#!/bin/bash

# script/k8s_update: Compiles the Kubernetes configuration for a given
# directory. Expects that the SETTINGS listed are all set as environment
# variables.
set -e

# Expected settings. Script will error if these are not provided.
SETTINGS=(
  CONTAINER_IMAGE
  PORT_PREFIX
  MAIN_DOMAIN
  AUTH_DOMAIN
  KV_MI_ID
  KV_MI_CLIENT_ID
  VMSS_CLIENT_ID
  TENANT_ID
)

# Loop all expected settings. Track ones that are missing and build
# concatenated list for envsubst. If any are missing, exit.
MISSING_SETTINGS=()
CONCAT_SETTINGS=""
for envvar in "${SETTINGS[@]}"; do
  CONCAT_SETTINGS="${CONCAT_SETTINGS} \$${envvar}"
  if [ -z "${!envvar}" ]; then
    MISSING_SETTINGS+=(${envvar})
  fi
done

if [[ ${#MISSING_SETTINGS[@]} > 0 ]]; then
  >&2 echo "The following variables need to be set:"
  for missing in "${MISSING_SETTINGS[@]}"; do
    >&2 echo $missing
  done
  exit 1
fi

# Check that a directory is provided as a command line argument.
if [ "$#" -ne 1 ] || ! [ -d $1 ]; then
  >&2 echo "You must provide a Kubernetes configuration directory."
  exit 1
fi

# Use Kustomize to compile Kubernetes configuration and pipe to envsubst to
# substitute the templated values.
kubectl kustomize $1 | envsubst "'${CONCAT_SETTINGS}'"