Add initial jq-based templating engine

See https://github.com/docker-library/bashbrew/blob/master/scripts/jq-template.awk

.gitattributes

@@ -0,0 +1 @@
+Dockerfile*  linguist-language=Dockerfile

.github/workflows/generate.sh

@@ -22,9 +22,8 @@ done
 jq -c . <<<"$strategy" > /dev/null # sanity check
 
 # now that we have a list of legit images with generate scripts, look for dangling Dockerfiles
-strategyDockerfiles="$(jq -c '[ .matrix.include[].meta.dockerfiles[], "cygwin/Dockerfile" ]' <<<"$strategy")"
 allDockerfiles="$(git ls-files '*/Dockerfile' | jq -Rsc 'rtrimstr("\n") | split("\n")')"
-danglingDockerfiles="$(jq -cn "$allDockerfiles - $strategyDockerfiles")"
+danglingDockerfiles="$(jq <<<"$strategy" -c --argjson allDockerfiles "$allDockerfiles" '$allDockerfiles - [ .matrix.include[].meta.dockerfiles[] ]')"
 
 strategy="$(jq -c --argjson danglingDockerfiles "$danglingDockerfiles" '.matrix.include[0] as $first | .matrix.include += [
 	$danglingDockerfiles[]

.github/workflows/verify-templating.yml

@@ -0,0 +1,25 @@
+name: Verify Templating
+
+on:
+  pull_request:
+  push:
+
+defaults:
+  run:
+    shell: 'bash -Eeuo pipefail -x {0}'
+
+jobs:
+  apply-templates:
+    name: Check For Uncomitted Changes
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Apply Templates
+        run: ./parallel.sh apply-templates.sh
+      - name: Git Diff (informational)
+        run: |
+          git diff || :
+      - name: Check Git Status
+        run: |
+          status="$(git status --short)"
+          [ -z "$status" ]

.gitignore

@@ -0,0 +1 @@
+/.jq-template.awk

.libs/deb-repo.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+deb-repo() {
+	[ -n "$uri" ]
+	[ -n "$suite" ]
+	#[ -n "$component" ] # if suite ends with /, this is optional
+	: "${arch:=amd64}"
+	[ -n "$package" ]
+
+	_deb-repo_packages() {
+		local packages
+		if [[ "$suite" == */ ]]; then
+			[ -z "${component:-}" ]
+			packages="$uri/${suite}Packages"
+		else
+			[ -n "$component" ]
+			packages="$uri/dists/$suite/$component/binary-$arch/Packages"
+		fi
+		{ wget -qO- "$packages.xz" | xz -d 2>/dev/null; } \
+		|| { wget -qO- "$packages.bz2" | bunzip2 2>/dev/null; } \
+		|| { wget -qO- "$packages.gz" | gunzip 2>/dev/null; } \
+		|| { wget -qO- "$packages.zstd" | zstd -d 2>/dev/null; } \
+		|| wget -qO- "$packages"
+	}
+
+	local versions version
+	versions="$(
+		_deb-repo_packages | gawk -F ':[[:space:]]+' -v package="$package" '
+			function do_the_thing() { if (pkg == package) { printf "%s %s\n", ver, sha256 }; pkg = ver = sha256 = "" }
+			$1 == "Package" { do_the_thing(); pkg = $2; ver = sha256 = "" }
+			$1 == "Version" { ver = $2 }
+			$1 == "SHA256" { sha256 = $2 }
+			END { do_the_thing() }
+		' | sort -rV
+	)"
+	version="$(head -1 <<<"$versions")" # TODO some way to get *not* the latest version?
+	if [ -z "$version" ]; then
+		echo >&2 "error: failed to find a version for '$package' in '$uri' (suite '$suite', comp '$component', arch '$arch')"
+		return 1
+	fi
+	local sha256="${version##* }"
+	version="${version% $sha256}"
+	[ "$sha256" != "$version" ] || sha256=
+
+	echo >&2 "deb $package: $version"
+	# TODO gather "supported arches" list
+
+	jq -nS --arg version "$version" --arg sha256 "$sha256" '
+		{
+			version: $version,
+		} | if $sha256 then .sha256 = $sha256 else . end
+	'
+}

