Add architecture (fix #30)

generate-stackbrew-library.sh

@@ -33,6 +33,22 @@ dirCommit() {
 	)
 }
 
+getArches() {
+	local repo="$1"; shift
+	local officialImagesUrl='https://github.com/docker-library/official-images/raw/master/library/'
+
+	eval "declare -g -A parentRepoToArches=( $(
+		find -name 'Dockerfile' -exec awk '
+				toupper($1) == "FROM" && $2 !~ /^('"$repo"'|scratch|microsoft\/[^:]+)(:|$)/ {
+					print "'"$officialImagesUrl"'" $2
+				}
+			' '{}' + \
+			| sort -u \
+			| xargs bashbrew cat --format '[{{ .RepoName }}:{{ .TagName }}]="{{ join " " .TagEntry.Architectures }}"'
+	) )"
+}
+getArches 'joomla'
+
 cat <<-EOH
 # this file is generated via https://github.com/joomla/docker-joomla/blob/$(fileCommit "$self")/$self
 
@@ -97,10 +113,12 @@ for phpVersion in "${phpVersions[@]}"; do
 		fi
 
 		variantParent="$(awk 'toupper($1) == "FROM" { print $2 }' "$dir/Dockerfile")"
+		variantArches="${parentRepoToArches[$variantParent]}"
 
 		echo
 		cat <<-EOE
 			Tags: $(join ', ' "${fullAliases[@]}")
+			Architectures: $(join ', ' $variantArches)
 			GitCommit: $commit
 			Directory: $dir
 		EOE