2339bacaf7
In order to make it possible to have a symbol tree we need to relax and remove the constraints that are being imposed by the linear constraints and later move those constraint checks and validations into the engines compilation stage. Part of blueprint taskflow-improved-scoping Change-Id: I6efdc821ff991e83572d89f56be5c678d007f9f8
63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# 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, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from taskflow import flow
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_LINK_METADATA = {'invariant': True}
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class Flow(flow.Flow):
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"""Linear flow pattern.
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A linear (potentially nested) flow of *tasks/flows* that can be
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applied in order as one unit and rolled back as one unit using
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the reverse order that the *tasks/flows* have been applied in.
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"""
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def __init__(self, name, retry=None):
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super(Flow, self).__init__(name, retry)
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self._children = []
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def add(self, *items):
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"""Adds a given task/tasks/flow/flows to this flow."""
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items = [i for i in items if i not in self._children]
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self._children.extend(items)
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return self
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def __len__(self):
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return len(self._children)
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def __iter__(self):
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for child in self._children:
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yield child
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@property
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def requires(self):
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requires = set()
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prior_provides = set()
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if self._retry is not None:
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requires.update(self._retry.requires)
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prior_provides.update(self._retry.provides)
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for item in self:
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requires.update(item.requires - prior_provides)
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prior_provides.update(item.provides)
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return frozenset(requires)
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def iter_links(self):
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for src, dst in zip(self._children[:-1], self._children[1:]):
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yield (src, dst, _LINK_METADATA.copy())
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