Hetzner Cloud Firewall Cloudflare IP Updater using either curl, wget or httpie.

update-hcfw.sh

#!/usr/bin/env bash

##############################################################
# Title          : Hetzner Firewall Cloudflare IP Updater    #
# Description    : Allows you to update your Hetzner Cloud   #
#                  Firewall to allow all incoming requests   #
#                  from Cloudflare.                          #
#                                                            #
# Author         : Sascha Greuel <hello@1-2.dev>             #
# Date           : 2021-03-30 09:30                          #
# License        : MIT                                       #
# Version        : 1.2.0                                     #
#                                                            #
# Usage          : bash update-hcfw.sh                       #
##############################################################

###
# You can either set the following option values manually,
# or append --client / --api-token / --firewall-id / --ports
# to the executed bash command.
###
CLIENT=""
API_TOKEN=""
FIREWALL_ID=""
PORTS="80,443"

###
# Helper functions
###
getClient()
{
  if command -v curl &>/dev/null; then
    CLIENT="curl"
  elif command -v wget &>/dev/null; then
    CLIENT="wget"
  elif command -v http &>/dev/null; then
    CLIENT="httpie"
  else
    echo "Error: This tool requires either curl, wget or httpie to be installed." >&2
    return 1
  fi
}

httpGet()
{
  case "$CLIENT" in
    curl) curl -A curl -s "$@" ;;
    wget) wget -qO- "$@" ;;
    httpie) http -b GET "$@" ;;
  esac
}

updateFirewall()
{
  API="https://api.hetzner.cloud/v1/firewalls/$FIREWALL_ID/actions/set_rules"
  AUTHORIZATION="Authorization: Bearer $API_TOKEN"
  CONTENT_TYPE="Content-Type: application/json"
  POST_DATA='{"rules":['"$1"']}'

  case "$CLIENT" in
    curl) curl -X POST -H "$AUTHORIZATION" -H "$CONTENT_TYPE" -d "$POST_DATA" "$API" ;;
    wget) wget -O- --header="$AUTHORIZATION" --header="$CONTENT_TYPE" --post-data="$POST_DATA" "$API" ;;
    httpie) echo "$POST_DATA" | http POST "$API" "$AUTHORIZATION" ;;
  esac
}
###

###
# Check prerequisites
###
while [ "$#" -gt 0 ]; do
  case "$1" in
    --client) CLIENT="$2" ;;
    --api-token) API_TOKEN="$2" ;;
    --firewall-id) FIREWALL_ID="$2" ;;
    --ports) PORTS="$2" ;;
  esac
  shift
done

if [ -z "$CLIENT" ]; then
  getClient || exit 1
fi

if ! httpGet github.com >/dev/null 2>&1; then
  echo -e "No active internet connection. Please try again."
  exit 1
fi

if [ -z "$API_TOKEN" ]; then
  echo -e "API Token missing. Please run ./$0 --api-token API_TOKEN"
  exit 1
fi

if [ -z "$FIREWALL_ID" ]; then
  echo -e "Firewall ID missing. Please run ./$0 --firewall-id YOUR-FIREWALL-ID"
  exit 1
fi

if [ -z "$PORTS" ]; then
  echo -e "Port(s) missing. Please run ./$0 --ports COMMA-SEPARATED-LIST-OF-PORTS"
  exit 1
fi

IPS=$(httpGet https://www.cloudflare.com/ips-v4)
IPS+=$(echo "" && httpGet https://www.cloudflare.com/ips-v6)
IPS=$(echo "$IPS" | sed "s/.*/\"&\"/;H;1h;"'$!d;x;s/\n/,/g')
RULES=()

# shellcheck disable=SC2116
for PORT in $(echo "${PORTS//,/ }"); do
  RULES+=('{"direction":"in","source_ips":['"$IPS"'],"protocol":"tcp","port":"'"$PORT"'"}')
done

updateFirewall "$(IFS=, ; echo "${RULES[*]}")"

exit 0