Gfilui

I want to upload a file to my dropbox when my pc is shutting down.

sudo vim /etc/systemd/system/upload.service
[Unit]
Description=upload files into dropbox
Before=network.target shutdown.target reboot.target
Requires=network-online.target

[Service]
ExecStop=/bin/true
ExecStart=/bin/bash /home/upload.sh 
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

And the upload.sh script.

cd /home
curl -X POST https://content.dropboxapi.com/2/files/upload 
 --header "Authorization: Bearer xxxx" 
 --header "Dropbox-API-Arg: "path":"/test.txt","mode":".tag":"overwrite"" 
 --header "Content-Type: application/octet-stream" 
 --data-binary @"test.txt"

bash upload.sh can executed successfully,and test.txt file uploaded into my dropbox.

sudo systemctl enable upload service 

To reboot my pc.

sudo journalctl -u upload 

Apr 13 23:58:52 localhost systemd[1]: Started upload files into dropbox.
Apr 13 23:58:52 localhost systemd[1]: Starting upload files into dropbox...
Apr 13 23:58:52 localhost bash[117]: % Total % Received % Xferd Average Speed Time Time Time Current
Apr 13 23:58:52 localhost bash[117]: Dload Upload Total Spent Left Speed
Apr 13 23:58:52 localhost bash[117]: 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0curl: (6) Could not resolve host: content.dropboxapi.com; Un
Apr 13 23:58:52 localhost systemd[1]: upload.service: main process exited, code=exited, status=6/NOTCONFIGURED
Apr 13 23:58:52 localhost systemd[1]: Unit upload.service entered failed state.
Apr 13 23:58:52 localhost systemd[1]: upload.service failed.

Some DNS error Could not resolve host: content.dropboxapi.com result in upload.service failed.

I have added Requires=network-online.target in upload.service,how to make DNS parser resolve the host at my pc's shutdowning time?

method 1: /etc/systemd/system/upload.service

1.1 /etc/systemd/system/upload.service

sudo vim /etc/systemd/system/upload.service
[Unit]
Description=upload files into dropbox
Before=shutdown.target reboot.target
Requires=network-online.target
After=network.target 

[Service]
ExecStop=/bin/true
ExecStart=/bin/bash /home/upload.sh 
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

1.2 vim /home/upload.sh

cd /home
curl -X POST https://content.dropboxapi.com/2/files/upload 
 --header "Authorization: Bearer xxxx" 
 --header "Dropbox-API-Arg: "path":"/test.txt","mode":".tag":"overwrite"" 
 --header "Content-Type: application/octet-stream" 
 --data-binary @"test.txt"

1.3 sudo systemctl enable upload service

method 2: /lib/systemd/system-shutdown/upload.service

2.1 /lib/systemd/system-shutdown/upload.service

sudo vim /lib/systemd/system-shutdown/upload.service
[Unit]
Description=upload files into dropbox
Before=shutdown.target reboot.target
Requires=network-online.target
After=network.target 

[Service]
ExecStop=/bin/true
ExecStart=/bin/bash /home/upload.sh 
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

2.2 vim /home/upload.sh

cd /home
curl -X POST https://content.dropboxapi.com/2/files/upload 
 --header "Authorization: Bearer xxxx" 
 --header "Dropbox-API-Arg: "path":"/test.txt","mode":".tag":"overwrite"" 
 --header "Content-Type: application/octet-stream" 
 --data-binary @"test.txt"

2.3 sudo systemctl enable /lib/systemd/system-shutdown/upload.service

The best way to run a program or script while the system is going down is by using the ExecStop= of the unit to run such program. The ExecStart= can either be a dummy script (such as /bin/true) or, in recent versions of systemd, it can even be omitted.

Regarding dependencies, you want to place your unit after the services you need, such as network-online.target and perhaps systemd-resolved.service if you're using it for DNS resolution. The reason for that is that systems are stopped at shutdown time in the reverse order in which they are started. So by ordering your service after the dependencies, it means your ExecStop= script will be run before the dependencies are stopped.

Something like this should work:

[Unit]
Description=upload files into dropbox
After=network.target systemd-resolved.service
Requires=network-online.target

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/true
ExecStop=/bin/bash /home/upload.sh 
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

Enable the unit as usual (the --now argument also starts it):

$ sudo systemctl enable --now upload.service

And it will perform the upload when stopped, which you can test with:

$ sudo systemctl stop upload.service

This was recently discussed in the systemd-devel mailing list.

Execstop and Execstart reversed

According to this Unix & Linux answer: How to run a script with systemd right before shutdown, your Execstop and Execstart are reversed.

The lines:

ExecStop=/bin/true
ExecStart=/bin/bash /home/upload.sh

Should read:

ExecStart=/bin/true
ExecStop=/bin/bash /home/upload.sh

The answer goes on to mention to restart services. So after creating the file, make sure to systemctl daemon-reload and systemctl enable yourservice --now

Alternate method not working

The before=, requires=, etc. can be confusing at times. You can put your script in /usr/lib/systemd/system-shutdown/ directory instead. It will be run immediately upon shutdown. See: https://superuser.com/questions/1016827/how-do-i-run-a-script-before-everything-else-on-shutdown-with-systemd

The /usr prefix may be different on some systems, ie just start directory name with /lib.