From 8a74ebaa6f4f604bd73765e962c63ac620e6694a Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:36:46 +0800
Subject: [PATCH 01/16] =?UTF-8?q?=F0=9F=94=A5=20Feature(logger):=20Add=20F?=
 =?UTF-8?q?ilter=20option=20to=20logger=20middleware?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/middleware/logger.md           |  2 ++
 middleware/logger/config.go         | 10 ++++++++
 middleware/logger/default_logger.go |  5 ++++
 middleware/logger/logger_test.go    | 39 +++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/docs/middleware/logger.md b/docs/middleware/logger.md
index 07ff07c4de..e06d0e58fc 100644
--- a/docs/middleware/logger.md
+++ b/docs/middleware/logger.md
@@ -139,6 +139,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | Property         | Type                       | Description                                                                                                                      | Default                                                               |
 |:-----------------|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------|
 | Next             | `func(fiber.Ctx) bool`    | Next defines a function to skip this middleware when returned true.                                                              | `nil`                                                                 |
+| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | Done             | `func(fiber.Ctx, []byte)` | Done is a function that is called after the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | CustomTags       | `map[string]LogFunc`       | tagFunctions defines the custom tag action.                                                                                      | `map[string]LogFunc`                                                  |
 | Format           | `string`                   | Format defines the logging tags.                                                                                                 | `[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n` |
@@ -157,6 +158,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 ```go
 var ConfigDefault = Config{
     Next:          nil,
+    Filter         nil,
     Done:          nil,
     Format:        "[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n",
     TimeFormat:    "15:04:05",
diff --git a/middleware/logger/config.go b/middleware/logger/config.go
index 4826151e46..0b9d5ffaf1 100644
--- a/middleware/logger/config.go
+++ b/middleware/logger/config.go
@@ -20,6 +20,12 @@ type Config struct {
 	// Optional. Default: nil
 	Next func(c fiber.Ctx) bool
 
+	// Filter is a function that is called before writing the log string.
+	// If it returns true, the log will be written; otherwise, it will be skipped.
+	//
+	// Optional. Default: nil
+	Filter func(c fiber.Ctx) bool
+
 	// Done is a function that is called after the log string for a request is written to Output,
 	// and pass the log string as parameter.
 	//
@@ -98,6 +104,7 @@ type LogFunc func(output Buffer, c fiber.Ctx, data *Data, extraParam string) (in
 // ConfigDefault is the default config
 var ConfigDefault = Config{
 	Next:              nil,
+	Filter:            nil,
 	Done:              nil,
 	Format:            defaultFormat,
 	TimeFormat:        "15:04:05",
@@ -126,6 +133,9 @@ func configDefault(config ...Config) Config {
 	if cfg.Next == nil {
 		cfg.Next = ConfigDefault.Next
 	}
+	if cfg.Filter == nil {
+		cfg.Filter = ConfigDefault.Filter
+	}
 	if cfg.Done == nil {
 		cfg.Done = ConfigDefault.Done
 	}
diff --git a/middleware/logger/default_logger.go b/middleware/logger/default_logger.go
index 369b2c8580..168ce7411d 100644
--- a/middleware/logger/default_logger.go
+++ b/middleware/logger/default_logger.go
@@ -90,6 +90,11 @@ func defaultLoggerInstance(c fiber.Ctx, data *Data, cfg Config) error {
 			buf.WriteString("\n")
 		}
 
+		// Check if Filter is defined and call it
+		if cfg.Filter != nil && !cfg.Filter(c) {
+			return nil // Skip logging if Filter returns false
+		}
+
 		// Write buffer to output
 		writeLog(cfg.Output, buf.Bytes())
 
diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index d459f22c59..ccf881bc70 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -171,6 +171,45 @@ func Test_Logger_Done(t *testing.T) {
 	require.Positive(t, buf.Len(), 0)
 }
 
