76 строки
2.7 KiB
Python
76 строки
2.7 KiB
Python
# Licensed to the Apache Software Foundation (ASF) under one
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# or more contributor license agreements. See the NOTICE file
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# distributed with this work for additional information
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# regarding copyright ownership. The ASF licenses this file
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# to you under the Apache License, Version 2.0 (the
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# "License"); you may not use this file except in compliance
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# with the License. You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing,
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# software distributed under the License is distributed on an
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# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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# KIND, either express or implied. See the License for the
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# specific language governing permissions and limitations
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# under the License.
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from abc import abstractmethod
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from typing import Sequence, Union
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class TaskMixin:
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"""
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Mixing implementing common chain methods like >> and <<.
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In the following functions we use:
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Task = Union[BaseOperator, XComArg]
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No type annotations due to cyclic imports.
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"""
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@property
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def roots(self):
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"""Should return list of root operator List[BaseOperator]"""
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raise NotImplementedError()
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@property
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def leaves(self):
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"""Should return list of leaf operator List[BaseOperator]"""
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raise NotImplementedError()
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@abstractmethod
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def set_upstream(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Set a task or a task list to be directly upstream from the current task."""
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raise NotImplementedError()
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@abstractmethod
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def set_downstream(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Set a task or a task list to be directly downstream from the current task."""
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raise NotImplementedError()
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def update_relative(self, other: "TaskMixin", upstream=True) -> None:
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"""
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Update relationship information about another TaskMixin. Default is no-op.
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Override if necessary.
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"""
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def __lshift__(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Implements Task << Task"""
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self.set_upstream(other)
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return other
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def __rshift__(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Implements Task >> Task"""
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self.set_downstream(other)
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return other
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def __rrshift__(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Called for Task >> [Task] because list don't have __rshift__ operators."""
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self.__lshift__(other)
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return self
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def __rlshift__(self, other: Union["TaskMixin", Sequence["TaskMixin"]]):
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"""Called for Task << [Task] because list don't have __lshift__ operators."""
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self.__rshift__(other)
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return self
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