tools: Move tini to ./tools and convert to multi-stage build

Previously the "tini" contained the entire build. Using the
multi-stage build creates a new "tini" base image, which only
contains the "/bin/tini". This image can be used as the base
image for packages requiring "tini".

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@docker.com>

base/tini/Makefile

@@ -1,29 +0,0 @@
-.PHONY: tag push
-
-BASE=alpine:3.5
-IMAGE=tini
-
-default: push
-
-hash: Dockerfile
-	DOCKER_CONTENT_TRUST=1 docker pull $(BASE)
-	tar cf - $^ | docker build --no-cache -t $(IMAGE):build -
-	docker run --rm --entrypoint sh $(IMAGE):build -c 'cat /Dockerfile /lib/apk/db/installed | sha1sum' | sed 's/ .*//' > hash
-
-push: hash
-	docker pull linuxkit/$(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:

test/virtsock/Dockerfile.build

@@ -1,11 +0,0 @@
-FROM linuxkit/go-compile:4513068d9a7e919e4ec42e2d7ee879ff5b95b7f5@sha256:bdfadbe3e4ec699ca45b67453662321ec270f2d1a1dbdbf09625776d3ebd68c5
-
-ENV VIRTSOCK_COMMIT=6b4dec728264e07c41e108caebd6bc2b72559a5f
-RUN mkdir -p $GOPATH/src/github.com/rneugeba && \
-  cd $GOPATH/src/github.com/rneugeba && \
-  git clone https://github.com/rneugeba/virtsock.git
-WORKDIR $GOPATH/src/github.com/rneugeba/virtsock
-RUN git checkout $VIRTSOCK_COMMIT
-RUN make build/virtsock_stress.linux
-
-ENTRYPOINT ["cat", "build/virtsock_stress.linux"]

test/virtsock/Dockerfile.pkg

@@ -1,3 +0,0 @@
-FROM scratch
-COPY . ./
-CMD ["/bin/tini", "/bin/virtsock_stress", "-s", "-v", "1"]

tools/tini/Dockerfile

@@ -1,16 +1,13 @@
-FROM alpine:3.5
-RUN \
-  apk update && apk upgrade && \
-  apk add \
-  cmake \
-  gcc \
-  make \
-  musl-dev \
-  vim \
-  && true
-
+FROM linuxkit/c-compile:f52f485825c890d581e82a62af6906c1d33d8e5d@sha256:473fd283a090d3546e93915adacf00c69a23ff615c95c968c4a40e8723985853 AS tini-build
 COPY . /
 ENV TINI_VERSION=0.13.0
 ADD https://github.com/krallin/tini/archive/v${TINI_VERSION}.tar.gz tini-${TINI_VERSION}.tar.gz
+
 RUN zcat tini-${TINI_VERSION}.tar.gz | tar xvf -
 RUN cd tini-${TINI_VERSION} && cmake . && make && cp -a tini-static /bin/tini
+
+FROM scratch
+ENTRYPOINT []
+CMD []
+WORKDIR /
+COPY --from=tini-build bin/tini bin/tini

tools/tini/Makefile

@@ -0,0 +1,26 @@
+.PHONY: tag push
+default: push
+
+IMAGE=tini
+SHA_IMAGE=alpine:3.5@sha256:dfbd4a3a8ebca874ebd2474f044a0b33600d4523d03b0df76e5c5986cb02d7e8
+DEPS=Dockerfile Makefile
+
+hash: $(DEPS)
+	find $^ -type f | xargs cat | docker run --rm -i $(SHA_IMAGE) sha1sum - | sed 's/ .*//' > hash
+
+tag: hash
+	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
+		(docker build --no-cache -t $(IMAGE):build . && \
+		 docker tag $(IMAGE):build linuxkit/$(IMAGE):$(shell cat hash))
+
+push: tag
+	docker pull linuxkit/$(IMAGE):$(shell cat hash) || \
+		docker push linuxkit/$(IMAGE):$(shell cat hash)
+	rm -f hash
+	docker rmi $(IMAGE):build || true
+
+clean:
+	rm -f hash
+	docker rmi $(IMAGE):build || true
+
+.DELETE_ON_ERROR:

tools/tini/README.md

@@ -0,0 +1,4 @@
+[tini](https://github.com/krallin/tini) is a tiny program which can be
+used as a minimal `init` process for container images.
+
+The `linuxkit/tini` image just contains `/bin/tini` and can be used as the base image by packages, requiring `tini`.