Source code for airflow.operators.latest_only

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This module contains an operator to run downstream tasks only for the
latest scheduled DagRun
from typing import Dict, Iterable, Union

import pendulum

from airflow.operators.branch import BaseBranchOperator

[docs]class LatestOnlyOperator(BaseBranchOperator): """ Allows a workflow to skip tasks that are not running during the most recent schedule interval. If the task is run outside of the latest schedule interval (i.e. external_trigger), all directly downstream tasks will be skipped. Note that downstream tasks are never skipped if the given DAG_Run is marked as externally triggered. """
[docs] ui_color = '#e9ffdb' # nyanza
[docs] def choose_branch(self, context: Dict) -> Union[str, Iterable[str]]: # If the DAG Run is externally triggered, then return without # skipping downstream tasks if context['dag_run'] and context['dag_run'].external_trigger:"Externally triggered DAG_Run: allowing execution to proceed.") return list(context['task'].get_direct_relative_ids(upstream=False)) now ='UTC') left_window = context['dag'].following_schedule(context['execution_date']) right_window = context['dag'].following_schedule(left_window) 'Checking latest only with left_window: %s right_window: %s now: %s', left_window, right_window, now, ) if not left_window < now <= right_window:'Not latest execution, skipping downstream.') # we return an empty list, thus the parent BaseBranchOperator # won't exclude any downstream tasks from skipping. return [] else:'Latest, allowing execution to proceed.') return list(context['task'].get_direct_relative_ids(upstream=False))

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