log

type Logger interface {
	// Debugf logs messages at DEBUG level.
	Debugf(format string, args ...interface{})
	// Infof logs messages at INFO level.
	Infof(format string, args ...interface{})
	// Warnf logs messages at WARN level.
	Warnf(format string, args ...interface{})
	// Errorf logs messages at ERROR level.
	Errorf(format string, args ...interface{})
	// Fatalf logs messages at FATAL level.
	Fatalf(format string, args ...interface{})
}