Use jq-template.awk

Author: tianon

.gitattributes

@@ -0,0 +1,3 @@
+**/Dockerfile        linguist-generated
+**/start-qemu        linguist-generated
+Dockerfile.template  linguist-language=Dockerfile

.github/workflows/verify-templating.yml

@@ -0,0 +1,24 @@
+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: ./apply-templates.sh
+      - name: Generate .travis.yml
+        run: ./travis.sh
+      - name: Check Git Status
+        run: |
+          status="$(git status --short)"
+          [ -z "$status" ]

.gitignore

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

4.1/Dockerfile

@@ -14,8 +14,8 @@ ENV QEMU_KEYS \
 
 # https://www.qemu.org/download/#source
 # https://download.qemu.org/?C=M;O=D
-ENV QEMU_VERSION %%QEMU_VERSION%%
-ENV QEMU_URL %%QEMU_URL%%
+ENV QEMU_VERSION {{ .version }}
+ENV QEMU_URL {{ .url }}
 
 RUN set -eux; \
 	\

4.2/Dockerfile

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -Eeuo pipefail
+
+[ -f versions.json ] # run "versions.sh" first
+
+jqt='.jq-template.awk'
+if [ -n "${BASHBREW_SCRIPTS:-}" ]; then
+	jqt="$BASHBREW_SCRIPTS/jq-template.awk"
+elif [ "$BASH_SOURCE" -nt "$jqt" ]; then
+	wget -qO "$jqt" 'https://github.com/docker-library/bashbrew/raw/5f0c26381fb7cc78b2d217d58007800bdcfbcfa1/scripts/jq-template.awk'
+fi
+
+if [ "$#" -eq 0 ]; then
+	versions="$(jq -r 'keys | map(@sh) | join(" ")' versions.json)"
+	eval "set -- $versions"
+fi
+
+generated_warning() {
+	cat <<-EOH
+		#
+		# NOTE: THIS DOCKERFILE IS GENERATED VIA "apply-templates.sh"
+		#
+		# PLEASE DO NOT EDIT IT DIRECTLY.
+		#
+
+	EOH
+}
+
+for version; do
+	export version
+
+	echo "processing $version ..."
+
+	{
+		generated_warning
+		gawk -f "$jqt" Dockerfile.template
+	} > "$version/Dockerfile"
+
+	cp -a start-qemu "$version/"
+done

5.0/Dockerfile

@@ -10,8 +10,10 @@ declare -A aliases=(
 self="$(basename "$BASH_SOURCE")"
 cd "$(dirname "$(readlink -f "$BASH_SOURCE")")"
 
-versions=( */ )
-versions=( "${versions[@]%/}" )
+if [ "$#" -eq 0 ]; then
+	versions="$(jq -r 'keys | map(@sh) | join(" ")' versions.json)"
+	eval "set -- $versions"
+fi
 
 # sort version numbers with highest first
 IFS=$'\n'; versions=( $(echo "${versions[*]}" | sort -rV) ); unset IFS
@@ -52,10 +54,8 @@ join() {
 	echo "${out#$sep}"
 }
 
-for version in "${versions[@]}"; do
-	commit="$(dirCommit "$version")"
-
-	fullVersion="$(git show "$commit":"$version/Dockerfile" | awk '$1 == "ENV" && $2 == "QEMU_VERSION" { print $3; exit }')"
+for version; do
+	fullVersion="$(jq -r --arg version "$version" '.[$version].version' versions.json)"
 
 	rcVersion="${version%-rc}"
 
@@ -69,6 +69,8 @@ for version in "${versions[@]}"; do
 		${aliases[$version]:-}
 	)
 
+	commit="$(dirCommit "$version")"
+
 	echo
 	cat <<-EOE
 		Tags: $(join ', ' "${versionAliases[@]}")