From 3bfafa2f4c4ecbbe3f567632fcf9bbbd2d7da063 Mon Sep 17 00:00:00 2001
From: Jon Friesen <jon@jonfriesen.ca>
Date: Fri, 14 Sep 2018 13:36:30 -0700
Subject: [PATCH] make coredns/Dockerfile use build stages (#424)

* make coredns/Dockerfile use build stages

This change makes the coredns Dockerfile use build stages to create
the binaries which are then copied to the image for running.

* removing deps
---
 coredns/Dockerfile | 43 +++++++++++++++++++++----------------------
 1 file changed, 21 insertions(+), 22 deletions(-)

diff --git a/coredns/Dockerfile b/coredns/Dockerfile
index c758c7a..0348f2c 100644
--- a/coredns/Dockerfile
+++ b/coredns/Dockerfile
@@ -1,32 +1,31 @@
-FROM alpine:latest
+FROM alpine:latest as builder
 LABEL maintainer "Jessie Frazelle <jess@linux.com>"
 
 ENV PATH /go/bin:/usr/local/go/bin:$PATH
 ENV GOPATH /go
 
-RUN	apk --no-cache add \
-	ca-certificates
+RUN    apk --no-cache add \
+    ca-certificates
 
 ENV COREDNS_VERSION v1.2.2
 
-RUN buildDeps=' \
-		go \
-		git \
-		gcc \
-		g++ \
-		libc-dev \
-		libgcc \
-		make \
-	' \
-	set -x \
-	&& apk --no-cache add $buildDeps \
-	&& git clone --depth 1 --branch ${COREDNS_VERSION} https://github.com/coredns/coredns /go/src/github.com/coredns/coredns \
-	&& cd /go/src/github.com/coredns/coredns \
-	&& make CHECKS="godeps" \
-	&& mv coredns /usr/bin/coredns \
-	&& apk del $buildDeps \
-	&& rm -rf /go \
-	&& echo "Build complete."
+RUN set -x \
+    && apk --no-cache add \
+        go \
+        git \
+        gcc \
+        g++ \
+        libc-dev \
+        libgcc \
+        make \
+    && git clone --depth 1 --branch ${COREDNS_VERSION} https://github.com/coredns/coredns /go/src/github.com/coredns/coredns \
+    && cd /go/src/github.com/coredns/coredns \
+    && make CHECKS="godeps" \
+    && mv coredns /usr/bin/coredns \
+    && echo "Build complete."
 
+FROM alpine:latest
 
-ENTRYPOINT [ "coredns", "-log" ]
+COPY --from=builder /usr/bin/coredns /usr/bin/coredns
+
+ENTRYPOINT [ "coredns", "-log" ]
\ No newline at end of file