Could not create Python virtual environment

I'm getting error while using rosinit. When i was using python 3.8 i got:

Launching ROS Core...

Could not find Python version 2.7 on your system. Use pyenv function to set the path

to the Python 2.7 executable.

After switching to 2.7 i got this error:

Could not create Python virtual environment. 'C:\Users\User

Name\AppData\Roaming\MathWorks\MATLAB\R2021a\ros1\win64\venv\Scripts\python.exe' is

not found. Verify installation of Python in your system and re-create the Python

virtual environment.

Answer 1

[Benjamin William Brokaw]

I was struggling with this problem for so long and it seems we are the only ones having this issue.

What ended up working for me was pip installing virtualenv and then creating a virtual python enviornment with 'virtualenv tmpenv' .

Next I coppied the contents of tmpenv over to AppData\Roaming\MathWorks\MATLAB\R2021a\ros1\win64\venv\

I had to create this outside of \venv\ because of the way the createOrGetLocalPython.m script works. There is a command to create the directory win64/venv/temp that will error out if the parent folders already exist.

I beleive the culprit is line 135 in createOrGetLocalPython.m:

[stat, res] = system(['"' pyexec '" ' fullfile(tempPythonExtractDir,'virtualenv-16.6.1','virtualenv.py') ' --no-setuptools --no-pip --no-wheel ' pyenvDir '  --system-site-packages']);

This line should setup the env for us, but in my case it was returning success but not actually creating it.

Hope this helps!

[Robert Watson]

I had a similar issue.

I traced the problem back to line 62 of createOrGetLocalPython.m:

if isempty(venvRoot)
        if ismac
            venvRoot = fullfile(getenv('HOME'),'.matlab',['R' version('-release')]); %on Mac's using prefdir causes several issues due to space in folder names
        else
            venvRoot = prefdir;
        end
end

For my windows 10 install, relyng on prefdir means that venvRoot ends up with the value

'C:\Users\User Name\AppData\Roaming\MathWorks\MATLAB\R2021b'

The space in the `User Name` subdirectory causes issues when running system calls on line 135, as the space character is not properly escaped.

As a workaround, I put a breakpoint on line 140 then ran the following before continuing

cmd = ['"' pyexec '" ' '"' fullfile(tempPythonExtractDir,'virtualenv-16.6.1','virtualenv.py') '"' ' --no-setuptools --no-pip --no-wheel ' '"' pyenvDir '"' '  --system-site-packages']
[stat, res] = system(cmd);

This seemed to solve the issue.

[Auwal SHEHU]

Hi Robert,

I have similar issue. Please I need your help.

[Auwal SHEHU]

Creating a Python virtual environment...Done.

Error using ros.internal.createOrGetLocalPython

Could not create Python virtual environment.

in Matlab

Answer 2

[Murat Belge]

ROS Toolbox creates a Python virtual environment in user's prefdir by default. If your user name contains spaces and this gets reflected in prefdir, this will create issues with Python virtual environment generation and later on with custom message generation, etc. To work around this, set 'MY_PYTHON_VENV' environment variable to a directory without spaces and run ros.internal.createOrGetLocalPython function as in the following:

>> setenv('MY_PYTHON_VENV','C:\temp\venv')

>> ros.internal.createOrGetLocalPython(true)

This will use 'C:\temp\venv' as the root directory for Python virtual environment.

[Hari Krishna Kakarla]

Minor update to the above Answer. For R2021a relase, The environment variable that has to be set is 'MY_PYTHON2_VENV'.

For the Release older than R2022a, Please execute these commands below and then run ros.internal.createOrGetLocalPython(true) function:

>> setenv('MY_PYTHON2_VENV','C:\temp\venv')

>> ros.internal.createOrGetLocalPython(true)

From R2022a onwards:

>> setenv('MY_PYTHON_VENV','C:\temp\venv')

>> ros.internal.createOrGetLocalPython(true)

Thanks

Hari

Answer 3

[Ricardo Antunes]

Nothing worked on 2023a.

I created a virtual env using python 3.9 (latest compatible with ROS toolbox at this point).

The pointed the ROS toolbox to the python on that envoirement. It worked fine.