.PHONY: tag push

BASE=alpine:3.5
IMAGE=mkimage-base

default: push

hash: Dockerfile mkimage.sh
	DOCKER_CONTENT_TRUST=1 docker pull $(BASE)
	tar cf - $^ | docker build --no-cache -t $(IMAGE):build -
	docker run --entrypoint=/bin/sh --rm $(IMAGE):build -c "cat $^ /lib/apk/db/installed | sha1sum" | sed 's/ .*//' > $@

push: hash
	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
		 (docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash) && \
		  docker push linuxkit/$(IMAGE):$(shell cat hash))
	docker rmi $(IMAGE):build
	rm -f hash

tag: hash
	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
		docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash)
	docker rmi $(IMAGE):build
	rm -f hash

clean:
	rm -f hash

.DELETE_ON_ERROR: