added buildx-qemu image

Makefile

@@ -1,7 +1,7 @@
 REGISTRY=registry.monotremata.xyz
 PLATFORMS=linux/amd64,linux/arm64
 
-IMAGES=agate mpd pleroma rainloop tor transmission webdav
+IMAGES=agate buildx-qemu mpd pleroma rainloop tor transmission webdav
 
 .PHONY: all $(IMAGES)
 
@@ -12,6 +12,9 @@ BUILDX=docker buildx build --platform $(PLATFORMS) --tag $(REGISTRY)/$@ --push $
 agate:
 	$(BUILDX)
 
+buildx-qemu:
+	$(BUILDX)
+
 mpd:
 	$(BUILDX)
 

README.md

@@ -16,6 +16,7 @@ docker registry.
 ## Currently implemented images:
 
 * agate
+* buildx-qemu (image I use to build the other images in my CI/CD)
 * mpd
 * pleroma
 * rainloop
@@ -23,6 +24,12 @@ docker registry.
 * transmission
 * webdav (really simple nginx + `nginx-mod-http-dav-ext` image)
 
+## Create buildx driver
+
+```sh
+docker buildx create --use
+```
+
 ## Enable multi-arch execution
 
 ```sh

buildx-qemu/Dockerfile

@@ -0,0 +1,30 @@
+FROM debian:bullseye-slim
+
+ARG TARGETARCH
+
+ENV DOCKER_URL=https://download.docker.com/linux/debian
+ENV GPG_FILE=/etc/apt/keyrings/docker.gpg
+ENV DEBIAN_VERSION=bullseye
+
+RUN apt-get update && \
+    apt-get install -y \
+        ca-certificates \
+        curl \
+        gnupg && \
+    rm -rf /var/lib/apt/lists/* && \
+    mkdir -p /etc/apt/keyrings && \
+    curl -fsSL "$DOCKER_URL/gpg" | gpg --dearmor -o "$GPG_FILE" && \
+    echo "deb [arch=$TARGETARCH signed-by=$GPG_FILE] $DOCKER_URL $DEBIAN_VERSION stable" > \
+        /etc/apt/sources.list.d/docker.list && \
+    apt-get update && \
+    apt-get install -y \
+        binfmt-support \
+        docker-ce-cli \
+        make \
+        qemu-user-static && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY entrypoint.sh /entrypoint.sh
+RUN chmod +x /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]

buildx-qemu/Makefile

@@ -0,0 +1,29 @@
+IMG_NAME=buildx-qemu
+REGISTRY=registry.monotremata.xyz
+IMG=$(REGISTRY)/$(IMG_NAME)
+PLATFORMS=linux/amd64,linux/arm64
+
+.PHONY: build push buildx
+
+ARCH=$(shell uname -m)
+
+ifeq ($(ARCH),x86_64)
+  TARGETARCH=amd64
+else ifeq ($(ARCH),aarch64)
+  TARGETARCH=arm64
+else
+  TARGETARCH=amd64
+endif
+
+build: Dockerfile entrypoint.sh
+	docker build -t $(IMG) --build-arg TARGETARCH=$(TARGETARCH) .
+
+push: build
+	docker image push $(IMG)
+
+buildx: Dockerfile entrypoint.sh
+	docker buildx build \
+	    --platform $(PLATFORMS) \
+	    --tag $(IMG) \
+	    --push \
+	    .

buildx-qemu/entrypoint.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+update-binfmts --enable
+docker buildx create --use
+docker buildx inspect --bootstrap
+
+exec "$@"