systemd doesn't work at reboot

Question

I made a test with a basic python script /home/pi/Documents/sample.py:

print("hello word")

then I wrote a service script /etc/systemd/system/my_boot.service:

[unit]
Description=Raspberry Pi My test
After=network.target
 
[Service]
Type=idle
ExecStart=/usr/bin/python3 /home/pi/Documents/sample.py
User=pi
 
[Install]
WantedBy=default.target

Then I Typed:

systemctl daemon-reload
systemctl enable my_boot.service
systemctl start my_boot.service

When I reboot, nothing happens although I can see the name of the service displayed in the boot sequence. I tried with python instead of python3. When I use the rc.local instead of systemd 'Hello world' is displayed correctly at boot. My config is Console mode automatic login. I'm using Wifi and SSH.

Answer 1

you can check to see if it ran by using: systemctl status my_boot and I would expect it to show that it ran and is terminated. You could also amend the python code to create a file and write to that, say /tmp/my_boot.log and check that.

I have an on-boot service that writes to a database on another Pi.

Answer 2

See StandardOutput in man systemd.exec; this defaults to journal which means you should find "hello word" in sudo journalctl -u my_boot. This may or may not end up also going to the console, and in looking through /lib/systemd/system/rc-local.service it's not clear why that would work from there.

In any case, your best bet is probably:

[Service]
StandardOutput=journal+console

There's no plain console.

I suspect there's a bit of an XY problem since using the system console to convey information to ??? is not a good methodology.

You may also want to try adding After=rc-local.service under Unit (see "Before=, After=" in man systemd.unit.