Build lightstep image based on alpine

Signed-off-by: Mikkel Oscar Lyderik Larsen <mikkel.larsen@zalando.de>

packaging/Dockerfile.alpine

@@ -0,0 +1,9 @@
+FROM golang:alpine
+
+ENV CGO_ENABLED 1
+ENV GOOS linux
+ENV GOARCH amd64
+
+# add build deps
+RUN apk add -U git build-base && \
+    go get github.com/Masterminds/glide

packaging/Dockerfile.lightstep

@@ -1,7 +1,12 @@
-FROM registry.opensource.zalan.do/stups/ubuntu:latest
+FROM registry.opensource.zalan.do/stups/alpine:latest
 MAINTAINER Skipper Maintainers <team-pathfinder@zalando.de>
+RUN apk --no-cache add ca-certificates && update-ca-certificates
+RUN mkdir -p /usr/bin
 ADD skipper eskip /usr/bin/
-EXPOSE 9090 9911
+ENV PATH $PATH:/usr/bin
 RUN mkdir -p /plugins
 ADD build/tracing_lightstep.so /plugins/
+
+EXPOSE 9090 9911
+
 ENTRYPOINT ["/usr/bin/skipper", "-plugindir", "/plugins"]

packaging/Makefile

@@ -1,18 +1,20 @@
 .PHONY: docker-push
 
-VERSION         ?= $(shell git rev-parse HEAD)
-REGISTRY        ?= registry-write.opensource.zalan.do/pathfinder
-IMAGE           ?= $(REGISTRY)/skipper:$(VERSION)
-LIGHTSTEP_IMAGE ?= $(REGISTRY)/skipper-lightstep:$(VERSION)
-CGO_ENABLED     ?= 0
+VERSION            ?= $(shell git rev-parse HEAD)
+REGISTRY           ?= registry-write.opensource.zalan.do/pathfinder
+IMAGE              ?= $(REGISTRY)/skipper:$(VERSION)
+LIGHTSTEP_IMAGE    ?= $(REGISTRY)/skipper-lightstep:$(VERSION)
+ALPINE_BUILD_IMAGE ?= $(REGISTRY)/skipper-alpine-build:latest
+PACKAGE            ?= github.com/zalando/skipper
+CGO_ENABLED        ?= 0
 
 default: docker-build
 
 skipper:
-	GOOS=linux GOARCH=amd64 CGO_ENABLED=$(CGO_ENABLED) go build github.com/zalando/skipper/cmd/skipper
+	GOOS=linux GOARCH=amd64 CGO_ENABLED=$(CGO_ENABLED) go build $(PACKAGE)/cmd/skipper
 
 eskip:
-	GOOS=linux GOARCH=amd64 CGO_ENABLED=$(CGO_ENABLED) go build github.com/zalando/skipper/cmd/eskip
+	GOOS=linux GOARCH=amd64 CGO_ENABLED=$(CGO_ENABLED) go build $(PACKAGE)/cmd/eskip
 
 clean:
 	rm -rf skipper eskip build/
@@ -31,7 +33,20 @@ plugins:
 		GOOS=linux GOARCH=amd64 CGO_ENABLED=1 make ;\
 		cp build/*.so $$CUR/build/
 
-docker-lightstep-build: skipper eskip plugins
+alpine.build: docker-alpine-build
+	docker run -v $(shell pwd)/..:/go/src/$(PACKAGE) \
+		-w /go/src/$(PACKAGE)/packaging $(ALPINE_BUILD_IMAGE) \
+		make skipper eskip
+
+alpine.plugins: docker-alpine-build
+	docker run -v $(shell pwd)/..:/go/src/$(PACKAGE) \
+		-w /go/src/$(PACKAGE)/packaging $(ALPINE_BUILD_IMAGE) \
+		make plugins
+
+docker-alpine-build:
+	docker build --rm -t $(ALPINE_BUILD_IMAGE) -f Dockerfile.alpine .
+
+docker-lightstep-build: alpine.build alpine.plugins
 	docker build -t $(LIGHTSTEP_IMAGE) -f Dockerfile.lightstep .
 
 docker-lightstep-push: