python - Python 标准库的入口点是如何注册的？

Question

常规 Python 包在其 setup.py 中注册入口点或在 pyporject.toml 中指定它们文件。如果他们不使用 distutils/setuptools 进行打包，则属于后者。例如，setuptools' own setup.py将此作为 setuptools.setup() 的参数之一:

    entry_points={
        "setuptools.finalize_distribution_options": [
            "parent_finalize = setuptools.dist:_Distribution.finalize_options",
            "features = setuptools.dist:Distribution._finalize_feature_opts",
            "keywords = setuptools.dist:Distribution._finalize_setup_keywords",
            "2to3_doctests = "
            "setuptools.dist:Distribution._finalize_2to3_doctests",
        ],

问题:

标准库包与 python 捆绑在一起时如何注册其入口点？

例如distutils本身有setup_keywords入口点组。

>>> for ep in pkg_resources.iter_entry_points(group='distutils.setup_keywords'):
>>>    print(ep)

convert_2to3_doctests = setuptools.dist:assert_string_list
dependency_links = setuptools.dist:assert_string_list
eager_resources = setuptools.dist:assert_string_list
exclude_package_data = setuptools.dist:check_package_data
extras_require = setuptools.dist:check_extras
include_package_data = setuptools.dist:assert_bool
install_requires = setuptools.dist:check_requirements
namespace_packages = setuptools.dist:check_nsp
package_data = setuptools.dist:check_package_data
# ... and so on ...

它们从哪里来？

如何列出所有标准库包的所有入口点？IE。不知道group名称 pkg_resources.iter_entry_points(group='<groupname>') ？

Answer 1

每个包的入口点都列在 entry_points.txt 文件中。例如:

$ find /path/to/envs/py38/lib/python3.8/ -name "entry_points.txt"
/path/to/envs/py38/lib/python3.8/site-packages/mypy-0.761.dist-info/entry_points.txt
/path/to/envs/py38/lib/python3.8/site-packages/Pygments-2.5.2.dist-info/entry_points.txt
/path/to/envs/py38/lib/python3.8/site-packages/pip-20.0.2-py3.8.egg-info/entry_points.txt
/path/to/envs/py38/lib/python3.8/site-packages/setuptools-45.2.0.post20200210-py3.8.egg-info/entry_points.txt
/path/to/envs/py38/lib/python3.8/site-packages/ipython-7.12.0.dist-info/entry_points.txt
/path/to/envs/py38/lib/python3.8/site-packages/wheel-0.34.2-py3.8.egg-info/entry_points.txt

正如我们所见distutils不宣传自己的入口点，这实际上是由 setuptools 完成的:

$ cat /path/to/envs/py38/lib/python3.8/site-packages/setuptools-45.2.0.post20200210-py3.8.egg-info/entry_points.txt
[console_scripts]
easy_install = setuptools.command.easy_install:main

[distutils.commands]
alias = setuptools.command.alias:alias
bdist_egg = setuptools.command.bdist_egg:bdist_egg
bdist_rpm = setuptools.command.bdist_rpm:bdist_rpm
bdist_wininst = setuptools.command.bdist_wininst:bdist_wininst
build_clib = setuptools.command.build_clib:build_clib
build_ext = setuptools.command.build_ext:build_ext
build_py = setuptools.command.build_py:build_py
develop = setuptools.command.develop:develop
dist_info = setuptools.command.dist_info:dist_info
easy_install = setuptools.command.easy_install:easy_install
egg_info = setuptools.command.egg_info:egg_info
install = setuptools.command.install:install
install_egg_info = setuptools.command.install_egg_info:install_egg_info
install_lib = setuptools.command.install_lib:install_lib
install_scripts = setuptools.command.install_scripts:install_scripts
rotate = setuptools.command.rotate:rotate
saveopts = setuptools.command.saveopts:saveopts
sdist = setuptools.command.sdist:sdist
setopt = setuptools.command.setopt:setopt
test = setuptools.command.test:test
upload_docs = setuptools.command.upload_docs:upload_docs

[distutils.setup_keywords]
convert_2to3_doctests = setuptools.dist:assert_string_list
dependency_links = setuptools.dist:assert_string_list
eager_resources = setuptools.dist:assert_string_list
entry_points = setuptools.dist:check_entry_points
exclude_package_data = setuptools.dist:check_package_data
extras_require = setuptools.dist:check_extras
include_package_data = setuptools.dist:assert_bool
install_requires = setuptools.dist:check_requirements
namespace_packages = setuptools.dist:check_nsp
package_data = setuptools.dist:check_package_data
packages = setuptools.dist:check_packages
python_requires = setuptools.dist:check_specifier
setup_requires = setuptools.dist:check_requirements
test_loader = setuptools.dist:check_importable
test_runner = setuptools.dist:check_importable
test_suite = setuptools.dist:check_test_suite
tests_require = setuptools.dist:check_requirements
use_2to3 = setuptools.dist:assert_bool
use_2to3_exclude_fixers = setuptools.dist:assert_string_list
use_2to3_fixers = setuptools.dist:assert_string_list
zip_safe = setuptools.dist:assert_bool

