Packaging Python Projects¶
This tutorial walks you through how to package a simple Python project. It will show you how to add the necessary files and structure to create the package, how to build the package, and how to upload it to the Python Package Index (PyPI).
If you have trouble running the commands in this tutorial, please copy the command and its output, then open an issue on the packaging-problems repository on GitHub. We’ll do our best to help you!
Some of the commands require a newer version of pip , so start by making sure you have the latest version installed:
python3 -m pip install --upgrade pip
py -m pip install --upgrade pip
A simple project¶
This tutorial uses a simple project named example_package_YOUR_USERNAME_HERE . If your username is me , then the package would be example_package_me ; this ensures that you have a unique package name that doesn’t conflict with packages uploaded by other people following this tutorial. We recommend following this tutorial as-is using this project, before packaging your own project.
Create the following file structure locally:
packaging_tutorial/ └── src/ └── example_package_YOUR_USERNAME_HERE/ ├── __init__.py └── example.py
The directory containing the Python files should match the project name. This simplifies the configuration and is more obvious to users who install the package.
__init__.py is required to import the directory as a package, and should be empty.
example.py is an example of a module within the package that could contain the logic (functions, classes, constants, etc.) of your package. Open that file and enter the following content:
def add_one(number): return number + 1
If you are unfamiliar with Python’s modules and import packages , take a few minutes to read over the Python documentation for packages and modules.
Once you create this structure, you’ll want to run all of the commands in this tutorial within the packaging_tutorial directory.
Creating the package files¶
You will now add files that are used to prepare the project for distribution. When you’re done, the project structure will look like this:
packaging_tutorial/ ├── LICENSE ├── pyproject.toml ├── README.md ├── src/ │ └── example_package_YOUR_USERNAME_HERE/ │ ├── __init__.py │ └── example.py └── tests/
Creating a test directory¶
tests/ is a placeholder for test files. Leave it empty for now.
Creating pyproject.toml¶
pyproject.toml tells “frontend” build tools like pip and build what “backend” tool to use to create distribution packages for your project. You can choose from a number of backends; this tutorial uses Hatchling by default, but it will work identically with setuptools , Flit , PDM , and others that support the [project] table for metadata .
Some build backends are part of larger tools that provide a command-line interface with additional features like project initialization and version management, as well as building, uploading, and installing packages. This tutorial uses single-purpose tools that work independently.
Open pyproject.toml and enter one of these [build-system] tables:
[build-system] requires = ["hatchling"] build-backend = "hatchling.build"
[build-system] requires = ["setuptools>=61.0"] build-backend = "setuptools.build_meta"
[build-system] requires = ["flit_core>=3.4"] build-backend = "flit_core.buildapi"
[build-system] requires = ["pdm-backend"] build-backend = "pdm.backend"
- requires is a list of packages that are needed to build your package. You don’t need to install them; build frontends like pip will install them automatically in a temporary, isolated virtual environment for use during the build process.
- build-backend is the name of the Python object that frontends will use to perform the build.
Configuring metadata¶
Open pyproject.toml and enter the following content. Change the name to include your username; this ensures that you have a unique package name that doesn’t conflict with packages uploaded by other people following this tutorial.
[project] name = "example_package_YOUR_USERNAME_HERE" version = "0.0.1" authors = [ name="Example Author", email="author@example.com" >, ] description = "A small example package" readme = "README.md" requires-python = ">=3.7" classifiers = [ "Programming Language :: Python :: 3", "License :: OSI Approved :: MIT License", "Operating System :: OS Independent", ] [project.urls] "Homepage" = "https://github.com/pypa/sampleproject" "Bug Tracker" = "https://github.com/pypa/sampleproject/issues"
- name is the distribution name of your package. This can be any name as long as it only contains letters, numbers, . , _ , and — . It also must not already be taken on PyPI. Be sure to update this with your username for this tutorial, as this ensures you won’t try to upload a package with the same name as one which already exists.
- version is the package version. See the version specifier specification for more details on versions. Some build backends allow it to be specified another way, such as from a file or a git tag.
- authors is used to identify the author of the package; you specify a name and an email for each author. You can also list maintainers in the same format.
- description is a short, one-sentence summary of the package.
- readme is a path to a file containing a detailed description of the package. This is shown on the package detail page on PyPI. In this case, the description is loaded from README.md (which is a common pattern). There also is a more advanced table form described in the project metadata specification .
- requires-python gives the versions of Python supported by your project. Installers like pip will look back through older versions of packages until it finds one that has a matching Python version.
- classifiers gives the index and pip some additional metadata about your package. In this case, the package is only compatible with Python 3, is licensed under the MIT license, and is OS-independent. You should always include at least which version(s) of Python your package works on, which license your package is available under, and which operating systems your package will work on. For a complete list of classifiers, see https://pypi.org/classifiers/.
- urls lets you list any number of extra links to show on PyPI. Generally this could be to the source, documentation, issue trackers, etc.
See the project metadata specification for details on these and other fields that can be defined in the [project] table. Other common fields are keywords to improve discoverability and the dependencies that are required to install your package.
Creating README.md¶
Open README.md and enter the following content. You can customize this if you’d like.
# Example Package This is a simple example package. You can use [Github-flavored Markdown](https://guides.github.com/features/mastering-markdown/) to write your content.
Creating a LICENSE¶
It’s important for every package uploaded to the Python Package Index to include a license. This tells users who install your package the terms under which they can use your package. For help picking a license, see https://choosealicense.com/. Once you have chosen a license, open LICENSE and enter the license text. For example, if you had chosen the MIT license:
Copyright (c) 2018 The Python Packaging Authority Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Most build backends automatically include license files in packages. See your backend’s documentation for more details.
Including other files¶
The files listed above will be included automatically in your source distribution . If you want to include additional files, see the documentation for your build backend.
Generating distribution archives¶
The next step is to generate distribution packages for the package. These are archives that are uploaded to the Python Package Index and can be installed by pip .
Make sure you have the latest version of PyPA’s build installed:
python3 -m pip install --upgrade build