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1# Licensed to the Apache Software Foundation (ASF) under one
2# or more contributor license agreements. See the NOTICE file
3# distributed with this work for additional information
4# regarding copyright ownership. The ASF licenses this file
5# to you under the Apache License, Version 2.0 (the
6# "License"); you may not use this file except in compliance
7# with the License. You may obtain a copy of the License at
8#
9# http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing,
12# software distributed under the License is distributed on an
13# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
14# KIND, either express or implied. See the License for the
15# specific language governing permissions and limitations
16# under the License.
17from __future__ import annotations
19import datetime
20from typing import TYPE_CHECKING, Any, Union
22from dateutil.relativedelta import relativedelta
23from pendulum import DateTime
25from airflow.exceptions import AirflowTimetableInvalid
26from airflow.timetables._cron import CronMixin
27from airflow.timetables.base import DagRunInfo, DataInterval, Timetable
28from airflow.utils.timezone import coerce_datetime, convert_to_utc, utcnow
30if TYPE_CHECKING:
31 from airflow.timetables.base import TimeRestriction
33Delta = Union[datetime.timedelta, relativedelta]
36class _DataIntervalTimetable(Timetable):
37 """Basis for timetable implementations that schedule data intervals.
39 This kind of timetable classes create periodic data intervals from an
40 underlying schedule representation (e.g. a cron expression, or a timedelta
41 instance), and schedule a DagRun at the end of each interval.
42 """
44 def _skip_to_latest(self, earliest: DateTime | None) -> DateTime:
45 """Bound the earliest time a run can be scheduled.
47 This is called when ``catchup=False``. See docstring of subclasses for
48 exact skipping behaviour of a schedule.
49 """
50 raise NotImplementedError()
52 def _align_to_next(self, current: DateTime) -> DateTime:
53 """Align given time to the next scheduled time.
55 For fixed schedules (e.g. every midnight); this finds the next time that
56 aligns to the declared time, if the given time does not align. If the
57 schedule is not fixed (e.g. every hour), the given time is returned.
58 """
59 raise NotImplementedError()
61 def _align_to_prev(self, current: DateTime) -> DateTime:
62 """Align given time to the previous scheduled time.
64 For fixed schedules (e.g. every midnight); this finds the prev time that
65 aligns to the declared time, if the given time does not align. If the
66 schedule is not fixed (e.g. every hour), the given time is returned.
68 It is not enough to use ``_get_prev(_align_to_next())``, since when a
69 DAG's schedule changes, this alternative would make the first scheduling
70 after the schedule change remain the same.
71 """
72 raise NotImplementedError()
74 def _get_next(self, current: DateTime) -> DateTime:
75 """Get the first schedule after the current time."""
76 raise NotImplementedError()
78 def _get_prev(self, current: DateTime) -> DateTime:
79 """Get the last schedule before the current time."""
80 raise NotImplementedError()
82 def next_dagrun_info(
83 self,
84 *,
85 last_automated_data_interval: DataInterval | None,
86 restriction: TimeRestriction,
87 ) -> DagRunInfo | None:
88 earliest = restriction.earliest
89 if not restriction.catchup:
90 earliest = self._skip_to_latest(earliest)
91 elif earliest is not None:
92 earliest = self._align_to_next(earliest)
93 if last_automated_data_interval is None:
94 # First run; schedule the run at the first available time matching
95 # the schedule, and retrospectively create a data interval for it.
96 if earliest is None:
97 return None
98 start = earliest
99 else: # There's a previous run.
100 # Alignment is needed when DAG has new schedule interval.
101 align_last_data_interval_end = self._align_to_prev(last_automated_data_interval.end)
102 if earliest is not None:
103 # Catchup is False or DAG has new start date in the future.
104 # Make sure we get the later one.
105 start = max(align_last_data_interval_end, earliest)
106 else:
107 # Data interval starts from the end of the previous interval.
108 start = align_last_data_interval_end
109 if restriction.latest is not None and start > restriction.latest:
110 return None
111 end = self._get_next(start)
112 return DagRunInfo.interval(start=start, end=end)
115class CronDataIntervalTimetable(CronMixin, _DataIntervalTimetable):
116 """Timetable that schedules data intervals with a cron expression.
118 This corresponds to ``schedule=<cron>``, where ``<cron>`` is either
119 a five/six-segment representation, or one of ``cron_presets``.
121 The implementation extends on croniter to add timezone awareness. This is
122 because croniter works only with naive timestamps, and cannot consider DST
123 when determining the next/previous time.
125 Don't pass ``@once`` in here; use ``OnceTimetable`` instead.
126 """
128 @classmethod
129 def deserialize(cls, data: dict[str, Any]) -> Timetable:
130 from airflow.serialization.serialized_objects import decode_timezone
132 return cls(data["expression"], decode_timezone(data["timezone"]))
134 def serialize(self) -> dict[str, Any]:
135 from airflow.serialization.serialized_objects import encode_timezone
137 return {"expression": self._expression, "timezone": encode_timezone(self._timezone)}
139 def _skip_to_latest(self, earliest: DateTime | None) -> DateTime:
140 """Bound the earliest time a run can be scheduled.
