Add support for multiple supported upstream architectures

6/Dockerfile

@@ -2,6 +2,7 @@
 
 # This image re-bundles the Docker image from the upstream provider, Elastic.
 FROM docker.elastic.co/elasticsearch/elasticsearch:6.8.10@sha256:f8e21f6b2ef75dcda374da505fcb0ff4bf7e8d025f12096c498123fa4e372c1b
+# Supported Bashbrew Architectures: amd64
 
 # The upstream image was built by:
 #   https://github.com/elastic/dockerfiles/tree/v6.8.10/elasticsearch

7/Dockerfile

@@ -1,7 +1,8 @@
 # Elasticsearch 7.8.0
 
 # This image re-bundles the Docker image from the upstream provider, Elastic.
-FROM docker.elastic.co/elasticsearch/elasticsearch:7.8.0@sha256:ddf17c4027bf3e154b776949a201c188de7c658ea3195ffae352f5771cd51aae
+FROM docker.elastic.co/elasticsearch/elasticsearch:7.8.0@sha256:161bc8c7054c622b057324618a2e8bc49ae703e64901b141a16d9c8bdd3b82f9
+# Supported Bashbrew Architectures: amd64 arm64v8
 
 # The upstream image was built by:
 #   https://github.com/elastic/dockerfiles/tree/v7.8.0/elasticsearch

Dockerfile.template

@@ -2,6 +2,7 @@
 
 # This image re-bundles the Docker image from the upstream provider, Elastic.
 FROM %%UPSTREAM_IMAGE_DIGEST%%
+# Supported Bashbrew Architectures: %%UPSTREAM_IMAGE_ARCHITECTURES%%
 
 # The upstream image was built by:
 #   %%UPSTREAM_DOCKERFILE_LINK%%

generate-stackbrew-library.sh

@@ -57,9 +57,12 @@ for version in "${versions[@]}"; do
 	versionAliases=( $fullVersion )
 	# TODO decide whether to support X.Y aliases as well
 
+	versionArches="$(git show "$commit":"$version/Dockerfile" | awk -F ': ' '$1 == "# Supported Bashbrew Architectures" { print $2; exit }')"
+
 	echo
 	cat <<-EOE
 		Tags: $(join ', ' "${versionAliases[@]}")
+		Architectures: $(join ', ' $versionArches)
 		GitCommit: $commit
 		Directory: $version
 	EOE

update.sh

@@ -46,11 +46,57 @@ for version in "${versions[@]}"; do
 
 	# Parse image manifest for sha
 	authToken="$(curl -fsSL "https://docker-auth.elastic.co/auth?service=token-service&scope=repository:$upstreamImageRepo:pull" | jq -r .token)"
-	digest="$(curl --head -fsSL -H 'Accept: application/vnd.docker.distribution.manifest.v2+json' -H "Authorization: Bearer $authToken" "https://docker.elastic.co/v2/$upstreamImageRepo/manifests/$fullVersion" | tr -d '\r' | gawk -F ':[[:space:]]+' '$1 == "Docker-Content-Digest" { print $2 }')"
+	manifestList="$(
+		curl -D- -fsSL \
+			-H 'Accept: application/vnd.docker.distribution.manifest.list.v2+json' \
+			-H 'Accept: application/vnd.docker.distribution.manifest.v2+json' \
+			-H "Authorization: Bearer $authToken" \
+			"https://docker.elastic.co/v2/$upstreamImageRepo/manifests/$fullVersion" \
+			| tr -d '\r'
+	)"
+	digest="$(gawk -F ':[[:space:]]+' '$1 == "Docker-Content-Digest" { print $2; exit }' <<<"$manifestList")"
+	manifestList="$(gawk '/^$/ { pre = 1; next } pre { print }' <<<"$manifestList")"
 
 	# Format image reference (image@sha)
 	upstreamImageDigest="$upstreamImage@$digest"
 
+	schemaVersion="$(jq -r '.schemaVersion' <<<"$manifestList")"
+	[ "$schemaVersion" = 2 ] # sanity check
+	mediaType="$(jq -r '.mediaType' <<<"$manifestList")"
+	case "$mediaType" in
+		'application/vnd.docker.distribution.manifest.v2+json')
+			upstreamImageArchitectures='amd64'
+			;;
+
+		'application/vnd.docker.distribution.manifest.list.v2+json')
+			upstreamImageArchitectures="$(
+				jq -r '
+					.manifests[].platform
+					| if .os != "linux" then
+						.os + "-"
+					else "" end
+					+ if .architecture == "arm" then
+						"arm32"
+					elif .architecture == "386" then
+						"i386"
+					else .architecture end
+					+ if .variant then
+						.variant
+					elif .architecture == "arm64" then
+						"v8"
+					else "" end
+				' <<<"$manifestList" \
+				| sort -u \
+				| xargs
+			)"
+			;;
+
+		*)
+			echo >&2 "error: unknown media type on '$upstreamImageDigest': '$mediaType'"
+			exit 1
+			;;
+	esac
+
 	upstreamDockerfileTag="v$fullVersion"
 	upstreamDockerfileLink="https://github.com/elastic/dockerfiles/tree/$upstreamDockerfileTag/$upstreamProduct"
 	upstreamDockerfile="${upstreamDockerfileLink//tree/raw}/Dockerfile"
@@ -65,6 +111,7 @@ for version in "${versions[@]}"; do
 
 	sed -e 's!%%VERSION%%!'"$fullVersion"'!g' \
 		-e 's!%%UPSTREAM_IMAGE_DIGEST%%!'"$upstreamImageDigest"'!g' \
+		-e 's!%%UPSTREAM_IMAGE_ARCHITECTURES%%!'"$upstreamImageArchitectures"'!g' \
 		-e 's!%%UPSTREAM_DOCKERFILE_LINK%%!'"$upstreamDockerfileLink"'!g' \
 		-e 's!%%UPSTREAM_DOCKER_BUILD%%!'"$upstreamDockerBuild"'!g' \
 		Dockerfile.template > "$version/Dockerfile"