c73c097560
Provides and requires properties are used to browse all required and provided values for the whole Flow. The same properties were added to the Task. Appropriate Task properties were renamed to rebind and save_as. Change-Id: I02eb02303a9701a13f1a54f06f20bbf9aebd1d04
92 lines
2.6 KiB
Python
92 lines
2.6 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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import abc
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from taskflow.openstack.common import uuidutils
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from taskflow import task
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from taskflow import utils
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def _class_name(obj):
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return ".".join([obj.__class__.__module__, obj.__class__.__name__])
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class Flow(object):
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"""The base abstract class of all flow implementations.
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It provides a name and an identifier (uuid or other) to the flow so that
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it can be uniquely identifed among many flows.
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Flows are expected to provide the following methods:
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- add
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- __len__
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"""
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__metaclass__ = abc.ABCMeta
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def __init__(self, name, uuid=None):
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self._name = str(name)
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if uuid:
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self._id = str(uuid)
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else:
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self._id = uuidutils.generate_uuid()
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@property
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def name(self):
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"""A non-unique name for this flow (human readable)"""
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return self._name
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@property
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def uuid(self):
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return self._id
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@abc.abstractmethod
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def __len__(self):
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"""Returns how many items are in this flow."""
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raise NotImplementedError()
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def __str__(self):
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lines = ["%s: %s" % (_class_name(self), self.name)]
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lines.append("%s" % (self.uuid))
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lines.append("%s" % (len(self)))
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return "; ".join(lines)
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def _extract_item(self, item):
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if isinstance(item, (task.BaseTask, Flow)):
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return item
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if issubclass(item, task.BaseTask):
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return item()
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task_factory = getattr(item, utils.TASK_FACTORY_ATTRIBUTE, None)
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if task_factory:
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return self._extract_item(task_factory(item))
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raise TypeError("Invalid item %r: it's not task and not flow" % item)
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@abc.abstractmethod
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def add(self, *items):
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"""Adds a given item/items to this flow."""
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raise NotImplementedError()
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@abc.abstractproperty
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def requires(self):
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"""Browse flow requirements."""
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@abc.abstractproperty
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def provides(self):
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"""Browse values provided by the flow."""
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