dd9d5c157e
Use a new rollback accumulator to collect which tasks need to be rolled back and use that in the ordered workflow code. Move the usage of provides/requires as functions and just let them be attributes of the flow objects.
88 lines
3.2 KiB
Python
88 lines
3.2 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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# Copyright (C) 2013 Rackspace Hosting 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 logging
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from taskflow import logbook
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from celery import chord
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LOG = logging.getLogger(__name__)
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class Flow(object):
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"""A linear chain of independent tasks that can be applied as one unit or
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rolled back as one unit."""
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def __init__(self, name, parents=None):
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self.name = name
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self.root = None
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self._tasks = []
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logbook.add_workflow(name)
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def chain_listeners(self, context, initial_task, callback_task):
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""" Register one listener for a task """
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if self.root is None:
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initial_task.name = '%s.%s' % (self.name, initial_task.name)
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self.root = initial_task.s(context)
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self._tasks.append(initial_task)
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LOG.info('WF %s root task set to %s' % (self.name, initial_task.name))
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callback_task.name = '%s.%s' % (self.name, callback_task.name)
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self._tasks.append(callback_task)
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initial_task.link(callback_task.s(context))
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def split_listeners(self, context, initial_task, callback_tasks):
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""" Register multiple listeners for one task """
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if self.root is None:
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initial_task.name = '%s.%s' % (self.name, initial_task.name)
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self.root = initial_task.s(context)
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self._tasks.append(initial_task)
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LOG.info('WF %s root task set to %s' % (self.name, initial_task.name))
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for task in callback_tasks:
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task.name = '%s.%s' % (self.name, task.name)
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self._tasks.append(task)
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initial_task.link(task.s(context))
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def merge_listeners(self, context, inital_tasks, callback_task):
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""" Register one listener for multiple tasks """
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header = []
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if self.root is None:
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self.root = []
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for task in initial_tasks:
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task.name = '%s.%s' % (self.name, task.name)
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self._tasks.append(task)
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header.append(task.s(context))
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if isinstance(self.root, list):
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self.root.append(task.s(context))
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LOG.info('WF %s added root task %s' %
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(self.name, task.name))
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callback_task.name = '%s.%s' % (self.name, callback_task.name)
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self._tasks.append(callback_task)
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#TODO: Need to set up chord so that it's not executed immediately
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c = chord(header, body=callback_task)
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def run(self, context, *args, **kwargs):
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""" Start root task and kick off workflow """
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self.root(context)
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LOG.info('WF %s has been started' % (self.name,))
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