golang logging example

logging.go

package logging

import (
	"io"
	"log"
	"os"
)

type Logger struct {
	Info    *log.Logger
	Warning *log.Logger
	Error   *log.Logger
}

func NewLogger(file *os.File) *Logger {
	infoWriter := io.MultiWriter(file, os.Stdout)
	infoLogger := log.New(infoWriter, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile)

	warningWriter := io.MultiWriter(file, os.Stdout)
	warningLogger := log.New(warningWriter, "WARNING: ", log.Ldate|log.Ltime|log.Lshortfile)

	errorWriter := io.MultiWriter(file, os.Stdout)
	errorLogger := log.New(errorWriter, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile)

	return &Logger{Info: infoLogger, Warning: warningLogger, Error: errorLogger}
}

func main() {
	logFp, err := os.OpenFile("logfile.txt", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
	if err != nil {
		log.Panicln(err)
	}
	defer logFp.Close()
	logger := NewLogger(logFp)

	logger.Info.Println("info")
	logger.Warning.Println("warn")
	logger.Error.Println("err")
}