Working with uv¶
uv is an extremely fast Python package and project manager, written in Rust. We will use uv as
the single tool that replaces pip, virtualenv, pyenv, and more. The main tasks for which we
will use uv are:
- run and install Python versions
- installing and managing a virtual environment
- build all the packages in the workspace or monorepo
- publish all the packages to PyPI
- run scripts and apps
Installing uv¶
On macOS and Linux you can install uv using curl:
$ curl -LsSf https://astral.sh/uv/install.sh | sh
If you need more specific information on installing and upgrading uv, please refer to
the official documentation.
Installing a Python version¶
The CGSE is guaranteed to work with Python 3.9.x. We will gradually include higher versions of Python, but currently these have not been tested. So, we will for the moment stick with Python 3.9.20. Install this version as follows:
$ uv python install 3.9.20
pyenv
When you are using pyenv to manage your Python versions, make sure you also have the same
Python version installed with pyenv and uv. Otherwise you will run into the following
error. This is a known issue with uv.
pyenv: version `3.9.20' is not installed (set by /Users/rik/github/cgse/libs/cgse-common/.python-version)
You can check which Python versions are installed already on your system:
$ uv python list --only-installed
cpython-3.12.8-macos-aarch64-none /Users/rik/Library/Application Support/uv/python/cpython-3.12.8-macos-aarch64-none/bin/python3.12
cpython-3.10.16-macos-aarch64-none /Users/rik/Library/Application Support/uv/python/cpython-3.10.16-macos-aarch64-none/bin/python3.10
cpython-3.9.21-macos-aarch64-none /Users/rik/Library/Application Support/uv/python/cpython-3.9.21-macos-aarch64-none/bin/python3.9
cpython-3.9.20-macos-aarch64-none /Users/rik/Library/Application Support/uv/python/cpython-3.9.20-macos-aarch64-none/bin/python3.9
cpython-3.9.6-macos-aarch64-none /Library/Developer/CommandLineTools/usr/bin/python3 -> ../../Library/Frameworks/Python3.framework/Versions/3.9/bin/python3
cpython-3.8.17-macos-aarch64-none /Users/rik/Library/Application Support/uv/python/cpython-3.8.17-macos-aarch64-none/bin/python3.8
Create a virtual environment¶
Pin a Python version
You can pin a python version with the command:
$ uv python pin 3.9.20
uv will search for a pinned version in the parent folders up to the root folder or your home directory.
You can create a virtual environment with uv for the specific Python version as follows. The
'--python' is optional and uv will use the default (pinned) Python version when creating a
venv without this option. We are working in a monorepo or what uv calls a workspace. There will
be only one virtual environment at the root of the monorepo, despite the fact that we have several
individual packages in our workspace. Don't worry, uv will always use the virtual environment at
the root and keep it up-to-date with the project your are currently working in.
When creating a virtual environment make sure you are in the root folder, e.g. ~/github/cgse.
$ cd ~/github/cgse
$ uv venv --python 3.9.20
If you want to name your virtual environment, use the optional argument --prompt <venv name> in
the above command, otherwise the virtual environment will get the same name as the project, i.e.
cgse.
Now, navigate to the package you will be working in and update the projects' environment, assuming
you are going to work in cgse-core, this will be:
$ cd ~/github/cgse/libs/cgse-core
$ uv sync
Your package(s) from the workspace should be installed as an editable install. You can check this with the command:
$ uv pip list -v
Using Python 3.9.20 environment at: /Users/rik/github/cgse/.venv
Package Version Editable project location
----------------- ----------- ---------------------------------------
apscheduler 3.11.0
cgse-common 0.4.0 /Users/rik/github/cgse/libs/cgse-common
cgse-core 0.4.0 /Users/rik/github/cgse/libs/cgse-core
...
To install any other project as an editable package:
$ uv pip install -e <project location>
Note
If you don't want to use the uv commands, you can activate the virtual environment and use the original pip
and python commands as you are used to, but I would recommend you try to get used to uv
for a while to experience its benefits.
$ source ~/github/cgse/.venv/bin/activate
Info
In a workspace, maintaining a virtual environment per package might be a hassle and most of the time that is not
needed. A good approach is to always use the virtual environment at the workspace root. This venv which will be
automatically created if you run a command or if you use uv sync in the package folder. With uv sync you can
make sure the virtual environment is up-to-date and contains only those dependencies that are required for the
package you are in. So, each time you switch to another package and want to run a comand or a test for that
package, use
$ uv sync
Adding and removing dependencies¶
If we need another Python package that we want to use and add this as a dependency to our project,
we don't just want to install it with the pip command, nor add it to the pyproject. toml file
ourselves. Instead, we use the uv add <package name> command, e.g. to install flask, we do:
$ uv add flask
Like wise, removing a dependency, we do that with the uv remove <package name> command, because
that will also remove the packages on which flask depended.
$ uv remove flask
Note
The commands above to add and remove dependencies will work on the pyproject.toml file of
the package you are currently working in. For example, if you're working in
cgse/libs/cgse-common, that pyproject.toml file will get the extra 'flask' dependency.
Syncing your environment¶
You can synchronise your environment explicitly with the uv sync command.
This is usually not needed since uv automatically synchronises your
environment when executing uv run. Using the command below will remove
any packages that are installed in your environment but are not specified in
your pyproject.toml or the uv.lock file. Use this command to clean your
environment.
$ uv sync
When syncing, uv prefers to keep the versions from the uv.lock file. You
can upgrade packages by name or upgrade all packages with the following
commands:
$ uv lock --upgrade-package <package name>
$ uv lock --upgrade
Building and publishing all packages¶
We have chosen for one and the same version number for all packages in the cgse monorepo. That
means that whenever we make a change to one of the packages and want to release that change, all
packages shall be rebuilt and published.
Warning
When working in a workspace, keep in mind that the commands uv run and uv sync by default work on the
workspace root. That means that when you run the uv run pip install <package> command, the .venv at the
workspace root will be updated or created if it didn't exist. Similar for the uv sync command, there is only
one uv.lock file at the root of the workspace.
Fortunately, with uv, that is done in a few commands.
When you are in the monorepo root folder, you can build all packages at once. They will be placed in
the dist folder of the root package. The bump script will automatically increase the version
number based on your input, i.e. 'patch', 'minor', or 'major'. Before building, clean up the dist
folder, then you can do a default uv publish afterwards.
$ cd <monorepo root>
$ uv run bump.py <part>
$ rm -r dist
$ uv build --all-packages
where <monorepo root> is the root folder of your local clone, e.g. ~/github/cgse, and
<part> stands for the part of the version number that shall be bumped, i.e. 'patch', 'minor',
or 'major'.
Publish all packages in the root dist folder to PyPI. The UV_PUBLISH_TOKEN can be defined in a (read protected) ~/. setenv.bash file:
$ uv publish --token $UV_PUBLISH_TOKEN
The above command will publish all package to PyPI. If you don't want the token to be in a shell
variable, you can omit the --token in the command above. You will then be asked for a username,
use __token__ as the username and then provide the token as a password.