Merge pull request #1332 from infosiftr/improved-variants

Add blurb for "*-stretch" and "*-xenial" tags; Improve variant detection for "windowsservercore-zzz" tags

.template-helpers/variant-buildpacks.md

@@ -1,7 +0,0 @@
-# Image Variants
-
-The `%%IMAGE%%` images come in many flavors, each designed for a specific use case.
-
-## `%%IMAGE%%:<version>`
-
-This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of. This tag is based off of [`buildpack-deps`](https://registry.hub.docker.com/_/buildpack-deps/). `buildpack-deps` is designed for the average user of docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.

.template-helpers/variant-default-buildpack-deps.md

@@ -0,0 +1 @@
+This tag is based off of [`buildpack-deps`](https://hub.docker.com/_/buildpack-deps/). `buildpack-deps` is designed for the average user of Docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.

.template-helpers/variant-default-debian.md

@@ -0,0 +1 @@
+Some of these tags may have names like %%DEB-SUITES%% in them. These are the suite code names for releases of [Debian](https://wiki.debian.org/DebianReleases) and indicate which release the image is based on.

.template-helpers/variant-default-ubuntu.md

@@ -0,0 +1 @@
+Some of these tags may have names like %%DEB-SUITES%% in them. These are the suite code names for releases of [Ubuntu](https://wiki.ubuntu.com/Releases) and indicate which release the image is based on.

.template-helpers/variant.sh

@@ -11,11 +11,59 @@ fi
 dir="$(dirname "$(readlink -f "$BASH_SOURCE")")"
 repoDir="$dir/../$repo"
 
+# prints "$2$1$3$1...$N"
+join() {
+	local sep="$1"; shift
+	local out; printf -v out "${sep//%/%%}%s" "$@"
+	echo "${out#$sep}"
+}
+
+commaJoin() {
+	local items=( $(xargs -n1 <<<"$1" | sort -u) ); shift
+	sep=', '
+	case "${#items[@]}" in
+		0)
+			return
+			;;
+		1)
+			echo "$items"
+			return
+			;;
+		2)
+			sep=' '
+			;;
+	esac
+
+	items[-1]="or ${items[-1]}"
+	join "$sep" "${items[@]}"
+}
+
+tagFiles() {
+	local tag="$1"; shift
+	local tagUltimate="${tag##*-}" # 3.6-stretch -> stretch
+	local tagPenultimate="${tag%-*}" # 2.7.15-windowsservercore-1803 -> 2.7.15-windowsservercore
+	tagPenultimate="${tagPenultimate##*-}" # 2.7.15-windowsservercore -> windowsservercore
+
+	echo \
+		"$repoDir/variant-$tag.md" \
+		"$repoDir/variant-$tagUltimate.md" \
+		"$repoDir/variant-$tagPenultimate.md" \
+		"$dir/variant-$tag.md" \
+		"$dir/variant-$tagUltimate.md" \
+		"$dir/variant-$tagPenultimate.md"
+}
+
+_repo() {
+	local repo=$1; shift
 # if we haven't set BASHBREW_LIBRARY explicitly (like Jenkins does, for example), don't trust the local library
-if [ -z "${BASHBREW_LIBRARY:-}" ]; then
-	repo="https://github.com/docker-library/official-images/raw/master/library/$repo"
-fi
+	if [ -z "${BASHBREW_LIBRARY:-}" ]; then
+		repo="https://github.com/docker-library/official-images/raw/master/library/$repo"
+	fi
+
+	echo "$repo"
+}
 
