Allow operation as systemd user unit [Clarification needed]

[Simon Kohlmeyer]

I'd like to run xss-lock as a systemd user unit. I added the following unit file:

# /home/foo.config/systemd/user/xss-lock-i3lock.service
[Unit]
Description=Run xss-lock with i3lock

[Service]
ExecStart=/usr/bin/xss-lock -- /usr/bin/i3lock

and everything seems to work, but I'm getting the following log output: xss-lock[17367]: Error getting current session: GDBus.Error:org.freedesktop.login1.NoSessionForPID: PID 17367 does not belong to any known session

I tried to look at the source, but couldn't figure out what the impact of that error is.

[Steven Allen]

xss-lock uses its PID to figure out which session it belongs to. To run as a systemd unit, it would have to fallback on the user's Display property (found in /org/freedesktop/login1/user/self) to find the default display.

[Simon Kohlmeyer]

I'm not very familiar with either session management or systemd, but it seems that this issue discussed that exact problem: https://github.com/systemd/systemd/issues/2356

[Steven Allen]

xss-lock already does that. Unfortunately, that only works when running within a session and systemd services don't run within any session.

[Steven Allen]

The C function would be sd_uid_get_display.

[Antoine Damhet]

I am coming way after the battle but my fork can take the session in argument. My graphical session id is exported in an environment variable on systemd --user then used by xss-lock.service.

[Former user]

I'm also running into this. Is this issue benign? Is there any workaround?

Thanks!

[Antoine Damhet]

@joweill My fork can lock any x session. My systemd unit file looks like:

[Unit]
Description=Auto lock
PartOf=graphical-session.target

[Service]
Type=simple
ExecStart=/usr/bin/xss-lock -l -s ${XDG_SESSION_ID} -- ${HOME}/.i3/lock.sh

[Install]
WantedBy=graphical-session.target

I just need to export XDG_SESSION_ID (of my X session) to systemd user

[Former user]

Thanks @xdbob looks like your fork indeed addresses the issue. However, I'm currently the xss-lock pacman package and I prefer to keep using a package from the official repos rather than maintaining my own package. At least unless there is a very good reason to switch. If I understand correctly, in this case, the only issue is log spam , but the locker actually works. Did I understand correctly?