delete intermediate container images for docker multi-stage build

Dockerfile

FROM golang:1.13.5 as tester
LABEL type=intermediate-container
COPY main.go /go/src/main.go
COPY Makefile /go/src/Makefile
WORKDIR /go/src
RUN make test

FROM golang:1.13.5 as builder
LABEL type=intermediate-container
COPY main.go /go/src/main.go
COPY Makefile /go/src/Makefile
WORKDIR /go/src
RUN make build

FROM alpine:3.8 as cert
LABEL type=intermediate-container
RUN apk --update add ca-certificates

FROM scratch
ENV PATH=/bin
COPY --from=builder /go/src/demo /bin/demo
COPY --from=cert /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
CMD ["demo"]
EXPOSE 8080

main.go

package main

import (
	"net/http"
)

func main() {
	http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
		w.Write([]byte("ok"))
	})
	http.ListenAndServe(":8080", nil)
}

Makefile

.PHONY: dependency
dependency:

.PHONY: build
build: dependency
	@GO111MODULE=off CGO_ENABLED=0 go build -a -ldflags '-extldflags "-static"' -o demo .

.PHONY: test
test: dependency
	@GO111MODULE=off go test ./...

.PHONY: image
image: dependency
	@docker build -t demo .

.PHONY: prune
prune:
	@docker image prune -f --filter label=type=intermediate-container

multi-stage-docker-build.md

TODO