Need a Python 3.8 virtual environment

[Steven Robbins]

Hi,

I'm trying to use a (non-Debian) python system built on python 3.8. Debian's
default is currently 3.9 so I am advised to use a virtual environment. Being
a newbie, I searched around and found a writeup covering several different
virtualization tools [1]. Note I am using Debian 'sid'.

I can use the tool "virtualenv" to create a virtual environment for default
python:

steve@riemann:/tmp$ virtualenv blah
created virtual environment CPython3.9.1.final.0-64 in 77ms
creator CPython3Posix(dest=/tmp/blah, clear=False, no_vcs_ignore=False,
global=False)
seeder FromAppData(download=False, pip=bundle, setuptools=bundle,
wheel=bundle, via=copy, app_data_dir=/home/steve/.local/share/virtualenv)
added seed packages: pip==20.1.1, pkg_resources==0.0.0,
setuptools==44.0.0, wheel==0.34.2
activators
BashActivator,CShellActivator,FishActivator,PowerShellActivator,PythonActivator,XonshActivator


But not for python 3.8:

steve@riemann:/tmp$ virtualenv -p python3.8 blah38
RuntimeError: failed to find interpreter for Builtin discover of
python_spec='python3.8'


I have installed literally all the Debian python packages whose name contains
'python3.8'. A very short list:

ii libpython3.8:amd64 3.8.7-1
amd64 Shared Python runtime library (version 3.8)
ii libpython3.8-dev:amd64 3.8.7-1
amd64 Header files and a static library for Python (v3.8)
ii libpython3.8-minimal:amd64 3.8.7-1
amd64 Minimal subset of the Python language (version 3.8)
ii libpython3.8-stdlib:amd64 3.8.7-1
amd64 Interactive high-level object-oriented language (standard
library, version 3.8)
ii python3.8 3.8.7-1
amd64 Interactive high-level object-oriented language (version 3.8)
ii python3.8-dev 3.8.7-1
amd64 Header files and a static library for Python (v3.8)
ii python3.8-minimal



I have also tried the module 'venv':

steve@riemann:/tmp$ python3.8 -m venv v38
The virtual environment was not created successfully because ensurepip is not
available. On Debian/Ubuntu systems, you need to install the python3-venv
package using the following command.

apt-get install python3-venv

You may need to use sudo with that command. After installing the python3-venv
package, recreate your virtual environment.

Failing command: ['/tmp/v38/bin/python3.8', '-Im', 'ensurepip', '--upgrade',
'--default-pip']

steve@riemann:/tmp$ python3.8 -m venv blah38
The virtual environment was not created successfully because ensurepip is not
available. On Debian/Ubuntu systems, you need to install the python3-venv
package using the following command.

apt-get install python3-venv

You may need to use sudo with that command. After installing the python3-venv
package, recreate your virtual environment.

Failing command: ['/tmp/blah38/bin/python3.8', '-Im', 'ensurepip', '--
upgrade', '--default-pip']


Note that I do have 'python3-venv' installed, but it is the 3.9 version:
ii python3-venv 3.9.1-1
amd64 pyvenv-3 binary for python3 (default python3 version)


Is there something I've missed?

Thank you,
-Steve

[1] https://linuxconfig.org/how-to-set-up-a-python-virtual-environment-on-debian-10-buster

[Jerome Kieffer]

On Tue, 02 Mar 2021 21:17:36 -0600
Steven Robbins <st...@sumost.ca> wrote:

> Hi,
>
> I'm trying to use a (non-Debian) python system built on python 3.8. Debian's
> default is currently 3.9 so I am advised to use a virtual environment. Being
> a newbie, I searched around and found a writeup covering several different
> virtualization tools [1]. Note I am using Debian 'sid'.

[...]

> Is there something I've missed?

Hi Steven,

I don't think there is any simple solution for you within the debian ecosystem.
As a developper, I faced the same issue and ended in installing `conda` to
have a quick access to the various python versions (then I create
some venv from the conda environments).

I doubt our use-case is common enough to justify having multiple python (again) in Debian.

Cheers,

Jerome

PS: venv are about 10x smaller than conda environments !

[Andrey Rahmatullin]

It looks like the only sane way to use non-default Python versions is to
build them locally using pyenv.

--
WBR, wRAR

[Pokoradi Balazs]

Hi Steven,

i tested in a freshly installed virtualbox machine and was able to create a virtual environment, using the following steps:

built python3.8.7 form tarball (https://www.python.org/ftp/python/3.8.7/Python-3.8.7.tar.xz)

ran python3.8 -m venv test387

and then could activate it.

I hope this helps,

Balazs

[Nicolas Chauvat]

Hi Steven,

On Tue, Mar 02, 2021 at 09:17:36PM -0600, Steven Robbins wrote:

> I'm trying to use a (non-Debian) python system built on python 3.8. Debian's

> ...

> Is there something I've missed?

Do you know https://github.com/saghul/pythonz ?

I do not use it myself, but a colleague told me he uses that when he
needs to test something with every python version available.

Hope this helps.

