Problems with Python3 and RPi.GPIO under root

[MyMirror]

Hi all,

may i ask for a little help?
I am really not a Linux specialist and would be glad if you could help me with this problem.

Environment: Raspi 3b with Bullseye
uname -a gives the following output: Linux MM3 6.1.21-v7+ #1642 SMP Mon Apr 3 17:20:52 BST 2023 armv7l GNU/Linux

Version of my MagicMirror: 2.25.0

If I start Python3 as normal user “pi” and call “import RPi.GPIO as GPIO”, then it works but not as root:

pi@MM3:~/MagicMirror $ pwd
/home/pi/MagicMirror
pi@MM3:~/MagicMirror $ whoami
pi
pi@MM3:~/MagicMirror $ python3
Python 3.9.7 (default, Oct 14 2023, 17:06:45) 
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import RPi.GPIO as GPIO
>>> 
pi@MM3:~/MagicMirror $ su - root
Passwort: 
root@MM3:~# pwd
/root
root@MM3:~# python3
Python 3.9.7 (default, Oct 14 2023, 17:06:45) 
[GCC 10.2.1 20210110] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import RPi.GPIO as GPIO
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'RPi'
>>> 
root@MM3:~

Unfortunately, I cannot start such a python script for a PIR as a service. What is the user root missing that the user “pi” has?

I want the Python script here: /lib/systemd/system to start as a service when starting the raspi: pir_sensor.service This is not done with the user “pi” but as “root” or “system”, right?
Contents of pir_sensor.service:

[Unit]
Description=MagicMirror PIR Service
After=multi-user.target

[Service]
Type=idle
WorkingDirectory=/home/pi/MagicMirror
Restart=on-failure
User=root
ExecStart=/usr/bin/python3.9 /home/pi/MagicMirror/pirx.py

[Install]
WantedBy=multi-user.target

And the start of my pirx.py looks like this:

#!/usr/bin/python3
# coding: utf8 #
import RPi.GPIO as GPIO

As user pi it works well, but as described above, not as root or “system”.
Can anyone help me to repair Python to work under root/system as well with RPi.GPIO?

Thanks
Jens

[sdetweil]

@MyMirror use pm2 to launch your script. it will launch as the user

see pm2 --help

after the appropriate pm2 start
do pm2 save
to have that task launched at boot