+func Test_Logger_Filter(t *testing.T) {
+	t.Parallel()
+	app := fiber.New()
+
+	var logOutput bytes.Buffer // 用于捕获日志输出
+
+	// 创建一个日志中间件，Filter只记录404状态的日志
+	app.Use(New(Config{
+		Output: &logOutput, // 将日志输出重定向到logOutput
+		Filter: func(c fiber.Ctx) bool {
+			return c.Response().StatusCode() == fiber.StatusNotFound
+		},
+	}))
+
+	// 测试404状态码
+	t.Run("Test Not Found", func(t *testing.T) {
+		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/nonexistent", nil))
+		require.NoError(t, err)
+		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
+
+		// 验证日志输出是否包含404的日志
+		require.Contains(t, logOutput.String(), "404") // 检查日志中是否包含404
+	})
+
+	// 测试200状态码
+	t.Run("Test OK", func(t *testing.T) {
+		app.Get("/", func(c fiber.Ctx) error {
+			return c.SendStatus(fiber.StatusOK)
+		})
+
+		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+		require.NoError(t, err)
+		require.Equal(t, fiber.StatusOK, resp.StatusCode)
+
+		// 验证日志输出是否不包含200的日志
+		require.NotContains(t, logOutput.String(), "200") // 检查日志中是否不包含200
+	})
+}
+
 // go test -run Test_Logger_ErrorTimeZone
 func Test_Logger_ErrorTimeZone(t *testing.T) {
 	t.Parallel()

From 0a70ee8d06849a684e75875d0038c3f2481632db Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:39:29 +0800
Subject: [PATCH 02/16] =?UTF-8?q?=F0=9F=93=9A=20Doc(logger):=20Clarify=20F?=
 =?UTF-8?q?ilter=20middleware=20description?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/middleware/logger.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/middleware/logger.md b/docs/middleware/logger.md
index e06d0e58fc..3fa390eaeb 100644
--- a/docs/middleware/logger.md
+++ b/docs/middleware/logger.md
@@ -139,7 +139,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | Property         | Type                       | Description                                                                                                                      | Default                                                               |
 |:-----------------|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------|
 | Next             | `func(fiber.Ctx) bool`    | Next defines a function to skip this middleware when returned true.                                                              | `nil`                                                                 |
-| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
+| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output. | `nil`                                                                 |
 | Done             | `func(fiber.Ctx, []byte)` | Done is a function that is called after the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | CustomTags       | `map[string]LogFunc`       | tagFunctions defines the custom tag action.                                                                                      | `map[string]LogFunc`                                                  |
 | Format           | `string`                   | Format defines the logging tags.                                                                                                 | `[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n` |

From efdd738c1135397693dfd8ac328d2ddd342793e8 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:48:44 +0800
Subject: [PATCH 03/16] =?UTF-8?q?=F0=9F=9A=A8=20Test(logger):=20Enhance=20?=
 =?UTF-8?q?logger=20filter=20test=20with=20parallel=20subtests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 middleware/logger/logger_test.go | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index ccf881bc70..ca26fc180e 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -175,28 +175,32 @@ func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()
 	app := fiber.New()
 
-	var logOutput bytes.Buffer // 用于捕获日志输出
+	var logOutput bytes.Buffer // Buffer to capture log output
 
-	// 创建一个日志中间件，Filter只记录404状态的日志
+	// Create a logging middleware that filters logs to only include 404 status codes
 	app.Use(New(Config{
-		Output: &logOutput, // 将日志输出重定向到logOutput
+		Output: &logOutput, // Redirect log output to the logOutput buffer
 		Filter: func(c fiber.Ctx) bool {
 			return c.Response().StatusCode() == fiber.StatusNotFound
 		},
 	}))
 
-	// 测试404状态码
+	// Log only 404 status codes
 	t.Run("Test Not Found", func(t *testing.T) {
+		t.Parallel()
+
 		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/nonexistent", nil))
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
-		// 验证日志输出是否包含404的日志
-		require.Contains(t, logOutput.String(), "404") // 检查日志中是否包含404
+		// Verify the log output contains the "404" message
+		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
 	})
 
-	// 测试200状态码
+	// Subtest for 200 status code
 	t.Run("Test OK", func(t *testing.T) {
+		t.Parallel()
+
 		app.Get("/", func(c fiber.Ctx) error {
 			return c.SendStatus(fiber.StatusOK)
 		})
@@ -205,8 +209,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
-		// 验证日志输出是否不包含200的日志
-		require.NotContains(t, logOutput.String(), "200") // 检查日志中是否不包含200
+		// Verify the log output does not contain the "200" message
+		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
 	})
 }
 

