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101 lines
3.1 KiB
Python
101 lines
3.1 KiB
Python
"""Time utilities."""
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import datetime
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import logging
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from typing import Tuple
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from zoneinfo import ZoneInfoNotFoundError
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import pytz
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from tzlocal import get_localzone
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logger = logging.getLogger(__name__)
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def get_tz_modifiers(tz_name: str) -> Tuple[str, str, float]:
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seconds_offset = (
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datetime.datetime.now(pytz.timezone(tz_name)).utcoffset().total_seconds()
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)
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hours_offset = int(seconds_offset / 60 / 60)
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minutes_offset = int(seconds_offset / 60 - hours_offset * 60)
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hour_modifier = f"{hours_offset} hour"
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minute_modifier = f"{minutes_offset} minute"
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return hour_modifier, minute_modifier, seconds_offset
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def get_tomorrow_at_time(hour: int) -> datetime.datetime:
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"""Returns the datetime of the following day at 2am."""
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try:
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tomorrow = datetime.datetime.now(get_localzone()) + datetime.timedelta(days=1)
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except ZoneInfoNotFoundError:
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tomorrow = datetime.datetime.now(datetime.timezone.utc) + datetime.timedelta(
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days=1
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)
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logger.warning(
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"Using utc for maintenance due to missing or incorrect timezone set"
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)
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return tomorrow.replace(hour=hour, minute=0, second=0).astimezone(
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datetime.timezone.utc
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)
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def is_current_hour(timestamp: int) -> bool:
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"""Returns if timestamp is in the current UTC hour."""
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start_of_next_hour = (
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datetime.datetime.now(datetime.timezone.utc).replace(
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minute=0, second=0, microsecond=0
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)
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+ datetime.timedelta(hours=1)
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).timestamp()
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return timestamp < start_of_next_hour
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def get_dst_transitions(
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tz_name: str, start_time: float, end_time: float
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) -> list[tuple[float, float]]:
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"""
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Find DST transition points and return time periods with consistent offsets.
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Args:
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tz_name: Timezone name (e.g., 'America/New_York')
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start_time: Start timestamp (UTC)
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end_time: End timestamp (UTC)
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Returns:
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List of (period_start, period_end, seconds_offset) tuples representing
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continuous periods with the same UTC offset
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"""
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try:
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tz = pytz.timezone(tz_name)
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except pytz.UnknownTimeZoneError:
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# If timezone is invalid, return single period with no offset
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return [(start_time, end_time, 0)]
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periods = []
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current = start_time
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# Get initial offset
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dt = datetime.datetime.utcfromtimestamp(current).replace(tzinfo=pytz.UTC)
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local_dt = dt.astimezone(tz)
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prev_offset = local_dt.utcoffset().total_seconds()
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period_start = start_time
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# Check each day for offset changes
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while current <= end_time:
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dt = datetime.datetime.utcfromtimestamp(current).replace(tzinfo=pytz.UTC)
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local_dt = dt.astimezone(tz)
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current_offset = local_dt.utcoffset().total_seconds()
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if current_offset != prev_offset:
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# Found a transition - close previous period
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periods.append((period_start, current, prev_offset))
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period_start = current
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prev_offset = current_offset
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current += 86400 # Check daily
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# Add final period
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periods.append((period_start, end_time, prev_offset))
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return periods
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