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"""Branching operators"""
from typing import Union, Iterable, Dict
from airflow.models import BaseOperator, SkipMixin
[docs]class BaseBranchOperator(BaseOperator, SkipMixin):
"""
This is a base class for creating operators with branching functionality,
similarly to BranchPythonOperator.
Users should subclass this operator and implement the function
`choose_branch(self, context)`. This should run whatever business logic
is needed to determine the branch, and return either the task_id for
a single task (as a str) or a list of task_ids.
The operator will continue with the returned task_id(s), and all other
tasks directly downstream of this operator will be skipped.
"""
[docs] def choose_branch(self, context): # type: (Dict) -> Union[str, Iterable[str]]
"""
Subclasses should implement this, running whatever logic is
necessary to choose a branch and returning a task_id or list of
task_ids.
:param context: Context dictionary as passed to execute()
:type context: dict
"""
raise NotImplementedError
[docs] def execute(self, context):
self.skip_all_except(context['ti'], self.choose_branch(context))