chore: build image using multi-stage builds (#276)

Dockerfile

@@ -12,10 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM alpine:3.5
+# builder image
+FROM golang:1.8 as builder
 
-RUN apk --update --no-cache add ca-certificates
+WORKDIR /go/src/github.com/kubernetes-incubator/external-dns
+COPY . .
+RUN make test
+RUN make build
 
-COPY build/linux-amd64/external-dns /external-dns
+# final image
+FROM registry.opensource.zalan.do/stups/alpine:latest
+MAINTAINER Team Teapot @ Zalando SE <team-teapot@zalando.de>
 
-ENTRYPOINT ["/external-dns"]
+COPY --from=builder /go/src/github.com/kubernetes-incubator/external-dns/build/external-dns /bin/external-dns
+
+ENTRYPOINT ["/bin/external-dns"]

Makefile

@@ -56,11 +56,8 @@ build/$(BINARY): $(SOURCES)
 build.push: build.docker
 	docker push "$(IMAGE):$(VERSION)"
 
-build.docker: build/linux-amd64/$(BINARY)
+build.docker:
 	docker build --rm --tag "$(IMAGE):$(VERSION)" .
 
-build/linux-amd64/$(BINARY): $(SOURCES)
-	CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o build/linux-amd64/$(BINARY) $(BUILD_FLAGS) -ldflags "$(LDFLAGS)" .
-
 clean:
 	@rm -rf build

delivery.yaml

@@ -0,0 +1,18 @@
+build_steps:
+- desc: Install docker
+  cmd: |
+    apt-get update
+    apt-get install -y apt-transport-https ca-certificates curl software-properties-common
+    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
+    add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
+    apt-get update
+    apt-get install -y docker-ce
+- desc: Build and push docker image
+  cmd: |
+    image=registry-write.opensource.zalan.do/teapot/external-dns:$(git describe --always --dirty --tags)
+    docker build --tag $image .
+    IS_PR_BUILD=${CDP_PULL_REQUEST_NUMBER+"true"}
+    if [[ ${CDP_TARGET_BRANCH} == "master" && ${IS_PR_BUILD} != "true" ]]
+    then
+      docker push $image
+    fi