57c4b1bdc2
This is first in series of changes that provides separation of flows into engines and pattens. Patterns define structure, while engine define how the task should be run according to said structure. This change adds the basic patterns and a very simple engine that is able to run flow defined with patterns by converting it to recursive structure of so-called 'actions'. For simplicity and ease of review certain major features like resumption, saving and passing on task results and notifications are left out for farther changes. Partially implements blueprint patterns-and-engines Co-authored-by: Anastasia Karpinska <akarpinska at griddynamics.com> Change-Id: I68515d8a5b30d5d047bf9beb67cc3e2111175190
149 lines
4.6 KiB
Python
149 lines
4.6 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 import blocks
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from taskflow import task
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from taskflow import test
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from taskflow.engines.action_engine import engine as eng
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class TestTask(task.Task):
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def __init__(self, values, name):
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super(TestTask, self).__init__(name)
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self.values = values
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def execute(self, **kwargs):
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self.values.append(self.name)
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return 5
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def revert(self, **kwargs):
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self.values.append(self.name + ' reverted')
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class FailingTask(TestTask):
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def execute(self, **kwargs):
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raise RuntimeError('Woot!')
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class NeverRunningTask(task.Task):
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def execute(self, **kwargs):
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assert False, 'This method should not be called'
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def revert(self, **kwargs):
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assert False, 'This method should not be called'
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class NastyTask(task.Task):
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def execute(self, **kwargs):
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pass
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def revert(self, **kwargs):
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raise RuntimeError('Gotcha!')
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class EngineTestBase(object):
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def setUp(self):
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super(EngineTestBase, self).setUp()
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self.values = []
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def _make_engine(self, _flow):
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raise NotImplementedError()
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class EngineTaskTest(EngineTestBase):
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def test_run_task_as_flow(self):
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flow = blocks.Task(TestTask(self.values, name='task1'))
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self._make_engine(flow).run()
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self.assertEquals(self.values, ['task1'])
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def test_invalid_block_raises(self):
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value = 'i am string, not block, sorry'
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flow = blocks.LinearFlow().add(value)
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with self.assertRaises(ValueError) as err:
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self._make_engine(flow)
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self.assertIn(value, str(err.exception))
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class EngineLinearFlowTest(EngineTestBase):
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def test_sequential_flow_one_task(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, name='task1'))
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)
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self._make_engine(flow).run()
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self.assertEquals(self.values, ['task1'])
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def test_sequential_flow_two_tasks(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, name='task1')),
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blocks.Task(TestTask(self.values, name='task2'))
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)
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self._make_engine(flow).run()
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self.assertEquals(self.values, ['task1', 'task2'])
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def test_sequential_flow_nested_blocks(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, 'task1')),
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blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, 'task2'))
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)
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)
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self._make_engine(flow).run()
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self.assertEquals(self.values, ['task1', 'task2'])
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def test_revert_exception_is_reraised(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(NastyTask),
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blocks.Task(FailingTask(self.values, 'fail'))
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)
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engine = self._make_engine(flow)
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with self.assertRaisesRegexp(RuntimeError, '^Gotcha'):
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engine.run()
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def test_revert_not_run_task_is_not_reverted(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(FailingTask(self.values, 'fail')),
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blocks.Task(NeverRunningTask)
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)
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self._make_engine(flow).run()
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self.assertEquals(self.values, ['fail reverted'])
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def test_correctly_reverts_children(self):
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flow = blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, 'task1')),
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blocks.LinearFlow().add(
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blocks.Task(TestTask(self.values, 'task2')),
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blocks.Task(FailingTask(self.values, 'fail'))
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)
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)
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engine = self._make_engine(flow)
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engine.run()
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self.assertEquals(self.values, ['task1', 'task2',
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'fail reverted',
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'task2 reverted', 'task1 reverted'])
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class SingleThreadedEngineTest(EngineTaskTest,
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EngineLinearFlowTest,
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test.TestCase):
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def _make_engine(self, flow):
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return eng.SingleThreadedActionEngine(flow)
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