When launching a Python script using shell_exec, the script doesn't work

Question

I have written a Python script that removes the background of an image using the rembg library and then composes the image using PIL.

For this project, a virtualenv was created and rembg was installed there. All of this is on an Ubuntu 20.04 server.

The project folder is located at /var/www/work/py/banner_generator and contains a virtual environment folder called venv. The Python script itself is located at /var/www/work/py/banner_generator/banner_generator.py. If I run the command /var/www/work/py/banner_generator/venv/bin/python3.8 /var/www/work/py/banner_generator/banner_generator.py from the console, it works as intended.

However, I need to run this script in a PHP script. When I execute the code in PHP:

$cmd = "/var/www/work/py/banner_generator/venv/bin/python3.8 /var/www/work/py/banner_generator/banner_generator.py";
$output = shell_exec($cmd);

echo $output;

Nothing happens. When I commented out the code and left only "print("work")" in the Python script, everything worked from PHP.

I decided to comment out my code and test it. First, in the Python script, I left only "print("work")" and checked it. In this case, everything worked from PHP. Then I decided to continue experimenting and uncommented all my imports, resulting in the following code:

import argparse
import os
from rembg import remove
from PIL import Image, ImageDraw, ImageFilter, ImageEnhance
import requests
from io import BytesIO

print("work")

I ran it again and it didn't work. The "work" statement didn't show up.

Then I started commenting out some imports and, through trial and error, discovered that the problem only occurred when importing rembg. In other words, the following code works:

import argparse
import os
# from rembg import remove
from PIL import Image, ImageDraw, ImageFilter, ImageEnhance
import requests
from io import BytesIO

print("work")

Interesting fact: PIL is only installed in the virtual environment, yet its import does not cause any problems. However, for some reason, importing rembg causes issues.

Answer 1

You could try setting the PYTHONPATH environment variable to include the path to the rembg library in your PHP script before running the Python script. For example:

putenv("PYTHONPATH=/var/www/work/py/banner_generator/venv/lib/python3.8/site-packages");
$cmd = "/var/www/work/py/banner_generator/venv/bin/python3.8/var/www/work/py/banner_generator/banner_generator.py";
$output = shell_exec($cmd);
echo $output;