[egg_info.writers]
PKG-INFO = setuptools.command.egg_info:write_pkg_info
dependency_links.txt = setuptools.command.egg_info:overwrite_arg
depends.txt = setuptools.command.egg_info:warn_depends_obsolete
eager_resources.txt = setuptools.command.egg_info:overwrite_arg
entry_points.txt = setuptools.command.egg_info:write_entries
namespace_packages.txt = setuptools.command.egg_info:overwrite_arg
requires.txt = setuptools.command.egg_info:write_requirements
top_level.txt = setuptools.command.egg_info:write_toplevel_names

[setuptools.finalize_distribution_options]
2to3_doctests = setuptools.dist:Distribution._finalize_2to3_doctests
features = setuptools.dist:Distribution._finalize_feature_opts
keywords = setuptools.dist:Distribution._finalize_setup_keywords
parent_finalize = setuptools.dist:_Distribution.finalize_options

[setuptools.installation]
eggsecutable = setuptools.command.easy_install:bootstrap

发现所有入口点

从 Python 3.8 开始，您可以使用 importlib.metadata.entry_points用于列出所有已安装软件包的入口点:

>>> from importlib.metadata import entry_points
>>> from pprint import pprint
>>> pprint(entry_points())
{'console_scripts': (EntryPoint(name='dmypy', value='mypy.dmypy.client:console_entry', group='console_scripts'),
                     EntryPoint(name='mypy', value='mypy.__main__:console_entry', group='console_scripts'),
                     EntryPoint(name='stubgen', value='mypy.stubgen:main', group='console_scripts'),
                     EntryPoint(name='pygmentize', value='pygments.cmdline:main', group='console_scripts'),
                     EntryPoint(name='pip', value='pip._internal.cli.main:main', group='console_scripts'),
                     EntryPoint(name='pip3', value='pip._internal.cli.main:main', group='console_scripts'),
                     EntryPoint(name='pip3.8', value='pip._internal.cli.main:main', group='console_scripts'),
                     EntryPoint(name='easy_install', value='setuptools.command.easy_install:main', group='console_scripts'),
                     EntryPoint(name='iptest', value='IPython.testing.iptestcontroller:main', group='console_scripts'),
                     EntryPoint(name='iptest3', value='IPython.testing.iptestcontroller:main', group='console_scripts'),
                     EntryPoint(name='ipython', value='IPython:start_ipython', group='console_scripts'),
                     EntryPoint(name='ipython3', value='IPython:start_ipython', group='console_scripts'),
                     EntryPoint(name='wheel', value='wheel.cli:main', group='console_scripts')),
 'distutils.commands': (EntryPoint(name='alias', value='setuptools.command.alias:alias', group='distutils.commands'),
                        EntryPoint(name='bdist_egg', value='setuptools.command.bdist_egg:bdist_egg', group='distutils.commands'),
                        EntryPoint(name='bdist_rpm', value='setuptools.command.bdist_rpm:bdist_rpm', group='distutils.commands'),
                        EntryPoint(name='bdist_wininst', value='setuptools.command.bdist_wininst:bdist_wininst', group='distutils.commands'),
                        EntryPoint(name='build_clib', value='setuptools.command.build_clib:build_clib', group='distutils.commands'),
                        EntryPoint(name='build_ext', value='setuptools.command.build_ext:build_ext', group='distutils.commands'),
                        EntryPoint(name='build_py', value='setuptools.command.build_py:build_py', group='distutils.commands'),
                        EntryPoint(name='develop', value='setuptools.command.develop:develop', group='distutils.commands'),
                        EntryPoint(name='dist_info', value='setuptools.command.dist_info:dist_info', group='distutils.commands'),
                        EntryPoint(name='easy_install', value='setuptools.command.easy_install:easy_install', group='distutils.commands'),
                        EntryPoint(name='egg_info', value='setuptools.command.egg_info:egg_info', group='distutils.commands'),
                        EntryPoint(name='install', value='setuptools.command.install:install', group='distutils.commands'),
                        EntryPoint(name='install_egg_info', value='setuptools.command.install_egg_info:install_egg_info', group='distutils.commands'),
                        EntryPoint(name='install_lib', value='setuptools.command.install_lib:install_lib', group='distutils.commands'),
                        EntryPoint(name='install_scripts', value='setuptools.command.install_scripts:install_scripts', group='distutils.commands'),
                        EntryPoint(name='rotate', value='setuptools.command.rotate:rotate', group='distutils.commands'),
                        EntryPoint(name='saveopts', value='setuptools.command.saveopts:saveopts', group='distutils.commands'),
                        EntryPoint(name='sdist', value='setuptools.command.sdist:sdist', group='distutils.commands'),
                        EntryPoint(name='setopt', value='setuptools.command.setopt:setopt', group='distutils.commands'),
                        EntryPoint(name='test', value='setuptools.command.test:test', group='distutils.commands'),
                        EntryPoint(name='upload_docs', value='setuptools.command.upload_docs:upload_docs', group='distutils.commands'),
                        EntryPoint(name='bdist_wheel', value='wheel.bdist_wheel:bdist_wheel', group='distutils.commands')),
