How does venv update $PATH without activating on Windows?

[bottomfeeder]

I have a library installed in a venv which adds an .exe in the venv/Scripts/ folder. My Python script can find this .exe without explicitly activating the venv first, if I pass the script to venv/Scripts/python.exe (actually, by putting venv/Scripts/python.exe in the shebang line and using the Windows Python Launcher).

#!C:\path\to\venv\Scripts\python.exe

import subprocess

subprocess.run(["library.exe"]) # library.exe is located at C:\path\to\venv\Scripts\library.exe

This works without having to run activate first, I can just double-click on the script. However, if I run the script in a different user account, then it no longer works:

  File "...\Python310\lib\subprocess.py", line 501, in run
    with Popen(*popenargs, **kwargs) as process:
  File "...\Python310\lib\subprocess.py", line 966, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "...\Python310\lib\subprocess.py", line 1435, in _execute_child
    hp, ht, pid, tid = _winapi.CreateProcess(executable, args,
FileNotFoundError: [WinError 2] The system cannot find the file specified

Other aspects of the venv seem to work fine in this account (can use installed libraries). How do I make this work for all accounts?

(sys.executable returns C:\path\to\venv\Scripts\python.exe in both accounts and permissions on the .exe make it accessible to both accounts. As a hack I am adding os.environ["PATH"] = f"{os.environ['PATH']};{os.path.dirname(sys.executable)}")

[DeaD_EyE]

This seeks ffmpeg-normalize.exe in all available PATHs.

subprocess.run(["ffmpeg-normalize.exe", r"C:\path\to\audio.mp3")

AFIK the ffmepg tools are not installed via pip.

If you installed ffmpeg as a normal user, then it does not appear in the PATH of other Windows users accounts. If it's installed systemwide, you'll find it somewhere in C:\Program files.

Install ffmepg system-wide to make it accessible to all users. Maybe you need to add the path of the bin directory to your system-wide PATH variable. Usually a normal user is not able to run from other users installed software, because it is in their home directory, which access is prevented to other users.

[bottomfeeder]

That's ffmpeg-normalize, not ffmpeg. It is a pip package. I'm not asking how to locate ffmpeg, I'm asking how to have python locate exes within a venv's Scripts/ directory (which is where ffmpeg-normalize.exe is located, but it could be any exe that has nothing to do with ffmpeg, ffmpeg-normalize was just the example I was working with).

[DeaD_EyE]

That's ffmpeg-normalize, not ffmpeg. It is a pip package. I'm not asking how to locate ffmpeg, I'm asking how to have python locate exes within a venv's Scripts/ directory (which is where ffmpeg-normalize.exe is located, but it could be any exe that has nothing to do with ffmpeg, ffmpeg-normalize was just the example I was working with).

You are making the wrong assumption.
Can't remember what you installed?!
The python package ffmpeg-normalize does not ship with executable files. It uses an existing ffmpeg installation, which is independent of Python.

https://pypi.org/project/ffmpeg-normalize/

• Install a recent version of ffmpeg
  
• Run pip3 install ffmpeg-normalize
• Run ffmpeg-normalize /path/to/your/file.mp4
  
• Done! 🎧 (the file will be in a folder called normalized)
  

The raised exception from subprocess.run is clear. Python could not find the executable file in PATH.

The path to the exe file ffmpeg.exe is constructed by this function: https://github.com/slhck/ffmpeg-normaliz...ls.py#L147

If a different user has no access to ffmpeg.exe you get the Exception you've posted. Install ffmpeg systemwide or for each user in %localappdata%\Programs\ and append it to the User-PATH.

You can test it by yourself:

from shutil import which


if ffmpeg := which("ffmpeg"):
    print(ffmpeg)
else:
    print("ffmpeg.exe not found")

If ffmpeg.exe was not found, then ffmpeg-normalize could not work.