setuptools Quickstart#

Installation#

To install the latest version of setuptools, use:

pip install --upgrade setuptools

Python packaging at a glance#

The landscape of Python packaging is shifting and Setuptools has evolved to only provide backend support, no longer being the de-facto packaging tool in the market. Every python package must provide a pyproject.toml and specify the backend (build system) it wants to use. The distribution can then be generated with whatever tool that provides a build sdist-like functionality. While this may appear cumbersome, given the added pieces, it in fact tremendously enhances the portability of your package. The change is driven under PEP 517. To learn more about Python packaging in general, navigate to the bottom of this page.

Basic Use#

For basic use of setuptools, you will need a pyproject.toml with the exact following info, which declares you want to use setuptools to package your project:

[build-system]
requires = ["setuptools"]
build-backend = "setuptools.build_meta"

Then, you will need to specify your package information such as metadata, contents, dependencies, etc.

Setuptools currently supports configurations from either setup.cfg, setup.py or pyproject.toml 2 files, however, configuring new projects via setup.py is discouraged 1.

The following example demonstrates a minimum configuration:

[metadata]
name = mypackage
version = 0.0.1

[options]
packages = mypackage
install_requires =
    requests
    importlib-metadata; python_version < "3.8"

See Configuring setuptools using setup.cfg files for more information.

from setuptools import setup

setup(
    name='mypackage',
    version='0.0.1',
    packages=['mypackage'],
    install_requires=[
        'requests',
        'importlib-metadata; python_version == "3.8"',
    ],
)

See Keywords for more information.

[project]
name = "mypackage"
version = "0.0.1"
dependencies = [
    "requests",
    'importlib-metadata; python_version<"3.8"',
]

See Configuring setuptools using pyproject.toml files for more information.

This is what your project would look like:

~/mypackage/
    pyproject.toml
    setup.cfg # or setup.py
    mypackage/__init__.py

Then, you need a builder, such as PyPA build which you can obtain via pip install build. After downloading it, invoke the builder:

python -m build

You now have your distribution ready (e.g. a tar.gz file and a .whl file in the dist directory), which you can upload to PyPI!

Of course, before you release your project to PyPI, you’ll want to add a bit more information to your setup script to help people find or learn about your project. And maybe your project will have grown by then to include a few dependencies, and perhaps some data files and scripts. In the next few sections, we will walk through the additional but essential information you need to specify to properly package your project.

Automatic package discovery#

For simple projects, it’s usually easy enough to manually add packages to the packages keyword in setup.cfg. However, for very large projects, it can be a big burden to keep the package list updated. Therefore, setuptools provides a convenient way to automatically list all the packages in your project directory:

[options]
packages = find: # OR `find_namespaces:` if you want to use namespaces

[options.packages.find] # (always `find` even if `find_namespaces:` was used before)
# This section is optional
# Each entry in this section is optional, and if not specified, the default values are:
# `where=.`, `include=*` and `exclude=` (empty).
include=mypackage*
exclude=mypackage.tests*
from setuptools import find_packages  # or find_namespace_packages

setup(
    # ...
    packages=find_packages(
        where='.',
        include=['mypackage*'],  # ["*"] by default
        exclude=['mypackage.tests'],  # empty by default
    ),
    # ...
)
# ...
[tool.setuptools.packages]
find = {}  # Scan the project directory with the default parameters

# OR
[tool.setuptools.packages.find]
where = ["src"]  # ["."] by default
include = ["mypackage*"]  # ["*"] by default
exclude = ["mypackage.tests*"]  # empty by default
namespaces = false  # true by default

When you pass the above information, alongside other necessary information, setuptools walks through the directory specified in where (omitted here as the package resides in the current directory) and filters the packages it can find following the include (defaults to none), then removes those that match the exclude and returns a list of Python packages. The above setup also allows you to adopt a src/ layout. For more details and advanced use, go to Package Discovery and Namespace Package.

Tip

Starting with version 61.0.0, setuptools’ automatic discovery capabilities have been improved to detect popular project layouts (such as the flat-layout and src-layout) without requiring any special configuration. Check out our reference docs for more information, but please keep in mind that this functionality is still considered experimental and might change (or even be removed) in future releases.

