Dockerfile.builder: use go get path@version syntax to download ineffa…

…ssign

Also clean the Go build and module download caches to reduce the
container image size.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

Dockerfile

@@ -13,7 +13,7 @@ FROM quay.io/cilium/cilium-envoy:a3385205ad620550b35d3b0b651e40898386e6e3 as cil
 # versions to be built while allowing the new versions to make changes
 # that are not backwards compatible.
 #
-FROM quay.io/cilium/cilium-builder:2020-03-21 as builder
+FROM quay.io/cilium/cilium-builder:2020-04-02 as builder
 LABEL maintainer="maintainer@cilium.io"
 WORKDIR /go/src/github.com/cilium/cilium
 COPY . ./

Dockerfile.builder

@@ -21,7 +21,7 @@ ENV GO_VERSION 1.14.1
 #
 RUN apt-get update \
     && DEBIAN_FRONTEND=noninteractive apt-get upgrade -y --no-install-recommends \
-	&& DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
+    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
 		apt-utils \
 		binutils \
 		ca-certificates \
@@ -53,7 +53,5 @@ RUN apt-get update \
 # Install Go
 #
 RUN curl -sfL https://dl.google.com/go/go${GO_VERSION}.linux-amd64.tar.gz | tar -xzC /usr/local && \
-        go get -d -u github.com/gordonklaus/ineffassign && \
-        cd /go/src/github.com/gordonklaus/ineffassign && \
-        git checkout -b 1003c8bd00dc2869cb5ca5282e6ce33834fed514 1003c8bd00dc2869cb5ca5282e6ce33834fed514 && \
-        go install
+        GO111MODULE=on go get github.com/gordonklaus/ineffassign@1003c8bd00dc2869cb5ca5282e6ce33834fed514 && \
+        go clean -cache -modcache

test/docker-compose.yml

@@ -15,7 +15,7 @@ services:
     command: "etcd -name etcd0 -advertise-client-urls http://0.0.0.0:4002 -listen-client-urls http://0.0.0.0:4002 -initial-cluster-token etcd-cluster-1 -initial-cluster-state new"
     privileged: true
   base_image:
-    image: "quay.io/cilium/cilium-builder:2020-02-26"
+    image: "quay.io/cilium/cilium-builder:2020-04-02"
     volumes:
       - "./../:/go/src/github.com/cilium/cilium/"
     privileged: true