generate-stackbrew-library.sh

#!/usr/bin/env bash
set -eu

declare -A aliases=(
	[4.1]='4'
	[5.0]='5 latest'
)

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

# sort version numbers with highest first
IFS=$'\n'; set -- $(sort -rV <<<"$*"); unset IFS

# 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
					}
				}
			')
	)
}

gawkParents='
	{ cmd = toupper($1) }
	cmd == "FROM" {
		print $2
		next
	}
	cmd == "COPY" {
		for (i = 2; i < NF; i++) {
			if ($i ~ /^--from=/) {
				gsub(/^--from=/, "", $i)
				print $i
				next
			}
		}
	}
'

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

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

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

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

	fullVersion="$(jq -r '.[env.version].version' versions.json)"

	versionAliases=( $fullVersion )
	if [ "$version" != "$fullVersion" ]; then
		versionAliases+=( $version )
	fi
	versionAliases+=( ${aliases[$version]:-} )

	suite="$(jq -r '.[env.version].debian.version' versions.json)"
	suiteAliases=( "${versionAliases[@]/%/-$suite}" )
	suiteAliases=( "${suiteAliases[@]//latest-/}" )
	versionAliases+=( "${suiteAliases[@]}" )

	parents="$(gawk "$gawkParents" "$version/Dockerfile")"
	arches=
	for parent in $parents; do
		parentArches="${parentRepoToArches[$parent]:-}"
		if [ -z "$parentArches" ]; then
			continue
		elif [ -z "$arches" ]; then
			arches="$parentArches"
		else
			arches="$(
				comm -12 \
					<(xargs -n1 <<<"$arches" | sort -u) \
					<(xargs -n1 <<<"$parentArches" | sort -u)
			)"
		fi
	done

	commit="$(dirCommit "$version")"

	echo
	cat <<-EOE
		Tags: $(join ', ' "${versionAliases[@]}")
		Architectures: $(join ', ' $arches)
		GitCommit: $commit
		Directory: $version
	EOE
done