class acetz(tzinfo):
"""An implementation of datetime.tzinfo using the ZoneSpecifier class
from AceTime/tools.
"""
def __init__(self, zone_info: ZoneInfo):
self.zone_info = zone_info
self.zs = ZoneSpecifier(zone_info, use_python_transition=True)
def utcoffset(self, dt: Optional[datetime]) -> timedelta:
assert dt
info = self.zs.get_timezone_info_for_datetime(dt)
if not info:
raise Exception(f'Unknown timezone info for '
f'{dt.year:04}-{dt.month:02}-{dt.day:02} '
f'{dt.hour:02}:{dt.minute:02}:{dt.second:02}')
return timedelta(seconds=info.total_offset)
def dst(self, dt: Optional[datetime]) -> timedelta:
assert dt
offset_info = self.zs.get_timezone_info_for_datetime(dt)
if not offset_info:
raise Exception(f'Unknown timezone info for '
f'{dt.year:04}-{dt.month:02}-{dt.day:02} '
f'{dt.hour:02}:{dt.minute:02}:{dt.second:02}')
return timedelta(seconds=offset_info.dst_offset)
def tzname(self, dt: Optional[datetime]) -> str:
assert dt
offset_info = self.zs.get_timezone_info_for_datetime(dt)
if not offset_info:
raise Exception(f'Unknown timezone info for '
f'{dt.year:04}-{dt.month:02}-{dt.day:02} '
f'{dt.hour:02}:{dt.minute:02}:{dt.second:02}')
return offset_info.abbrev
def fromutc(self, dt: Optional[datetime]) -> datetime:
"""Override the default implementation in tzinfo which does not make
sense for acetz.
The 'dt' passed into this function from datetime.astimezone() is a weird
one: the components are in UTC time, but the timezone is the target
tzinfo, in other words, the same acetz as self.
Warning: Do NOT call dt.isoformat() from this method, because it causes
an infinite recursion as it tries to figure out the UTC offset. Use
{dt.date()} and {dt.time()} instead.
"""
if not isinstance(dt, datetime):
raise TypeError("fromutc() requires a datetime argument")
if dt.tzinfo is not self:
raise ValueError("dt.tzinfo is not self")
# Extract the epoch_seconds of the source 'dt'
assert dt is not None
utcdt = dt.replace(tzinfo=timezone.utc)
unix_seconds = int(utcdt.timestamp())
epoch_seconds = unix_seconds - SECONDS_SINCE_UNIX_EPOCH
# Search the transitions for the matching Transition
offset_info = self.zs.get_timezone_info_for_seconds(epoch_seconds)
if not offset_info:
raise ValueError(f"transition not found for {epoch_seconds}")
# Convert the date/time fields into local date/time and attach
# the current acetz object.
newutcdt = utcdt + timedelta(seconds=offset_info.total_offset)
newdt = newutcdt.replace(tzinfo=self, fold=offset_info.fold)
return newdt
def zone_specifier(self) -> ZoneSpecifier:
return self.zs
def main() -> None:
# Configure command line flags.
parser = argparse.ArgumentParser(description='Zone Agent.')
parser.add_argument(
'--viewing_months',
help='Number of months to use for calculations (12, 13, 14, 36)',
type=int,
default=14)
parser.add_argument('--transition',
help='Print the transition instead of timezone info',
action='store_true')
parser.add_argument('--debug',
help='Print debugging info',
action='store_true')
parser.add_argument(
'--in_place_transitions',
help='Use in-place Transition array to determine Active Transitions',
action="store_true",
default=True)
parser.add_argument('--no_in_place_transitions',
help='Disable --in_place_transitions',
action="store_false",
dest='in_place_transitions')
parser.add_argument('--optimize_candidates',
help='Optimize the candidate transitions',
action='store_true',
default=True)
parser.add_argument('--no_optimize_candidates',
help='Disable --optimize_candidates',
action='store_false',
dest='optimize_candidates')
parser.add_argument('--zone', help='Name of time zone', required=True)
parser.add_argument('--year', help='Year of interest', type=int)
parser.add_argument('--date', help='DateTime of interest')
args = parser.parse_args()
# Configure logging
logging.basicConfig(level=logging.INFO)
# Find the zone.
zone_info = cast(ZoneInfo, zone_infos.ZONE_INFO_MAP.get(args.zone))
if not zone_info:
logging.error("Zone '%s' not found", args.zone)
sys.exit(1)
# Create the ZoneSpecifier for zone
zone_specifier = ZoneSpecifier(
zone_info_data=zone_info,
viewing_months=args.viewing_months,
debug=args.debug,
in_place_transitions=args.in_place_transitions,
optimize_candidates=args.optimize_candidates)
if args.year:
zone_specifier.init_for_year(args.year)
if args.debug:
logging.info('==== Final matches and transitions')
zone_specifier.print_matches_and_transitions()
elif args.date:
dt: datetime = datetime.strptime(args.date, "%Y-%m-%dT%H:%M")
if args.transition:
transition = zone_specifier.get_transition_for_datetime(dt)
if transition:
logging.info(transition)
else:
logging.error('Transition not found')
else:
offset_info = zone_specifier.get_timezone_info_for_datetime(dt)
if not offset_info:
logging.info('Invalid time')
else:
logging.info(
'%s (%s)',
to_utc_string(
offset_info.utc_offset,
offset_info.dst_offset,
),
offset_info.abbrev,
)
else:
print("One of --year or --date must be provided")
sys.exit(1)
