philomena/scripts/lib.sh

#!/usr/bin/env bash
# This file is meant to be sourced by other scripts, not executed directly.
# It contains a bunch of helper functions for writing bash scripts.

# This output stream is used by subshells to send their output to the root process stdout.
global_stdout=3
eval "exec $global_stdout>&1"

# Log a message at the info level
function info {
  local message=$1

  echo -e "\033[32;1m[INFO]\033[0m \033[0;32m$message\033[0m" >&2
}

# Log a message at the warn level
function warn {
  local message=$1

  echo -e "\033[33;1m[WARN]\033[0m \033[0;33m$message\033[0m" >&2
}

# Log a message at the error level
function error {
  local message=$1

  echo -e "\033[31;1m[ERROR]\033[0m \033[0;31m$message\033[0m" >&2
}

# Log a message at the error level and exit with a non-zero status
function die {
  local message=$1

  error "$message"
  exit 1
}

# Log the command and execute it
function step {
  local cmd="$1"
  if [[ $cmd == exec ]]; then
    cmd=("${@:2}")
  else
    cmd=("${@:1}")
  fi

  # If the process runs in a parallel subshell - use the TASK env var to prefix
  # its log with the task name.
  local task="${TASK:-}"

  if [[ -n $task ]]; then
    task="($task) "
  fi

  colorized_cmd=$(colorize_command "${cmd[@]}")

  echo >&$global_stdout -e "\033[32;1m$task❱\033[0m $colorized_cmd" >&2

  "$@"
}

# Returns a command with syntax highlighting
function colorize_command {
  local program=$1
  shift

  local args=()
  for arg in "$@"; do
    if [[ $arg =~ ^- ]]; then
      args+=("\033[34;1m${arg}\033[0m")
    else
      args+=("\033[0;33m${arg}\033[0m")
    fi
  done

  # On old versions of bash, for example 4.2.46 if the `args` array is empty,
  # then an `unbound variable` is thrown.
  #
  # Luckily, we don't pass commands without positional arguments to this function,
  # and we use bash >= v5. If this ever becomes a problem, you know the why.
  echo -e "\033[1;32m${program}\033[0m ${args[*]}"
}