shell-base/script

#!/bin/sh

set -eu

usage() {
	printf "Usage: %s [-l DEBUG_LEVEL] [-h]\n" "$0"
}

help() {
    cat << EOH
 SYNOPSIS
    $0 [-l DEBUG_LEVEL] [-h]

 DESCRIPTION

    $0 does things!

 OPTIONS

    -h    Show this help

    -l debug|info|notice|warning|error
          Debug level
EOH
}

on_interrupt() {
	log -l notice ""
	log -l notice "Process aborted!"

	exit 130
}

main() {
	while getopts "l:h" option; do
		case "${option}" in
			h) help; exit 0;;
			l) LOG_VERBOSE="$OPTARG";;
			?) log -l error "$(usage)"; exit 1;;
		esac
	done

	# log [-t] [-l debug|info|notice|warning|error] message

	exit 0
}

log() {
	LOG_VERBOSE="${LOG_VERBOSE:-info}"
	LEVEL=info
	TIME=

	while getopts "tl:" option; do
		case "${option}" in
			l) LEVEL="$OPTARG"; shift $((OPTIND-1));;
			t) TIME="$(printf "[%s] " "$(date +'%Y-%m-%dT%H:%M:%S.%s')")"; shift $((OPTIND-1));;
			*) exit 1;;
		esac
	done

	if [ -t 2 ] && [ -z "${NO_COLOR-}" ]; then
		case "${LEVEL}" in
			debug) COLOR="$(tput setaf 3)";;
			notice) COLOR="$(tput setaf 4)";;
			warning) COLOR="$(tput setaf 5)";;
			error) COLOR="$(tput setaf 1)";;
			*) COLOR="$(tput sgr0)";;
		esac
	fi

	case "${LEVEL}" in
		debug) LEVEL=100;;
		notice) LEVEL=250;;
		warning) LEVEL=300;;
		error) LEVEL=400;;
		*) LEVEL=200;;
	esac

	case "${LOG_VERBOSE}" in
		debug) LOG_VERBOSE_VALUE=100;;
		notice) LOG_VERBOSE_VALUE=250;;
		warning) LOG_VERBOSE_VALUE=300;;
		error) LOG_VERBOSE_VALUE=400;;
		*) LOG_VERBOSE_VALUE=200;;
	esac

	if [ $LEVEL -ge $LOG_VERBOSE_VALUE ]; then
		printf "%s\n" "$*" | while IFS='' read -r LINE; do
			printf "%s%s%s\n" "${COLOR:-}" "${TIME:-}" "$LINE" >&2
		done
	fi
}

trap on_interrupt INT

main "$@"