log zap 設定流程

generate core

生成一個 logger

Core := zapcore.NewCore(encoder, mainWriter, logLevel)
//  

Logger = zap.New(core, zap.AddCaller(), zap.AddCallerSkip(1))

每個 zapcore.Core 實例都代表了一個日誌寫入管道 要生成一個 logger core， 有三個要素

1. level
2. encoder
3. writer (output)

level

level 從最低到最高分別是

1. Debug
2. Info
3. Warn
4. Error
5. DPanic
6. Panic
7. Fatal

可以直接用

EmailLevel := zapcore.ErrorLevel

或是

var logLevel zapcore.Level
if err := logLevel.UnmarshalText([]byte(logLevelString)); err != nil {
    panic(err)
}

設定log level

encoder

func getEncoder() zapcore.Encoder {
	encoderConfig := zapcore.EncoderConfig{
		TimeKey:        "time",
		LevelKey:       "level",
		NameKey:        "logger",
		CallerKey:      "caller",
		FunctionKey:    zapcore.OmitKey,
		MessageKey:     "message",
		StacktraceKey:  "stacktrace",
		LineEnding:     zapcore.DefaultLineEnding,      // 範例 : \n
		EncodeLevel:    zapcore.CapitalLevelEncoder,    // 範例 : INFO
		EncodeTime:     zapcore.RFC3339TimeEncoder,     // 範例 : 2021-08-31T15:00:00+08:00
		EncodeDuration: zapcore.SecondsDurationEncoder, // 範例 : 0.000000
		EncodeCaller:   zapcore.ShortCallerEncoder,     // 範例 : main.go:14
	}
	// encoderConfig.EncodeTime = zapcore.RFC3339TimeEncoder
	// encoderConfig.EncodeLevel = zapcore.CapitalLevelEncoder
	return zapcore.NewJSONEncoder(encoderConfig)
}

// SecondsDurationEncoder 使用範例

start := time.Now()
// 假設這裡是執行任務的代碼
duration := time.Since(start)
logger.Info("Task completed", zap.Duration("duration", duration))

writer

writer 的作用是將 log 寫入到指定的地方

ex : 寫到console.log

mainWriter := getLogWriter(config.Get("log.logDir"))

func getLogWriter(logPath string) zapcore.WriteSyncer {
	lumberjackLogger := &lumberjack.Logger{
		Filename:   logPath,
		MaxSize:    config.GetInt("log.logMaxSize"), // megabytes
		MaxBackups: config.GetInt("log.logMaxBackups"),
		MaxAge:     config.GetInt("log.logMaxAge"), // days
		Compress:   true,
	}

	// MultiWriteSyncer will write logs to both the console and the file
	return zapcore.NewMultiWriteSyncer(
		zapcore.AddSync(os.Stdout),
		zapcore.AddSync(lumberjackLogger),
	)
}

// 客製化 writer


	EmailCore := zapcore.NewCore(
		encoder,
		&EmailWriteSyncer{},
		EmailLevel,
	)



type CustomLogger struct {
	*zap.Logger
}

// 新的LogIf方法
func (l *CustomLogger) LogIf(err error) {
	if err != nil {
		l.Error("Error Occurred:", zap.Error(err))
	}
}

// NewCustomLoggerFactory 創建一個新的CustomLogger實例
func NewCustomLoggerFactory(z *zap.Logger) *CustomLogger {
	return &CustomLogger{z}
}

var Logger *zap.Logger
var AccessLogger *zap.Logger
var NewCustomLogger *CustomLogger

type EmailWriteSyncer struct{}

func (e *EmailWriteSyncer) Write(p []byte) (n int, err error) {
	subject := "ERP SYSTEM Error Log Message" // Email 主旨
	body := string(p)

	_, sendErr := e.sendEmail(subject, body)
	if sendErr != nil {
		fmt.Println("Failed to send email:", sendErr)
	}

	return len(p), nil
}

func (e *EmailWriteSyncer) Sync() error {
	return nil // 沒有同步/刷新的需求
}

func (e *EmailWriteSyncer) sendEmail(

    subject string,
    body string,
) (bool, error) {
    // 這裡是寄信的代碼
    return true, nil
}

generate logger

生成一個 logger

Logger = zap.New(core, zap.AddCaller(), zap.AddCallerSkip(1))

如果有多個 core 可以用 TEE 來合併

// TEE 會將 log 寫入到兩個 core
Logger = zap.New(zapcore.NewTee(core, EmailCore), zap.AddCaller(), zap.AddCallerSkip(1))

如果想要 紀錄 json 的時候，可以用

func RequestLogger() gin.HandlerFunc {
	return func(c *gin.Context) {

		// Read and save the request body
		bodyBytes, err := io.ReadAll(c.Request.Body)
		if err != nil {
			global.AccessLog.Error("Failed to read request body", zap.Error(err))
		}
		// Replace the original body so subsequent handlers can read it
		c.Request.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))

		c.Next()

		var requestBody map[string]interface{}
		if err := json.Unmarshal(bodyBytes, &requestBody); err != nil {
			global.AccessLog.Error("JSON parse fail", zap.Error(err))
			return
		}

		global.AccessLog.Info(
			"RequestLogger",
			zap.String("method", c.Request.Method),
			zap.String("uri", c.Request.RequestURI),
			zap.String("proto", c.Request.Proto),
			zap.Int("status", c.Writer.Status()),
			zap.String("user-agent", c.Request.UserAgent()),
			zap.String("ip", c.ClientIP()),
			zap.Any("header", c.Request.Header),
		)

		global.AccessLog.Info("requestBody", zap.Any("requestBody", requestBody))

	}
}