正文
]
return
spam
@eggsample.hookimpl
def eggsample_prep_condiments(condiments):
"""Here the caller passes a mutable object, so we mess with it directly."""
try:
del condiments[
"steak sauce"
]
except KeyError:
pass
condiments[
"spam sauce"
] = 42
return
"Now this is what I call a condiments tray!"
并在打包信息中标注相同的命名空间：
from setuptools import setup
setup(
name="eggsample-spam",
install_requires="eggsample",
entry_points={"eggsample": ["spam = eggsample_spam"]},
py_modules=["eggsample_spam"],
)
其原理也是通过 Python 的
from importlib.metadata import entry_points
找到注册到 Python 解释器
entry_points
中的包，并 根据命名空间获取需要的内容。
stevedore
stevedore 是 Openstack 开发和维护的一个插件工具。该 插件为 Openstack 的 ceilometer 提供插件功能。
stevedore 则是推荐使用继承的方式规范插件接口。
首先创建一个插件基类：
# stevedore/example/base.py
# -*- coding: utf-8 -*-
# Copyright (C) 2020 Red Hat, Inc.
#
# 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 abc
class FormatterBase(metaclass=abc.ABCMeta):
"""Base class for example plugin used in the tutorial.
"""
def __init__(self, max_width=60):
self.max_width = max_width
@abc.abstractmethod
def format(self, data):
"""Format the data and return unicode text.
:param data: A dictionary with string keys and simple types as
values.
:type data: dict(str:?)
:returns: Iterable producing the formatted text.
"""
然后实现一个简单的插件：
# stevedore/example/simple.py
# Copyright (C) 2020 Red Hat, Inc.
#
# 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.
from stevedore.example import base
class Simple(base.FormatterBase):
"""A very basic formatter."""
def format(self, data):
"""Format the data and return unicode text.
:param data: A dictionary with string keys and simple types as
values.
:type data: dict(str:?)
"""
for name, value in sorted(data.items()):
line = '{name} = {value}\n'.format(
name=name,
value=value,
)
yield line
最后打包。打包的时候，将插件注册到
entry_points
中。
# stevedore/example/setup.py
# Copyright (C) 2020 Red Hat, Inc.
#
# 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
