| # Copyright 2016 Twitter. All rights reserved. |
| # |
| # Licensed 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. |
| '''custom_grouping.py: interface module for custom grouping''' |
| from abc import abstractmethod |
| |
| class ICustomGrouping(object): |
| '''Interface for custom grouping class''' |
| |
| @abstractmethod |
| def prepare(self, context, component, stream, target_tasks): |
| """Tells the stream grouping at runtime the tasks in the target bolt |
| |
| This information should be used in ``choose_tasks()`` to determine the target tasks. |
| |
| :param context: topology-worker context |
| :param component: source component name |
| :param stream: stream id used for this grouping |
| :type target_tasks: list of int |
| :param target_tasks: list of target task ids |
| """ |
| pass |
| |
| @abstractmethod |
| def choose_tasks(self, values): |
| """Implements a custom stream grouping |
| |
| :param values: the values to group on |
| :rtype: list of int |
| :return: list of task ids to which these values are emitted |
| """ |
| pass |