Function New

middleware/logger/logger.go:30–155

New creates a new middleware handler

(config ...Config)

// New creates a new middleware handler
func New(config ...Config) fiber.Handler {
	// Set default config
	cfg := configDefault(config...)

	// Get timezone location
	tz, err := time.LoadLocation(cfg.TimeZone)
	if err != nil {
		cfg.timeZoneLocation = time.Local
	} else {
		cfg.timeZoneLocation = tz
	}

	// Check if format contains latency
	cfg.isLatencyEnabled = strings.Contains(cfg.Format, "${"+TagLatency+"}")

	timeEnabled := strings.Contains(cfg.Format, "${"+TagTime+"}")
	var timestamp *atomic.Value
	if timeEnabled {
		if cfg.TimeDone != nil {
			// Caller-managed lifecycle: dedicated updater so it can be stopped
			// via TimeDone (useful for tests and short-lived apps).
			timestamp = &atomic.Value{}
			timestamp.Store(time.Now().In(cfg.timeZoneLocation).Format(cfg.TimeFormat))
			startTimestampUpdater(timestamp, &cfg)
		} else {
			// Process-lifetime shared updater, deduplicated by format/zone/interval.
			timestamp = sharedTimestamp(cfg.TimeFormat, cfg.timeZoneLocation, cfg.TimeInterval)
		}
	}
	// Set PID once
	pid := strconv.Itoa(os.Getpid())

	// Set variables
	var (
		once       sync.Once
		errHandler fiber.ErrorHandler

		dataPool = sync.Pool{New: func() any { return new(Data) }}
	)

	// Err padding starts at the documented default and grows once on first
	// request to fit the longest registered route path.
	errPadding := defaultErrPadding
	errPaddingStr := strconv.Itoa(errPadding)

	// Before handling func
	cfg.BeforeHandlerFunc(&cfg)

	// Logger data
	// instead of analyzing the template inside(handler) each time, this is done once before
	// and we create several slices of the same length with the functions to be executed and fixed parts.
	template, err := logtemplate.Build[fiber.Ctx, Data](cfg.Format, createTagMap(&cfg))
	if err != nil {
		if translated := translateBuildError(err); translated != nil {
			panic(translated)
		}
		panic(err)
	}