Managing user startup applications with systemd

I recently switched to systemd to manage my startup applications, so this is a short post explaining the process.

For more details, Arch Linux wiki has a detailed page about using systemd to start user applications.

Non-GUI applications

For non-GUI applications, the setup is very easy. Creating a .service file in ~/.config/systemd/user and using systemctl to enable the service should be enough.

Here is a sample service file for devmon, a mount helper. The file should be located at ~/.config/systemd/user/devmon.service.

[Unit]
Description=Devmon - Automounts and unmounts optical and removable drives

[Service]
ExecStart=/usr/bin/devmon

[Install]
WantedBy=default.target

The service can then be used as a normal systemctl service, and enabled using

systemctl --user enable devmon

The logs can be checked by using

journalctl --user

GUI applications

For GUI applications, the only difference is that the DISPLAY and XAUTHORITY environment variables need to be set.

On Arch Linux, these variables are exposed to systemd by the script located at /etc/X11/xinit/xinitrc.d/50-systemd-user.sh but when I tried to launch a GUI application from a service file using the same configuration as above, the variables did not seem to be available.

It seems to be a timing issue, so the simplest way I found to work around it was to start the applications in my ~/.xprofile (any file which runs once X is launched should be just fine).

First, I created a target for my applications in ~/.config/systemd/user/user-applications.target with the following content.

[Unit]
Description=User Applications
Requires=default.target
After=default.target

Then, I added services for my applications wanted by the above target. The is an example for Telegram Desktop, located at ~/.config/systemd/user/telegram.service.

[Unit]
Description=Telegram Desktop

[Service]
ExecStart=/usr/bin/telegram-desktop -startintray

[Install]
WantedBy=user-applications.target

As usual, the service needs to be enabled with systemctl --user enable telegram in order to start automatically. Finally, all the applications can be started by adding the following line to ~/.xprofile or any other file you use to do stuff at boot time.

systemctl --user start user-applications.target

Note that if some services need other environment variables to be exposed, this can be done by adding the following before the above line.

systemctl --user import-environment VAR_TO_EXPOSE
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