multistage build

Dockerfile

@@ -1,8 +1,30 @@
+FROM golang:alpine as build
+
+WORKDIR /tmp/build
+
+COPY resin-xbuild.go /tmp/build
+
+RUN go build -ldflags "-w -s" resin-xbuild.go
+
+RUN apk add --no-cache curl
+
+ENV QEMU_RELEASE_TAG v2.9.0+resin1
+ENV QEMU_RELEASE_FILE qemu-2.9.0.resin1-arm.tar.gz
+ENV QEMU_RELEASE_SHA256 b39d6a878c013abb24f4cccc7c3a79829546ae365069d5712142a4ad21bcb91b
+
+RUN QEMU_URL="https://github.com/resin-io/qemu/releases/download/${QEMU_RELEASE_TAG}/${QEMU_RELEASE_FILE}" ; \
+    curl -fsSL  ${QEMU_URL} -o ${QEMU_RELEASE_FILE}
+
+RUN echo "${QEMU_RELEASE_SHA256}  ${QEMU_RELEASE_FILE}" > ${QEMU_RELEASE_FILE}.sha256sum \
+    sha256sum -c ${QEMU_RELEASE_FILE}.sha256sum
+
+RUN tar --strip 1 -xzf ${QEMU_RELEASE_FILE}
+
 FROM arm32v6/alpine
 
 ENV QEMU_EXECVE 1
 
-COPY qemu-arm-static /usr/bin
-COPY resin-xbuild /usr/bin
+COPY --from=build /tmp/build/qemu-arm-static /usr/bin
+COPY --from=build /tmp/build/resin-xbuild /usr/bin
 
 RUN [ "/usr/bin/qemu-arm-static", "/bin/sh", "-exc", "ln -s resin-xbuild /usr/bin/cross-build-start; ln -s resin-xbuild /usr/bin/cross-build-end; ln /bin/sh /bin/sh.real" ]

build.sh

@@ -1,3 +0,0 @@
-#!/bin/sh -ex
-
-go build -ldflags "-w -s" resin-xbuild.go

get-qemu.sh

@@ -1,16 +0,0 @@
-#!/bin/sh -ex
-
-QEMU_RELEASE_TAG="v2.9.0+resin1"
-QEMU_RELEASE_FILE="qemu-2.9.0.resin1-arm.tar.gz"
-QEMU_RELEASE_SHA256="b39d6a878c013abb24f4cccc7c3a79829546ae365069d5712142a4ad21bcb91b"
-
-QEMU_URL="https://github.com/resin-io/qemu/releases/download/${QEMU_RELEASE_TAG}/${QEMU_RELEASE_FILE}"
-curl -fsSL  ${QEMU_URL} -o ${QEMU_RELEASE_FILE}
-
-echo "${QEMU_RELEASE_SHA256}  ${QEMU_RELEASE_FILE}" > ${QEMU_RELEASE_FILE}.sha256sum
-sha256sum -c ${QEMU_RELEASE_FILE}.sha256sum
-rm -f ${QEMU_RELEASE_FILE}.sha256sum
-
-rm -f qemu-arm-static
-tar --strip 1 -xzf ${QEMU_RELEASE_FILE}
-rm -f ${QEMU_RELEASE_FILE}