generate-stackbrew-library.sh

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

self="$(basename "$BASH_SOURCE")"
cd "$(dirname "$(readlink -f "$BASH_SOURCE")")"

if [ "$#" -eq 0 ]; then
	versions="$(jq -r 'keys | map(@sh) | join(" ")' versions.json)"
	eval "set -- $versions"
fi

# get the most recent commit which modified any of "$@"
fileCommit() {
	git log -1 --format='format:%H' HEAD -- "$@"
}

# get the most recent commit which modified "$1/Dockerfile" or any file COPY'd from "$1/Dockerfile"
dirCommit() {
	local dir="$1"; shift
	(
		cd "$dir"
		fileCommit \
			Dockerfile \
			$(git show HEAD:./Dockerfile | awk '
				toupper($1) == "COPY" {
					for (i = 2; i < NF; i++) {
						print $i
					}
				}
			')
	)
}

getArches() {
	local repo="$1"; shift
	local officialImagesBase="${BASHBREW_LIBRARY:-https://github.com/docker-library/official-images/raw/HEAD/library}/"

	local parentRepoToArchesStr
	parentRepoToArchesStr="$(
		find -name 'Dockerfile' -exec awk -v officialImagesBase="$officialImagesBase" '
				toupper($1) == "FROM" && $2 !~ /^('"$repo"'|scratch|.*\/.*)(:|$)/ {
					printf "%s%s\n", officialImagesBase, $2
				}
			' '{}' + \
			| sort -u \
			| xargs -r bashbrew cat --format '["{{ .RepoName }}:{{ .TagName }}"]="{{ join " " .TagEntry.Architectures }}"'
	)"
	eval "declare -g -A parentRepoToArches=( $parentRepoToArchesStr )"
}
getArches 'buildpack-deps'

cat <<-EOH
# this file is generated via https://github.com/docker-library/buildpack-deps/blob/$(fileCommit "$self")/$self

Maintainers: Tianon Gravi <admwiggin@gmail.com> (@tianon),
             Joseph Ferguson <yosifkit@gmail.com> (@yosifkit)
GitRepo: https://github.com/docker-library/buildpack-deps.git
EOH

# prints "$2$1$3$1...$N"
join() {
	local sep="$1"; shift
	local out; printf -v out "${sep//%/%%}%s" "$@"
	echo "${out#$sep}"
}

for version; do
	export version
	# buster, bullseye, focal, etc
	codename="$(basename "$version")"
	# debian, ubuntu
	dist="$(dirname "$version")"

	versionAliases=( "$codename" )
	suite="$(jq -r '.[env.version].suite // empty' versions.json)"
	if [ -n "$suite" ]; then
		versionAliases+=( "$suite" )
	fi

	if [ "$suite" = 'stable' ]; then
		versionAliases+=( latest )
	fi

	parent="$(awk 'toupper($1) == "FROM" { print $2 }' "$version/curl/Dockerfile")"
	arches="${parentRepoToArches[$parent]}"

	variants="$(jq -r '.[env.version].variants | map(@sh) | join(" ")' versions.json)"
	eval "variants=( $variants )"
	for variant in "${variants[@]}"; do
		commit="$(dirCommit "$version/$variant")"

		variantAliases=( "${versionAliases[@]/%/${variant:+-$variant}}" )
		variantAliases=( "${variantAliases[@]//latest-/}" )

		variantArches="$arches"
		case "$version" in
			debian/trixie | ubuntu/focal)
				# trixie on riscv64 doesn't have git yet (at the very least, probably more once we get past that one), so we just exclude the upper variants for now and can revisit later
				# focal on riscv64 doesn't have mercurial, so we just exclude the upper focal variants from riscv64 entirely
				if [ "$variant" != 'curl' ]; then
					variantArches="$(sed -r -e 's/ riscv64 / /g' <<<" $variantArches ")"
				fi
				;;
		esac

		echo
		cat <<-EOE
			Tags: $(join ', ' "${variantAliases[@]}")
			Architectures: $(join ', ' $variantArches)
			GitCommit: $commit
			Directory: $version${variant:+/$variant}
		EOE
	done
done