From a652e629feefeea449799faa1efaaf709f20717d Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 17:11:39 +0800
Subject: [PATCH 04/16] =?UTF-8?q?=F0=9F=94=92=20Test(logger):=20Add=20mute?=
 =?UTF-8?q?x=20to=20prevent=20race=20conditions=20in=20logger=20test?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 middleware/logger/logger_test.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index ca26fc180e..a90a78806a 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -176,6 +176,7 @@ func Test_Logger_Filter(t *testing.T) {
 	app := fiber.New()
 
 	var logOutput bytes.Buffer // Buffer to capture log output
+	var mu sync.Mutex
 
 	// Create a logging middleware that filters logs to only include 404 status codes
 	app.Use(New(Config{
@@ -194,6 +195,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
 		// Verify the log output contains the "404" message
+		mu.Lock()
+		defer mu.Unlock()
 		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
 	})
 
@@ -210,6 +213,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
 		// Verify the log output does not contain the "200" message
+		mu.Lock()
+		defer mu.Unlock()
 		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
 	})
 }

From c1f227825b6c33c3f4f80f6c59f9103e65dff15e Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:36:46 +0800
Subject: [PATCH 05/16] =?UTF-8?q?=F0=9F=94=A5=20Feature(logger):=20Add=20F?=
 =?UTF-8?q?ilter=20option=20to=20logger=20middleware?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/middleware/logger.md           |  2 ++
 middleware/logger/config.go         | 10 ++++++++
 middleware/logger/default_logger.go |  5 ++++
 middleware/logger/logger_test.go    | 39 +++++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/docs/middleware/logger.md b/docs/middleware/logger.md
index 07ff07c4de..e06d0e58fc 100644
--- a/docs/middleware/logger.md
+++ b/docs/middleware/logger.md
@@ -139,6 +139,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | Property         | Type                       | Description                                                                                                                      | Default                                                               |
 |:-----------------|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------|
 | Next             | `func(fiber.Ctx) bool`    | Next defines a function to skip this middleware when returned true.                                                              | `nil`                                                                 |
+| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | Done             | `func(fiber.Ctx, []byte)` | Done is a function that is called after the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | CustomTags       | `map[string]LogFunc`       | tagFunctions defines the custom tag action.                                                                                      | `map[string]LogFunc`                                                  |
 | Format           | `string`                   | Format defines the logging tags.                                                                                                 | `[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n` |
@@ -157,6 +158,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 ```go
 var ConfigDefault = Config{
     Next:          nil,
+    Filter         nil,
     Done:          nil,
     Format:        "[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n",
     TimeFormat:    "15:04:05",
diff --git a/middleware/logger/config.go b/middleware/logger/config.go
index 4826151e46..0b9d5ffaf1 100644
--- a/middleware/logger/config.go
+++ b/middleware/logger/config.go
@@ -20,6 +20,12 @@ type Config struct {
 	// Optional. Default: nil
 	Next func(c fiber.Ctx) bool
 
+	// Filter is a function that is called before writing the log string.
+	// If it returns true, the log will be written; otherwise, it will be skipped.
+	//
+	// Optional. Default: nil
+	Filter func(c fiber.Ctx) bool
+
 	// Done is a function that is called after the log string for a request is written to Output,
 	// and pass the log string as parameter.
 	//
@@ -98,6 +104,7 @@ type LogFunc func(output Buffer, c fiber.Ctx, data *Data, extraParam string) (in
 // ConfigDefault is the default config
 var ConfigDefault = Config{
 	Next:              nil,
+	Filter:            nil,
 	Done:              nil,
 	Format:            defaultFormat,
 	TimeFormat:        "15:04:05",
@@ -126,6 +133,9 @@ func configDefault(config ...Config) Config {
 	if cfg.Next == nil {
 		cfg.Next = ConfigDefault.Next
 	}
+	if cfg.Filter == nil {
+		cfg.Filter = ConfigDefault.Filter
+	}
 	if cfg.Done == nil {
 		cfg.Done = ConfigDefault.Done
 	}
diff --git a/middleware/logger/default_logger.go b/middleware/logger/default_logger.go
index 369b2c8580..168ce7411d 100644
--- a/middleware/logger/default_logger.go
+++ b/middleware/logger/default_logger.go
@@ -90,6 +90,11 @@ func defaultLoggerInstance(c fiber.Ctx, data *Data, cfg Config) error {
 			buf.WriteString("\n")
 		}
 
