feh can't display image

Question

I have written a python script that displays the image from the URL.

def image_func(link_image):
    img_cmd = "feh -F %s" %(link_image)
    os.system(img_cmd)
    os.system("pkill feh")

If I run the python program directly using

python main.py

it runs without any issue.

But if I run from the .service file .. it throws this error.

feh ERROR: You have no HOME, cannot read themes

I am running this from the root terminal rather than the user terminal.

.service file

[Unit]
Description=My device boot script service
After=multi-user.target

[Service]
Type=idle
user=user1
Environment=DISPLAY=:0
Restart=always
ExecStart=/root/MediaPlayer/venv/Include/start.sh > /dev/null

[Install]
WantedBy=multi-user.target

Answer 1

I do not understand why do you use Type=idle. Man systemd.service says:

Note that this type is useful only to improve console output, it is not useful as a general unit ordering tool ...

As far as I know you do not have any console output so this option seems to be unnecessary. You want to output graphics as far as I understand to display an image. Usually you can do this only After=graphical.target. The service is missing a HOME variable. In respect of the comments from @Dirk you are running your python script (not a bash script) as root from the command line. You should do exactly the same within the unit. By default root is used for executing. There is also no suppressing of (error) messages with redirection to /dev/null so you can look with journalctl -b -e if there are some messages from the python script. I would configure your unit as follows:

[Unit]
Description=My device boot script service
After=graphical.target

[Service]
Environment=DISPLAY=:0
Restart=always
ExecStart=/usr/bin/python main.py

[Install]
WantedBy=graphical.target