BackGo/pkg/logger/logger.go

package logger

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

// LogLevel type for defining different logging levels.
type LogLevel int

const (
    // Define different log levels.
    LogLevelInfo LogLevel = iota
    LogLevelWarning
    LogLevelError
)

// Logger wraps the standard log.Logger from the Go standard library.
// It adds additional functionality like setting log levels.
type Logger struct {
    *log.Logger
    level LogLevel
}

// NewLogger creates a new Logger instance. By default, it logs to stdout with LogLevelInfo.
func NewLogger() *Logger {
    return &Logger{
        Logger: log.New(os.Stdout, "", log.LstdFlags),
        level:  LogLevelInfo,
    }
}

// SetLevel changes the logging level of the Logger.
func (l *Logger) SetLevel(level LogLevel) {
    l.level = level
}

// LogToFile configures the logger to log to a specified file.
func (l *Logger) LogToFile(filePath string) error {
    file, err := os.OpenFile(filePath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        return err
    }
    l.SetOutput(file)
    return nil
}

// LogToStdout configures the logger to log to stdout.
func (l *Logger) LogToStdout() {
    l.SetOutput(os.Stdout)
}

// LogToBoth configures the logger to log to both a file and stdout.
func (l *Logger) LogToBoth(filePath string) error {
    file, err := os.OpenFile(filePath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
    if err != nil {
        return err
    }
    multi := io.MultiWriter(file, os.Stdout)
    l.SetOutput(multi)
    return nil
}

// Info logs a message at level Info, respecting the set log level.
func (l *Logger) Info(msg string) {
    if l.level <= LogLevelInfo {
        l.Println("INFO: " + msg)
    }
}

// Warning logs a message at level Warning, respecting the set log level.
func (l *Logger) Warning(msg string) {
    if l.level <= LogLevelWarning {
        l.Println("WARNING: " + msg)
    }
}

// Error logs a message at level Error, respecting the set log level.
func (l *Logger) Error(msg string) {
    if l.level <= LogLevelError {
        l.Println("ERROR: " + msg)
    }
}