sync_images

#! /bin/sh
set -euo pipefail

# This script parses image configuration files located in `./config`
# directory and then checks if images are downloaded and checksums are
# correct.

PACKER_CACHE_DIR="${PACKER_CACHE_DIR:-packer_cache}"
PACKER_CONFIGS="${PACKER_CONFIGS:-config}"

compute_checksum() {
	image_file="${1}"

	sha1sum "${image_file}" | awk -P '{ print $1 }'
}

force_download_image() {
	packer_cache="${PACKER_CACHE}"

	config="${1}"
	image="${2}"

	wget -N -q -O "${packer_cache}/${image}" `get_param ${config} iso_url`
}

get_param() {
	json_file="${1}"
	param_name="${2}"

	jq -r ".${param_name}" "${json_file}"
}

main() {
	packer_cache="${PACKER_CACHE_DIR}"
	packer_configs="${PACKER_CONFIGS}"

	for config in `ls ${packer_configs}/alt-*.json`
	do
		image=`get_param ${config} iso_target_path`
		echo "Checking" `get_param ${config} descr`
		echo "Image: ${image}"
		img_stored_cksum=`get_param ${config} iso_checksum `

		if test -e "${packer_cache}/${image}"; then
			img_real_cksum=`compute_checksum "${packer_cache}/${image}"`

			if test "${img_real_cksum}" == "${img_stored_cksum}"; then
				echo "Image ${image} is already downloaded and correct"
			else
				echo "Image ${image} is broken"
				echo "Downloading image ${image}"
				force_download_image "${config}" "${image}"
			fi
		else
			echo "No file present for image ${image}"
			echo "Downloading image ${image}"
			force_download_image "${config}" "${image}"
		fi
	done
}

main