9d0b16e7fb
Most TaskFlow exception don't have 'Exception' suffix in their names, so we drop it from the few that have it, for sake of consistency and more concise and expressive code. MissingDependencies parent object is changed from InvalidState to InvariantViolation, which is more appropriate. Unused ClosedException is dropped. Breaking change: any client code that used renamed exceptions, ClosedException or relied on catching MissingDependencies as InvariantViolationException is affected. Change-Id: I649b7760d382ccb6df333bdffd667ba6b67a431e
97 lines
3.4 KiB
Python
97 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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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 exceptions
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from taskflow import flow
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class Flow(flow.Flow):
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""""Unordered Flow pattern.
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A unordered (potentially nested) flow of *tasks/flows* that can be
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executed in any order as one unit and rolled back as one unit.
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NOTE(harlowja): Since the flow is unordered there can *not* be any
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dependency between task/flow inputs (requirements) and
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task/flow outputs (provided names/values).
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"""
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def __init__(self, name):
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super(Flow, self).__init__(name)
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# NOTE(imelnikov): A unordered flow is unordered, so we use
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# set instead of list to save children, children so that
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# people using it don't depend on the ordering
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self._children = set()
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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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# check that items are actually independent
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provides = self.provides
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old_requires = self.requires
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for item in items:
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item_provides = item.provides
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bad_provs = item_provides & old_requires
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if bad_provs:
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raise exceptions.InvariantViolation(
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"%(item)s provides %(oo)s that are required "
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"by other item(s) of unordered flow %(flow)s"
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% dict(item=item.name, flow=self.name,
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oo=sorted(bad_provs)))
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same_provides = provides & item.provides
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if same_provides:
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raise exceptions.DependencyFailure(
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"%(item)s provides %(value)s but is already being"
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" provided by %(flow)s and duplicate producers"
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" are disallowed"
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% dict(item=item.name, flow=self.name,
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value=sorted(same_provides)))
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provides |= item.provides
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for item in items:
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bad_reqs = provides & item.requires
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if bad_reqs:
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raise exceptions.InvariantViolation(
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"%(item)s requires %(oo)s that are provided "
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"by other item(s) of unordered flow %(flow)s"
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% dict(item=item.name, flow=self.name,
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oo=sorted(bad_reqs)))
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self._children.update(items)
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return self
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@property
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def provides(self):
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provides = set()
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for subflow in self:
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provides.update(subflow.provides)
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return provides
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@property
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def requires(self):
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requires = set()
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for subflow in self:
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requires.update(subflow.requires)
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return requires
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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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