Dockerfile

FROM alpine:3.6

RUN apk add --no-cache \
		ca-certificates

ENV DOCKER_CHANNEL test
ENV DOCKER_VERSION 17.10.0-ce-rc1
# TODO ENV DOCKER_SHA256
# https://github.com/docker/docker-ce/blob/5b073ee2cf564edee5adca05eee574142f7627bb/components/packaging/static/hash_files !!
# (no SHA file artifacts on download.docker.com yet as of 2017-06-07 though)

RUN set -ex; \
# why we use "curl" instead of "wget":
# + wget -O docker.tgz https://download.docker.com/linux/static/stable/x86_64/docker-17.03.1-ce.tgz
# Connecting to download.docker.com (54.230.87.253:443)
# wget: error getting response: Connection reset by peer
	apk add --no-cache --virtual .fetch-deps \
		curl \
		tar \
	; \
	\
# this "case" statement is generated via "update.sh"
	apkArch="$(apk --print-arch)"; \
	case "$apkArch" in \
		x86_64) dockerArch='x86_64' ;; \
		aarch64) dockerArch='aarch64' ;; \
		ppc64le) dockerArch='ppc64le' ;; \
		s390x) dockerArch='s390x' ;; \
		*) echo >&2 "error: unsupported architecture ($apkArch)"; exit 1 ;;\
	esac; \
	\
	if ! curl -fL -o docker.tgz "https://download.docker.com/linux/static/${DOCKER_CHANNEL}/${dockerArch}/docker-${DOCKER_VERSION}.tgz"; then \
		echo >&2 "error: failed to download 'docker-${DOCKER_VERSION}' from '${DOCKER_CHANNEL}' for '${dockerArch}'"; \
		exit 1; \
	fi; \
	\
	tar --extract \
		--file docker.tgz \
		--strip-components 1 \
		--directory /usr/local/bin/ \
	; \
	rm docker.tgz; \
	\
	apk del .fetch-deps; \
	\
	dockerd -v; \
	docker -v

COPY docker-entrypoint.sh /usr/local/bin/

ENTRYPOINT ["docker-entrypoint.sh"]
CMD ["sh"]