Runs a cloudflare ddns script to update the zerotier network address via Systemd

cloudflare-ddns.service

# /etc/systemd/system/cloudflare-ddns.service

[Unit]
Description=Zerotier DDNS Client
Wants=network-online.target
After=network.target

[Service]
Type=oneshot
Environment=ZONE=bla.com
Environment=HOST=zt.blah.com
Environment=USE_DYNAMIC_HOSTNAME=true
Environment=API=yourcoolapikey
Environment=PROXY=false
Environment=FORCE_CREATE=true
Environment=MASTER_API_KEY=false
Environment=ZEROTIER_NETWORK_ID=somenetworkid
ExecStart=/usr/local/bin/update-zerotier-ddns.sh

# don't use 'nobody' if your script needs to access user files
# (if User is not set the service will run as root)
#User=nobody

# Useful during debugging; remove it once the service is working
#StandardOutput=console
StandardOutput=journal+console

[Install]

update-zerotier-ddns.sh

#!/bin/bash

# Put this in /usr/local/bin/update-zerotier-ddns.sh
# Ensure you also have the script in /usr/local/bin/cloudflare-ddns.sh
# You can get mine here: https://raw.githubusercontent.com/hongkongkiwi/docker-cloudflare-ddns/master/cloudflare.sh

# Check that we have the required tools
command -v zerotier-cli >/dev/null 2>&1 || { echo >&2 "I require zerotier-cli but it's not installed.  Aborting."; exit 1; }
command -v tr >/dev/null 2>&1 || { echo >&2 "I require tr but it's not installed.  Aborting."; exit 1; }

# Enforces required env variables
required_vars=(ZEROTIER_NETWORK_ID)
for required_var in "${required_vars[@]}"; do
    if [[ -z ${!required_var} ]]; then
        error=1
        echo >&2 "Error: $required_var env variable not set."
    fi
done

if [[ -n $error ]]; then
    exit 1
fi

if [[ ! -z "$USE_DYNAMIC_HOSTNAME" ]]; then
  MY_HOSTNAME=`echo "$HOSTNAME" | tr '[:upper:]' '[:lower:]'`
  [[ ! -z "$MY_HOSTNAME" ]] || { echo >&2 "USE_DYNAMIC_HOSTNAME is set, but HOSTNAME variable is not set.  Aborting."; exit 1; }
  HOST="${MY_HOSTNAME}.${HOST}"
  echo "Dynamic Hostname: $HOST"
fi

echo "ZeroTier Network ID: $ZEROTIER_NETWORK_ID"

export NEW_IP_ADDR=`zerotier-cli get $ZEROTIER_NETWORK_ID ip`
bash "/usr/local/bin/cloudflare-ddns.sh"