docker/generate-stackbrew-library.sh

#!/bin/bash
set -Eeuo pipefail

declare -A release_channel=(
	[stable]='2020.03'
	[latest]='2020.03'
)

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

# Get the most recent commit which modified any of "$@".
fileCommit() {
	commit="$(git log -1 --format='format:%H' HEAD -- "$@")"
	if [ -z "$commit" ]; then
		# return some valid sha1 hash to make bashbrew happy
		echo '0000000000000000000000000000000000000000'
	else
		echo "$commit"
	fi
}

# Get the most recent commit which modified "$1/Dockerfile" or any file that
# the Dockerfile copies into the rootfs (with COPY).
dockerfileCommit() {
	local dir="$1"; shift
	(
		cd "$dir";
		fileCommit Dockerfile \
			$(awk '
				toupper($1) == "COPY" {
					for (i = 2; i < NF; i++)
							print $i;
				}
			' Dockerfile)
	)
}

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

	eval "declare -g -A parentRepoToArches=( $(
		find -maxdepth 3 -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 'friendica'

# Header.
cat <<-EOH
# This file is generated via https://github.com/friendica/docker/blob/$(fileCommit "$self")/$self

Maintainers: Friendica <info@friendi.ca> (@friendica), Philipp Holzer <admin@philipp.info> (@nupplaphil)
GitRepo: https://github.com/friendica/docker.git
EOH

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

# Generate each of the tags.
versions=( */ )
versions=( "${versions[@]%/}" )
for version in "${versions[@]}"; do
	variants=( $version/*/ )
	variants=( $(for variant in "${variants[@]%/}"; do
		echo "$(basename "$variant")"
	done) )
	for variant in "${variants[@]}"; do
		commit="$(dockerfileCommit "$version/$variant")"

		versionAliases=( )
		versionPostfix=""

		versionAliases+=( "$version$versionPostfix" )
		if [ "$version" == *-rc ]; then
			versionAliases+=( "rc" )
		fi
		if [ "$version" == *-dev ]; then
			versionAliases+=( "dev" )
		fi

		for channel in "${!release_channel[@]}"; do
			if [ "$version" = "${release_channel[$channel]}" ]; then
				versionAliases+=( "$channel" )
			fi
		done

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

		if [ "$variant" = "apache" ]; then
			variantAliases+=( "${versionAliases[@]}" )
		fi

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

		cat <<-EOE

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