 'distutils.setup_keywords': (EntryPoint(name='convert_2to3_doctests', value='setuptools.dist:assert_string_list', group='distutils.setup_keywords'),
                              EntryPoint(name='dependency_links', value='setuptools.dist:assert_string_list', group='distutils.setup_keywords'),
                              EntryPoint(name='eager_resources', value='setuptools.dist:assert_string_list', group='distutils.setup_keywords'),
                              EntryPoint(name='entry_points', value='setuptools.dist:check_entry_points', group='distutils.setup_keywords'),
                              EntryPoint(name='exclude_package_data', value='setuptools.dist:check_package_data', group='distutils.setup_keywords'),
                              EntryPoint(name='extras_require', value='setuptools.dist:check_extras', group='distutils.setup_keywords'),
                              EntryPoint(name='include_package_data', value='setuptools.dist:assert_bool', group='distutils.setup_keywords'),
                              EntryPoint(name='install_requires', value='setuptools.dist:check_requirements', group='distutils.setup_keywords'),
                              EntryPoint(name='namespace_packages', value='setuptools.dist:check_nsp', group='distutils.setup_keywords'),
                              EntryPoint(name='package_data', value='setuptools.dist:check_package_data', group='distutils.setup_keywords'),
                              EntryPoint(name='packages', value='setuptools.dist:check_packages', group='distutils.setup_keywords'),
                              EntryPoint(name='python_requires', value='setuptools.dist:check_specifier', group='distutils.setup_keywords'),
                              EntryPoint(name='setup_requires', value='setuptools.dist:check_requirements', group='distutils.setup_keywords'),
                              EntryPoint(name='test_loader', value='setuptools.dist:check_importable', group='distutils.setup_keywords'),
                              EntryPoint(name='test_runner', value='setuptools.dist:check_importable', group='distutils.setup_keywords'),
                              EntryPoint(name='test_suite', value='setuptools.dist:check_test_suite', group='distutils.setup_keywords'),
                              EntryPoint(name='tests_require', value='setuptools.dist:check_requirements', group='distutils.setup_keywords'),
                              EntryPoint(name='use_2to3', value='setuptools.dist:assert_bool', group='distutils.setup_keywords'),
                              EntryPoint(name='use_2to3_exclude_fixers', value='setuptools.dist:assert_string_list', group='distutils.setup_keywords'),
                              EntryPoint(name='use_2to3_fixers', value='setuptools.dist:assert_string_list', group='distutils.setup_keywords'),
                              EntryPoint(name='zip_safe', value='setuptools.dist:assert_bool', group='distutils.setup_keywords')),
 'egg_info.writers': (EntryPoint(name='PKG-INFO', value='setuptools.command.egg_info:write_pkg_info', group='egg_info.writers'),
                      EntryPoint(name='dependency_links.txt', value='setuptools.command.egg_info:overwrite_arg', group='egg_info.writers'),
                      EntryPoint(name='depends.txt', value='setuptools.command.egg_info:warn_depends_obsolete', group='egg_info.writers'),
                      EntryPoint(name='eager_resources.txt', value='setuptools.command.egg_info:overwrite_arg', group='egg_info.writers'),
                      EntryPoint(name='entry_points.txt', value='setuptools.command.egg_info:write_entries', group='egg_info.writers'),
                      EntryPoint(name='namespace_packages.txt', value='setuptools.command.egg_info:overwrite_arg', group='egg_info.writers'),
                      EntryPoint(name='requires.txt', value='setuptools.command.egg_info:write_requirements', group='egg_info.writers'),
                      EntryPoint(name='top_level.txt', value='setuptools.command.egg_info:write_toplevel_names', group='egg_info.writers')),
 'pygments.lexers': (EntryPoint(name='ipython', value='IPython.lib.lexers:IPythonLexer', group='pygments.lexers'),
                     EntryPoint(name='ipython3', value='IPython.lib.lexers:IPython3Lexer', group='pygments.lexers'),
                     EntryPoint(name='ipythonconsole', value='IPython.lib.lexers:IPythonConsoleLexer', group='pygments.lexers')),
 'setuptools.finalize_distribution_options': (EntryPoint(name='2to3_doctests', value='setuptools.dist:Distribution._finalize_2to3_doctests', group='setuptools.finalize_distribution_options'),
                                              EntryPoint(name='features', value='setuptools.dist:Distribution._finalize_feature_opts', group='setuptools.finalize_distribution_options'),
                                              EntryPoint(name='keywords', value='setuptools.dist:Distribution._finalize_setup_keywords', group='setuptools.finalize_distribution_options'),
                                              EntryPoint(name='parent_finalize', value='setuptools.dist:_Distribution.finalize_options', group='setuptools.finalize_distribution_options')),
 'setuptools.installation': (EntryPoint(name='eggsecutable', value='setuptools.command.easy_install:bootstrap', group='setuptools.installation'),)}