+		// Check if Filter is defined and call it
+		if cfg.Filter != nil && !cfg.Filter(c) {
+			return nil // Skip logging if Filter returns false
+		}
+
 		// Write buffer to output
 		writeLog(cfg.Output, buf.Bytes())
 
diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index d459f22c59..ccf881bc70 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -171,6 +171,45 @@ func Test_Logger_Done(t *testing.T) {
 	require.Positive(t, buf.Len(), 0)
 }
 
+func Test_Logger_Filter(t *testing.T) {
+	t.Parallel()
+	app := fiber.New()
+
+	var logOutput bytes.Buffer // 用于捕获日志输出
+
+	// 创建一个日志中间件，Filter只记录404状态的日志
+	app.Use(New(Config{
+		Output: &logOutput, // 将日志输出重定向到logOutput
+		Filter: func(c fiber.Ctx) bool {
+			return c.Response().StatusCode() == fiber.StatusNotFound
+		},
+	}))
+
+	// 测试404状态码
+	t.Run("Test Not Found", func(t *testing.T) {
+		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/nonexistent", nil))
+		require.NoError(t, err)
+		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
+
+		// 验证日志输出是否包含404的日志
+		require.Contains(t, logOutput.String(), "404") // 检查日志中是否包含404
+	})
+
+	// 测试200状态码
+	t.Run("Test OK", func(t *testing.T) {
+		app.Get("/", func(c fiber.Ctx) error {
+			return c.SendStatus(fiber.StatusOK)
+		})
+
+		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
+		require.NoError(t, err)
+		require.Equal(t, fiber.StatusOK, resp.StatusCode)
+
+		// 验证日志输出是否不包含200的日志
+		require.NotContains(t, logOutput.String(), "200") // 检查日志中是否不包含200
+	})
+}
+
 // go test -run Test_Logger_ErrorTimeZone
 func Test_Logger_ErrorTimeZone(t *testing.T) {
 	t.Parallel()

From 279476160aad0f50a691bab11db6f0d393079003 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:39:29 +0800
Subject: [PATCH 06/16] =?UTF-8?q?=F0=9F=93=9A=20Doc(logger):=20Clarify=20F?=
 =?UTF-8?q?ilter=20middleware=20description?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/middleware/logger.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/middleware/logger.md b/docs/middleware/logger.md
index e06d0e58fc..3fa390eaeb 100644
--- a/docs/middleware/logger.md
+++ b/docs/middleware/logger.md
@@ -139,7 +139,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | Property         | Type                       | Description                                                                                                                      | Default                                                               |
 |:-----------------|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------|
 | Next             | `func(fiber.Ctx) bool`    | Next defines a function to skip this middleware when returned true.                                                              | `nil`                                                                 |
-| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
+| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output. | `nil`                                                                 |
 | Done             | `func(fiber.Ctx, []byte)` | Done is a function that is called after the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | CustomTags       | `map[string]LogFunc`       | tagFunctions defines the custom tag action.                                                                                      | `map[string]LogFunc`                                                  |
 | Format           | `string`                   | Format defines the logging tags.                                                                                                 | `[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n` |

From 2fd940e5a1bee0db6cb731594942fac8acb08651 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 16:48:44 +0800
Subject: [PATCH 07/16] =?UTF-8?q?=F0=9F=9A=A8=20Test(logger):=20Enhance=20?=
 =?UTF-8?q?logger=20filter=20test=20with=20parallel=20subtests?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 middleware/logger/logger_test.go | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index ccf881bc70..ca26fc180e 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -175,28 +175,32 @@ func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()
 	app := fiber.New()
 
-	var logOutput bytes.Buffer // 用于捕获日志输出
+	var logOutput bytes.Buffer // Buffer to capture log output
 
-	// 创建一个日志中间件，Filter只记录404状态的日志
+	// Create a logging middleware that filters logs to only include 404 status codes
 	app.Use(New(Config{
-		Output: &logOutput, // 将日志输出重定向到logOutput
+		Output: &logOutput, // Redirect log output to the logOutput buffer
 		Filter: func(c fiber.Ctx) bool {
 			return c.Response().StatusCode() == fiber.StatusNotFound
 		},
 	}))
 
