Rewrite the image builder in Golang

Author: sprat

Dockerfile

@@ -24,33 +24,29 @@ RUN \
 --mount=type=cache,target=/root/.cache/go-build \
 CGO_ENABLED=0 go build -o /go/bin/init -v --ldflags '-s -w -extldflags=-static'
 
+# =========================================================
+FROM golang:1.25.2-alpine AS imager-build
+WORKDIR /go/src
+COPY imager/go.mod imager/go.sum ./
+RUN go mod download
+COPY imager .
+RUN \
+--mount=type=cache,target=/root/.cache/go-build \
+go generate -v ./... && \
+go test && \
+CGO_ENABLED=0 go build -o /go/bin/imager -v --ldflags '-s -w -extldflags=-static' cmd/main.go
+
 # =========================================================
 FROM alpine:3.22.2 AS alpine-base
 
 # =========================================================
 FROM alpine-base AS imager
-SHELL ["/bin/ash", "-euxo", "pipefail", "-c"]
-RUN \
-echo "@edge-community https://dl-cdn.alpinelinux.org/alpine/edge/community" >>/etc/apk/repositories && \
-apk add --no-cache \
-bash \
-binutils \
-coreutils \
-cpio \
-dosfstools \
-findutils \
-mtools \
-pigz \
-qemu-img \
-sfdisk \
-xorriso \
-zstd \
-xz \
-systemd-efistub@edge-community
+RUN apk add --no-cache binutils systemd-efistub
+# TODO: embed init
 COPY --from=init /go/bin/init /usr/share/claylinux/init
-COPY build-image.sh /usr/bin/build-image
+COPY --from=imager-build /go/bin/imager /bin/imager
 WORKDIR /out
-ENTRYPOINT ["build-image"]
+ENTRYPOINT ["/bin/imager"]
 
 # =========================================================
 FROM alpine-base AS bootable-alpine-rootfs
@@ -110,14 +106,14 @@ RUN if [ "$UCODE" != "none" ]; then apk add --no-cache "${UCODE}-ucode"; fi
 # hadolint ignore=DL3006
 FROM imager AS test
 ARG FORMAT=efi
-RUN --mount=from=test-rootfs,target=/system build-image --format "$FORMAT"
+RUN --mount=from=test-rootfs,target=/system /bin/imager --format "$FORMAT"
 
 # =========================================================
 # Generate a qemu image running our custom OS image
 FROM alpine-base AS emulator
 RUN apk add --no-cache bash qemu-system-x86_64 ovmf
 COPY emulator.sh /entrypoint
-ENTRYPOINT ["/entrypoint"]
 COPY --from=test /out /images
 ARG FORMAT
 ENV FORMAT="$FORMAT"
+ENTRYPOINT ["/entrypoint"]