Source code for taskflow.engines.worker_based.engine

# -*- coding: utf-8 -*-

#    Copyright (C) 2014 Yahoo! Inc. All Rights Reserved.
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from taskflow.engines.action_engine import engine
from taskflow.engines.worker_based import executor
from taskflow.engines.worker_based import protocol as pr

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