Use multi-stage Dockerfile for image build

* Go build the Matchbox binary in the container image
in a docker.io/golang builder stage rather building
the binary separately

.dockerignore

@@ -1,2 +1,7 @@
-*
-!bin/matchbox
+bin/
+contrib/
+docs/
+examples/
+scripts/
+_output/
+

Dockerfile

@@ -1,5 +1,9 @@
+FROM docker.io/golang:1.14.9 AS builder
+COPY . src
+RUN cd src && make build
+
 FROM docker.io/alpine:3.12
 LABEL maintainer="Dalton Hubble <dghubble@gmail.com>"
-COPY bin/matchbox /matchbox
+COPY --from=builder /go/src/bin/matchbox /matchbox
 EXPOSE 8080
 ENTRYPOINT ["/matchbox"]

Makefile

@@ -36,16 +36,15 @@ fmt:
 	@test -z $$(go fmt ./...)
 
 .PHONY: image
-image:
-	@buildah bud -t $(LOCAL_REPO):$(VERSION) .
-	@buildah tag $(LOCAL_REPO):$(VERSION) $(LOCAL_REPO):latest
+image: \
+	image-amd64 \
+	image-arm64
 
-.PHONY: push
-push:
-	@buildah tag $(LOCAL_REPO):$(VERSION) $(IMAGE_REPO):$(VERSION)
-	@buildah tag $(LOCAL_REPO):$(VERSION) $(IMAGE_REPO):latest
-	@buildah push docker://$(IMAGE_REPO):$(VERSION)
-	@buildah push docker://$(IMAGE_REPO):latest
+image-%:
+	buildah bud -f Dockerfile \
+	-t $(LOCAL_REPO):$(VERSION)-$* \
+	--arch $* --override-arch $* \
+	--format=docker .
 
 .PHONY: update
 update: