#!/bin/bash

set -euo pipefail

GO_VERSION="1.11.5"

if [ $CF_STACK == "cflinuxfs2" ]; then

GO_SHA256="51cab63f3de5e2f75a9036801712e4d7ae9bf226f0b61abce8d784e698148d3b"

elif [ $CF_STACK == "cflinuxfs3" ]; then

GO_SHA256="ee770df4e1863ee8e07574cb48e0245b61bec8f118faf6ec3742ea89eb20db28"

else

echo " **ERROR** Unsupported stack"

echo " See https://docs.cloudfoundry.org/devguide/deploy-apps/stacks.html for more info"

exit 1

fi

export GoInstallDir="/tmp/go$GO_VERSION"

mkdir -p $GoInstallDir

if [ ! -f $GoInstallDir/go/bin/go ]; then

URL=https://buildpacks.cloudfoundry.org/dependencies/go/go${GO_VERSION}.linux-amd64-${CF_STACK}-${GO_SHA256:0:8}.tar.gz

echo "-----> Download go ${GO_VERSION}"

curl -s -L --retry 15 --retry-delay 2 $URL -o /tmp/go.tar.gz

DOWNLOAD_SHA256=$(shasum -a 256 /tmp/go.tar.gz | cut -d ' ' -f 1)

if [[ $DOWNLOAD_SHA256 != $GO_SHA256 ]]; then

echo " **ERROR** SHA256 mismatch: got $DOWNLOAD_SHA256 expected $GO_SHA256"

exit 1

fi

tar xzf /tmp/go.tar.gz -C $GoInstallDir

rm /tmp/go.tar.gz

fi

if [ ! -f $GoInstallDir/go/bin/go ]; then

echo " **ERROR** Could not download go"

exit 1

fi