Netlify DDNS

netlify-ddns.bash

#!/usr/bin/env bash

# options
TTL="120"
SUBDOMAINS=(host1 host2 host3)
ACCESS_TOKEN="???"
DOMAIN="lyte.dev"

# constants
DNS_ZONE="$(<<< "$DOMAIN" sd "\." "_")"
API="https://api.netlify.com/api/v1"
URL="$API/dns_zones/$DNS_ZONE/dns_records?access_token=$ACCESS_TOKEN" 

# setup
CURL_FLAGS="-sL"
curl="curl $CURL_FLAGS"

# fetch IP addresses
MY_IPV4="$($curl -4 ifconfig.io)"
MY_IPV6="$($curl -6 ifconfig.io)"

# fetch current netlify DNS state
CURRENT_DNS_JSON="$(curl -sL "$URL" | jq -r 'map(select(.type == "A" or .type == "AAAA"))')"
jsq() {
	<<< "$CURRENT_DNS_JSON" jq "$@"
}

delete_netlify_dns_record_by_subdomain_if_exists() {
	SUBDOMAIN="$1"; shift
	if jsq -e "map(select(.hostname == \"$SUBDOMAIN.$DOMAIN\"))[0]" > /dev/null; then
		RECORD_ID="$(jsq -r "map(select(.hostname == \"$SUBDOMAIN.$DOMAIN\"))[0].id")"
		$curl -X DELETE "$API/dns_zones/$DNS_ZONE/dns_records/$RECORD_ID?access_token=$ACCESS_TOKEN" > /dev/null
	fi
}

create_netlify_dns_record() {
	SUBDOMAIN="$1"; shift
	PAYLOAD="$(jq -n -r \
		--arg type "A" \
		--arg name "$SUBDOMAIN" \
		--arg val  "$MY_IPV4" \
		--arg ttl  "$TTL" \
		'{type:$type,hostname:$name,value:$val,ttl:$ttl}')"
	<<< "$PAYLOAD" $curl -d @- -H 'content-type:application/json' "$API/dns_zones/$DNS_ZONE/dns_records?access_token=$ACCESS_TOKEN" > /dev/null
}

setup_netlify_dns_record() {
	SUBDOMAIN="$1"; shift
	echo "Setting up $SUBDOMAIN.$DOMAIN"
	delete_netlify_dns_record_by_subdomain_if_exists "$SUBDOMAIN"
	create_netlify_dns_record "$SUBDOMAIN"
}

for s in "${SUBDOMAINS[@]}"; do
	setup_netlify_dns_record "$s"
done