generate-stackbrew-library.sh

#!/bin/bash
set -eu

declare -A aliases=(
	[4.0]='4 latest'
	[3.2]='3'
)

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

versions=( */ )
versions=( "${versions[@]%/}" )

# sort version numbers with highest first
IFS=$'\n'; versions=( $(echo "${versions[*]}" | 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
					}
				}
			')
	)
}

getArches() {
	local repo="$1"; shift
	local officialImagesUrl='https://github.com/docker-library/official-images/raw/master/library/'

	eval "declare -A -g 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 'redis'

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

Maintainers: Tianon Gravi <admwiggin@gmail.com> (@tianon),
             Joseph Ferguson <yosifkit@gmail.com> (@yosifkit)
GitRepo: https://github.com/docker-library/redis.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 in "${versions[@]}"; do
	for v in \
		'' 32bit alpine \
	; do
		dir="$version${v:+/$v}"
		variant="$(basename "$v")"

		[ -f "$dir/Dockerfile" ] || continue

		commit="$(dirCommit "$dir")"

		fullVersion="$(git show "$commit":"$dir/Dockerfile" | awk '$1 == "ENV" && $2 == "REDIS_VERSION" { print $3; exit }')"
		versionAliases=(
			$fullVersion
			$version
			${aliases[$version]:-}
		)

		if [ -n "$variant" ]; then
			variantAliases=( "${versionAliases[@]/%/-$variant}" )
			variantAliases=( "${variantAliases[@]//latest-/}" )
		else
			variantAliases=( "${versionAliases[@]}" )
		fi

		variantParent="$(awk 'toupper($1) == "FROM" { print $2 }' "$version/$variant/Dockerfile")"

		suite="${variantParent#*:}" # "jessie-slim", "stretch"
		suite="${suite%-slim}" # "jessie", "stretch"

		if [ "$v" = 'alpine' ]; then
			suite="alpine$suite" # "alpine3.8"
			suiteAliases=( "${versionAliases[@]/%/-$suite}" )
		else
			suiteAliases=( "${variantAliases[@]/%/-$suite}" )
		fi
		suiteAliases=( "${suiteAliases[@]//latest-/}" )
		variantAliases+=( "${suiteAliases[@]}" )

		case "$v" in
			32bit) variantArches='amd64' ;;
			*) variantArches="${parentRepoToArches[$variantParent]}" ;;
		esac

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