Correct support for systemd-sleep

[ciphorg]

Background

I noticed the service declared [Unit] After=multi-user.target and would fail to restart following a systemd-sleep events. The service correctly starts on a fresh boot, but would not be triggered by a sleep.target trigger (suspend, hibernate, hybrid, etc...).

The service should only start after a successful boot (at-least multi-user.target), but still requires a dependency trigger on sleep.target to restart on wake.

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[Install] WantedBy= ... has the effect of a dependency of type Wants=, Requires=, or Upholds= being added from the listed unit to the current unit. [1]
Additionally, multi-user.target is triggered after poweroff.target & rescue.target, but not triggered again after sleep.target [2] [3]

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Changes

Full support for restarting after systemd-sleep should just require After=sleep.target added to the service's [Unit] section. This change should safely and reliably request OpenLinkHub to resume after sleep.target without effecting systemd's critical chain. This should avoid having to be overly complex in handling the boot->sleep->wake->shutdown cycle, and for systemd to "want" the service to start on boot (not require it) and to also restart the service after resuming from any sleep state.

[Unit]
After=sleep.target

[Service]
...

[Install]
WantedBy=multi-user.target