| # |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you under the Apache License, Version 2.0 (the |
| # "License"); you may not use this file except in compliance |
| # with the License. You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, |
| # software distributed under the License is distributed on an |
| # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| # KIND, either express or implied. See the License for the |
| # specific language governing permissions and limitations |
| # under the License. |
| from __future__ import annotations |
| |
| import datetime |
| from typing import Sequence |
| |
| from airflow.sensors.base import BaseSensorOperator |
| from airflow.triggers.temporal import DateTimeTrigger |
| from airflow.utils import timezone |
| from airflow.utils.context import Context |
| |
| |
| class DateTimeSensor(BaseSensorOperator): |
| """ |
| Waits until the specified datetime. |
| |
| A major advantage of this sensor is idempotence for the ``target_time``. |
| It handles some cases for which ``TimeSensor`` and ``TimeDeltaSensor`` are not suited. |
| |
| **Example** 1 : |
| If a task needs to wait for 11am on each ``execution_date``. Using |
| ``TimeSensor`` or ``TimeDeltaSensor``, all backfill tasks started at |
| 1am have to wait for 10 hours. This is unnecessary, e.g. a backfill |
| task with ``{{ ds }} = '1970-01-01'`` does not need to wait because |
| ``1970-01-01T11:00:00`` has already passed. |
| |
| **Example** 2 : |
| If a DAG is scheduled to run at 23:00 daily, but one of the tasks is |
| required to run at 01:00 next day, using ``TimeSensor`` will return |
| ``True`` immediately because 23:00 > 01:00. Instead, we can do this: |
| |
| .. code-block:: python |
| |
| DateTimeSensor( |
| task_id="wait_for_0100", |
| target_time="{{ next_execution_date.tomorrow().replace(hour=1) }}", |
| ) |
| |
| :param target_time: datetime after which the job succeeds. (templated) |
| """ |
| |
| template_fields: Sequence[str] = ("target_time",) |
| |
| def __init__(self, *, target_time: str | datetime.datetime, **kwargs) -> None: |
| super().__init__(**kwargs) |
| |
| # self.target_time can't be a datetime object as it is a template_field |
| if isinstance(target_time, datetime.datetime): |
| self.target_time = target_time.isoformat() |
| elif isinstance(target_time, str): |
| self.target_time = target_time |
| else: |
| raise TypeError( |
| f"Expected str or datetime.datetime type for target_time. Got {type(target_time)}" |
| ) |
| |
| def poke(self, context: Context) -> bool: |
| self.log.info("Checking if the time (%s) has come", self.target_time) |
| return timezone.utcnow() > timezone.parse(self.target_time) |
| |
| |
| class DateTimeSensorAsync(DateTimeSensor): |
| """ |
| Waits until the specified datetime occurs. |
| |
| Deferring itself to avoid taking up a worker slot while it is waiting. |
| It is a drop-in replacement for DateTimeSensor. |
| |
| :param target_time: datetime after which the job succeeds. (templated) |
| """ |
| |
| def execute(self, context: Context): |
| self.defer( |
| trigger=DateTimeTrigger(moment=timezone.parse(self.target_time)), |
| method_name="execute_complete", |
| ) |
| |
| def execute_complete(self, context, event=None): |
| """Callback for when the trigger fires - returns immediately.""" |
| return None |