Factorio server auto update script and systemd service file.

factorio_update.sh

#!/bin/bash

# if the script hangs on wget download, replace `wget` with `wget -4`

: '
/etc/systemd/system/factorio.service

[Unit]
Descritpion=Factorio Headless Server
After=network.target
After=systemd-user-sessions.service
After=network-online.target

[Service]
Type=simple
User=root
ExecStart=/opt/factorio/bin/x64/factorio --start-server-load-latest

[Install]
WantedBy=multi-user.target
'

# check permission for writing to /opt
if [ "$EUID" -ne 0 ]
  then echo "Please run as root"
  exit
fi

# parse download page
stable_version=$(wget -qO- https://www.factorio.com/download | \
    grep -oP '(?<=/get-download/)[0-9]+\.[0-9]+\.[0-9]+' | \
    sort -Vu | tail -n 1)

# validate stable_version
if [ -z "$stable_version" ]; then
    echo "Failed to get stable_version from factorio website"
    exit 1
fi

# get current version
current_version=$( /opt/factorio/bin/x64/factorio --version | grep -oP 'Version: \K[0-9]+\.[0-9]+\.[0-9]+' )

# validate current_version
if [ -z "$current_version" ]; then
    echo "Failed to get current_version from factorio local executable"
    exit 1
fi

# compare version
echo -e "Online: $stable_version"
echo -e "Installed: $current_version"

if [ "$stable_version" == "$current_version" ]; then
    exit 0
fi

# apply update
wget -O factorio_headless.tar.xz https://www.factorio.com/get-download/stable/headless/linux64

echo "decompressing"
tar -xJf factorio_headless.tar.xz

echo "stopping factorio"
systemctl stop factorio

echo "installing files"
cp -r factorio /opt/
rm -fr factorio

echo "starting factorio"
systemctl start factorio