package logger import ( "fmt" "log" "os" ) type LogLevel int var Default Interface = Logger{Writer: log.New(os.Stdout, "\r\n", log.LstdFlags)} const ( Info LogLevel = iota + 1 Warn Error ) // Interface logger interface type Interface interface { LogMode(LogLevel) Interface Info(string, ...interface{}) Warn(string, ...interface{}) Error(string, ...interface{}) } // Writer log writer interface type Writer interface { Print(...interface{}) } type Logger struct { Writer logLevel LogLevel } func (logger Logger) LogMode(level LogLevel) Interface { return Logger{Writer: logger.Writer, logLevel: level} } // Info print info func (logger Logger) Info(msg string, data ...interface{}) { if logger.logLevel <= Info { logger.Print("[info] " + fmt.Sprintf(msg, data...)) } } // Warn print warn messages func (logger Logger) Warn(msg string, data ...interface{}) { if logger.logLevel <= Warn { logger.Print("[warn] " + fmt.Sprintf(msg, data...)) } } // Error print error messages func (logger Logger) Error(msg string, data ...interface{}) { if logger.logLevel <= Error { logger.Print("[error] " + fmt.Sprintf(msg, data...)) } }