func New(config ...Config) fiber.Handler
func RegisterTag(tag string, fn LogFunc) error
func MustRegisterTag(tag string, fn LogFunc)

import (
    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/logger"
    "github.com/gofiber/fiber/v3/middleware/requestid"
)

// Initialize default config
app.Use(logger.New())

// Or extend your config for customization
// Log remote IP and port
app.Use(logger.New(logger.Config{
    Format: "[${ip}]:${port} ${status} - ${method} ${path}\n",
}))

// Logging Request ID
app.Use(requestid.New()) // Ensure requestid middleware is used before the logger
app.Use(logger.New(logger.Config{
    // requestid.New() registers ${requestid} automatically.
    Format: "${pid} ${requestid} ${status} - ${method} ${path}\n",
}))

// Changing TimeZone & TimeFormat
app.Use(logger.New(logger.Config{
    Format:     "${pid} ${status} - ${method} ${path}\n",
    TimeFormat: "02-Jan-2006",
    TimeZone:   "America/New_York",
}))

// Custom File Writer
accessLog, err := os.OpenFile("./access.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
if err != nil {
    log.Fatalf("error opening access.log file: %v", err)
}
defer accessLog.Close()
app.Use(logger.New(logger.Config{
    Stream: accessLog,
}))

// Add Custom Tags
app.Use(logger.New(logger.Config{
    CustomTags: map[string]logger.LogFunc{
        "custom_tag": func(output logger.Buffer, c fiber.Ctx, data *logger.Data, extraParam string) (int, error) {
            return output.WriteString("it is a custom tag")
        },
    },
}))

// Callback after log is written
app.Use(logger.New(logger.Config{
    TimeFormat: time.RFC3339Nano,
    TimeZone:   "Asia/Shanghai",
    Done: func(c fiber.Ctx, logString []byte) {
        if c.Response().StatusCode() != fiber.StatusOK {
            reporter.SendToSlack(logString)
        }
    },
}))

// Disable colors when outputting to default format
app.Use(logger.New(logger.Config{
    DisableColors: true,
}))

// Force the use of colors
app.Use(logger.New(logger.Config{
    ForceColors: true,
}))

// Use predefined formats
app.Use(logger.New(logger.Config{
    Format: logger.CommonFormat,
}))

app.Use(logger.New(logger.Config{
    Format: logger.CombinedFormat,
}))

app.Use(logger.New(logger.Config{
    Format: logger.JSONFormat,
}))

app.Use(logger.New(logger.Config{
    Format: logger.ECSFormat,
}))

app := fiber.New(fiber.Config{
    ErrorHandler: func(c fiber.Ctx, err error) error {
        code := fiber.StatusInternalServerError
        if fiberErr, ok := err.(*fiber.Error); ok {
            code = fiberErr.Code
        }
        return c.Status(code).JSON(fiber.Map{"error": "request failed"})
    },
})

app.Use(logger.New(logger.Config{
    Format: "${status} ${method} ${path} ${error}\n",
}))

app.Get("/reports", func(_ fiber.Ctx) error {
    return fiber.NewError(fiber.StatusInternalServerError, "report generation failed")
})

app.Use(requestid.New())
app.Use(logger.New(logger.Config{
    Format: "${requestid} ${status} ${method} ${path}\n",
}))

package tenantmw

import (
    "sync"

    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/logger"
)

type tenantContextKey struct{}

var tenantKey tenantContextKey

var registerLoggerTagsOnce sync.Once

func New() fiber.Handler {
    registerLoggerTagsOnce.Do(func() {
        logger.MustRegisterTag("tenant", func(output logger.Buffer, c fiber.Ctx, _ *logger.Data, _ string) (int, error) {
            tenant, _ := fiber.ValueFromContext[string](c, tenantKey)
            return output.WriteString(tenant)
        })
    })

    return func(c fiber.Ctx) error {
        fiber.StoreInContext(c, tenantKey, "acme")
        return c.Next()
    }
}

app.Use(tenantmw.New())
app.Use(logger.New(logger.Config{
    Format: "${tenant} ${status} ${method} ${path}\n",
}))

app.Use(logger.New(logger.Config{
    Format: "${tenant} ${status} ${method} ${path}\n",
    CustomTags: map[string]logger.LogFunc{
        "tenant": func(output logger.Buffer, c fiber.Ctx, _ *logger.Data, _ string) (int, error) {
            return output.WriteString("override")
        },
    },
}))

package main

import (
    "github.com/gofiber/contrib/fiberzap/v2"
    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/log"
    "github.com/gofiber/fiber/v3/middleware/logger"
)

func main() {
    // Create a new Fiber instance
    app := fiber.New()

    // Create a new zap logger which is compatible with Fiber AllLogger interface
    zap := fiberzap.NewLogger(fiberzap.LoggerConfig{
        ExtraKeys: []string{"request_id"},
    })

    // Use the logger middleware with the zap logger
    app.Use(logger.New(logger.Config{
        Stream: logger.LoggerToWriter(zap, log.LevelDebug),
    }))

    // Define a route
    app.Get("/", func(c fiber.Ctx) error {
        return c.SendString("Hello, World!")
    })

    // Start server on http://localhost:3000
    app.Listen(":3000")
}

var ConfigDefault = Config{
    Next:              nil,
    Skip:              nil,
    Done:              nil,
    Format:            DefaultFormat,
    TimeFormat:        "15:04:05",
    TimeZone:          "Local",
    TimeInterval:      500 * time.Millisecond,
    Stream:            os.Stdout,
    BeforeHandlerFunc: beforeHandlerFunc,
    LoggerFunc:        defaultLoggerInstance,
    enableColors:      true,
}

logger.MustRegisterTag("tenant", func(output logger.Buffer, c fiber.Ctx, _ *logger.Data, _ string) (int, error) {
    return output.WriteString(logger.SanitizeValue(c.Get("X-Tenant-ID")))
})

// Logger variables
const (
    TagPid               = "pid"
    TagTime              = "time"
    TagReferer           = "referer"
    TagProtocol          = "protocol"
    TagScheme            = "scheme"
    TagPort              = "port"
    TagIP                = "ip"
    TagIPs               = "ips"
    TagHost              = "host"
    TagMethod            = "method"
    TagPath              = "path"
    TagURL               = "url"
    TagUA                = "ua"
    TagLatency           = "latency"
    TagStatus            = "status"         // response status
    TagResBody           = "resBody"        // response body
    TagReqHeaders        = "reqHeaders"
    TagQueryStringParams = "queryParams"    // request query parameters
    TagBody              = "body"           // request body
    TagBytesSent         = "bytesSent"
    TagBytesReceived     = "bytesReceived"
    TagRoute             = "route"
    TagError             = "error"
    TagReqHeader         = "reqHeader:"     // request header
    TagRespHeader        = "respHeader:"    // response header
    TagQuery             = "query:"         // request query
    TagForm              = "form:"          // request form
    TagCookie            = "cookie:"        // request cookie
    TagLocals            = "locals:"
    // colors
    TagBlack             = "black"
    TagRed               = "red"
    TagGreen             = "green"
    TagYellow            = "yellow"
    TagBlue              = "blue"
    TagMagenta           = "magenta"
    TagCyan              = "cyan"
    TagWhite             = "white"
    TagReset             = "reset"
)