fancy-bashing.sh

#!/usr/bin/env bash

function printDebug() {
  if [ -z "${1}" ]; then
    return 1
  fi

  # That 2:
  # FUNCNAME contains the printDebug call too and we want to ignore it.
  if [[ ${#FUNCNAME[@]} -gt 2 ]]; then
    echo "<debug> [$(date +'%H:%M%P')] Called from '${FUNCNAME[1]}'"
  else
    echo "Do not call me, bitch!"

    return 1
  fi

  return 0
}

function trace() {
  rndID=$RANDOM
  echo "==== TRACE (traceID: ${rndID}) ===="
  echo "Call tree:"

  i=-1
  for fn in ${FUNCNAME[@]}; do
    i=$(( i + 1 ))
    if [[ i -eq 0 ]]; then
      continue
    fi

    indent=$(( i - 1 ))

    printf "%$(( indent * 2 ))s=> %s\n" "" "${fn}"
  done

  echo -e "\nArguments:"

  i=1
  for arg in "${@}"; do
    echo "  ${i} -> ${arg}"
    i=$(( i + 1 ))
  done
  echo "==== TRACE END (traceID: ${rndID}) ===="
}

function fstRequired() {
  if [ -z "${2}" ]; then
    echo "Missing argument (${1})" >&2
    shift
    trace "${@}"

    return 1
  fi

  return 0
}

function sndRequired() {
  if [ -z "${3}" ]; then
    echo "Missing argument (${1})" >&2
    shift
    trace "${@}"

    return 1
  fi

  return 0
}

function fancyFunc() {
  fstRequired "host" "$@" || return 1
  sndRequired "port" "$@" || return 1

  printDebug "$@"

  echo "${1} -> ${2}"
}

echo ">>>>> This should print out a trace:"
fancyFunc "localhost"

echo -e "\n\n>>>>> This should be fine because it has second argument:"
fancyFunc "localhost" "9876"

echo -e "\n\n>>>>> This should tell you to feck off:"
printDebug "call me maybe"

output

>>>>> This should print out a trace:
Missing argument (port)
==== TRACE (traceID: 16942) ====
Call tree:
=> sndRequired
  => fancyFunc
    => main

Arguments:
  1 -> localhost
==== TRACE END (traceID: 16942) ====


>>>>> This should be fine because it has second argument:
<debug> [02:17am] Called from 'fancyFunc'
localhost -> 9876


>>>>> This should tell you to feck off:
Do not call me, bitch!