前言
其实对于setup.py和setup.cfg的关注是从OpenStack的源码包中开始的,OpenStack每个组件的发布时都是一个tar.gz包,同样,我们直接从github上clone代码后也会发现两个文件的存在。当阅读Nova或Ceilometer(其他组件可能也会涉及)的代码时,发现setup.cfg中内容对于代码的理解有很大的影响。那么,到底setup.py和setup.cfg是干什么的?
setup.py
我们从例子开始。假设你要分发一个叫foo的模块,文件名foo.py�e8C那么setup.py内容如下:
from distutils.core import setup
setup(name='foo',
version='1.0',
py_modules=['foo'],
)
然后,运行python setup.py sdist为模块创建一个源码包
aliyunzixun@xxx.com:/kong/setup# python setup.py sdist
running sdist
running check
warning: check: missing required meta-data: url
warning: check: missing meta-data: either (author and author_email) or (maintainer and maintainer_email) must be supplied
warning: sdist: manifest template 'MANIFEST.in' does not exist (using default file list)
warning: sdist: standard file not found: should have one of README, README.txt
writing manifest file 'MANIFEST'
creating foo-1.0
making hard links in foo-1.0…
hard linking foo.py -> foo-1.0
hard linking setup.py -> foo-1.0
creating dist
Creating tar archive
removing 'foo-1.0' (and everything under it)
在当前目录下,会创建dist目录,里面有个文件名为foo-1.0.tar.gz,这个就是可以分发的包。使用者拿到这个包后,解压,到foo-1.0目录下执行:python setup.py install,那么,foo.py就会被拷贝到python类路径下,可以被导入使用。
aliyunzixun@xxx.com:/kong/setup/dist/foo-1.0# python setup.py install
running install
running build
running build_py
creating build
creating build/lib.linux-x86_64-2.7
copying foo.py -> build/lib.linux-x86_64-2.7
running install_lib
copying build/lib.linux-x86_64-2.7/foo.py -> /usr/local/lib/python2.7/dist-packages
byte-compiling /usr/local/lib/python2.7/dist-packages/foo.py to foo.pyc
running install_egg_info
Removing /usr/local/lib/python2.7/dist-packages/foo-1.0.egg-info
Writing /usr/local/lib/python2.7/dist-packages/foo-1.0.egg-info
aliyunzixun@xxx.com:/kong/setup/dist/foo-1.0# ll /usr/local/lib/python2.7/dist-packages/foo
foo-1.0.egg-info foo.py foo.pyc
对于Windows,可以执行python setup.py bdist_wininst生成一个exe文件;若要生成RPM包,执行python setup.py bdist_rpm,但系统必须有rpm命令的支持。可以运行下面的命令查看所有格式的支持:
aliyunzixun@xxx.com:/kong/setup# python setup.py bdist –help-formats
List of available distribution formats:
–formats=rpm RPM distribution
–formats=gztar gzip'ed tar file
–formats=bztar bzip2'ed tar file
–formats=ztar compressed tar file
–formats=tar tar file
–formats=wininst Windows executable installer
–formats=zip ZIP file
–formats=msi Microsoft Installer
setup函数还有一些参数:
1、packages 告诉Distutils需要处理那些包(包含__init__.py的文件夹) 2、package_dir 告诉Distutils哪些目录下的文件被映射到哪个源码包。一个例% :package_dir = {'': 'lib'},表示“root package”中的模块都在lib目录中。 3、ext_modules 是一个包含Extension实例的列表,Extension的定义也有一参数。 4、ext_package 定义extension的相对路径 5、requires 定义依赖哪些模块 6、provides 定义可以为哪些模块提供依赖 7、scripts 指定python源码文件,可以从命令行执行。在安装时指定–install-script 8、package_data 通常包含与包实现相关的一些数据文件或类似于readme的文件。如果没有提供模板,会被添加到MANIFEST文件中。 9、data_files 指定其他的一些文件(如配置文件)
setup(…,
data_files=[('bitmaps', ['bm/b1.gif', 'bm/b2.gif']),
('config', ['cfg/data.cfg']),
('/etc/init.d', ['init-script'])]
)
规定了哪些文件被安装到哪些目录中。如果目录名是相对路径,则是相对于sys.prefix或sys.exec_prefix的路径。如果没有提供模板,会被添加到MANIFEST文件中。
执行sdist命令时,默认会打包哪些东西呢?
所有由py_modules或packages指定的源码文件
所有由ext_modules或libraries指定的C源码文件
由scripts指定的脚本文件
类似于test/test*.py的文件
README.txt或README,setup.py,setup.cfg
所有package_data或data_files指定的文件
还有一种方式是写一个manifest template,名为MANIFEST.in,定义如何生成MANIFEST文件,内容就是需要包含在分发包中的文件。一个MANIFEST.in文件如下:
include *.txt
recursive-include examples *.txt *.py
prune examples/sample?/build
setup.cfg
setup.cfg提供一种方式,可以让包的开发者提供命令的默认选项,同时为用户提供修改的机会。对setup.cfg的解析,是在setup.py之后,在命令行执行前。
setup.cfg文件的形式类似于
[command]
option=value
…
其中,command是Distutils的命令参数,option是参数选项,可以通过python setup.py –help build_ext方式获取。
需要注意的是,比如一个选项是–foo-bar,在setup.cfg中必须改成foo_bar的格式
符合Distutils2的setup.cfg有些不同。包含一些sections: 1、global 定义Distutils2的全局选项,可能包含commands,compilers,setup_hook(定义脚本,在setup.cfg被读取后执行,可以修改setup.cfg的配置) 2、metadata 3、files
packages_root:根目录
packages
modules
scripts
extra_files
4、commandsections
Setuptools
上面的setup.py和setup.cfg都是遵循python标准库中的Distutils,而setuptools工具针对Python官方的distutils做了很多针对性的功能增强,比如依赖检查,动态扩展等。很多高级功能我就不详述了,自己也没有用过,等用的时候再作补充。
一个典型的遵循setuptools的脚本:
