build.sh

#!/usr/bin/env bash
set -Eeuo pipefail

[ -f versions.json ] # run "versions.sh" first

if [ "$#" -eq 0 ]; then
	dirs="$(jq -r 'to_entries | map(.key + "/" + (.value.variants[])) | map(@sh) | join(" ")' versions.json)"
	eval "set -- $dirs"
fi

for dir; do
	base="busybox:${dir////-}"
	(
		set -x
		docker build -t "$base-builder" -f "$dir/Dockerfile.builder" "$dir"
		docker run --rm "$base-builder" tar cC rootfs . | xz -T0 -z9 > "$dir/busybox.tar.xz"
		docker build -t "$base-test" "$dir"
		docker run --rm "$base-test" sh -xec 'true'

		# detect whether the current host _can_ ping
		# (QEMU user-mode networking does not route ping traffic)
		shouldPing=
		if docker run --rm "$base-builder" ping -c 1 google.com &> /dev/null; then
			shouldPing=1
		fi

		if [ -n "$shouldPing" ]; then
			if ! docker run --rm "$base-test" ping -c 1 google.com; then
				sleep 1
				docker run --rm "$base-test" ping -c 1 google.com
			fi
		else
			docker run --rm "$base-test" nslookup google.com
		fi

		docker images "$base-test"
	)
done