Inspect an image without downloading it (chatgpt enhanced)

dockersize.sh

#!/bin/bash
# https://stackoverflow.com/questions/33352901/get-the-size-of-a-docker-image-before-a-pull
dockersize() { docker manifest inspect -v "$1" | jq -c 'if type == "array" then .[] else . end | select(.Descriptor.platform.architecture != "unknown")' | jq -r '[ ( .Descriptor.platform | [ .os, .architecture, .variant, ."os.version" ] | del(..|nulls) | join("/") ), ( [ ( .OCIManifest // .SchemaV2Manifest ).layers[].size ] | add ) ] | join(" ")' | numfmt --to iec --format '%.2f' --field 2 | sort | column -t; }

skopeosize() {
	local image="docker://$1"
	local repository="$image"
	local manifest

	if [[ "${image##*/}" == *:* ]]; then
		repository="${image%:*}"
	fi

	manifest=$(skopeo inspect --raw "$image") || return

	if jq -e '(.manifests // []) | length > 0' >/dev/null <<<"$manifest"; then
		jq -r '.manifests[] | select(.platform.architecture != null and .platform.architecture != "unknown") | [ .platform.os, .platform.architecture, .digest, .platform.variant ] | @tsv' <<<"$manifest" |
			while IFS=$'\t' read -r os architecture digest variant; do
				skopeo inspect "$repository@$digest" |
					jq -r --arg os "$os" --arg architecture "$architecture" --arg variant "$variant" '[ ( [ $os, $architecture, $variant ] | map(select(. != null and . != "")) | join("/") ), ( [ .LayersData[].Size ] | add ) ] | join(" ")'
			done
	else
		skopeo inspect --override-os linux "$image" |
			jq -r '[ ( [ .Os, .Architecture ] | map(select(. != null and . != "")) | join("/") ), ( [ .LayersData[].Size ] | add ) ] | join(" ")'
	fi | numfmt --to iec --format '%.2f' --field 2 | column -t
}

if command -v docker >/dev/null 2>&1; then
	dockersize "$@"
elif command -v skopeo >/dev/null 2>&1; then
	skopeosize "$@"
else
	echo "Neither docker nor skopeo is installed." >&2
	return 1
fi