archlinux pacman auto update

auto-update

########### /usr/local/bin/auto-update

#!/usr/bin/env bash

set -Eeuo pipefail

declare -i RETRY=3
while ! pacman -Syu --noconfirm; do
	RETRY=$((RETRY - 1))
	if [[ $RETRY -le 0 ]]; then
		echo "still not update after 3 tries, maybe network issue." >&2
		exit 1
	fi
	echo "update failed, retry $RETRY..."
done

CURRENT_KERNEL=$(uname -r)
LATEST_KERNEL=$(pacman -Q linux | cut -d' ' -f2)

simple_check() {
	if bootctl status --no-pager | grep -F 'No such file'; then
		echo "failed check kernel version, bootctl report missing files, wall to everyone..." >&2
		wall 'Something wrong when updating kernel, please check it manually. (journalctl -b -u auto-update.service)'
		exit 1
	fi
}

echo "update success!" >&2

if [[ $CURRENT_KERNEL != "$LATEST_KERNEL" ]]; then
	echo "current kernel: $CURRENT_KERNEL, latest kernel: $LATEST_KERNEL, rebooting..." >&2
	simple_check

	if [[ $(who | grep -vP '\btty\d+\b' | wc -w) -ge 1 ]]; then
		echo "some user login, alert and schedule reboot in 5 minutes" >&2
		wall '系统更新了内核，5分钟后自动重启，运行 `systemctl reboot --when=cancel` 取消此操作。
Kernel updated, system will reboot in 5 minutes, run `systemctl reboot --when=cancel` to cancel.'
		systemctl reboot --no-wall --when=+5min
	else
		echo "all clear, reboot now!!!" >&2
		systemctl reboot
	fi
else
	echo "kernel version has no change" >&2
fi

auto-update.service

########### /etc/systemd/system/auto-update.service

[Unit]
Description=系统自动更新
Requires=multi-user.target
After=multi-user.target

[Service]
Type=oneshot
RemainAfterExit=no
ExecStart=/bin/bash /usr/local/bin/auto-update
Restart=no
TimeoutSec=30min
EnvironmentFile=/etc/profile.d/50-environment.sh

auto-update.timer

########### /etc/systemd/system/auto-update.timer

[Unit]
Description=系统自动更新计时器
Requires=multi-user.target
After=multi-user.target

[Install]
WantedBy=timers.target

[Timer]
OnCalendar=*-*-* 03:00:00