5de514f1f8
Introduces a new threading backend for oslo.service that provides a complete alternative to the eventlet-based backend. This backend includes: • A ThreadGroup and Thread implementation using the Python threading module. • A reimplementation of all looping call utilities ( FixedIntervalLoopingCall, DynamicLoopingCall, etc.) using threading.Event and futurist.ThreadPoolExecutor. • A service management layer based on cotyledon, including Service,ServiceWrapper, Launcher, and ProcessLauncher. • A new ThreadingBackend class that exposes all components needed for integration into oslo.service. This change provides a robust and eventlet-free alternative backend while maintaining API compatibility. Change-Id: Ia7518401ccdcc28afbffd4ffe5c3b772f3617001
105 lines
3.2 KiB
Python
105 lines
3.2 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 __future__ import annotations
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import abc
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from typing import Any
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from oslo_service.backend.exceptions import BackendComponentNotAvailable
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class BaseBackend(abc.ABC):
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"""Base class for all backend implementations."""
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@abc.abstractmethod
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def get_service_components(self) -> dict[str, Any]:
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"""Return the backend components.
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This method should return a dictionary containing all the components
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required for the backend to function. For example:
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{
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"ServiceLauncher": Class or function,
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"ProcessLauncher": Class or function,
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"Service": Class or function,
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"LoopingCall": Class or function,
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...
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}
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"""
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pass
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class ServiceBase(metaclass=abc.ABCMeta):
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"""Base class for all services."""
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@abc.abstractmethod
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def start(self):
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"""Start service."""
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@abc.abstractmethod
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def stop(self):
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"""Stop service."""
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@abc.abstractmethod
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def wait(self):
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"""Wait for service to complete."""
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@abc.abstractmethod
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def reset(self):
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"""Reset service.
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Called in case a service running in daemon mode receives SIGHUP.
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"""
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class ComponentRegistry:
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"""A registry to manage access to backend components.
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This class ensures that attempting to access a missing component
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raises an explicit error, improving clarity and debugging. It acts
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as a centralized registry for backend components.
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"""
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def __init__(self, components):
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"""Initialize the registry with a dictionary of components.
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:param components: A dictionary containing backend components,
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where the keys are component names and the values are the
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respective implementations.
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"""
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self._components = components
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def __getitem__(self, key):
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"""Retrieve a component by its key from the registry.
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:param key: The name of the component to retrieve.
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:raises NotImplementedError: If the component is not registered
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or available.
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:return: The requested component instance.
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"""
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if key not in self._components or self._components[key] is None:
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raise BackendComponentNotAvailable(
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f"Component '{key}' is not available in this backend.")
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return self._components[key]
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def __contains__(self, key):
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"""Check if a component is registered and available.
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:param key: The name of the component to check.
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:return: True if the component is registered and available,
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False otherwise.
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"""
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return key in self._components and self._components[key] is not None
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