turbaszek commented on a change in pull request #10153: URL: https://github.com/apache/airflow/pull/10153#discussion_r484263443
########## File path: airflow/utils/task_group.py ########## @@ -0,0 +1,392 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. +""" +A TaskGroup is a collection of closely related tasks on the same DAG that should be grouped +together when the DAG is displayed graphically. +""" + +from typing import TYPE_CHECKING, Dict, Generator, List, Optional, Sequence, Set, Union + +from airflow.exceptions import AirflowException, DuplicateTaskIdFound + +if TYPE_CHECKING: + from airflow.models.baseoperator import BaseOperator + from airflow.models.dag import DAG + + +class TaskGroup: + """ + A collection of tasks. When set_downstream() or set_upstream() are called on the + TaskGroup, it is applied across all tasks within the group if necessary. + + :param group_id: a unique, meaningful id for the TaskGroup. group_id must not conflict + with group_id of TaskGroup or task_id of tasks in the DAG. Root TaskGroup has group_id + set to None. + :type group_id: str + :param prefix_group_id: If set to True, child task_id and group_id will be prefixed with + this TaskGroup's group_id. If set to False, child task_id and group_id are not prefixed. + Default is True. + :type prerfix_group_id: bool + :param parent_group: The parent TaskGroup of this TaskGroup. parent_group is set to None + for the root TaskGroup. + :type parent_group: TaskGroup + :param dag: The DAG that this TaskGroup belongs to. + :type dag: airflow.models.DAG + :param tooltip: The tooltip of the TaskGroup node when displayed in the UI + :type tooltip: str + :param ui_color: The fill color of the TaskGroup node when displayed in the UI + :type ui_color: str + :param ui_fgcolor: The label color of the TaskGroup node when displayed in the UI + :type ui_fgcolor: str + """ + + def __init__( + self, + group_id: Optional[str], + prefix_group_id: bool = True, + parent_group: Optional["TaskGroup"] = None, + dag: Optional["DAG"] = None, + tooltip: str = "", + ui_color: str = "CornflowerBlue", + ui_fgcolor: str = "#000", + ): + from airflow.models.dag import DagContext + + self.prefix_group_id = prefix_group_id + + if group_id is None: + # This creates a root TaskGroup. + if parent_group: + raise AirflowException("Root TaskGroup cannot have parent_group") + # used_group_ids is shared across all TaskGroups in the same DAG to keep track + # of used group_id to avoid duplication. + self.used_group_ids: Set[Optional[str]] = set() + self._parent_group = None + else: + if not isinstance(group_id, str): + raise ValueError("group_id must be str") + if not group_id: + raise ValueError("group_id must not be empty") + + dag = dag or DagContext.get_current_dag() + + if not parent_group and not dag: + raise AirflowException("TaskGroup can only be used inside a dag") + + self._parent_group = parent_group or TaskGroupContext.get_current_task_group(dag) + if not self._parent_group: + raise AirflowException("TaskGroup must have a parent_group except for the root TaskGroup") + self.used_group_ids = self._parent_group.used_group_ids + + self._group_id = group_id + if self.group_id in self.used_group_ids: + raise DuplicateTaskIdFound(f"group_id '{self.group_id}' has already been added to the DAG") + self.used_group_ids.add(self.group_id) + self.used_group_ids.add(self.downstream_join_id) + self.used_group_ids.add(self.upstream_join_id) + self.children: Dict[str, Union["BaseOperator", "TaskGroup"]] = {} + if self._parent_group: + self._parent_group.add(self) + + self.tooltip = tooltip + self.ui_color = ui_color + self.ui_fgcolor = ui_fgcolor + + # Keep track of TaskGroups or tasks that depend on this entire TaskGroup separately + # so that we can optimize the number of edges when entire TaskGroups depend on each other. + self.upstream_group_ids: Set[Optional[str]] = set() + self.downstream_group_ids: Set[Optional[str]] = set() + self.upstream_task_ids: Set[Optional[str]] = set() + self.downstream_task_ids: Set[Optional[str]] = set() + + @classmethod + def create_root(cls, dag: "DAG"): Review comment: ```suggestion def create_root(cls, dag: "DAG") -> "TaskGroup": ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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