env: add dockerfile for cross compiling go for s390x

Update golang/go#16443

Change-Id: I59edb7334ad6236981b96faddb8aeb564579435b
Reviewed-on: https://go-review.googlesource.com/27242
Reviewed-by: Brad Fitzpatrick <[email protected]>

env/linux-s390x-stretch/Dockerfile

@@ -0,0 +1,65 @@
+# Copyright 2016 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# Linux builder VM running Debian stretch (i.e. Debian testing)
+# Docker tag gobuilders/linux-s390x-stretch
+
+FROM debian:stretch
+MAINTAINER golang-dev <[email protected]>
+
+ENV DEBIAN_FRONTEND noninteractive
+
+# curl: for getting and unpacking Go 1.4 source
+# git-core: for interacting with the Go source & subrepos
+# gcc, libc-dev: for building Go's bootstrap 'dist' prog
+# gcc-s390x-linux-gnu, libc6-dev-s390x-cross: for s390x builds
+# systemd: for init when image is used with docker2boot
+# net-tools, ifupdown, isc-dhcp-client: required for networking in a VM on GCE
+# procps, lsof, psmisc: misc tools
+RUN apt-get update && apt-get install -y \
+	bzip2 \
+	ca-certificates \
+	curl \
+	git-core \
+	gcc \
+	libc6-dev \
+	gcc-s390x-linux-gnu \
+	libc6-dev-s390x-cross \
+	systemd \
+	net-tools \
+	ifupdown \
+	isc-dhcp-client \
+	procps \
+	lsof \
+	psmisc \
+	--no-install-recommends \
+	&& rm -rf /var/lib/apt/lists/*
+
+RUN mkdir -p /go1.4-amd64 \
+	&& ( \
+		curl --silent https://storage.googleapis.com/golang/go1.4.3.linux-amd64.tar.gz | tar -C /go1.4-amd64 -zxv \
+	) \
+	&& mv /go1.4-amd64/go /go1.4 \
+	&& rm -rf /go1.4-amd64 \
+	&& rm -rf /go1.4/pkg/linux_amd64_race \
+		/go1.4/api \
+		/go1.4/blog \
+		/go1.4/doc \
+		/go1.4/misc \
+		/go1.4/test \
+	&& find /go1.4 -type d -name testdata | xargs rm -rf
+
+RUN curl -o /usr/local/bin/stage0 https://storage.googleapis.com/go-builder-data/stage0.linux-amd64.92ebb4ec \
+	&& chmod +x /usr/local/bin/stage0
+
+COPY buildlet.service /etc/systemd/system/buildlet.service
+RUN systemctl enable /etc/systemd/system/buildlet.service
+
+RUN rm -f /lib/systemd/system/multi-user.target.wants/systemd-logind.service
+RUN (echo "[Journal]"; echo "ForwardToConsole=yes") > /etc/systemd/journald.conf
+
+RUN (echo "auto lo"; echo "iface lo inet loopback"; echo "auto eth0"; echo "iface eth0 inet dhcp") > /etc/network/interfaces
+
+ENV GOROOT_BOOTSTRAP=/go1.4 GOOS=linux GOARCH=s390x CC_FOR_TARGET=s390x-linux-gnu-gcc
+COPY build-release.sh /usr/bin/

env/linux-s390x-stretch/Makefile

@@ -0,0 +1,6 @@
+# Copyright 2016 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+docker: Dockerfile
+	docker build --rm --force-rm -t gobuilders/linux-s390x-stretch .

env/linux-s390x-stretch/README

@@ -0,0 +1,10 @@
+The docker image created from this directory can be used to cross compile go
+from linux/amd64 to linux/s390x.
+
+How to use:
+
+$ docker run --rm -it -v $(pwd)/artifacts:/artifacts \
+    gobuilders/linux-s390x-stretch build-release.sh $GIT_REV
+
+This will make the built go artifact, go-${GIT_REV}-linux-s390x.tar.gz,
+available in the directory you mounted as `/artifacts` in the container.

env/linux-s390x-stretch/build-release.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+# Copyright 2016 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+set -e
+
+GIT_REV=$1
+if [[ -z "$GIT_REV" ]]; then
+	GIT_REV=master
+fi
+
+# fetch the source
+git clone https://go.googlesource.com/go /usr/src/go
+(
+cd /usr/src/go
+# checkout the specific revision
+git checkout "$GIT_REV"
+
+cd /usr/src/go/src
+# build
+./bootstrap.bash
+
+cd /
+mv /usr/src/go-${GOOS}-${GOARCH}-bootstrap /go
+mkdir -p /artifacts
+# tarball the artifact
+tar -czvf /artifacts/go-${GIT_REV}-${GOOS}-${GOARCH}.tar.gz /go
+)

env/linux-s390x-stretch/buildlet.service

@@ -0,0 +1,8 @@
+[Unit]
+Description=Buildlet
+
+[Service]
+ExecStart=/usr/local/bin/stage0
+
+[Install]
+WantedBy=multi-user.target