auto system update with dnf

dnf-autoupdate-boot.service.in

[Unit]
Before=getty-pre.target
Before=multi-user.target graphical.target

[Service]
Type=oneshot
ExecStart=@libexec@/dnf-autoupdate-boot.sh
StandardInput=tty
StandardOutput=tty
StandardError=tty

[Install]
WantedBy=basic.target
Also=dnf-autoupdate.timer

dnf-autoupdate-boot.sh.in

#!/bin/bash

boot_timeout=30 # delay update on boot for 30 seconds, allowing user to skip

. '@configfile@' 2> /dev/null

export LC_ALL=C.UTF-8

if ! (dnf --cacheonly --assumeno update &> /dev/null); then
	dnf --cacheonly --assumeno update 2>&1 | head -n-1
	echo
	if ! read -p "DNF Updates available, apply now? (auto apply in $boot_timeout secs) [y/N] " -t "$boot_timeout" -r reply; then
		reply=y
	fi
	if [ "$reply" = "y" ] || [ "$reply" = "Y" ]; then
		dnf --cacheonly --assumeyes update
	fi
fi

rm -f '@statefile@'

dnf-autoupdate-timer.sh.in

#!/bin/bash

reboot_on_idle=0 # reboot if security updates were installed and no user sessions present

. '@configfile@' 2> /dev/null

sec_update_installed=0

. '@statefile@' 2> /dev/null

export LC_ALL=C.UTF-8

if ! dnf --refresh --assumeno update --security; then
	if dnf --assumeyes update --security; then
		sec_update_installed=1
	fi
fi

umask 077
echo "sec_update_installed=$sec_update_installed" > '@statefile@'

dnf --downloadonly update

if [ $sec_update_installed -ne 0 ] && [ $reboot_on_idle -ne 0 ]; then
	sessions="$(busctl get-property org.freedesktop.login1 /org/freedesktop/login1 org.freedesktop.login1.Manager NCurrentSessions | awk '{ print $2 }')"
	if [ "$sessions" = "0" ]; then
		systemctl reboot
	fi
fi

dnf-autoupdate.service.in

[Service]
Type=oneshot
ExecStart=@libexec@/dnf-autoupdate-timer.sh

dnf-autoupdate.spec

Name:    dnf-autoupdate
Version: 20230622
Release: 1%{?dist}
Summary: Automatic system update using dnf
License: Unlicense

BuildArch: noarch
Source0: %{name}-boot.sh.in
Source1: %{name}-timer.sh.in
Source2: %{name}-boot.service.in
Source3: %{name}.service.in
Source4: %{name}.timer

BuildRequires: systemd-rpm-macros
Requires: systemd

%description
Automatic system update using dnf.

%build
for f in %{SOURCE0} %{SOURCE1} %{SOURCE2} %{SOURCE3}; do
	sed 's!@libexec@!%{_libexecdir}!g; s!@configfile@!%{_sysconfdir}/%{name}.conf!g; s!@statefile@!/run/%{name}.state!g' < "$f" > "$(basename "$f" | sed 's!\.in$!!')"
done

%install
install -Dm755 -t %{buildroot}/%{_libexecdir} %{name}-boot.sh
install -Dm755 -t %{buildroot}/%{_libexecdir} %{name}-timer.sh
install -Dm644 -t %{buildroot}/%{_unitdir} %{name}-boot.service
install -Dm644 -t %{buildroot}/%{_unitdir} %{name}.service
install -Dm644 -t %{buildroot}/%{_unitdir} %{SOURCE4}

%files
%{_libexecdir}/%{name}-boot.sh
%{_libexecdir}/%{name}-timer.sh
%{_unitdir}/%{name}-boot.service
%{_unitdir}/%{name}.service
%{_unitdir}/%{name}.timer

%post
%systemd_post %{name}-boot.service
%systemd_post %{name}.service
%systemd_post %{name}.timer

%preun
%systemd_preun %{name}-boot.service
%systemd_preun %{name}.service
%systemd_preun %{name}.timer

%postun
%systemd_postun %{name}-boot.service
%systemd_postun %{name}.service
%systemd_postun %{name}.timer

dnf-autoupdate.timer

[Timer]
OnBootSec=10min
OnUnitInactiveSec=4h
RandomizedDelaySec=10min

[Install]
WantedBy=timers.target
Also=dnf-autoupdate-boot.service