
This is hopefully useful to understand why this happens in this order. Change-Id: I8ff63417489a8d4bada12acc91dbc6bca69df2ba
104 lines
4.0 KiB
Python
104 lines
4.0 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 weakref
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from taskflow import exceptions as excp
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from taskflow import states as st
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from taskflow.types import failure
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class RetryScheduler(object):
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"""Schedules retry atoms."""
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def __init__(self, runtime):
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self._runtime = weakref.proxy(runtime)
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self._retry_action = runtime.retry_action
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self._storage = runtime.storage
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def schedule(self, retry):
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"""Schedules the given retry atom for *future* completion.
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Depending on the atoms stored intention this may schedule the retry
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atom for reversion or execution.
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"""
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intention = self._storage.get_atom_intention(retry.name)
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if intention == st.EXECUTE:
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return self._retry_action.schedule_execution(retry)
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elif intention == st.REVERT:
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return self._retry_action.schedule_reversion(retry)
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elif intention == st.RETRY:
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self._retry_action.change_state(retry, st.RETRYING)
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# This will force the subflow to start processing right *after*
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# this retry atom executes (since they will be blocked on their
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# predecessor getting out of the RETRYING/RUNNING state).
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self._runtime.retry_subflow(retry)
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return self._retry_action.schedule_execution(retry)
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else:
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raise excp.ExecutionFailure("Unknown how to schedule retry with"
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" intention: %s" % intention)
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class TaskScheduler(object):
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"""Schedules task atoms."""
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def __init__(self, runtime):
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self._storage = runtime.storage
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self._task_action = runtime.task_action
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def schedule(self, task):
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"""Schedules the given task atom for *future* completion.
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Depending on the atoms stored intention this may schedule the task
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atom for reversion or execution.
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"""
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intention = self._storage.get_atom_intention(task.name)
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if intention == st.EXECUTE:
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return self._task_action.schedule_execution(task)
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elif intention == st.REVERT:
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return self._task_action.schedule_reversion(task)
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else:
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raise excp.ExecutionFailure("Unknown how to schedule task with"
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" intention: %s" % intention)
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class Scheduler(object):
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"""Safely schedules atoms using a runtime ``fetch_scheduler`` routine."""
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def __init__(self, runtime):
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self._runtime = weakref.proxy(runtime)
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def schedule(self, atoms):
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"""Schedules the provided atoms for *future* completion.
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This method should schedule a future for each atom provided and return
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a set of those futures to be waited on (or used for other similar
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purposes). It should also return any failure objects that represented
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scheduling failures that may have occurred during this scheduling
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process.
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"""
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futures = set()
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for atom in atoms:
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scheduler = self._runtime.fetch_scheduler(atom)
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try:
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futures.add(scheduler.schedule(atom))
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except Exception:
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# Immediately stop scheduling future work so that we can
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# exit execution early (rather than later) if a single atom
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# fails to schedule correctly.
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return (futures, [failure.Failure()])
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return (futures, [])
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