142 The logic is that we move start_date up until one period before, so the
143 current time is AFTER the period end, and the job can be created...
145 This is slightly different from the delta version at terminal values.
146 If the next schedule should start *right now*, we want the data interval
147 that start now, not the one that ends now.
148 """
149 current_time = coerce_datetime(utcnow())
150 last_start = self._get_prev(current_time)
151 next_start = self._get_next(last_start)
152 if next_start == current_time: # Current time is on interval boundary.
153 new_start = last_start
154 elif next_start > current_time: # Current time is between boundaries.
155 new_start = self._get_prev(last_start)
156 else:
157 raise AssertionError("next schedule shouldn't be earlier")
158 if earliest is None:
159 return new_start
160 return max(new_start, self._align_to_next(earliest))
162 def infer_manual_data_interval(self, *, run_after: DateTime) -> DataInterval:
163 # Get the last complete period before run_after, e.g. if a DAG run is
164 # scheduled at each midnight, the data interval of a manually triggered
165 # run at 1am 25th is between 0am 24th and 0am 25th.
166 end = self._align_to_prev(run_after)
167 return DataInterval(start=self._get_prev(end), end=end)
170class DeltaDataIntervalTimetable(_DataIntervalTimetable):
171 """Timetable that schedules data intervals with a time delta.
173 This corresponds to ``schedule=<delta>``, where ``<delta>`` is
174 either a ``datetime.timedelta`` or ``dateutil.relativedelta.relativedelta``
175 instance.
176 """
178 def __init__(self, delta: Delta) -> None:
179 self._delta = delta
181 @classmethod
182 def deserialize(cls, data: dict[str, Any]) -> Timetable:
183 from airflow.serialization.serialized_objects import decode_relativedelta
185 delta = data["delta"]
186 if isinstance(delta, dict):
187 return cls(decode_relativedelta(delta))
188 return cls(datetime.timedelta(seconds=delta))
190 def __eq__(self, other: Any) -> bool:
191 """
192 Return if the offsets match.
194 This is only for testing purposes and should not be relied on otherwise.
195 """
196 if not isinstance(other, DeltaDataIntervalTimetable):
197 return NotImplemented
198 return self._delta == other._delta
200 @property
201 def summary(self) -> str:
202 return str(self._delta)
204 def serialize(self) -> dict[str, Any]:
205 from airflow.serialization.serialized_objects import encode_relativedelta
207 delta: Any
208 if isinstance(self._delta, datetime.timedelta):
209 delta = self._delta.total_seconds()
210 else:
211 delta = encode_relativedelta(self._delta)
212 return {"delta": delta}
214 def validate(self) -> None:
215 now = datetime.datetime.now()
216 if (now + self._delta) <= now:
217 raise AirflowTimetableInvalid(f"schedule interval must be positive, not {self._delta!r}")
219 def _get_next(self, current: DateTime) -> DateTime:
220 return convert_to_utc(current + self._delta)
222 def _get_prev(self, current: DateTime) -> DateTime:
223 return convert_to_utc(current - self._delta)
225 def _align_to_next(self, current: DateTime) -> DateTime:
226 return current
228 def _align_to_prev(self, current: DateTime) -> DateTime:
229 return current
231 @staticmethod
232 def _relativedelta_in_seconds(delta: relativedelta) -> int:
233 return (
234 delta.years * 365 * 24 * 60 * 60
235 + delta.months * 30 * 24 * 60 * 60
236 + delta.days * 24 * 60 * 60
237 + delta.hours * 60 * 60
238 + delta.minutes * 60
239 + delta.seconds
240 )
242 def _round(self, dt: DateTime) -> DateTime:
243 """Round the given time to the nearest interval."""
244 if isinstance(self._delta, datetime.timedelta):
245 delta_in_seconds = self._delta.total_seconds()
246 else:
247 delta_in_seconds = self._relativedelta_in_seconds(self._delta)
248 dt_in_seconds = dt.timestamp()
249 rounded_dt = dt_in_seconds - (dt_in_seconds % delta_in_seconds)
250 return DateTime.fromtimestamp(rounded_dt, tz=dt.tzinfo)
252 def _skip_to_latest(self, earliest: DateTime | None) -> DateTime:
253 """Bound the earliest time a run can be scheduled.
255 The logic is that we move start_date up until one period before, so the
256 current time is AFTER the period end, and the job can be created...
258 This is slightly different from the cron version at terminal values.
259 """
260 round_current_time = self._round(coerce_datetime(utcnow()))
261 new_start = self._get_prev(round_current_time)
262 if earliest is None:
263 return new_start
264 return max(new_start, earliest)
266 def infer_manual_data_interval(self, run_after: DateTime) -> DataInterval:
267 return DataInterval(start=self._get_prev(run_after), end=run_after)