Bash script to retrieve kcadm.sh from Keycloak server running on Kubernetes

get_kcadm.sh

#!/usr/bin/env bash

# Exit on error
set -e

# Variables
SCRIPT_NAME="$(basename "$0")"
OUTDIR="$PWD/kcadm"

# Color codes
NC="\e[0m"
BOLD="\e[1m"
DIM="\e[2m"
Y="\e[33m"
R="\e[31m"
G="\e[32m"

# Utility function to output error message
error() {
  >&2 echo -e "${R}ERROR: $*${NC}"
}

# Utility function to output warning message
warn() {
  >&2 echo -e "${Y}WARN: $*${NC}"
}

# Utility function to exit script with optional error message
die() {
  if test "$#" -gt 0; then
    error "$*"
  fi

  exit 1
}

# Output help usage
usage() {
  echo
  echo "Retrieve necessary files to get a working local copy of the Keycloak"
  echo "admin CLI (ie. kcadm.sh)."
  echo
  echo -e "${BOLD}Usage:${NC}"
  echo
  echo -e "    ${DIM}\$${NC} $SCRIPT_NAME [OPTIONS]"
  echo
  echo -e "${BOLD}Options:${NC}"
  echo
  echo "    -v, --version    Set Keycloak server version"
  echo "    -h, --help       Show this help message"
  echo
}

_kubectl() {
  kubectl -n "$NAMESPACE" "$@"
}

# Utility function to get an item list returned by a provided command
# and ask user to choose one item
list_select() {
  local question="$1"
  local destination="${2:-SELECTED_ITEM}"
  local data_cmd="$3"
  local ifs="$4"

  if test -z "$question"; then
    die "no question specified"
  fi

  if test -z "$data_cmd"; then
    die "no command to get data was provided"
  fi

  local data=()

  while IFS=$ifs read -r line; do
    data+=("$line")
  done < <($data_cmd)

  local len=${#data[@]}

  if test "$len" -eq 0; then
    die "no data found"
  elif test "$len" -eq 1; then
    export "$destination"="${data[0]}"
  else
    local choice=""

    while test -z "$choice"; do
      echo "$question"

      for i in "${!data[@]}"; do
        echo -e "\t[$i] ${data[i]}"
      done

      read -rep "Select an item: " "choice"

      if test -z "${data[choice]}"; then
        error "invalid choice"
        choice=""
      fi
    done

    export "$destination"="${data[choice]}"
  fi
}

# Check that kubectl command is available
check_kubectl() {
  if test -z "$(command -v kubectl)"; then
    die "missing kubectl binary"
  fi
}

# Check output directory does not already contain kcadm.sh
check_outdir() {
  if test -f "$OUTDIR/kcadm.sh"; then
    warn "kcadm.sh is already installed."
    read -rep "Continue anyway? [Y/n] " "choice"

    case $choice in
      [nN] ) exit;;
    esac
  fi
}

# Get version used in container by looking at the container image tag
get_version() {
  if test -n "$VERSION"; then
    echo "${DIM}Assuming Keycloak version $VERSION as requested by user.${NC}"
  else
    local version

    version=$(_kubectl get po "$POD" -ojsonpath='{.spec.containers[0].image}' | grep -oP '.+:\K(\d+.\d+.\d+)$')

    if test -z "$version"; then
      error "failed to detect keycloak version"
      echo "Use ${DIM}--version${NC} option to manually set the Keycloak server version"
      die
    fi

    VERSION="$version"
  fi
}

get_files() {
  mkdir -p "$OUTDIR"/client/lib
  _kubectl exec -i -c keycloak "$POD" -- cat /opt/keycloak/bin/kcadm.sh > "$OUTDIR"/kcadm.sh
  chmod +x "$OUTDIR"/kcadm.sh
  _kubectl exec -i -c keycloak "$POD" -- cat /opt/keycloak/bin/client/keycloak-admin-cli-"$VERSION".jar > "$OUTDIR"/client/keycloak-admin-cli-"$VERSION".jar

  local libfiles

  libfiles=$(_kubectl exec -i -c keycloak "$POD" -- ls /opt/keycloak/bin/client/lib)

  for libfile in $libfiles; do
    _kubectl exec -i -c keycloak "$POD" -- cat /opt/keycloak/bin/client/lib/"$libfile" > "$OUTDIR"/client/lib/"$libfile"
  done
}

# Read script flags
while getopts 'hv:-:' OPT; do
  # support long options: https://stackoverflow.com/a/28466267/519360
  if test "$OPT" = "-"; then # long option: reformulate OPT and OPTARG
    OPT="${OPTARG%%=*}" # extract long option name
    # shellcheck disable=SC2295
    OPTARG="${OPTARG#$OPT}" # extract long option argument (may be empty)
    OPTARG="${OPTARG#=}" # if long option argument, remove assigning `=`
  fi

  # Handle flags
  case "$OPT" in
    v | version ) VERSION="$OPTARG" ;;
    h | help )    usage; exit 0 ;;
    ??* )         die "illegal option --${OPT}" ;; # bad long option
    ? )           exit 1 ;; # bad short option (error reported via getopts)
  esac
done

main() {
  echo -e "${DIM}Performing initial checks...${NC}"
  check_kubectl
  check_outdir

  list_select "Select Keycloak Namespace:" "NAMESPACE" "kubectl get ns -ocustom-columns=NAME:.metadata.name --no-headers"
  list_select "Select Pod:" "POD" "kubectl get pods -n $NAMESPACE --field-selector=status.phase=Running -ocustom-columns=NAME:.metadata.name --no-headers"

  echo -e "${DIM}Detecting Keycloak version...${NC}"
  get_version

  echo -e "${DIM}Retrieving files...${NC}"
  get_files

  echo -e "${G}Keycloak admin CLI is available in $OUTDIR.${NC}"
  echo -e "${DIM}Run \"PATH=$OUTDIR:\$PATH\" to make it available system wide.${NC}"
}

main