Noob question: setting up a virtual environment for python (packages)

jones · 2023-09-02 21:03:15

Hope this is the right forum.

So. Python noob here.
Alright. It's trivial to install python. But to install packages from the python ecosystem, one should use a virtual environment or bear the responsibility of managing the magical clusterf... um, chaos of conflicting package names, (co-)dependencies if one were to install a python package in a non-virtual environment, i.e. possibly overwriting or editing a file which was created by pacman or will be in a future moment.

In the the last section on the wiki page, it says to install python-pipenv (sure, already done) and then

Basic usage
All commands can be executed in the project folder, and pipenv will recognize the specific situation - whether a virtualenv exists in the directory, locating it, and running on the specific virtual interpreter when pipenv is executed.
More information at [1], [2], [3].

The first link is: https://pipenv.pypa.io/en/latest/
On there, it says to install pipenv with:

$ pip install --user pipenv

which produces

error: externally-managed-environment

× This environment is externally managed
╰─> To install Python packages system-wide, try 'pacman -S
    python-xyz', where xyz is the package you are trying to
    install.
    
    If you wish to install a non-Arch-packaged Python package,
    create a virtual environment using 'python -m venv path/to/venv'.
    Then use path/to/venv/bin/python and path/to/venv/bin/pip.
    
    If you wish to install a non-Arch packaged Python application,
    it may be easiest to use 'pipx install xyz', which will manage a
    virtual environment for you. Make sure you have python-pipx
    installed via pacman.

note: If you believe this is a mistake, please contact your Python installation or OS distribution provider. You can override this, at the risk of breaking your Python installation or OS, by passing --break-system-packages.
hint: See PEP 668 for the detailed specification.

Ok.
I'm not trying to be obtuse, I rather want to make sure when I ask: the wiki wasn't simply updated, right? Because as it is, it links to the installation of pipenv through pip while its own 3-4 lines before that already include the correct (for the lack of a better term) way of installing pipenv.

Also, then on to installing python packages in that virtual environment, one should first activate the virtual environment via

$ pipenv shell

and then run something like

pipenv install ABCsomething

right?
(Or would someone know a link to a solid website for it, which is very much written like "this is one true way how it can be set up"? )

Trilby · 2023-09-02 21:12:30

jones wrote:

$ pip install --user pipenv
which produces [an error]

Was that command run within a previously created virtual environment directory?

EDIT: nevermind, I confirmed that this error message shows up even in a venv directory. I have no experience with python-pipenv, but it is clearly not doing what the wiki says it's supposed to do.

Last edited by Trilby (2023-09-02 21:19:47)

Raynman · 2023-09-02 21:36:07

jones wrote:

Because as it is, it links to the installation of pipenv through pip while its own 3-4 lines before that already include the correct (for the lack of a better term) way of installing pipenv.

It links to the pipenv home page and it does so in a section titled "6.2 Basic usage". As you say, installation has been handled in 6.1, so it just tells you to look there for usage information. Many projects have a section/chapter in their documentation covering (manual) installation, but you want to install stuff through pacman unless there's a good reason not to, so you wouldn't normally go and copy-paste installation commands, except maybe into a PKGBUILD.

one should first activate the virtual environment via
$ pipenv shell

That's what realpython.com says, but the other linked docs say that you can start in an empty dir and the first time you use `pipenv install`, it will create the venv:
https://pipenv.pypa.io/en/latest/instal … ur-project

The archwiki said "pipenv will recognize the specific situation", which seems to mean it will create a venv in the current dir if one doesn't exist yet and you can do `install` with or without activating the venv first.

Last edited by Raynman (2023-09-02 21:37:21)

Arch Linux

#1 2023-09-02 21:03:15

Noob question: setting up a virtual environment for python (packages)

#2 2023-09-02 21:12:30

Re: Noob question: setting up a virtual environment for python (packages)

#3 2023-09-02 21:36:07

Re: Noob question: setting up a virtual environment for python (packages)

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