Convert "generate-stackbrew-library.sh" to output the new 2822-based format

generate-stackbrew-library.sh

@@ -1,44 +1,78 @@
 #!/bin/bash
-set -e
+set -eu
 
 latest='uclibc'
 
+self="$(basename "$BASH_SOURCE")"
 cd "$(dirname "$(readlink -f "$BASH_SOURCE")")"
 
-versions=( */ )
-versions=( "${versions[@]%/}" )
-url='git://github.com/docker-library/busybox'
+variants=( */ )
+variants=( "${variants[@]%/}" )
 
-echo '# maintainer: InfoSiftr <github@infosiftr.com> (@infosiftr)'
-echo '# maintainer: Jérôme Petazzoni <jerome@docker.com> (@jpetazzo)'
+# get the most recent commit which modified any of "$@"
+fileCommit() {
+	git log -1 --format='format:%H' HEAD -- "$@"
+}
 
-for version in "${versions[@]}"; do
-	commit="$(cd "$version" && git log -1 --format='format:%H' -- Dockerfile $(awk 'toupper($1) == "COPY" || toupper($1) == "ADD" { for (i = 2; i < NF; i++) { print $i } }' Dockerfile))"
-	fullVersion="$(grep -m1 'ENV BUSYBOX_VERSION ' "$version/Dockerfile.builder" | cut -d' ' -f3)"
-	fullVersion="${fullVersion#*:}"
-	fullVersion="${fullVersion%-*}"
+# 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($1) ~ /^(COPY|ADD)$/ {
+					for (i = 2; i < NF; i++) {
+						print $i
+					}
+				}
+			')
+	)
+}
 
-	suffix="-$version"
+cat <<-EOH
+# this file is generated via https://github.com/docker-library/busybox/blob/$(fileCommit "$self")/$self
+
+Maintainers: Tianon Gravi <admwiggin@gmail.com> (@tianon),
+             Joseph Ferguson <yosifkit@gmail.com> (@yosifkit),
+             Jérôme Petazzoni <jerome@docker.com> (@jpetazzo)
+GitRepo: https://github.com/docker-library/busybox.git
+EOH
+
+# prints "$2$1$3$1...$N"
+join() {
+	local sep="$1"; shift
+	local out; printf -v out "${sep//%/%%}%s" "$@"
+	echo "${out#$sep}"
+}
+
+for variant in "${variants[@]}"; do
+	commit="$(dirCommit "$variant")"
+
+	fullVersion="$(git show "$commit":"$variant/Dockerfile.builder" | awk '$1 == "ENV" && $2 == "BUSYBOX_VERSION" { print $3; exit }')"
 
 	versionAliases=()
 	while [ "${fullVersion%.*}" != "$fullVersion" ]; do
-		versionAliases+=( $fullVersion$suffix )
-		if [ "$version" = "$latest" ]; then
-			versionAliases+=( $fullVersion )
-		fi
+		versionAliases+=( $fullVersion )
 		fullVersion="${fullVersion%.*}"
 	done
-	versionAliases+=( $fullVersion$suffix )
-	if [ "$version" = "$latest" ]; then
-		versionAliases+=( $fullVersion )
-	fi
-	versionAliases+=( $version )
-	if [ "$version" = "$latest" ]; then
-		versionAliases+=( latest )
+	versionAliases+=(
+		$fullVersion
+		latest
+	)
+
+	variantAliases=( "${versionAliases[@]/%/-$variant}" )
+	variantAliases=( "${variantAliases[@]//latest-/}" )
+
+	if [ "$variant" = "$latest" ]; then
+		variantAliases+=( "${versionAliases[@]}" )
 	fi
 
 	echo
-	for va in "${versionAliases[@]}"; do
-		echo "$va: ${url}@${commit} $version"
-	done
+	cat <<-EOE
+		Tags: $(join ', ' "${variantAliases[@]}")
+		GitCommit: $commit
+		Directory: $variant
+	EOE
 done