This adds a simple configuration for sending snapshots to a remote
system using zfs-replicate that ties into the autoSnapshot settings
already present in services.zfs.autoSnapshot.
If lib.optional is given a false value it will return an empty list.
Thusly the set-environment script can have
```
export GTK_USE_PORTAL=
```
This can rub certain bugs the wrong way #65679
so lets make sure this isn't set in the environment
at all.
Prior to this change GTK_USE_PORTAL was unconditionally
set to "1". For this to not break things you have to have some
sort of portal implementation in extraPortals.
Setting GTK_USE_PORTAL in this manner is actually only useful
when using portals for applications outside flatpak. For example
people using non-flatpak Firefox who want native filechoosers.
It's also WIP for electron applications to support this.
The following configuration generates a systemd unit that doesn't
start.
```nix
{
services.syncthing = {
enable = true;
user = "my-user";
};
}
```
It fails with
```
systemd[1]: Started Syncthing service.
systemd[6745]: syncthing.service: Failed to determine group credentials: No such process
systemd[6745]: syncthing.service: Failed at step GROUP spawning /nix/store/n1ydz3i08nqp1ajc50ycy1zribmphqc9-syncthing-1.1.4-bin/bin/syncthing: No such process
systemd[1]: syncthing.service: Main process exited, code=exited, status=216/GROUP
systemd[1]: syncthing.service: Failed with result 'exit-code'.
```
This is due to the fact that `syncthing` group (default) is not
created if the user is overridden.
Add a separate check for setting up the default group, so that
user/group are created independently.
This is to fix the following error in the test on aarch64-linux:
store# [ 126.911144] thanos[739]: level=error ts=2019-06-16T14:00:26.59870538Z caller=main.go:182 msg="running command failed" err="error executing compaction: first pass of downsampling failed: create dir: mkdir /var/lib/thanos-compact/downsample: no space left on device"
store# [ 126.942655] systemd[1]: thanos-compact.service: Main process exited, code=exited, status=1/FAILURE
Upstream switched to a different type of ipset table, whereas we
create ipset in post-start which overrides upstream, and renders
sshguard ineffective.
Remove ipset creation from post-start, and let it get automatically
by upstream script (sshg-fw-ipset) as part of startup
