Dockerfile

@@ -1,6 +1,21 @@
-FROM python:3.7-alpine as base
+ARG FROM_ARCH=amd64
 
-FROM base as builder
+FROM alpine as builder
+
+# Download QEMU, see https://github.com/ckulka/docker-multi-arch-example
+ADD https://github.com/balena-io/qemu/releases/download/v3.0.0%2Bresin/qemu-3.0.0+resin-arm.tar.gz .
+RUN tar zxvf qemu-3.0.0+resin-arm.tar.gz --strip-components 1
+ADD https://github.com/balena-io/qemu/releases/download/v3.0.0%2Bresin/qemu-3.0.0+resin-aarch64.tar.gz .
+RUN tar zxvf qemu-3.0.0+resin-aarch64.tar.gz --strip-components 1
+
+FROM $FROM_ARCH/python:3.7-alpine as base
+
+# Add QEMU
+# Add QEMU
+COPY --from=builder qemu-arm-static /usr/bin
+COPY --from=builder qemu-aarch64-static /usr/bin
+
+FROM base as builderfinal
 
 # add build utils (gcc, others)
 RUN apk add build-base

hooks/build

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Custom build script to build images for all supported architectures.
+# Example for IMAGE_NAME: ckulka/baikal:apache
+
+for arch in amd64 arm32v7 arm64v8
+do
+  echo "Building $IMAGE_NAME-$arch"
+  docker build --build-arg FROM_ARCH=$arch --file $DOCKERFILE_PATH --tag $IMAGE_NAME-$arch .
+done

hooks/post_push

@@ -0,0 +1,34 @@
+#!/bin/bash
+
+# Use manifest-tool to create the manifest, given the experimental
+# "docker manifest" command isn't available yet on Docker Hub.
+curl -Lo manifest-tool https://github.com/estesp/manifest-tool/releases/download/v0.9.0/manifest-tool-linux-amd64
+chmod +x manifest-tool
+
+# Generate the manifest file.
+# Parameter 1 is the multi-arch image name, e.g. ckulka/baikal:0.5.1
+# Parameter 2 is the base-image for the variants, e.g. ckulka/baikal:0.5.1-apache
+function generate_manifest {
+  cat > manifest-generated.yaml << EOF
+image: $1
+manifests:
+  - image: $2-amd64
+    platform:
+      architecture: amd64
+      os: linux
+  - image: $2-arm32v7
+    platform:
+      architecture: arm
+      os: linux
+      variant: v7
+  - image: $2-arm64v8
+    platform:
+      architecture: arm64
+      os: linux
+      variant: v8
+EOF
+}
+
+echo "Pushing multi-arch manifest $IMAGE_NAME"
+generate_manifest $IMAGE_NAME $IMAGE_NAME
+./manifest-tool push from-spec manifest-generated.yaml

hooks/pre_build

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# Register qemu-*-static for all supported processors except the 
+# current one, but also remove all registered binfmt_misc before
+docker run --rm --privileged multiarch/qemu-user-static:register --reset

hooks/push

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+# Custom build script to push images for all supported architectures.
+
+for arch in amd64 arm32v7 arm64v8
+do
+  echo "Pushing $IMAGE_NAME-$arch"
+  docker push $IMAGE_NAME-$arch
+done