Simple Multi-level logger based on go standard log library

mlog.go

package main

import (
	"fmt"
	"log"
)

var (
	Ldebug = "DEBG "
	Linfo  = "INFO "
)

type Logger interface {
	// Info is equivalent to Print() and logs the message at level Info.
	Info(v ...any)
	// Infof is equivalent to Printf() and logs the message at level Info.
	Infof(format string, v ...any)
	// Infoln is equivalent to Println() and logs the message at level Info.
	Infoln(v ...any)

	// Debug is equivalent to Print() and logs the message at level Debug.
	Debug(v ...any)
	// Debugf is equivalent to Printf() and logs the message at level Debug.
	Debugf(format string, v ...any)
	// Debugln is equivalent to Println() and logs the message at level Debug.
	Debugln(v ...any)
}

type Outputter interface {
	Output(calldepth int, s string) error
}

type MultiLogger map[string]Outputter

func (ml MultiLogger) Add(key string, l Outputter) MultiLogger {
	ml[key] = l
	return ml
}

func (ml MultiLogger) Remove(key string) {
	delete(ml, key)
}

func (ml MultiLogger) Debug(v ...interface{}) {
	if l, ok := ml[Ldebug]; ok {
		l.Output(2, Ldebug+fmt.Sprint(v...))
	}
}

func (ml MultiLogger) Debugf(format string, v ...interface{}) {
	if l, ok := ml[Ldebug]; ok {
		l.Output(2, Ldebug+fmt.Sprintf(format, v...))
	}
}

func (ml MultiLogger) Debugln(v ...interface{}) {
	if l, ok := ml[Ldebug]; ok {
		l.Output(2, Ldebug+fmt.Sprintln(v...))
	}
}

func (ml MultiLogger) Info(v ...interface{}) {
	if l, ok := ml[Linfo]; ok {
		l.Output(2, Linfo+fmt.Sprint(v...))
	}
}

func (ml MultiLogger) Infof(format string, v ...interface{}) {
	if l, ok := ml[Linfo]; ok {
		l.Output(2, Linfo+fmt.Sprintf(format, v...))
	}
}

func (ml MultiLogger) Infoln(v ...interface{}) {
	if l, ok := ml[Linfo]; ok {
		l.Output(2, Linfo+fmt.Sprintln(v...))
	}
}

func main() {
	l := log.Default()

	ml := make(MultiLogger)
	ml.Add(Ldebug, l)
	ml.Add(Linfo, l)
	ml.Debug("This is debug")
	ml.Info("This is info")
	// Output:
	// 2021/11/23 23:57:01 DEBG This is debug
	// 2021/11/23 23:57:01 INFO This is info
}