Source code for airflow.operators.latest_only

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"""Contains an operator to run downstream tasks only for the latest scheduled DagRun."""
from __future__ import annotations

from typing import TYPE_CHECKING, Iterable

import pendulum

from airflow.operators.branch import BaseBranchOperator
from airflow.utils.context import Context

    from airflow.models import DAG, DagRun

[docs]class LatestOnlyOperator(BaseBranchOperator): """ Skip tasks that are not running during the most recent schedule interval. If the task is run outside 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: Context) -> str | Iterable[str]: # If the DAG Run is externally triggered, then return without # skipping downstream tasks dag_run: DagRun = context["dag_run"] if dag_run.external_trigger:"Externally triggered DAG_Run: allowing execution to proceed.") return list(context["task"].get_direct_relative_ids(upstream=False)) dag: DAG = context["dag"] next_info = dag.next_dagrun_info(dag.get_run_data_interval(dag_run), restricted=False) now ="UTC") if next_info is None:"Last scheduled execution: allowing execution to proceed.") return list(context["task"].get_direct_relative_ids(upstream=False)) left_window, right_window = next_info.data_interval "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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