Bash logger

logger.sh

#!/usr/bin/env bash

Logger() {
	local LogLevel
	
	Entry() {
		log.debug() {
			LogLevel=debug
			format.print "$@"
		}
	
		log.info() {
			LogLevel=info
			format.print "$@"
		}
	
		log.warn() {
			LogLevel=warn
			format.print "$@"
		}
		
		log.error() {
			LogLevel=error
			format.print "$@"
		}
	
		log.fatal() {
			LogLevel=fatal
			format.print "$@"
		}
	}

	Formatter() {
		format.leveltext() {
			local leveltext=${LogLevel^^}
			
			# Fixed width.
			printf "[%-5s]$*" "$leveltext"
		}

		format.print() {
			local leveltext=$(format.leveltext)
			echo >&2 "$leveltext" "$*"
		}
	}

	self.init() {
		# Load submodule
		Entry
		Formatter
		
		# Set default log level
		LogLevel=debug
	}

	# Initialize this module
	self.init
}

init() {
	# Load module
	Logger
}

main() {
	init

	log.debug "Debug level"
	log.info  "Info level"
	log.warn  "Warn level"
	log.error "Error level"
}

[[ "${BASH_SOURCE[0]:-}" == "$0" ]] && main