#!/bin/bash

# This will generate a openstack-style config drive image suitable for
# use with cloud-init.  You may optionally pass in an ssh public key
# (using the -k/--ssh-key option) and a user-data blog (using the
# -u/--user-data option).

usage () {
	echo "usage: ${0##*/}: [--ssh-key <pubkey>] [--vendor-data <file>] [--user-data <file>] [--hostname <hostname>] <imagename>"
}

ARGS=$(getopt \
	-o k:u:v:h: \
	--long help,hostname:,ssh-key:,user-data:,vendor-data: -n "${0##*/}" \
	-- "$@")

# shellcheck disable=SC2181
if [ $? -ne 0 ]; then
	usage >&2
	exit 2
fi

eval set -- "$ARGS"

while :; do
	case "$1" in
		--help)
			usage
			exit 0
			;;
		-k|--ssh-key)
			ssh_key="$2"
			shift 2
			;;
		-u|--user-data)
			user_data="$2"
			shift 2
			;;
		-v|--vendor-data)
			vendor_data="$2"
			shift 2
			;;
		-h|--hostname)
			hostname="$2"
			shift 2
			;;
		--)	shift
			break
			;;
	esac
done

config_image=$1
shift

if [ "${ssh_key}" ] && [ -f "${ssh_key}" ]; then
	echo "adding pubkey from ${ssh_key}"
	ssh_key_data=$(cat "${ssh_key}")
fi

uuid=$(uuidgen)
if ! [ "${hostname}" ]; then
	hostname="${uuid}"
fi

trap 'rm -rf $config_dir' EXIT
config_dir=$(mktemp -t -d configXXXXXX)

if [ "${user_data}" ] && [ -f "${user_data}" ]; then
	echo "adding user data from ${user_data}"
	cp "${user_data}" "${config_dir}/user-data"
else
	touch "${config_dir}/user-data"
fi

if [ "${vendor_data}" ] && [ -f "${vendor_data}" ]; then
	echo "adding vendor data from ${vendor_data}"
	cp "${vendor_data}" "${config_dir}/vendor-data"
fi

cat > "${config_dir}/meta-data" <<-EOF
instance-id: ${uuid}
hostname: ${hostname}
local-hostname: ${hostname}
EOF

if [ "${ssh_key_data}" ]; then
	cat >> "${config_dir}/meta-data" <<-EOF
	public-keys:
	  - |
	    ${ssh_key_data}
	EOF
fi

#PS1="debug> " bash --norc

echo "generating configuration image at ${config_image}"
if ! mkisofs -o "${config_image}" -V cidata -r -J --quiet "${config_dir}"; then
	echo "ERROR: failed to create ${config_image}" >&2
	exit 1
fi
chmod a+r "${config_image}"