Formal docker images for conftest

The makefile is required as goreleaser is fairly limited about what it can do with images.
The examples images should make demos easier, as it includes all of the
required tools to run the existing set of demos.

Dockerfile

@@ -4,8 +4,36 @@ WORKDIR /
 COPY . /
 RUN go build .
 
+
 FROM bats/bats:v1.1.0 as acceptance
 COPY --from=builder /conftest /usr/local/bin
 COPY acceptance.bats /acceptance.bats
-COPY testdata /testdata
+COPY examples /examples
 RUN ./acceptance.bats
+
+
+FROM golang:1.12-alpine as examples
+
+ENV TERRAFORM_VERSION=0.12.0-rc1 \
+    KUSTOMIZE_VERSION=2.0.3
+
+COPY --from=builder /conftest /usr/local/bin
+COPY examples /examples
+
+RUN apk add --update npm make git jq ca-certificates openssl unzip wget && \
+    cd /tmp && \
+    wget https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/terraform_${TERRAFORM_VERSION}_linux_amd64.zip && \
+    unzip terraform_${TERRAFORM_VERSION}_linux_amd64.zip -d /usr/local/bin
+
+RUN wget -O /usr/local/bin/kustomize https://github.com/kubernetes-sigs/kustomize/releases/download/v${KUSTOMIZE_VERSION}/kustomize_${KUSTOMIZE_VERSION}_linux_amd64 && \
+    chmod +x /usr/local/bin/kustomize
+
+RUN go get -u cuelang.org/go/cmd/cue
+
+WORKDIR /examples
+
+
+FROM scratch
+COPY --from=builder /conftest /
+ENTRYPOINT ["/conftest"]
+CMD ["--help"]

Makefile

@@ -0,0 +1,28 @@
+
+TAG=$(shell git describe --abbrev=0 --tags)
+
+NAME=conftest
+IMAGE=instrumenta/$(NAME)
+
+COMMAND=docker
+BUILD=DOCKER_BUILDKIT=1 $(COMMAND) build
+PUSH=$(COMMAND) push
+
+all: push
+
+examples:
+	$(BUILD) --target examples -t instrumenta/conftest:examples .
+
+acceptance:
+	$(BUILD) --target acceptance .
+
+conftest:
+	$(BUILD) -t $(IMAGE):$(TAG) .
+	$(COMMAND) tag $(IMAGE):$(TAG) $(IMAGE):latest
+
+push: example conftest
+	$(PUSH) $(IMAGE):$(TAG)
+	$(PUSH) $(IMAGE):latest
+	$(PUSH) $(IMAGE):examples
+
+.PHONY: examples acceptance conftest push all