7fe6bf0d6b
In order to make it simpler (and less code) just prefer to use object types that already exist instead of trying to make dictionaries also behave like objects. For those that really need this kind of functionality: https://pypi.python.org/pypi/attrdict Change-Id: Ib7ddfa517f0500082fafac2c3e53fd6a158a6ddf
87 lines
3.0 KiB
Python
87 lines
3.0 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 contextlib
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import logging
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import six
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from stevedore import driver
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from taskflow import exceptions as exc
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from taskflow.utils import misc
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# NOTE(harlowja): this is the entrypoint namespace, not the module namespace.
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BACKEND_NAMESPACE = 'taskflow.jobboards'
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LOG = logging.getLogger(__name__)
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def fetch(name, conf, namespace=BACKEND_NAMESPACE, **kwargs):
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"""Fetch a jobboard backend with the given configuration.
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This fetch method will look for the entrypoint name in the entrypoint
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namespace, and then attempt to instantiate that entrypoint using the
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provided name, configuration and any board specific kwargs.
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NOTE(harlowja): to aid in making it easy to specify configuration and
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options to a board the configuration (which is typical just a dictionary)
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can also be a uri string that identifies the entrypoint name and any
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configuration specific to that board.
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For example, given the following configuration uri:
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zookeeper://<not-used>/?a=b&c=d
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This will look for the entrypoint named 'zookeeper' and will provide
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a configuration object composed of the uris parameters, in this case that
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is {'a': 'b', 'c': 'd'} to the constructor of that board instance (also
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including the name specified).
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"""
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if isinstance(conf, six.string_types):
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conf = {'board': conf}
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board = conf['board']
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try:
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uri = misc.parse_uri(board)
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except (TypeError, ValueError):
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pass
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else:
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board = uri.scheme
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conf = misc.merge_uri(uri, conf.copy())
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LOG.debug('Looking for %r jobboard driver in %r', board, namespace)
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try:
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mgr = driver.DriverManager(namespace, board,
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invoke_on_load=True,
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invoke_args=(name, conf),
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invoke_kwds=kwargs)
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return mgr.driver
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except RuntimeError as e:
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raise exc.NotFound("Could not find jobboard %s" % (board), e)
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@contextlib.contextmanager
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def backend(name, conf, namespace=BACKEND_NAMESPACE, **kwargs):
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"""Fetches a jobboard, connects to it and closes it on completion.
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This allows a board instance to fetched, connected to, and then used in a
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context manager statement with the board being closed upon context
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manager exit.
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"""
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jb = fetch(name, conf, namespace=namespace, **kwargs)
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jb.connect()
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with contextlib.closing(jb):
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yield jb
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