down to ~80MB but we can do better

Author: adamancini

Dockerfile

@@ -5,19 +5,29 @@ RUN apk add --no-cache --update bash ca-certificates curl make git openssh-clien
 RUN git clone https://github.com/docker/swarmkit.git swarmkit && cd swarmkit && make bin/swarmctl && cp bin/swarmctl /usr/bin/swarmctl && rm -rf /go/src/github.com/docker/swarmkit
 
 FROM alpine:3.9 as build-protoc
-# should stay consistent with the version in .circleci/config.yml
 ARG PROTOC_VERSION=3.6.1
+RUN apk add --update --no-cache unzip curl
 # download and install protoc binary and .proto files
 RUN curl --silent --show-error --location --output protoc.zip \
   https://github.com/google/protobuf/releases/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-x86_64.zip \
   && unzip -d /usr/local protoc.zip include/\* bin/\* \
   && rm -f protoc.zip
 
-FROM alpine:3.9
+FROM alpine:3.9 as build-docker
+ARG DOCKER_CLIENT_VERSION=18.09.1
+RUN apk add --update --no-cache curl
+RUN curl -SsL --output docker.tgz \
+  https://download.docker.com/linux/static/stable/x86_64/docker-$DOCKER_CLIENT_VERSION.tgz \
+  && tar xvzf docker.tgz \
+  && cp docker/docker /usr/bin/docker \
+  && rm -f docker.tgz
 
+FROM alpine:3.9
+RUN apk add --no-cache --update bash jq
 # WORKDIR /go/src/github.com/docker
 # RUN git clone https://github.com/docker/swarmkit.git swarmkit && cd swarmkit && make bin/swarmctl && cp bin/swarmctl /usr/bin/swarmctl && rm -rf /go/src/github.com/docker/swarmkit
-COPY --from=build-swarmctl /usr/bin/swarmctl /usr/bin/swarmctl
+COPY --from=build-swarmctl /usr/bin/swarmctl /usr/bin
 COPY --from=build-protoc /usr/local/. /usr/local
+COPY --from=build-docker /usr/bin/docker /usr/bin
 COPY ip-util-check /usr/bin
 CMD [ "/usr/bin/ip-util-check" ]