>>> next(bd)
0
>>> 0 <= next(bd) <= 0.5
True
"""
delay = 0
factor = 1
"Multiplier applied to delay"
jitter = 0
"Number or callable returning extra seconds to add to delay"
@jaraco.functools.save_method_args
def __init__(self, delay=0, factor=1, limit=float('inf'), jitter=0):
self.delay = delay
self.factor = factor
if isinstance(limit, numbers.Number):
limit_ = limit
def limit(n):
return max(0, min(limit_, n))
self.limit = limit
if isinstance(jitter, numbers.Number):
jitter_ = jitter
def jitter():
return jitter_
self.jitter = jitter
def __call__(self):
time.sleep(next(self))
def __next__(self):
delay = self.delay
self.bump()
return delay
def __iter__(self):
return self
def bump(self):
self.delay = self.limit(self.delay * self.factor + self.jitter())
def reset(self):
saved = self._saved___init__
self.__init__(*saved.args, **saved.kwargs)

36
lib/tempora/utc.py Normal file
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"""
Facilities for common time operations in UTC.
Inspired by the `utc project <https://pypi.org/project/utc>`_.
>>> dt = now()
>>> dt == fromtimestamp(dt.timestamp())
True
>>> dt.tzinfo
datetime.timezone.utc
>>> from time import time as timestamp
>>> now().timestamp() - timestamp() < 0.1
True
>>> (now() - fromtimestamp(timestamp())).total_seconds() < 0.1
True
>>> datetime(2018, 6, 26, 0).tzinfo
datetime.timezone.utc
>>> time(0, 0).tzinfo
datetime.timezone.utc
"""
import datetime as std
import functools
__all__ = ['now', 'fromtimestamp', 'datetime', 'time']
now = functools.partial(std.datetime.now, std.timezone.utc)
fromtimestamp = functools.partial(std.datetime.fromtimestamp, tz=std.timezone.utc)
datetime = functools.partial(std.datetime, tzinfo=std.timezone.utc)
time = functools.partial(std.time, tzinfo=std.timezone.utc)