[Docker] Add support for arm32/64 (#2104)

Dockerfile

@@ -1,4 +1,23 @@
-FROM php:7-apache
+ARG FROM_ARCH=amd64
+
+# Multi-stage build, see https://docs.docker.com/develop/develop-images/multistage-build/
+FROM alpine AS builder
+
+# Download QEMU
+ADD https://github.com/balena-io/qemu/releases/download/v5.2.0%2Bbalena4/qemu-5.2.0.balena4-arm.tar.gz .
+RUN tar zxvf qemu-5.2.0.balena4-arm.tar.gz --strip-components 1
+ADD https://github.com/balena-io/qemu/releases/download/v5.2.0%2Bbalena4/qemu-5.2.0.balena4-aarch64.tar.gz .
+RUN tar zxvf qemu-5.2.0.balena4-aarch64.tar.gz --strip-components 1
+
+FROM $FROM_ARCH/php:7-apache
+
+LABEL description="RSS-Bridge is a PHP project capable of generating RSS and Atom feeds for websites that don't have one."
+LABEL repository="https://github.com/RSS-Bridge/rss-bridge"
+LABEL website="https://github.com/RSS-Bridge/rss-bridge"
+
+# Add QEMU
+COPY --from=builder qemu-arm-static /usr/bin
+COPY --from=builder qemu-aarch64-static /usr/bin
 
 ENV APACHE_DOCUMENT_ROOT=/app
 

hooks/build

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+# Custom build script to build images for all supported architectures.
+# Example for IMAGE_NAME: rss-builder/rss-builder:stable
+
+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.
+MANIFEST_TOOL_VERSION=$(curl -s https://api.github.com/repos/estesp/manifest-tool/releases/latest | grep 'tag_name' | cut -d\" -f4)
+curl -Lo manifest-tool https://github.com/estesp/manifest-tool/releases/download/$MANIFEST_TOOL_VERSION/manifest-tool-linux-amd64
+chmod +x manifest-tool
+
+# Generate the manifest file.
+# Parameter 1 is the multi-arch image name, e.g. rss-bridge/rss-bridge:stable
+function generate_manifest {
+  cat > manifest-generated.yaml << EOF
+image: $1
+manifests:
+  - image: $1-amd64
+    platform:
+      architecture: amd64
+      os: linux
+  - image: $1-arm32v7
+    platform:
+      architecture: arm
+      os: linux
+      variant: v7
+  - image: $1-arm64v8
+    platform:
+      architecture: arm64
+      os: linux
+      variant: v8
+EOF
+}
+
+echo "Pushing multi-arch manifest $IMAGE_NAME"
+generate_manifest $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