`airflow.models.xcom_arg`¶

Module Contents¶

class airflow.models.xcom_arg.XComArg(operator: BaseOperator, key: str = XCOM_RETURN_KEY)[source]¶

Bases: airflow.models.taskmixin.TaskMixin

Class that represents a XCom push from a previous operator. Defaults to "return_value" as only key.

Current implementation supports: xcomarg >> op xcomarg << op op >> xcomarg (by BaseOperator code) op << xcomarg (by BaseOperator code)

Example: The moment you get a result from any operator (decorated or regular) you can

any_op = AnyOperator()
xcomarg = XComArg(any_op)
# or equivalently
xcomarg = any_op.output
my_op = MyOperator()
my_op >> xcomarg

      
    

This object can be used in legacy Operators via Jinja.

Example: You can make this result to be part of any generated string

any_op = AnyOperator()
xcomarg = any_op.output
op1 = MyOperator(my_text_message=f"the value is {xcomarg}")
op2 = MyOperator(my_text_message=f"the value is {xcomarg['topic']}")

Parameters

operator (airflow.models.baseoperator.BaseOperator) -- operator to which the XComArg belongs to
key (str) -- key value which is used for xcom_pull (key in the XCom table)

operator[source]¶: Returns operator of this XComArg.

roots[source]¶: Required by TaskMixin

leaves[source]¶: Required by TaskMixin

key[source]¶: Returns keys of this XComArg

__eq__(self, other)[source]¶

__getitem__(self, item)[source]¶: Implements xcomresult['some_result_key']

__str__(self)[source]¶

Backward compatibility for old-style jinja used in Airflow Operators

Example: to use XComArg at BashOperator:

BashOperator(cmd=f"... { xcomarg } ...")

Returns

set_upstream(self, task_or_task_list: Union[TaskMixin, Sequence[TaskMixin]], edge_modifier: Optional[EdgeModifier] = None)[source]¶: Proxy to underlying operator set_upstream method. Required by TaskMixin.

set_downstream(self, task_or_task_list: Union[TaskMixin, Sequence[TaskMixin]], edge_modifier: Optional[EdgeModifier] = None)[source]¶: Proxy to underlying operator set_downstream method. Required by TaskMixin.

resolve(self, context: Dict)[source]¶: Pull XCom value for the existing arg. This method is run during op.execute() in respectable context.

airflow.models.xcom_arg¶

Module Contents¶

`airflow.models.xcom_arg`¶