Source code for taskflow.engines.worker_based.worker

# -*- 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.

import os
import platform
import socket
import sys

import futurist
from oslo_utils import reflection

from taskflow.engines.worker_based import endpoint
from taskflow.engines.worker_based import server
from taskflow import logging
from taskflow import task as t_task
from taskflow.utils import banner
from taskflow.utils import misc
from taskflow.utils import threading_utils as tu

LOG = logging.getLogger(__name__)

[docs]class Worker(object): """Worker that can be started on a remote host for handling tasks requests. :param url: broker url :param exchange: broker exchange name :param topic: topic name under which worker is stated :param tasks: task list that worker is capable of performing, items in the list can be one of the following types; 1, a string naming the python module name to search for tasks in or the task class name; 2, a python module to search for tasks in; 3, a task class object that will be used to create tasks from. :param executor: custom executor object that can used for processing requests in separate threads (if not provided one will be created) :param threads_count: threads count to be passed to the default executor (used only if an executor is not passed in) :param transport: transport to be used (e.g. amqp, memory, etc.) :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`) """ def __init__(self, exchange, topic, tasks, executor=None, threads_count=None, url=None, transport=None, transport_options=None, retry_options=None): self._topic = topic self._executor = executor self._owns_executor = False if self._executor is None: self._executor = futurist.ThreadPoolExecutor( max_workers=threads_count) self._owns_executor = True self._endpoints = self._derive_endpoints(tasks) self._exchange = exchange self._server = server.Server(topic, exchange, self._executor, self._endpoints, url=url, transport=transport, transport_options=transport_options, retry_options=retry_options) @staticmethod def _derive_endpoints(tasks): """Derive endpoints from list of strings, classes or packages.""" derived_tasks = misc.find_subclasses(tasks, t_task.Task) return [endpoint.Endpoint(task) for task in derived_tasks] @misc.cachedproperty def banner(self): """A banner that can be useful to display before running.""" connection_details = self._server.connection_details transport = connection_details.transport if transport.driver_version: transport_driver = "%s v%s" % (transport.driver_name, transport.driver_version) else: transport_driver = transport.driver_name try: hostname = socket.getfqdn() except socket.error: hostname = "???" try: pid = os.getpid() except OSError: pid = "???" chapters = { 'Connection details': { 'Driver': transport_driver, 'Exchange': self._exchange, 'Topic': self._topic, 'Transport': transport.driver_type, 'Uri': connection_details.uri, }, 'Powered by': { 'Executor': reflection.get_class_name(self._executor), 'Thread count': getattr(self._executor, 'max_workers', "???"), }, 'Supported endpoints': [str(ep) for ep in self._endpoints], 'System details': { 'Hostname': hostname, 'Pid': pid, 'Platform': platform.platform(), 'Python': sys.version.split("\n", 1)[0].strip(), 'Thread id': tu.get_ident(), }, } return banner.make_banner('WBE worker', chapters)
[docs] def run(self, display_banner=True, banner_writer=None): """Runs the worker.""" if display_banner: if banner_writer is None: for line in self.banner.splitlines(): else: banner_writer(self.banner) self._server.start()
[docs] def wait(self): """Wait until worker is started.""" self._server.wait()
[docs] def stop(self): """Stop worker.""" self._server.stop() if self._owns_executor: self._executor.shutdown()
if __name__ == '__main__': import argparse import logging as log parser = argparse.ArgumentParser() parser.add_argument("--exchange", required=True) parser.add_argument("--connection-url", required=True) parser.add_argument("--topic", required=True) parser.add_argument("--task", action='append', metavar="TASK", default=[]) parser.add_argument("-v", "--verbose", action='store_true') args = parser.parse_args() if args.verbose: log.basicConfig(level=logging.DEBUG, format="") w = Worker(, args.topic, args.task, url=args.connection_url)