.libs/git.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+git-tags() {
+	local repo="$1"; shift
+	[ -n "$repo" ]
+
+	local tag
+	tag="$(
+		git ls-remote --tags "$repo" \
+			| cut -d/ -f3 \
+			| cut -d^ -f1 \
+			| grep -vE -- '-(rc|alpha|beta)' \
+			| sort -Vu \
+			| tail -1
+	)"
+	local version="${tag#v}"
+
+	local base; base="$(basename "$repo")"
+	echo >&2 "git $base: $version"
+
+	jq -nc --arg tag "$tag" --arg version "$version" '
+		{
+			version: $version,
+			tag: $tag,
+		}
+	'
+}
+
+git-ref-commit() {
+	local repo="$1"; shift
+	local ref="$1"; shift
+
+	local commit
+	commit="$(git ls-remote "$repo" "$ref" | cut -d$'\t' -f1)"
+
+	local base; base="$(basename "$repo")"
+	echo >&2 "git $base - $ref: $commit"
+
+	jq -nc --arg commit "$commit" '{ version: $commit }'
+}
+
+github-file-commit() {
+	local repo="$1"; shift
+	local branch="$1"; shift
+	local file="$1"; shift
+	[ -n "$repo" ]
+	[ -n "$branch" ]
+	[ -n "$file" ]
+
+	local atom
+	atom="$(wget -qO- "https://github.com/$repo/commits/$branch/$file.atom")"
+	local commit
+	commit="$(awk <<<"$atom" -F ' *[<>/]+' '$2 == "id" && $3 ~ /Commit/ { print $4; exit }')"
+
+	echo >&2 "github $repo - $file: $commit"
+
+	jq -nc --arg commit "$commit" '{ version: $commit }'
+}

.libs/pypi.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+pypi() {
+	local package="$1"; shift
+	[ -n "$package" ]
+
+	local json version
+	json="$(wget -qO- "https://pypi.org/pypi/$package/json")"
+	version="$(jq <<<"$json" -r '.info.version')" # TODO some way to only get versions matching a particular string? ("1.14.x" etc. instead of just latest)
+
+	echo >&2 "pip $package: $version"
+
+	jq <<<"$json" -c '
+		.info
+		| (
+			.classifiers
+			| map(
+				match("^(?:Programming Language :: )?Python :: ([0-9]+[.][0-9]+)$")
+				| .captures[0].string
+				| split(".")
+				| map(tonumber)
+			)
+			| sort[-1]
+			| join(".")
+		) as $python
+		| {
+			version: .version,
+			python: { version: $python },
+		}
+	'
+}

