airflow/sensors/weekday_sensor.py

# -*- coding: utf-8 -*-
#
# 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 airflow.contrib.utils.weekday import WeekDay
from airflow.sensors.base_sensor_operator import BaseSensorOperator
from airflow.utils import timezone
from airflow.utils.decorators import apply_defaults


class DayOfWeekSensor(BaseSensorOperator):
    """
    Waits until the first specified day of the week. For example, if the execution
    day of the task is '2018-12-22' (Saturday) and you pass 'FRIDAY', the task will wait
    until next Friday.

    **Example** (with single day): ::

        weekend_check = DayOfWeekSensor(
            task_id='weekend_check',
            week_day='Saturday',
            use_task_execution_day=True,
            dag=dag)

    **Example** (with multiple day using set): ::

        weekend_check = DayOfWeekSensor(
            task_id='weekend_check',
            week_day={'Saturday', 'Sunday'},
            use_task_execution_day=True,
            dag=dag)

    **Example** (with :class:`~airflow.contrib.utils.weekday.WeekDay` enum): ::

        # import WeekDay Enum
        from airflow.contrib.utils.weekday import WeekDay

        weekend_check = DayOfWeekSensor(
            task_id='weekend_check',
            week_day={WeekDay.SATURDAY, WeekDay.SUNDAY},
            use_task_execution_day=True,
            dag=dag)

    :param week_day: Day of the week to check (full name). Optionally, a set
        of days can also be provided using a set.
        Example values:

            * ``"MONDAY"``,
            * ``{"Saturday", "Sunday"}``
            * ``{WeekDay.TUESDAY}``
            * ``{WeekDay.SATURDAY, WeekDay.SUNDAY}``

    :type week_day: set or str or airflow.contrib.utils.weekday.WeekDay
    :param use_task_execution_day: If ``True``, uses task's execution day to compare
        with week_day. Execution Date is Useful for backfilling.
        If ``False``, uses system's day of the week. Useful when you
        don't want to run anything on weekdays on the system.
    :type use_task_execution_day: bool
    """

    @apply_defaults
    def __init__(self, week_day,
                 use_task_execution_day=False,
                 *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.week_day = week_day
        self.use_task_execution_day = use_task_execution_day
        if isinstance(self.week_day, str):
            self._week_day_num = {WeekDay.get_weekday_number(week_day_str=self.week_day)}
        elif isinstance(self.week_day, WeekDay):
            self._week_day_num = {self.week_day}
        elif isinstance(self.week_day, set):
            if all(isinstance(day, str) for day in self.week_day):
                self._week_day_num = {WeekDay.get_weekday_number(day) for day in week_day}
            elif all(isinstance(day, WeekDay) for day in self.week_day):
                self._week_day_num = self.week_day
        else:
            raise TypeError(
                'Unsupported Type for week_day parameter: {}. It should be one of str'
                ', set or Weekday enum type'.format(type(week_day)))

    def poke(self, context):
        self.log.info('Poking until weekday is in %s, Today is %s',
                      self.week_day,
                      WeekDay(timezone.utcnow().isoweekday()).name)
        if self.use_task_execution_day:
            return context['execution_date'].isoweekday() in self._week_day_num
        else:
            return timezone.utcnow().isoweekday() in self._week_day_num