+bbRepo="$(_repo "$repo")"
 IFS=$'\n'
 tags=( $(bashbrew cat -f '
 	{{- $archSpecific := getenv "ARCH_SPECIFIC_DOCS" -}}
@@ -24,16 +72,13 @@ tags=( $(bashbrew cat -f '
 		{{- join "\n" .Tags -}}
 		{{- "\n" -}}
 	{{- end -}}
-' "$repo") )
+' "$bbRepo") )
 unset IFS
 
 text=
 declare -A includedFiles=()
 for tag in "${tags[@]}"; do
-	for f in \
-		"$repoDir/variant-$tag.md" "$repoDir/variant-${tag##*-}.md" \
-		"$dir/variant-$tag.md" "$dir/variant-${tag##*-}.md" \
-	; do
+	for f in $(tagFiles "$tag"); do
 		if [ -n "${includedFiles[$f]}" ]; then
 			# make sure we don't duplicate variant sections
 			break
@@ -52,25 +97,63 @@ for tag in "${tags[@]}"; do
 done
 
 if [ "$text" ]; then
-	buildpacks=
-	potentialTags="$(bashbrew list --uniq "$repo" | cut -d: -f2)"
+	default="$([ -f "$repoDir/variant.md" ] && cat "$repoDir/variant.md" || cat "$dir/variant.md")"
+	default+=$'\n' # parameter expansion eats the trailing newline
+
+	# buildpack-deps text
+	potentialTags="$(bashbrew list --uniq "$bbRepo" | cut -d: -f2)"
 	for tag in $potentialTags; do
-		baseImage="$(bashbrew cat -f '{{ .ArchDockerFrom (.TagEntry.Architectures | first) .TagEntry }}' "$repo:$tag")"
+		baseImage="$(bashbrew cat -f '{{ .ArchDockerFrom (.TagEntry.Architectures | first) .TagEntry }}' "$bbRepo:$tag")"
 		case "$baseImage" in
 			buildpack-deps:*-*) ;; # "scm", "curl" -- not large images
-			buildpack-deps:*) buildpacks=1; break ;;
+			buildpack-deps:*)
+				default+=$'\n' # give a little space
+				default+="$(< "$dir/variant-default-buildpack-deps.md")"
+				default+=$'\n' # parameter expansion eats the trailing newline
+				break
+				;;
 		esac
 	done
 
-	echo
-	echo
+	if [ "$repo" != 'debian' ] && [ "$repo" != 'ubuntu' ]; then
+		# what is 'jessie', 'stretch' and 'sid'
+		# https://github.com/docker-library/python/issues/343
+		debian=( $(bashbrew list --uniq "$(_repo 'debian')" | grep -vE 'stable|slim|backports|experimental|testing' | cut -d: -f2) )
+		ubuntu=( $(bashbrew list "$(_repo 'ubuntu')" | grep -vE 'devel|latest|[0-9]' | cut -d: -f2) )
+		foundDebianTags=
+		foundUbuntuTags=
+		for tag in ${tags[@]}; do
+			for suite in "${debian[@]}"; do
+				case "$tag" in
+					*-"$suite" | "$suite"-* | *-"$suite"-* | "$suite" )
+						foundDebianTags+=" $suite"
+						;;
+				esac
+			done
+			for suite in "${ubuntu[@]}"; do
+				case "$tag" in
+					*-"$suite" | "$suite"-* | *-"$suite"-* | "$suite" )
+						foundUbuntuTags+=" $suite"
+						;;
+				esac
+			done
+		done
 
-	if [ -n "$buildpacks" ]; then
-		f='variant-buildpacks.md'
-	else
-		f='variant.md'
+		if [ -n "$foundDebianTags" ]; then
+			default+=$'\n' # give a little space
+			default+="$( sed -e 's/%%DEB-SUITES%%/'"$(commaJoin "$foundDebianTags")"'/' "$dir/variant-default-debian.md" )"
+			default+=$'\n' # parameter expansion eats the trailing newline
+		fi
+		if [ -n "$foundUbuntuTags" ]; then
+			default+=$'\n' # give a little space
+			default+="$( sed -e 's/%%DEB-SUITES%%/'"$(commaJoin "$foundUbuntuTags")"'/' "$dir/variant-default-ubuntu.md" )"
+			default+=$'\n' # parameter expansion eats the trailing newline
+		fi
 	fi
-	[ -f "$repoDir/$f" ] && cat "$repoDir/$f" || cat "$dir/$f"
 
+	echo
+	echo
+
+	echo -n "$default"
 	echo "$text"
 fi