kubectl-switch_ws

#!/usr/bin/env bash

set -eu

_switchws_inline_fzf='fzf --height=50% --reverse -0 --inline-info --border --header-lines=1'
_exit='[exit]'
_parent='..'
_version='0.2.1'

help () {
   # Display Help
   echo "Usage: $0 [-h|-v]"
   echo "Interactive workspace switcher for kcp."
   echo
   echo "Flags:"
   echo "-h     print this help."
   echo "-v     print version and exit."
}


print_workspace () {
    echo -e "Workspace: \033[1;32m$1\033[0m"
}

printn () {
  if [ ! -z "${1:-}" ]; then
    echo "${1:-}\n"
  fi
}

print_parent () {
  if [[ ${1:-} == *":"* ]] || [[ ${1:-} == *"/"* ]]; then
    printn "$_parent"
  fi
}

# ensure prerequisites are present.
startup_check () {
  if ! command -v kubectl-ws &> /dev/null; then
    echo "error: could not find kubectl-ws. See https://docs.kcp.io/kcp/latest/setup/kubectl-plugin/ for installation instructions"
    exit 1
  fi

  if ! command -v fzf &> /dev/null; then
    echo "error: could not find fzf. See https://github.com/junegunn/fzf#installation for installation instructions"
    exit 1
  fi

  if ! kubectl api-resources | grep -e '^workspaces' >/dev/null; then
    echo "error: target does not expose workspace resource type. Is this a kcp environment?"
    exit 1
  fi
}

main () {
  # print current workspace once when starting switch-ws.
  local current_workspace=$(kubectl ws current --short)
  print_workspace "$current_workspace"

  # start main loop of plugin.
  while true; do

    # get child workspaces in current workspace.
    output=$(kubectl get workspace -o custom-columns=NAME:.metadata.name,TYPE:.spec.type.name,SHARD:".metadata.annotations.internal\.tenancy\.kcp\.io/shard",PHASE:.status.phase)
    header=$(echo -e "$output" | head -n1)
    workspaces=$(echo -e "$output" | tail -n+2)

    # construct list by injecting parent pseudo element into list and pipe into fzf for selection.
    workspace=$(echo -e "$(printn "$header")$(print_parent "$current_workspace")$(printn "$workspaces")$_exit" | $_switchws_inline_fzf | awk '{print $1}')

    if [ "$workspace" == "$_exit" ] || [ "$workspace" == "" ]; then
       # if [exit] was selected (or nothing at all, corresponds to pressing ESC), the plugin should exit.
       exit 0
     else
       # switch to selected workspace.
       current_workspace=$(switch_workspace "$workspace")
     fi

    # delete previous output of workspace and print the new "current workspace".
    echo -e "\e[1A\e[K$(print_workspace "$current_workspace")"
  done
}

switch_workspace () {
    local stderr=""
    local stdout=""
    {
    IFS=$'\n' read -r -d '' stderr;
    IFS=$'\n' read -r -d '' stdout;
    } < <((printf '\0%s\0' "$(kubectl ws use --short "$1")" 1>&2) 2>&1)
    local exitcode=$?

    if [ $exitcode -ne 0 ]; then
        echo "$stderr"
        exit $exitcode
    fi

    echo "$stdout"
}

while getopts "hv" option; do
   case $option in
      h) # display help
        help
        exit 0;;
      v)
        echo "$_version"
        exit 0;;
   esac
done

startup_check
main