:py:mod:`airflow.models.taskmixin`
==================================

.. py:module:: airflow.models.taskmixin


Module Contents
---------------

Classes
~~~~~~~

.. autoapisummary::

   airflow.models.taskmixin.DependencyMixin
   airflow.models.taskmixin.TaskMixin
   airflow.models.taskmixin.DAGNode


.. py:class:: DependencyMixin

   Mixing implementing common dependency setting methods methods like >> and <<.

   .. py:method:: roots(self)
      :property:

      List of root nodes -- ones with no upstream dependencies.

      a.k.a. the "start" of this sub-graph


   .. py:method:: leaves(self)
      :property:

      List of leaf nodes -- ones with only upstream dependencies.

      a.k.a. the "end" of this sub-graph


   .. py:method:: set_upstream(self, other)
      :abstractmethod:

      Set a task or a task list to be directly upstream from the current task.


   .. py:method:: set_downstream(self, other)
      :abstractmethod:

      Set a task or a task list to be directly downstream from the current task.


   .. py:method:: update_relative(self, other, upstream=True)

      Update relationship information about another TaskMixin. Default is no-op.
      Override if necessary.


   .. py:method:: __lshift__(self, other)

      Implements Task << Task


   .. py:method:: __rshift__(self, other)

      Implements Task >> Task


   .. py:method:: __rrshift__(self, other)

      Called for Task >> [Task] because list don't have __rshift__ operators.


   .. py:method:: __rlshift__(self, other)

      Called for Task << [Task] because list don't have __lshift__ operators.


.. py:class:: TaskMixin

   Bases: :py:obj:`DependencyMixin`

   :meta private:

   .. py:method:: __init_subclass__(cls)
      :classmethod:


.. py:class:: DAGNode

   Bases: :py:obj:`DependencyMixin`

   A base class for a node in the graph of a workflow -- an Operator or a Task Group, either mapped or
   unmapped.

   .. py:attribute:: dag
      :annotation: :Optional[airflow.models.dag.DAG]

      
   .. py:attribute:: task_group
      :annotation: :Optional[airflow.utils.task_group.TaskGroup]

      The task_group that contains this node


   .. py:attribute:: start_date
      :annotation: :Optional[pendulum.DateTime]

      
   .. py:attribute:: end_date
      :annotation: :Optional[pendulum.DateTime]

      
   .. py:attribute:: upstream_task_ids
      :annotation: :Set[str]

      
   .. py:attribute:: downstream_task_ids
      :annotation: :Set[str]

      
   .. py:method:: node_id(self)
      :property:


   .. py:method:: label(self)
      :property:


   .. py:method:: has_dag(self)


   .. py:method:: dag_id(self)
      :property:

      Returns dag id if it has one or an adhoc/meaningless ID


   .. py:method:: log(self)
      :property:


   .. py:method:: roots(self)
      :property:

      List of root nodes -- ones with no upstream dependencies.

      a.k.a. the "start" of this sub-graph


   .. py:method:: leaves(self)
      :property:

      List of leaf nodes -- ones with only upstream dependencies.

      a.k.a. the "end" of this sub-graph


   .. py:method:: set_downstream(self, task_or_task_list, edge_modifier = None)

      Set a node (or nodes) to be directly downstream from the current node.


   .. py:method:: set_upstream(self, task_or_task_list, edge_modifier = None)

      Set a node (or nodes) to be directly downstream from the current node.


   .. py:method:: downstream_list(self)
      :property:

      List of nodes directly downstream


   .. py:method:: upstream_list(self)
      :property:

      List of nodes directly upstream


   .. py:method:: get_direct_relative_ids(self, upstream = False)

      Get set of the direct relative ids to the current task, upstream or
      downstream.


   .. py:method:: get_direct_relatives(self, upstream = False)

      Get list of the direct relatives to the current task, upstream or
      downstream.


   .. py:method:: serialize_for_task_group(self)
      :abstractmethod:

      This is used by SerializedTaskGroup to serialize a task group's content.


   .. py:method:: iter_mapped_dependants(self)

      Return mapped nodes that depend on the current task the expansion.

      For now, this walks the entire DAG to find mapped nodes that has this
      current task as an upstream. We cannot use ``downstream_list`` since it
      only contains operators, not task groups. In the future, we should
      provide a way to record an DAG node's all downstream nodes instead.