🔥 Feature: Add AllLogger to Config

docs/middleware/logger.md

@@ -88,6 +88,33 @@
 app.Use(logger.New(logger.Config{
     DisableColors: true,
 }))
+
+// Use Custom Logger with Fiber Logger Interface
+type dumbLogger struct {
+	logger fiberlog.AllLogger
+    level  log.Level
+}
+
+func (l *dumbLogger) Write(p []byte) (n int, err error) {
+	switch l.level {
+	case log.LevelDebug:
+		l.logger.Debug(string(p))
+	case log.LevelError:
+		l.logger.Error(string(p))
+    }
+	return len(p), nil
+}
+
+func LoggerToWriter(customLogger fiberlog.AllLogger, level fiberlog.Level) io.Writer {
+	return &dumbLogger{
+        logger: customLogger,
+        level: level,
+    }
+}
+
+app.Use(logger.New(logger.Config{
+    Output:     LoggerToWriter(fiberlog.DefaultLogger(), fiberlog.LevelError),
+}))
 ```
 
 :::tip
@@ -108,6 +135,7 @@
 | TimeZone         | `string`                   | TimeZone can be specified, such as "UTC" and "America/New_York" and "Asia/Chongqing", etc                                        | `"Local"`                                                             |
 | TimeInterval     | `time.Duration`            | TimeInterval is the delay before the timestamp is updated.                                                                       | `500 * time.Millisecond`                                              |
 | Output           | `io.Writer`                | Output is a writer where logs are written.                                                                                       | `os.Stdout`                                                           |
+| LoggerFunc           | `func(c fiber.Ctx, data *Data, cfg Config) error`  | You can use custom loggers with Fiber by using this field. This field is really useful if you're using Zerolog, Zap, Logrus, apex/log etc. If you don't define anything for this field, it'll use the default logger of Fiber.  | `see default_logger.go defaultLoggerInstance`                                                           |                                           |
 | DisableColors    | `bool`                     | DisableColors defines if the logs output should be colorized.                                                                    | `false`                                                               |
 | enableColors     | `bool`                     | Internal field for enabling colors in the log output. (This is not a user-configurable field)                                    | -                                                                     |
 | enableLatency    | `bool`                     | Internal field for enabling latency measurement in logs. (This is not a user-configurable field)                                 | -                                                                     |

log/default.go

@@ -210,6 +210,10 @@
 	l.stdlog.SetOutput(writer)
 }
 
+func (l *defaultLogger) SetFlags(flag int) {
+	l.stdlog.SetFlags(flag)
+}
+
 // DefaultLogger returns the default logger.
 func DefaultLogger() AllLogger {
 	return logger

log/log.go

@@ -56,6 +56,7 @@ type CommonLogger interface {
 type ControlLogger interface {
 	SetLevel(level Level)
 	SetOutput(w io.Writer)
+	SetFlags(flags int)
 }
 
 // AllLogger is the combination of Logger, FormatLogger, CtxLogger and ControlLogger.

middleware/logger/logger_test.go

@@ -15,6 +15,7 @@
 	"time"
 
 	"github.com/gofiber/fiber/v3"
+	fiberlog "github.com/gofiber/fiber/v3/log"
 	"github.com/gofiber/fiber/v3/middleware/requestid"
 	"github.com/stretchr/testify/require"
 	"github.com/valyala/bytebufferpool"
@@ -181,6 +182,45 @@
 	require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 }
 
+type dumbLogger struct {
+	logger fiberlog.AllLogger
+}
+
+func (l *dumbLogger) Write(p []byte) (n int, err error) {
+	l.logger.Error(string(p))
+	return len(p), nil
+}
+
+func LoggerToWriter(customLogger fiberlog.AllLogger) io.Writer {
+	return &dumbLogger{logger: customLogger}
+}
+
+// go test -run Test_Logger_Fiber_Logger
+func Test_Logger_Fiber_Logger(t *testing.T) {
+	t.Parallel()
+	app := fiber.New()
+
+	buf := bytebufferpool.Get()
+	defer bytebufferpool.Put(buf)
+
+	logger := fiberlog.DefaultLogger()
+	logger.SetFlags(0)
+	logger.SetOutput(buf)
+	app.Use(New(Config{
+		Format: "${error}",
+		Output: LoggerToWriter(logger),
+	}))
+
+	app.Get("/", func(_ fiber.Ctx) error {
+		return errors.New("some random error")
+	})
+
+	resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+	require.NoError(t, err)
+	require.Equal(t, fiber.StatusInternalServerError, resp.StatusCode)
+	require.Equal(t, "[Error] some random error\n", buf.String())
+}
+
 type fakeErrorOutput int
 
 func (o *fakeErrorOutput) Write([]byte) (int, error) {
@@ -729,6 +769,19 @@
 		benchmarkSetup(bb, app, "/")
 	})
 
+	b.Run("DefaultFormatWithFiberLog", func(bb *testing.B) {
+		app := fiber.New()
+		logger := fiberlog.DefaultLogger()
+		logger.SetOutput(io.Discard)
+		app.Use(New(Config{
+			Output: LoggerToWriter(logger),
+		}))
+		app.Get("/", func(c fiber.Ctx) error {
+			return c.SendString("Hello, World!")
+		})
+		benchmarkSetup(bb, app, "/")
+	})
+
 	b.Run("WithTagParameter", func(bb *testing.B) {
 		app := fiber.New()
 		app.Use(New(Config{
@@ -872,6 +925,19 @@
 		benchmarkSetupParallel(bb, app, "/")
 	})
 
+	b.Run("DefaultFormatWithFiberLog", func(bb *testing.B) {
+		app := fiber.New()
+		logger := fiberlog.DefaultLogger()
+		logger.SetOutput(io.Discard)
+		app.Use(New(Config{
+			Output: LoggerToWriter(logger),
+		}))
+		app.Get("/", func(c fiber.Ctx) error {
+			return c.SendString("Hello, World!")
+		})
+		benchmarkSetupParallel(bb, app, "/")
+	})
+
 	b.Run("DefaultFormatDisableColors", func(bb *testing.B) {
 		app := fiber.New()
 		app.Use(New(Config{