Cascading data fetch from etcd to docker -e string

etcd-data-to-docker-env-cascading

etcdTestData(){
  etcdctl set /env/globals/DB_HOST "global_database" 1> /dev/null
  etcdctl set /env/staging/DB_HOST "staging_database" 1> /dev/null
  etcdctl set /env/repo1/DB_HOST "repo1_database" 1> /dev/null
  etcdctl set /env/repo2/staging/DB_HOST "repo2_staging_database" 1> /dev/null
}

##
# this will fetch data from:
# /env/globals
# /env/${env}/
# /env/${repo}
# /env/${repo}/${env}
# in a cascading fashion, overwriting as it gets more specific
# this allows us to set things like:
# /env/globals/DB_HOST
# /env/staging/DB_HOST and pick the correct one depending
#
environmentFromEtcd(){
  local env=$1
  local repo=$2
  local global=$3
  declare -a loop_order=("/env/${global}" "/env/${env}" "/env/${repo}" "/env/${repo}/${env}")
  declare -A envs=()
  # loop over of tree order, generate a key based array that get overwritten
  for x in ${!loop_order[@]}; do
    local k=${loop_order[$x]}
    for i in $(etcdctl ls $k 2> /dev/null); do
      key=$(echo $i | sed -r "s#$k/##gi" | tr '[:lower:]' '[:upper:]') ;
      val=$(etcdctl get ${i} 2> /dev/null);
      if [ ! -z $val ]; then
        envs[$key]=${val};
      fi
    done;
  done

  local env_string=''
  #create a string from the key based array
  for y in ${!envs[@]}; do
    v=${envs[$y]}
    env_string="${env_string}-e ${y}=${v} "
  done
  echo " ${env_string} "
}

# generate some data
etcdTestData
# fetch the data
docker_string_prod_repo=$(environmentFromEtcd "production" "repo" "globals")
echo "Production string for repo:"
echo "----> ${docker_string_prod_repo}"
docker_string_prod_repo1=$(environmentFromEtcd "production" "repo1" "globals")
echo "Production string for repo1:"
echo "----> ${docker_string_prod_repo1}"
docker_string_staging1=$(environmentFromEtcd "staging" "repo" "globals")
echo "Staging string for repo:"
echo "----> ${docker_string_staging1}"
docker_string_staging2=$(environmentFromEtcd "staging" "repo2" "globals")
echo "Staging string for repo2:"
echo "----> ${docker_string_staging2}"