eaad725508
Add an easy to use helper function that is exposed to fetch a conductor in a way that matches how engines and persistence backends and jobboards are loaded. This also adjusts the single threaded conductor to be now named blocking conductor and exposes an entrypoint backend fetch() function to load current and future conductors. Change-Id: Id146d847c329d3e8510a8f24c3ec8b918680ddb5
46 lines
1.6 KiB
Python
46 lines
1.6 KiB
Python
# -*- 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
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# 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 logging
|
|
|
|
import stevedore.driver
|
|
|
|
from taskflow import exceptions as exc
|
|
|
|
# NOTE(harlowja): this is the entrypoint namespace, not the module namespace.
|
|
CONDUCTOR_NAMESPACE = 'taskflow.conductors'
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
def fetch(kind, name, jobboard, namespace=CONDUCTOR_NAMESPACE, **kwargs):
|
|
"""Fetch a conductor backend with the given options.
|
|
|
|
This fetch method will look for the entrypoint 'kind' in the entrypoint
|
|
namespace, and then attempt to instantiate that entrypoint using the
|
|
provided name, jobboard and any board specific kwargs.
|
|
"""
|
|
LOG.debug('Looking for %r conductor driver in %r', kind, namespace)
|
|
try:
|
|
mgr = stevedore.driver.DriverManager(
|
|
namespace, kind,
|
|
invoke_on_load=True,
|
|
invoke_args=(name, jobboard),
|
|
invoke_kwds=kwargs)
|
|
return mgr.driver
|
|
except RuntimeError as e:
|
|
raise exc.NotFound("Could not find conductor %s" % (kind), e)
|