apply-templates.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+jqt="$(dirname "$BASH_SOURCE")"
+jqt="$jqt/.jq-template.awk"
+if [ -n "${BASHBREW_SCRIPTS:-}" ]; then
+	jqt="$BASHBREW_SCRIPTS/jq-template.awk"
+elif [ "$BASH_SOURCE" -nt "$jqt" ]; then
+	# https://github.com/docker-library/bashbrew/blob/master/scripts/jq-template.awk
+	jqtNew="$jqt.new.$$" # using a (unique) ".new" file so this is safe to run concurrently
+	wget -qO "$jqtNew" 'https://github.com/docker-library/bashbrew/raw/1da7341a79651d28fbcc3d14b9176593c4231942/scripts/jq-template.awk'
+	mv -f "$jqtNew" "$jqt"
+fi
+jqt="$(readlink -ve "$jqt")"
+
+dirs="$(find "$@" -type f -name versions.json -exec bash -Eeuo pipefail -c 'for d; do dir="$(dirname "${d#./}")"; printf " %q" "$dir"; done' -- '{}' +)"
+eval "set -- $dirs"
+
+if [ "$#" -eq 0 ]; then
+	echo >&2 "error: failed to find any 'versions.json' files!"
+	exit 1
+fi
+
+generated_warning() {
+	cat <<-EOH
+		#
+		# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
+		#
+		# PLEASE DO NOT EDIT IT DIRECTLY.
+		#
+
+	EOH
+}
+
+for dir; do
+	export dir
+
+	template="$dir"
+	while [ ! -s "$template/Dockerfile.template" ]; do
+		if [ "$template" = '.' ]; then
+			echo >&2 "error: failed to find template for '$dir'!"
+			exit 1
+		fi
+		template="$(dirname "$template")"
+	done
+
+	variants="$(jq -r '.variants // [""] | map(@sh) | join(" ")' "$dir/versions.json")"
+	eval "variants=( $variants )"
+
+	text="$dir"
+	if [ "$dir" != "$template" ]; then
+		text+=" ($template)"
+	fi
+	template="$template/Dockerfile.template"
+
+	for variant in "${variants[@]}"; do
+		export variant
+
+		echo "processing $text${variant:+" variant '$variant'"} ..."
+
+		(
+			cd "$dir"
+			generated_warning
+			gawk -f "$jqt"
+		) < "$template" > "$dir/Dockerfile${variant:+".$variant"}"
+	done
+done

backblaze-b2/Dockerfile

@@ -1,9 +1,16 @@
-FROM python:3.9-alpine3.14
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM python:3.10-alpine3.15
 
 # https://pypi.org/project/b2/
 ENV BACKBLAZE_B2_VERSION 3.2.1
 
 RUN set -eux; \
-	pip install --no-cache-dir "b2 == $BACKBLAZE_B2_VERSION"
+	pip install --no-cache-dir "b2 == $BACKBLAZE_B2_VERSION"; \
+	b2 version
 
 CMD ["b2", "--help"]

backblaze-b2/Dockerfile.template

@@ -0,0 +1,10 @@
+FROM python:{{ .python.version }}-alpine3.15
+
+# https://pypi.org/project/b2/
+ENV BACKBLAZE_B2_VERSION {{ .version }}
+
+RUN set -eux; \
+	pip install --no-cache-dir "b2 == $BACKBLAZE_B2_VERSION"; \
+	b2 version
+
+CMD ["b2", "--help"]

backblaze-b2/versions.json

@@ -0,0 +1,6 @@
+{
+  "python": {
+    "version": "3.10"
+  },
+  "version": "3.2.1"
+}

backblaze-b2/versions.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+[ -e versions.json ]
+
+dir="$(readlink -ve "$BASH_SOURCE")"
+dir="$(dirname "$dir")"
+source "$dir/../.libs/pypi.sh"
+
+json="$(pypi 'b2')"
+
+jq <<<"$json" -S . > versions.json

beets/Dockerfile

@@ -1,7 +1,15 @@
-FROM python:3.9-alpine3.14
+#
+# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+FROM python:3.9-alpine3.15
 
 ENV BEETS_VERSION 1.6.0
 
-RUN pip install --no-cache-dir beets==$BEETS_VERSION
+RUN set -eux; \
+	pip install --no-cache-dir "beets == $BEETS_VERSION"; \
+	beet --version
 
 CMD ["beet"]

beets/Dockerfile.template

@@ -0,0 +1,9 @@
+FROM python:{{ .python.version }}-alpine3.15
+
+ENV BEETS_VERSION {{ .version }}
+
+RUN set -eux; \
+	pip install --no-cache-dir "beets == $BEETS_VERSION"; \
+	beet --version
+
+CMD ["beet"]

beets/versions.json

@@ -0,0 +1,6 @@
+{
+  "python": {
+    "version": "3.9"
+  },
+  "version": "1.6.0"
+}

beets/versions.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+[ -e versions.json ]
+
+dir="$(readlink -ve "$BASH_SOURCE")"
+dir="$(dirname "$dir")"
+source "$dir/../.libs/pypi.sh"
+
+json="$(pypi 'beets')"
+
+jq <<<"$json" -S . > versions.json