86 lines
4.3 KiB
Python
86 lines
4.3 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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from taskflow.engines.action_engine import engine
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from taskflow.engines.worker_based import executor
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from taskflow.engines.worker_based import protocol as pr
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class WorkerBasedActionEngine(engine.ActionEngine):
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"""Worker based action engine.
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Specific backend options (extracted from provided engine options):
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:param exchange: broker exchange exchange name in which executor / worker
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communication is performed
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:param url: broker connection url (see format in kombu documentation)
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:param topics: list of workers topics to communicate with (this will also
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be learned by listening to the notifications that workers
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emit).
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:param transport: transport to be used (e.g. amqp, memory, etc.)
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:param transition_timeout: numeric value (or None for infinite) to wait
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for submitted remote requests to transition out
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of the (PENDING, WAITING) request states. When
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expired the associated task the request was made
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for will have its result become a
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:py:class:`~taskflow.exceptions.RequestTimeout`
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exception instead of its normally returned
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value (or raised exception).
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:param transport_options: transport specific options (see:
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http://kombu.readthedocs.org/ for what these
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options imply and are expected to be)
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:param retry_options: retry specific options
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(see: :py:attr:`~.proxy.Proxy.DEFAULT_RETRY_OPTIONS`)
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:param worker_expiry: numeric value (or negative/zero/None for
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infinite) that defines the number of seconds to
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continue to send messages to workers that
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have **not** responded back to a prior
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notification/ping request (this defaults
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to 60 seconds).
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"""
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def __init__(self, flow, flow_detail, backend, options):
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super(WorkerBasedActionEngine, self).__init__(flow, flow_detail,
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backend, options)
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# This ensures that any provided executor will be validated before
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# we get to far in the compilation/execution pipeline...
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self._task_executor = self._fetch_task_executor(self._options,
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self._flow_detail)
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@classmethod
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def _fetch_task_executor(cls, options, flow_detail):
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try:
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e = options['executor']
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if not isinstance(e, executor.WorkerTaskExecutor):
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raise TypeError("Expected an instance of type '%s' instead of"
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" type '%s' for 'executor' option"
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% (executor.WorkerTaskExecutor, type(e)))
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return e
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except KeyError:
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return executor.WorkerTaskExecutor(
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uuid=flow_detail.uuid,
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url=options.get('url'),
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exchange=options.get('exchange', 'default'),
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retry_options=options.get('retry_options'),
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topics=options.get('topics', []),
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transport=options.get('transport'),
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transport_options=options.get('transport_options'),
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transition_timeout=options.get('transition_timeout',
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pr.REQUEST_TIMEOUT),
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worker_expiry=options.get('worker_expiry',
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pr.EXPIRES_AFTER),
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)
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