795aad12aa
This patch introduces a new backend system in oslo.service, enabling the dynamic loading of backends based on a configurable constant (`DEFAULT_BACKEND`). Key updates include: - A `get_backend()` method in `backend/__init__.py` to dynamically load backends based on the `DEFAULT_BACKEND` constant, which can be overridden at import time. - Validation of backends against an enumeration type to ensure correctness - Improved caching mechanism for loaded backends, reducing overhead during repeated calls to `get_backend()`. - Robust error handling for invalid or non-existent backend modules. - Unit tests covering: - Default backend behavior. - Cache functionality and invalidation. - Error handling for missing backend modules. - Retrieval of components from loaded backends. - Simplifies backend configuration by relying on a single constant that can be overridden at import time. - Ensures modularity and flexibility to support multiple backends like Eventlet and Threading. - Enhances testability through isolation and comprehensive mocks. - Maintains backward compatibility with the existing implementation while providing a clear migration path. This patch introduces the backend system without altering the current behavior of oslo.service, ensuring a seamless integration. Change-Id: I57a6371aea42d2dfc1ad06a0bbf60000e6682be3
68 lines
2.5 KiB
Python
68 lines
2.5 KiB
Python
# Copyright (C) 2024 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain 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,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from oslo_service.backend.base import BaseBackend
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from oslo_service import loopingcall
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from oslo_service import service
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from oslo_service import threadgroup
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class EventletBackend(BaseBackend):
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"""Backend implementation for Eventlet.
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In this revision, this is a "stub" for a real backend; right now it imports
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the regular implementation of oslo.service, which will be moved
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entirely into a backend in a subsequent patch.
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"""
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@staticmethod
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def get_service_components():
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"""Return the components provided by the Eventlet backend."""
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return {
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# Classes
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"ServiceBase": service.ServiceBase,
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"ServiceLauncher": service.ServiceLauncher,
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"Launcher": service.Launcher,
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"ProcessLauncher": service.ProcessLauncher,
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"Service": service.Service,
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"Services": service.Services,
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"ServiceWrapper": service.ServiceWrapper,
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"SignalHandler": service.SignalHandler,
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"SignalExit": service.SignalExit,
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# Looping call-related classes
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"LoopingCallBase": loopingcall.LoopingCallBase,
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"LoopingCallDone": loopingcall.LoopingCallDone,
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"LoopingCallTimeOut": loopingcall.LoopingCallTimeOut,
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"FixedIntervalLoopingCall": loopingcall.FixedIntervalLoopingCall,
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"FixedIntervalWithTimeoutLoopingCall":
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loopingcall.FixedIntervalWithTimeoutLoopingCall,
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"DynamicLoopingCall": loopingcall.DynamicLoopingCall,
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"BackOffLoopingCall": loopingcall.BackOffLoopingCall,
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"RetryDecorator": loopingcall.RetryDecorator,
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# Threadgroup call-related classes
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"ThreadGroup": threadgroup.ThreadGroup,
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"Thread": threadgroup.Thread,
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# Functions
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"launch": service.launch,
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"_is_daemon": service._is_daemon,
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"_is_sighup_and_daemon": service._is_sighup_and_daemon,
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}
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