install-kubectl.sh

#/usr/bin/env bash

function exit_message() {
    echo "ERROR: $1" >&2
    exit 1
}

# Usage info
function show_help() {
cat << EOF
Usage: ${0##*/} [OPTIONS]
Fetch and install the kubectl utility
Arguments:
     -h (--help)                   display this help and exit
     -v (--version)                install a particular version of kubectl
EOF
}

# trap 'exit_message oops' ERR

while (( "$#" )); do
  case "$1" in
    -h|--help)
    show_help && exit 0
    ;;
    -v|--version)
    VERSION=$2
    shift 2
    ;;
    *)
    echo "Unknown option: <${1}>"
    echo
    show_help
    exit 1
    ;;
esac
done


### installing kubectl

stable_version=$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)
version=${VERSION:-$stable_version}

DOWNLOAD="YES"

KUBECTL=$(which kubectl)
if [ "$KUBECTL" ]
then
  current_version=$(kubectl version --short --client | awk '{print $NF}' )
  if [ "$current_version" == "$version" ]
  then
    DOWNLOAD="NO"
  fi
fi

# echo $DOWNLOAD "$current_version" ?= "$version"
if [ $DOWNLOAD == "YES" ]
then
  arch=$(uname -s | tr '[:upper:]' '[:lower:]')  # linux|darwin
  url="https://storage.googleapis.com/kubernetes-release/release/${version}/bin/${arch}/amd64/kubectl"
  echo "installing kubectl $version $arch to /usr/local/bin"
  curl -s -O $url
  chmod a+x kubectl
  mv kubectl /usr/local/bin
  KUBECTL=/usr/local/bin/kubectl
fi

echo "kubectl binary is located at $KUBECTL"
$KUBECTL version --client