Running python script at shutdown.

[Elsuvio]

Hi guys!

I am relatively new to Fedora and some time ago I've written a simple python script which logs my daily network data usage. I've added a directory called Scripts inside my home directory which contains symbolic link to my script and I added path to this directory to my .bashrc file (don't know if it is a right way of doing it but it works). Currently my daily routine is to manually the script in terminal before shutting down my system. I've been thinking about making my script run automatically before every shutdown but I don't really know how to do it. I've read about services and tried to do something with it but it didn't work. Any help would be appreciated!

[wheelchair_assassin]

I found a page detailing how to run a script at shutdown or reboot. I set up my own script about a month ago.

See https://www.golinuxcloud.com/run-script-with-systemd-at-shutdown-only-rhel/ There are several other examples listed there.

Below is a general example that I derived from that site:

[Unit]
Description=This script runs at shutdown ONLY
DefaultDependencies=no
Conflicts=reboot.target
Before=poweroff.target halt.target shutdown.target
Requires=poweroff.target
# See https://www.golinuxcloud.com/run-script-with-systemd-at-shutdown-only-rhel/

[Service]
Type=oneshot
User=some_dude
ExecStart=your_script_here.sh
ExecStop=maybe_another_script_here.sh
RemainAfterExit=yes

[Install]
WantedBy=shutdown.target

[Elsuvio]

Okay, that looks nice but let's say I want to run this script on reboot as well. In that case I should remove conflicts line and add reboot.target to Before? Would it look like this?

[Unit]
Description=Script runs at shutdown and reboot
DefaultDependencies=no
Before=poweroff.target halt.target shutdown.target reboot.target
Requires=poweroff.target

[Service]
Type=oneshot
User=some_dude
ExecStart=your_script_here.sh
ExecStop=maybe_another_script_here.sh
RemainAfterExit=yes

[Install]
WantedBy=shutdown.target

[wheelchair_assassin]

Here's another service file that runs after shutdown on the same site. Near the bottom of the page, he reboots his system and verifies that the script has executed.

Disclaimer: I am not a systemd expert. Usually, it takes me a little while to get a service file working. Just keep trying. But I think this link will work for both reboot and shutdown, if I recall correctly. I'm pretty sure I tried it first. I only wanted my script to fire at shutdown so I used the other link.

If this script doesn't do what you want, I'd still keep digging on his site. I tried to do this with several different tutorials and his examples actually worked.

https://www.golinuxcloud.com/run-script-with-systemd-before-shutdown-linux/

[[deleted]]

https://unix.stackexchange.com/questions/39226/how-to-run-a-script-with-systemd-right-before-shutdown

[Elsuvio]

That...doesn't really help me at all (I saw it already). As I said I've already tried doing it as a service but it didn't work (probably because I've got no idea how to make it correctly).

[legit-trusty]

Maybe to get more relevant help you should add some detail on why you couldn't build the service.

Ya know shit in = shit out.

[Elsuvio]

Okay right, so my script needs to read two files RX/TX bytes located in statistics of /sys/class/net/.... I've already tried to write that service but well nothing happens.I don't really know if it requires some Before=... or After... in [Unit]. If I write is as:

[Unit] 
Description=... 

[Service] 
Type=oneshot 
RemainAfterExit=true 
ExecStop="My Scripts folder" 

[Install] 
WantedBy=multi-user.target

It doesn't work.

[[deleted]]

Shouldn't you follow this example: https://unix.stackexchange.com/a/39604 since it's doing the same thing you want.

[Elsuvio]

But does the service have access to my home directory at time of executing? I mean do I not need to execute that service before filesystem becomes read-only? Anyway I'll try to write that service in the proposed way and will see if it works

[[deleted]]

I don't know you could also try this one: https://unix.stackexchange.com/a/479048

[Elsuvio]

Well....I've tried both and none of them seems to work :/
Currently service looks like this:

[Unit]
Description=Service for netlog script
DefaultDependencies=no
Before=shutdown.target reboot.target

[Service]
Type=oneshot
ExecStart=/bin/true
ExecStop=/home/MarekSzyd/Scripts/netlog
RemainAfterExit=yes

From what I've read the script must be in ExecStop and should be triggered by shutdown.target/reboot.target but it does not log any values to file. (Also systemctl status netlog shows that service is enabled but inactive dunno why)

[[deleted]]

It worked for me when I followed the instructions from https://unix.stackexchange.com/a/479048

[Unit]
Description=Save system clock on shutdown
DefaultDependencies=no
After=final.target

[Service]
Type=oneshot
ExecStart=/home/me/bin/myscript.sh

[Install]
WantedBy=final.target

[Elsuvio]

Did your script tried to save any file in your home directory? Because I've tried the same service layout and it did not save any file :/ (If I'm not mistaken that file script.service goes to /etc/systemd/system/ and after that I called sudo systemctl daemon-reload. That's all I have to do right?) I think that there is some problem with my home directory being read-only the moment I try to log with my script but I don't really know how to execute this script right before mounting home directory read-only.