获取所有气流叶节点/任务 [英] Get all Airflow Leaf Nodes/Tasks

问题描述

我想构建一些我需要捕获所有叶子任务并向其添加下游依赖关系的东西，以使我们的数据库中的工作完成。有没有简单的方法可以找到Airflow中DAG的所有叶节点？

I want to build something where I need to capture all of the leaf tasks and add a downstream dependency to them to make a job complete in our database. Is there an easy way to find all the leaf nodes of a DAG in Airflow?

推荐答案

使用 upstream_task_ids 和 downstream_task_ids @property 来自 BaseOperator

Use upstream_task_ids and downstream_task_ids @property from BaseOperator

def get_start_tasks(dag: DAG) -> List[BaseOperator]:
    # returns list of "head" / "root" tasks of DAG
    return [task for task in dag.tasks if not task.upstream_task_ids]


def get_end_tasks(dag: DAG) -> List[BaseOperator]:
    # returns list of "leaf" tasks of DAG
    return [task for task in dag.tasks if not task.downstream_task_ids]

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类型注释 来自 Python 3.6 +

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