2b827e1e36
To make it possible to alter the runtime flow via a simple conditional like structure make it possible to have the graph flow link function take a decider that is expected to be some callable that will decide (via a boolean return) whether the edge should actually be traversed when running. When a decider returns false; the affected + successors will be set into the IGNORE state and they will be exempt from future runtime and scheduling decisions. Part of blueprint taskflow-conditional-execution Change-Id: Iab0ee46f86d6b8e747911174d54a7295b3fa404d
76 lines
2.0 KiB
Python
76 lines
2.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2014 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 logging
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import os
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import sys
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logging.basicConfig(level=logging.ERROR)
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top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
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os.pardir,
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os.pardir))
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sys.path.insert(0, top_dir)
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from taskflow import engines
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from taskflow.patterns import graph_flow as gf
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from taskflow.persistence import backends
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from taskflow import task
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from taskflow.utils import persistence_utils as pu
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class DummyTask(task.Task):
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def execute(self):
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print("Running %s" % self.name)
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def allow(history):
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print(history)
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return False
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r = gf.Flow("root")
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r_a = DummyTask('r-a')
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r_b = DummyTask('r-b')
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r.add(r_a, r_b)
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r.link(r_a, r_b, decider=allow)
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backend = backends.fetch({
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'connection': 'memory://',
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})
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book, flow_detail = pu.temporary_flow_detail(backend=backend)
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e = engines.load(r, flow_detail=flow_detail, book=book, backend=backend)
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e.compile()
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e.prepare()
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e.run()
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print("---------")
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print("After run")
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print("---------")
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entries = [os.path.join(backend.memory.root_path, child)
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for child in backend.memory.ls(backend.memory.root_path)]
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while entries:
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path = entries.pop()
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value = backend.memory[path]
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if value:
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print("%s -> %s" % (path, value))
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else:
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print("%s" % (path))
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entries.extend(os.path.join(path, child)
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for child in backend.memory.ls(path))
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