23dfff4105
In order to move away from the existing flows having their own implementation of running, start moving the existing flows to be patterns that only structure tasks (and impose constraints about how the group of tasks can run) in useful ways. Let the concept of running those patterns be handled by an engine instead of being handled by the flow itself. This will allow for varying engines to be able to run flows in whichever way the engine chooses (as long as the constraints set up by the flow are observed). Currently threaded flow and graph flow are broken by this commit, since they have not been converted to being a structure of tasks + constraints. The existing engine has not yet been modified to run those structures either, work is underway to remediate this. Part of: blueprint patterns-and-engines Followup bugs that must be addressed: Bug: 1221448 Bug: 1221505 Change-Id: I3a8b96179f336d1defe269728ebae0caa3d832d7
92 lines
3.4 KiB
Python
92 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.engines.action_engine import base_action as base
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from taskflow import exceptions
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from taskflow.openstack.common import excutils
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from taskflow.openstack.common import uuidutils
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from taskflow import states
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from taskflow.utils import misc
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class TaskAction(base.Action):
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def __init__(self, task, engine):
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self._task = task
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self._result_mapping = task.provides
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self._args_mapping = task.requires
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try:
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self._id = engine.storage.get_uuid_by_name(self._task.name)
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except exceptions.NotFound:
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self._id = uuidutils.generate_uuid()
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engine.storage.add_task(task_name=self.name, uuid=self.uuid)
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engine.storage.set_result_mapping(self.uuid, self._result_mapping)
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@property
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def name(self):
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return self._task.name
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@property
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def uuid(self):
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return self._id
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def _change_state(self, engine, state):
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"""Check and update state of task."""
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engine.storage.set_task_state(self.uuid, state)
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engine.on_task_state_change(self, state)
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def _update_result(self, engine, state, result=None):
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"""Update result and change state."""
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if state == states.PENDING:
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engine.storage.reset(self.uuid)
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else:
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engine.storage.save(self.uuid, result, state)
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engine.on_task_state_change(self, state, result)
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def execute(self, engine):
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if engine.storage.get_task_state(self.uuid) == states.SUCCESS:
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return
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try:
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kwargs = engine.storage.fetch_mapped_args(self._args_mapping)
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self._change_state(engine, states.RUNNING)
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result = self._task.execute(**kwargs)
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except Exception:
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failure = misc.Failure()
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self._update_result(engine, states.FAILURE, failure)
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failure.reraise()
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else:
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self._update_result(engine, states.SUCCESS, result)
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def revert(self, engine):
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if engine.storage.get_task_state(self.uuid) == states.PENDING:
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# NOTE(imelnikov): in all the other states, the task
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# execution was at least attempted, so we should give
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# task a chance for cleanup
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return
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kwargs = engine.storage.fetch_mapped_args(self._args_mapping)
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self._change_state(engine, states.REVERTING)
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try:
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self._task.revert(result=engine.storage.get(self._id),
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**kwargs)
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self._change_state(engine, states.REVERTED)
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except Exception:
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with excutils.save_and_reraise_exception():
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self._change_state(engine, states.FAILURE)
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else:
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self._update_result(engine, states.PENDING)
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