1caf6fb316
Increase the number of comments which will help users of these 2 modules better understand there desired usage. Change-Id: Ief248770de3bedd7fc87bfcfbce4da77c011de7f
88 lines
2.8 KiB
Python
88 lines
2.8 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# vim: tabstop=4 shiftwidth=4 softtabstop=4
|
|
|
|
# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License"); you may
|
|
# not use this file except in compliance with the License. You may obtain
|
|
# a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
# License for the specific language governing permissions and limitations
|
|
# under the License.
|
|
|
|
import abc
|
|
|
|
import six
|
|
|
|
from taskflow.openstack.common import uuidutils
|
|
from taskflow.utils import reflection
|
|
|
|
|
|
class Flow(six.with_metaclass(abc.ABCMeta)):
|
|
"""The base abstract class of all flow implementations.
|
|
|
|
It provides a name and an identifier (uuid) to the flow so that it can be
|
|
uniquely identifed among many flows while executing or while referencing
|
|
the results (or other metadata) of this flow in storage.
|
|
|
|
NOTE(harlowja): if a flow is placed in another flow as a subflow, a desired
|
|
way to compose flows together, then it is valid and permissible that during
|
|
execution the subflow & parent flow may be flattened into a new flow. Since
|
|
a flow is just a 'structuring' concept this is typically a behavior that
|
|
should not be worried about (as it is not visible to the user), but it is
|
|
worth mentioning here.
|
|
|
|
Flows are expected to provide the following methods/properties:
|
|
- add
|
|
- __len__
|
|
- requires
|
|
- provides
|
|
"""
|
|
|
|
def __init__(self, name, uuid=None):
|
|
self._name = str(name)
|
|
if uuid:
|
|
self._id = str(uuid)
|
|
else:
|
|
self._id = uuidutils.generate_uuid()
|
|
|
|
@property
|
|
def name(self):
|
|
"""A non-unique name for this flow (human readable)"""
|
|
return self._name
|
|
|
|
@property
|
|
def uuid(self):
|
|
"""A unique identifier for this flow"""
|
|
return self._id
|
|
|
|
@abc.abstractmethod
|
|
def __len__(self):
|
|
"""Returns how many items are in this flow."""
|
|
raise NotImplementedError()
|
|
|
|
def __str__(self):
|
|
lines = ["%s: %s" % (reflection.get_class_name(self), self.name)]
|
|
lines.append("%s" % (self.uuid))
|
|
lines.append("%s" % (len(self)))
|
|
return "; ".join(lines)
|
|
|
|
@abc.abstractmethod
|
|
def add(self, *items):
|
|
"""Adds a given item/items to this flow."""
|
|
raise NotImplementedError()
|
|
|
|
@abc.abstractproperty
|
|
def requires(self):
|
|
"""Browse argument requirement names this flow requires to run."""
|
|
|
|
@abc.abstractproperty
|
|
def provides(self):
|
|
"""Browse argument names provided by the flow."""
|