--
Nicolas Chauvat

logilab.fr - services en informatique scientifique et gestion de connaissances

[Julien Palard]

Le 2021-03-03 à 04:17, Steven Robbins a écrit :
> I'm trying to use a (non-Debian) python system built on python 3.8. Debian's
> default is currently 3.9 so I am advised to use a virtual environment.

As other told, the right way is probably to compile it yourself (or use
pyenv, but I don't like pyenv "shims", I prefer to keep it simple).

I'm using a bash function [1] to easily recompile needed Pythons (I test
some projects with Python 3.5 to 3.9), but it's not that hard without my
bash function:

apt install make build-essential libbz2-dev liblzma-dev libssl-dev
llvm libreadline-dev libncurses5-dev libffi-dev zlib1g-dev tk-dev
libsqlite3-dev xz-utils
wget the version you want from https://www.python.org/ftp/python
tar -xzf it
./configure --prefix=$HOME/.local/
make -j $(nproc)
make altinstall

You'll get a `python3.8` binary in ~/.local/bin, you can create venvs
with it as:

python3.8 -m venv the_venv_path

[1]:
https://github.com/JulienPalard/dotfiles/blob/0b5feb79b1ba648b7212162b68da5a182e0341c1/.bashrc#L196
--
[Julien Palard](https://mdk.fr)

[Yaroslav Halchenko]

On Tue, 02 Mar 2021, Steven Robbins wrote:

> Hi,

> I'm trying to use a (non-Debian) python system built on python 3.8. Debian's
> default is currently 3.9 so I am advised to use a virtual environment. Being
> a newbie, I searched around and found a writeup covering several different
> virtualization tools [1]. Note I am using Debian 'sid'.

I know that it is not a "proper" Debian answer, but in such cases I just
quickly install miniconda with a needed python version. I keep a
miniconda installation with conda environments for different Pythons
for such cases.

--
Yaroslav O. Halchenko
Center for Open Neuroscience http://centerforopenneuroscience.org
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
WWW: http://www.linkedin.com/in/yarik

[Andrey Rahmatullin]

On Wed, Mar 03, 2021 at 08:32:01AM -0500, Yaroslav Halchenko wrote:
> > I'm trying to use a (non-Debian) python system built on python 3.8. Debian's
> > default is currently 3.9 so I am advised to use a virtual environment. Being
> > a newbie, I searched around and found a writeup covering several different
> > virtualization tools [1]. Note I am using Debian 'sid'.
>
> I know that it is not a "proper" Debian answer

Sure, the only proper Debian answer would be "actually you don't need this
version".

--
WBR, wRAR

[Jeremy Stanley]

On 2021-03-03 10:45:46 +0000 (+0000), Julien Palard wrote:
[...]

> I'm using a bash function [1] to easily recompile needed Pythons (I test
> some projects with Python 3.5 to 3.9), but it's not that hard without my
> bash function:

[...]

This is pretty much identical to how I tackle it too, though I build
from tags checked out of the cpython Git repository.

If you're looking for prebuilt debs, I know some folks use this,
from what I understand the packages should be compatible with
reasonably contemporary Debian releases:

https://launchpad.net/~deadsnakes/+archive/ubuntu/ppa

--
Jeremy Stanley

[Stefano Rivera]

Hi Steven (2021.03.03_03:17:36_+0000)

> steve@riemann:/tmp$ python3.8 -m venv blah38
> The virtual environment was not created successfully because ensurepip is not
> available. On Debian/Ubuntu systems, you need to install the python3-venv
> package using the following command.
>
> apt-get install python3-venv
>
> You may need to use sudo with that command. After installing the python3-venv
> package, recreate your virtual environment.
>
> Failing command: ['/tmp/blah38/bin/python3.8', '-Im', 'ensurepip', '--
> upgrade', '--default-pip']
>
>
> Note that I do have 'python3-venv' installed, but it is the 3.9 version:
> ii python3-venv 3.9.1-1
> amd64 pyvenv-3 binary for python3 (default python3 version)
>
>
> Is there something I've missed?

You need python3.8-venv. But even then you may run into a
missing/incompatible distutils (#979819):
https://bugs.debian.org/979819

You can see if you have, by running the failing ensurepip command by
hand.

Hopefully we'll make that situation better soon...

BTW: There's a deadsnakes-like archive for Debian:
https://people.debian.org/~paravoid/python-all/

SR

--
Stefano Rivera
http://tumbleweed.org.za/
+1 415 683 3272

[Andrey Rahmatullin]

On Wed, Mar 03, 2021 at 05:39:04PM +0000, Stefano Rivera wrote:
> You need python3.8-venv.
Which doesn't exist, at least in the current repos.

--
WBR, wRAR

[Matthias Klose]

you rebuild it from python3-stdlib-extensions. but yes, the binaries don't exist
in the archive.

[Karthik]

try using pyenv
https://mentors.debian.net/package/pyenv/

[Steven Robbins]

Thank you so much to the many folks on debian-python who responded with
instructions and pointers!

On Wednesday, March 3, 2021 4:45:46 A.M. CST Julien Palard wrote:

> As other told, the right way is probably to compile it yourself (or use
> pyenv, but I don't like pyenv "shims", I prefer to keep it simple).

Thank you for the detailed instructions! I used this method to build python
myself and now I have the virtual environment set up.

Regards,
-Steve