mirror of
https://github.com/blakeblackshear/frigate.git
synced 2026-08-12 05:41:12 +03:00
Martin Weinelt
38cabaa6aa
This provides a helper to look up the correct timezone name independent of the casing of the given timezone name.
108 lines
3.4 KiB
Python
108 lines
3.4 KiB
Python
"""Time utilities."""
|
|
|
|
import datetime
|
|
import logging
|
|
from typing import Final
|
|
from zoneinfo import ZoneInfo, ZoneInfoNotFoundError, available_timezones
|
|
|
|
from tzlocal import get_localzone
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
TIMEZONE_CASEFOLD_INDEX: Final = {
|
|
timezone.casefold(): timezone for timezone in available_timezones()
|
|
}
|
|
|
|
|
|
def get_normalized_tz_name(tz_name: str) -> str:
|
|
tz = TIMEZONE_CASEFOLD_INDEX.get(tz_name.casefold())
|
|
if tz:
|
|
return tz
|
|
|
|
raise ValueError(f"Unknown timezone: {tz_name}")
|
|
|
|
|
|
def get_tz_modifiers(tz_name: str) -> tuple[str, str, float]:
|
|
seconds_offset = (
|
|
datetime.datetime.now(ZoneInfo(get_normalized_tz_name(tz_name)))
|
|
.utcoffset()
|
|
.total_seconds()
|
|
)
|
|
hours_offset = int(seconds_offset / 60 / 60)
|
|
minutes_offset = int(seconds_offset / 60 - hours_offset * 60)
|
|
hour_modifier = f"{hours_offset} hour"
|
|
minute_modifier = f"{minutes_offset} minute"
|
|
return hour_modifier, minute_modifier, seconds_offset
|
|
|
|
|
|
def get_tomorrow_at_time(hour: int) -> datetime.datetime:
|
|
"""Returns the datetime of the following day at 2am."""
|
|
try:
|
|
tomorrow = datetime.datetime.now(get_localzone()) + datetime.timedelta(days=1)
|
|
except (ValueError, ZoneInfoNotFoundError):
|
|
tomorrow = datetime.datetime.now(datetime.UTC) + datetime.timedelta(days=1)
|
|
logger.warning(
|
|
"Using utc for maintenance due to missing or incorrect timezone set"
|
|
)
|
|
|
|
return tomorrow.replace(hour=hour, minute=0, second=0).astimezone(datetime.UTC)
|
|
|
|
|
|
def is_current_hour(timestamp: int) -> bool:
|
|
"""Returns if timestamp is in the current UTC hour."""
|
|
start_of_next_hour = (
|
|
datetime.datetime.now(datetime.UTC).replace(minute=0, second=0, microsecond=0)
|
|
+ datetime.timedelta(hours=1)
|
|
).timestamp()
|
|
return timestamp < start_of_next_hour
|
|
|
|
|
|
def get_dst_transitions(
|
|
tz_name: str, start_time: float, end_time: float
|
|
) -> list[tuple[float, float, int]]:
|
|
"""
|
|
Find DST transition points and return time periods with consistent offsets.
|
|
|
|
Args:
|
|
tz_name: Timezone name (e.g., 'America/New_York')
|
|
start_time: Start timestamp (UTC)
|
|
end_time: End timestamp (UTC)
|
|
|
|
Returns:
|
|
List of (period_start, period_end, seconds_offset) tuples representing
|
|
continuous periods with the same UTC offset
|
|
"""
|
|
try:
|
|
tz = ZoneInfo(get_normalized_tz_name(tz_name))
|
|
except (ValueError, ZoneInfoNotFoundError):
|
|
# If timezone is invalid, return single period with no offset
|
|
return [(start_time, end_time, 0)]
|
|
|
|
periods = []
|
|
current = start_time
|
|
|
|
# Get initial offset
|
|
dt = datetime.datetime.fromtimestamp(current, tz=datetime.UTC)
|
|
local_dt = dt.astimezone(tz)
|
|
prev_offset = local_dt.utcoffset().total_seconds()
|
|
period_start = start_time
|
|
|
|
# Check each day for offset changes
|
|
while current <= end_time:
|
|
dt = datetime.datetime.fromtimestamp(current, tz=datetime.UTC)
|
|
local_dt = dt.astimezone(tz)
|
|
current_offset = local_dt.utcoffset().total_seconds()
|
|
|
|
if current_offset != prev_offset:
|
|
# Found a transition - close previous period
|
|
periods.append((period_start, current, prev_offset))
|
|
period_start = current
|
|
prev_offset = current_offset
|
|
|
|
current += 86400 # Check daily
|
|
|
|
# Add final period
|
|
periods.append((period_start, end_time, prev_offset))
|
|
|
|
return periods
|