Now, let’s change gears and look at creating our own packages. If you want to
make your code accessible to someone else to use via pip install, you need to
make it a package. In fact, as you’ll see at the end of this section, even if
you just want to develop an application, it’s much better to be working in a
package. I won’t show you the internals of setting up a setuptools package, but
we’ll just go over how you work with it and how it is distributed.
To install a local package, use:
pip install .This will copy the files into site-packages. If you want to actively develop a
module, include the -e option instead (setuptools only, command varies on
other tools):
pip install -e .This uses symlink(s) so that you can edit the local files and immediately see the changes (after restarting Python, as usual). If you want to produce an SDist for distributing the source, use
pip install build
python -m build --sdistIf you want to produce a wheel for distribution, use
python -m build --wheelYou’ll see old tutorials directly call python setup.py ...; if you can
possibly avoid doing that, please do! The setup.py file is still a good idea
for setuptools, but it’s not even required there (and doesn’t exist for any
other packaging software). (It’s also quite valid to use pipx to install build,
but remember the command is pyproject-build if you do that).
Distributions¶
Wheel: fast and simple¶
A wheel is just a normal zipped file with the extension .whl. It contains
folders that get copied to specific locations, and a metadata folder.
It does not contain setup.py/setup.cfg/pyproject.toml.
Why use wheels?
Secure installs - arbitrary code does not run
Fast installs - files are just copied inplace
Reliable - does not depend on pretty much anything being on user’s machine, including setuptools!
Faster first imports - pip makes .pyc files when it installs
Can be tagged for Python version, OS, and/or architecture (supports binaries!).
SDist: Source distribution¶
This is a .tar.gz file holding the files needed to make a wheel. It is often a
subset of the files in the GitHub repo, though sometimes it contains generated
files, like version.py or maybe Cython/SWIG generated source files. If there
is no matching wheel (only for projects with binary components, in general),
then pip gets the SDist and builds/installs manually.