Docker buildx

Dockerfile

@@ -8,7 +8,7 @@
 #
 
 #FROM debian:bookworm-slim
-FROM ubuntu:22.04
+FROM ubuntu:22.04 AS build
 
 #ARG TARGET_ARCH=arm-linux-gnueabihf
 ARG TARGET_ARCH=aarch64-linux-gnu
@@ -37,5 +37,6 @@ RUN ./configure --prefix=/usr --host=${TARGET_ARCH}
 RUN make
 RUN make binary-dist
 
-#ENTRYPOINT [ "/bin/bash", "-l" ]
-CMD [ "/bin/bash", "-l" ]
+# Minimal export stage: only copy dist artifacts
+FROM scratch AS export
+COPY --from=build /opt/dist/ .

README.md

@@ -56,9 +56,25 @@ During development, periodically run `autoscan` to detect if changes should be m
 
 ## Cross-platform using Docker
 
-There is a `Dockerfile` that can be used to build for armhf and aarch64 on non-linux hosts that support Docker desktop.  See `build-all.sh` for an
-automated script that generates build artifacts for both.
+There is a `Dockerfile` that can be used to build for armhf and aarch64 on non-linux hosts that support Docker Desktop.  A `docker-bake.hcl` file plus the
+`build-all.sh` helper script will perform parallel multi-architecture builds using Docker Buildx.
 
+```
+./build-all.sh
+
+```
+Resulting tarballs are copied to `dist/`.
+
+To build only one architecture:
+```
+docker buildx bake armhf
+docker buildx bake arm64
+```
+
+Override args example:
+```
+docker buildx bake armhf --set armhf.args.TARGET_ARCH=arm-linux-gnueabihf
+```
 
 # Supported Platforms
 

build-all.sh

@@ -1,20 +1,13 @@
-#!/bin/bash -ueE
+#!/usr/bin/env bash
+set -ueE
 
 main() {
-  docker build -t bootcount-builder-armv7 \
-    --build-arg TARGET_ARCH=arm-linux-gnueabihf .
-  docker build -t bootcount-builder-armv8 \
-    --build-arg TARGET_ARCH=aarch64-linux-gnu .
-
-  for V in v7 v8; do
-    TARBALL=$(docker run --rm -it bootcount-builder-arm$V ls -1 dist/ | tr -d '\r' | tr -d '\n')
-    CONTAINER=$(docker create bootcount-builder-arm$V)
-    docker cp "$CONTAINER:/opt/dist/$TARBALL" .
-    docker rm "$CONTAINER"
-  done
+  mkdir -p dist
+  docker buildx bake "$@"
+  ls -lh dist/
 }
 
-if [[ "${BASH_SOURCE[0]}" == "$0" ]]; then
+if [[ ${BASH_SOURCE[0]} == "$0" ]]; then
   set -o pipefail
   main "$@"
 fi

docker-bake.hcl

@@ -0,0 +1,22 @@
+group "default" {
+  targets = ["armhf", "arm64"]
+}
+
+target "arm64" {
+  context = "."
+  dockerfile = "Dockerfile"
+  tags = ["bootcount-builder:arm64"]
+  args = {
+    // this is already the default in the Dockerfile:
+    // TARGET_ARCH = "aarch64-linux-gnu"
+  }
+  output = ["type=local,dest=dist/"]
+}
+
+target "armhf" {
+  inherits = ["arm64"]
+  args = {
+    TARGET_ARCH = "arm-linux-gnueabihf"
+  }
+  tags = ["bootcount-builder:armhf"]
+}