3a8a78ee64
Instead of using strings (which can be easy to mistype and get wrong), provide a set of constants that can be used to attach and use these keys in flows and at compilation. This also helps make it more clear what the keys do and where they are used. Change-Id: I5283b27617961136a4582bbcfce4617f05e8dd1d
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 = {flow.LINK_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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