etcd directory to env file, supports recursion

etcdenv.sh

#!/bin/bash

set -eo pipefail

usage(){
  echo "etcdenv - Recursively prints etcd dir as environment file"
  echo "Usage: etcdenv rootdir"
  exit 1
}

[ $# -eq 0 ] && usage

rootdir=$1
keys=$(etcdctl ls --recursive $rootdir)

for key in $keys; do
  subname=${key#"$rootdir/"} #strip prefix
  envname=${subname//\//_} #convert / to _
  val="$(etcdctl get $key 2>/dev/null || exit 0)"

  if [ -n "$val" ]; then
    echo $envname=$val
  fi
done