77 lines
2.0 KiB
Python
77 lines
2.0 KiB
Python
# Copyright 2012 OpenStack Foundation
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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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"""This module provides support for dependency injection.
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Providers are registered via the ``@provider()`` decorator, and dependencies on
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them are registered with ``@requires()``. Providers are available to their
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consumers via an attribute. See the documentation for the individual functions
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for more detail.
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See also:
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https://en.wikipedia.org/wiki/Dependency_injection
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"""
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from keystone.common import provider_api
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from keystone.i18n import _
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REGISTRY = provider_api.ProviderAPIs
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GET_REQUIRED = object()
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GET_OPTIONAL = object()
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def get_provider(name, optional=GET_REQUIRED):
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return None
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class UnresolvableDependencyException(Exception):
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"""Raised when a required dependency is not resolvable.
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See ``resolve_future_dependencies()`` for more details.
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"""
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def __init__(self, name, targets):
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msg = _('Unregistered dependency: %(name)s for %(targets)s') % {
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'name': name, 'targets': targets}
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super(UnresolvableDependencyException, self).__init__(msg)
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def provider(name):
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"""Deprecated, does nothing."""
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def wrapper(cls):
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return cls
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return wrapper
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def requires(*dependencies):
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"""Deprecated, does nothing."""
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def wrapped(cls):
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return cls
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return wrapped
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def resolve_future_dependencies(__provider_name=None):
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"""Deprecated, does nothing."""
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return {}
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def reset():
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"""Deprecated, does nothing."""
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