Entry points and automatic script creation#

Setuptools supports automatic creation of scripts upon installation, that runs code within your package if you specify them as entry points. This is what allows you to run commands like pip install instead of having to type python -m pip install. The following configuration examples show how to accomplish this:

[options.entry_points]
console_scripts =
    cli-name = mypkg.mymodule:some_func
setup(
    # ...
    entry_points={
        'console_scripts': [
            'cli-name = mypkg.mymodule:some_func',
        ]
    }
)
[project.scripts]
cli-name = "mypkg.mymodule:some_func"

When this project is installed, a cli-name executable will be created. cli-name will invoke the function some_func in the mypkg/mymodule.py file when called by the user. Note that you can also use the entry-points mechanism to advertise components between installed packages and implement plugin systems. For detailed usage, go to Entry Points.

Dependency management#

Packages built with setuptools can specify dependencies to be automatically installed when the package itself is installed. The example below show how to configure this kind of dependencies:

[options]
install_requires =
    docutils
    requests <= 0.4
setup(
    # ...
    install_requires=["docutils", "requests <= 0.4"],
    # ...
)
[project]
# ...
dependencies = [
    "docutils",
    "requires <= 0.4",
]
# ...

Each dependency is represented by a string that can optionally contain version requirements (e.g. one of the operators <, >, <=, >=, == or !=, followed by a version identifier), and/or conditional environment markers, e.g. sys_platform == "win32" (see Version specifiers for more information).

When your project is installed, all of the dependencies not already installed will be located (via PyPI), downloaded, built (if necessary), and installed. This, of course, is a simplified scenario. You can also specify groups of extra dependencies that are not strictly required by your package to work, but that will provide additional functionalities. For more advanced use, see Dependencies Management in Setuptools.

Including Data Files#

The distutils have traditionally allowed installation of “data files”, which are placed in a platform-specific location. Setuptools offers three ways to specify data files to be included in your packages. For the simplest use, you can simply use the include_package_data keyword:

[options]
include_package_data = True
setup(
    # ...
    include_package_data=True,
    # ...
)
[tool.setuptools]
include-package-data = true
# This is already the default behaviour if your are using
# pyproject.toml to configure your build.
# You can deactivate that with `include-package-data = false`

This tells setuptools to install any data files it finds in your packages. The data files must be specified via the distutils’ MANIFEST.in file or automatically added by a Revision Control System plugin. For more details, see Data Files Support.

Development mode#

setuptools allows you to install a package without copying any files to your interpreter directory (e.g. the site-packages directory). This allows you to modify your source code and have the changes take effect without you having to rebuild and reinstall. Here’s how to do it:

pip install --editable .

This creates a link file in your interpreter site package directory which associate with your source code. For more information, see “Development Mode”.

Tip

Prior to pip v21.1, a setup.py script was required to be compatible with development mode. With late versions of pip, setup.cfg-only projects may be installed in this mode.

If you are experimenting with configuration using, or have version of pip older than v21.1, you might need to keep a setup.py file in file in your repository if you want to use editable installs (for the time being).

A simple script will suffice, for example:

from setuptools import setup

setup()

You can still keep all the configuration in setup.cfg (or pyproject.toml).

Uploading your package to PyPI#

After generating the distribution files, the next step would be to upload your distribution so others can use it. This functionality is provided by twine and is documented in the Python packaging tutorial.

Transitioning from setup.py to setup.cfg#

To avoid executing arbitrary scripts and boilerplate code, we are transitioning into a full-fledged setup.cfg to declare your package information instead of running setup(). This inevitably brings challenges due to a different syntax. Here we provide a quick guide to understanding how setup.cfg is parsed by setuptools to ease the pain of transition.

Resources on Python packaging#

Packaging in Python can be hard and is constantly evolving. Python Packaging User Guide has tutorials and up-to-date references that can help you when it is time to distribute your work.


Notes

1(1,2,3,4,5,6)

The setup.py file should be used only when custom scripting during the build is necessary. Examples are kept in this document to help people interested in maintaining or contributing to existing packages that use setup.py. Note that you can still keep most of configuration declarative in setup.cfg or pyproject.toml and use setup.py only for the parts not supported in those files (e.g. C extensions).

2(1,2,3,4,5,6)

While the [build-system] table should always be specified in the pyproject.toml file, support for adding package metadata and build configuration options via the [project] and [tool.setuptools] tables is still experimental and might change in future releases. See Configuring setuptools using pyproject.toml files.