487cc51832
Deprecate the usage of an engines 'task_notifier' in favor of the more appropriately named 'atom_notifier' and mark the 'task_notifier' property as subject to removal in a future version. This makes the usage of this notifier more clear since it is not only used for task notification but also for retry notification (which is why naming it atom notifier is more suited to its actual usage). Change-Id: I79d58a08fd8e6d7c8990e70bdfaae415202aa929
116 lines
3.9 KiB
Python
116 lines
3.9 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2013 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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import six
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from taskflow.types import notifier
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from taskflow.utils import deprecation
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from taskflow.utils import misc
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@six.add_metaclass(abc.ABCMeta)
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class EngineBase(object):
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"""Base for all engines implementations.
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:ivar notifier: A notification object that will dispatch events that
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occur related to the flow the engine contains.
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:ivar task_notifier: A notification object that will dispatch events that
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occur related to the tasks the engine contains.
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occur related to the tasks the engine
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contains (deprecated).
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:ivar atom_notifier: A notification object that will dispatch events that
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occur related to the atoms the engine contains.
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"""
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def __init__(self, flow, flow_detail, backend, options):
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self._flow = flow
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self._flow_detail = flow_detail
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self._backend = backend
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if not options:
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self._options = {}
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else:
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self._options = dict(options)
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self._notifier = notifier.Notifier()
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self._atom_notifier = notifier.Notifier()
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@property
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def notifier(self):
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"""The flow notifier."""
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return self._notifier
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@property
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@deprecation.moved_property('atom_notifier', version="0.6",
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removal_version="?")
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def task_notifier(self):
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"""The task notifier."""
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return self._atom_notifier
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@property
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def atom_notifier(self):
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"""The atom notifier."""
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return self._atom_notifier
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@property
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def options(self):
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"""The options that were passed to this engine on construction."""
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return self._options
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@misc.cachedproperty
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def storage(self):
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"""The storage unit for this flow."""
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return self._storage_factory(self._flow_detail, self._backend)
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@abc.abstractproperty
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def _storage_factory(self):
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"""Storage factory that will be used to generate storage objects."""
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@abc.abstractmethod
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def compile(self):
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"""Compiles the contained flow into a internal representation.
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This internal representation is what the engine will *actually* use to
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run. If this compilation can not be accomplished then an exception
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is expected to be thrown with a message indicating why the compilation
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could not be achieved.
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"""
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@abc.abstractmethod
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def prepare(self):
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"""Performs any pre-run, but post-compilation actions.
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NOTE(harlowja): During preparation it is currently assumed that the
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underlying storage will be initialized, all final dependencies
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will be verified, the tasks will be reset and the engine will enter
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the PENDING state.
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"""
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@abc.abstractmethod
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def run(self):
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"""Runs the flow in the engine to completion (or die trying)."""
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@abc.abstractmethod
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def suspend(self):
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"""Attempts to suspend the engine.
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If the engine is currently running tasks then this will attempt to
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suspend future work from being started (currently active tasks can
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not currently be preempted) and move the engine into a suspend state
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which can then later be resumed from.
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"""
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