[systemd-devel] Xorg or Wayland Environment

[Michael Biebl]

A useful command in this context is

systemctl --user show-environment

Am So., 19. Sept. 2021 um 11:53 Uhr schrieb Mantas Mikulėnas
<grawity at gmail.com>:
>
> On Sun, Sep 19, 2021 at 4:05 AM Ed Greshko <ed.greshko at greshko.com> wrote:
>>
>> Not a everyday systemd service writer....
>>
>> I've written a user service file to start an app on login.  It works well for Xorg with Environment=DISPLAY=:0.
>>
>> But I've found that under Wayland the DISPLAY=:1 after a logout of Xorg and login to a
>> Wayland session.
>>
>> What would be the proper way to get the DISPLAY environment varible use it as opposed
>> to "hard" coding it?
>
>
> The proper way is to have the desktop environment upload DISPLAY (and whatever else is relevant, such as XAUTHORITY or WAYLAND_DISPLAY or XDG_SESSION_TYPE) into systemd --user, so that it would be automatically available to your service without doing anything special.
>
> For example, gnome-session does this for GNOME (it calls systemd's UnsetAndSetEnvironment in gsm-util.c), and /etc/X11/xinit/xinitrc.d/50-systemd-user.sh handles the bare minimum for other Xorg-based desktops (when startx is used).
>
> If KDE integrates with systemd --user in any way (i.e. if it actually has a "plasma-core.target" that you mention), I'd really expect it to do the same before it tries to start its own targets, otherwise they would be kind of useless.
>
> --
> Mantas Mikulėnas