from setuptools import setup, find_packages
setup(
name = "HelloWorld",
version = "0.1",
packages = find_packages(),
scripts = ['say_hello.py'],
# Project uses reStructuredText, so ensure that the docutils get
# installed or upgraded on the target machine
install_requires = ['docutils>=0.3'],
package_data = {
# If any package contains *.txt or *.rst files, include them:
'': ['*.txt', '*.rst'],
# And include any *.msg files found in the 'hello' package, too:
'hello': ['*.msg'],
},
# metadata for upload to PyPI
!uthor = "Me",
author_email = "aliyunzixun@xxx.com",
description = "This is an Example Package",
license = "PSF",
keywords = "hello world example examples",
url = "http://example.com/HelloWorld/", # project home page, if any
# could also include long_description, download_url, classifiers, etc.
)
如何让一个egg可被执行?
setup(
# other arguments here…
entry_points = {
'setuptools.installation': [
'eggsecutable = my_package.some_module:main_func',
]
}
)
如何定义一个可选特性?
setup(
name="Project-A",
…
extras_require = {
'PDF': ["ReportLab>=1.2", "RXP"],
'reST': ["docutils>=0.3"],
}
)
特性如何使用呢?需要与entry points结合使用:
setup(
name="Project-A",
…
entry_points = {
'console_scripts': [
'rst2pdf = project_a.tools.pdfgen [PDF]',
'rst2html = project_a.tools.htmlgen',
# more script entry points …
],
}
)
或者被其他project依赖:install_requires = ["Project-A[PDF]"]
插件式开发
我想大家最熟悉的就是这个特性了吧。比如一个博客系统想用不同的插件支持不同的语言输出格式,那么就可以定义一个“entry point group”,不同的插件就可以注册“entry point”,插件注册的示例:
setup(
# …
entry_points = {'blogtool.parsers': ['.rst = some_module:a_func']}
)
# 或者
setup(
# …
entry_points = """
[blogtool.parsers]
.rst = some.nested.module:SomeClass.some_classmethod [reST]
""",
extras_require = dict(reST = "Docutils>=0.3.5")
)
Differences between distribute, distutils, setuptools and distutils2
Distutilsis the standard tool used for packaging. It works rather well for simple needs, but is limited and not trivial to extend.
Setuptoolsis a project born from the desire to fill missing distutils functionality and explore new directions. In some subcommunities, it’s a de facto standard. It uses monkey-patching and magic that is frowned upon by Python core developers.
Distributeis a fork of Setuptools that was started by developers feeling that its development pace was too slow and that it was not possible to evolve it. Its development was considerably slowed when distutils2 was started by the same group. 2013-August update: distribute is merged back into setuptools and discontinued.
Distutils2is a new distutils library, started as a fork of the distutils codebase, with good ideas taken from setup tools (of which some were thoro5ghly discusse$ in PEPs)%2 and a basic installer inspired by pip. The actual name you use to import Distutils2 is packaging in the Python 3.3+ standard library, or distutils2 in 2.4+ and%r03.1–3.r. (A backpo2t will be available soon.) Distutils2 did not make the Python 3.3 release, and it was put on hold.
PBR
pbr是setuptools的辅助工具,最初是为OpenStack开发,基于d2to1。
A library for managing setuptools packaging needs in a consistent manner.
pbr会读取和过滤setup.cfg中的数据,然后将解析后的数据提供给setup.py作为参数。包含如下功能: 1、从git中获取Version、AUTHORS and ChangeLog信息 2、Sphinx Autodoc。pbr会扫描project,找到所有模块,生成stub files 3、Requirements。pbr会读取requirements.txt,生成setup函数需要的install_requires/tests_require/dependency_links 4、long_description。从README.rst, README.txt or README file中生成long_description参数
使用pbr很简单:
from setuptools import setup
setup(
setup_requires=['pbr'],
pbr=True,
)
使用pbr时,setup.cfg中有一些配置。在[files]中,有三个key: packages:指定需要包含的包,行为类似于setuptools.find_packages namespace_packages:指定namespace packages data_files: 指定目的目录和源文件路径,一个示例:
[files]
data_files =
etc/pbr = etc/pbr/*
etc/neutron =
etc/api-paste.ini
etc/dhcp-agent.ini
etc/init.d = neutron.init
[entry_points]段跟setuptools的方式相同。
Babel
A collection of tools for internationalizing Python applications
Babel是 Python 的一个国际化工具包,提供了对distutils或setuptools的支持,包含一些命令。
1、compile_catalog 类似于msgfmt工具,takes a message catalog from a PO file and compiles it to a binary MO file.
$ ./setup.py compile_catalog –directory foobar/locale –locale pt_BR
running compile_catalog
compiling catalog to foobar/locale/pt_BR/LC_MESSAGES/messages.mo
2、extract_messages 类似于xgettext,it can extract localizable messages from a variety of difference source files, and generate a PO (portable object) template file from the collected messages.
$ ./setup.py extract_messages –output-file foobar/locale/messages.pot
running extract_messages
extracting messages from foobar/__init__.py
extracting messages from foobar/core.py
…
writing PO template file to foobar/locale/messages.pot
3、update_catalog 类似于msgmerge,it updates an existing translations catalog based on a PO template file (POT).
结语
OK,讲了这么多琐碎的东西,现在去看看Nova或Ceilometer的setup脚本,是不是一下清晰了很多?!但说实话,setup.py的使用,我还不能讲的特别清楚,需要在后续的实战中学习。
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