-	// 测试404状态码
+	// Log only 404 status codes
 	t.Run("Test Not Found", func(t *testing.T) {
+		t.Parallel()
+
 		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/nonexistent", nil))
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
-		// 验证日志输出是否包含404的日志
-		require.Contains(t, logOutput.String(), "404") // 检查日志中是否包含404
+		// Verify the log output contains the "404" message
+		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
 	})
 
-	// 测试200状态码
+	// Subtest for 200 status code
 	t.Run("Test OK", func(t *testing.T) {
+		t.Parallel()
+
 		app.Get("/", func(c fiber.Ctx) error {
 			return c.SendStatus(fiber.StatusOK)
 		})
@@ -205,8 +209,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
-		// 验证日志输出是否不包含200的日志
-		require.NotContains(t, logOutput.String(), "200") // 检查日志中是否不包含200
+		// Verify the log output does not contain the "200" message
+		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
 	})
 }
 

From 7dcc9045c9d1896cf82204621fa29939531c40c1 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 17:11:39 +0800
Subject: [PATCH 08/16] =?UTF-8?q?=F0=9F=94=92=20Test(logger):=20Add=20mute?=
 =?UTF-8?q?x=20to=20prevent=20race=20conditions=20in=20logger=20test?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 middleware/logger/logger_test.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index ca26fc180e..a90a78806a 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -176,6 +176,7 @@ func Test_Logger_Filter(t *testing.T) {
 	app := fiber.New()
 
 	var logOutput bytes.Buffer // Buffer to capture log output
+	var mu sync.Mutex
 
 	// Create a logging middleware that filters logs to only include 404 status codes
 	app.Use(New(Config{
@@ -194,6 +195,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
 		// Verify the log output contains the "404" message
+		mu.Lock()
+		defer mu.Unlock()
 		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
 	})
 
@@ -210,6 +213,8 @@ func Test_Logger_Filter(t *testing.T) {
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
 		// Verify the log output does not contain the "200" message
+		mu.Lock()
+		defer mu.Unlock()
 		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
 	})
 }

From d6e64a0745db8d979b4d2ad7c22f37ee4d311d5f Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Thu, 27 Feb 2025 17:31:44 +0800
Subject: [PATCH 09/16] =?UTF-8?q?=F0=9F=9A=A8=20Test(logger):=20Refactor?=
 =?UTF-8?q?=20logger=20test=20to=20improve=20test=20isolation?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 middleware/logger/logger_test.go | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index a90a78806a..d165c66e97 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -175,12 +175,8 @@ func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()
 	app := fiber.New()
 
-	var logOutput bytes.Buffer // Buffer to capture log output
-	var mu sync.Mutex
-
 	// Create a logging middleware that filters logs to only include 404 status codes
 	app.Use(New(Config{
-		Output: &logOutput, // Redirect log output to the logOutput buffer
 		Filter: func(c fiber.Ctx) bool {
 			return c.Response().StatusCode() == fiber.StatusNotFound
 		},
@@ -190,13 +186,18 @@ func Test_Logger_Filter(t *testing.T) {
 	t.Run("Test Not Found", func(t *testing.T) {
 		t.Parallel()
 
+		logOutput := bytes.Buffer{}
+
+		// Redirect log output to the logOutput buffer
+		app.Use(New(Config{
+			Output: &logOutput,
+		}))
+
 		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/nonexistent", nil))
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
 		// Verify the log output contains the "404" message
-		mu.Lock()
-		defer mu.Unlock()
 		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
 	})
 
@@ -204,17 +205,22 @@ func Test_Logger_Filter(t *testing.T) {
 	t.Run("Test OK", func(t *testing.T) {
 		t.Parallel()
 
+		logOutput := bytes.Buffer{}
+
 		app.Get("/", func(c fiber.Ctx) error {
 			return c.SendStatus(fiber.StatusOK)
 		})
 
+		// Redirect log output to the logOutput buffer
+		app.Use(New(Config{
+			Output: &logOutput,
+		}))
+
 		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
 		// Verify the log output does not contain the "200" message
-		mu.Lock()
-		defer mu.Unlock()
 		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
 	})
 }

From 93b57a995231ab38a52c2c255c0a93de69d24909 Mon Sep 17 00:00:00 2001
From: Juan Calderon-Perez <jgcalderonperez@protonmail.com>
Date: Thu, 27 Feb 2025 08:21:37 -0500
Subject: [PATCH 10/16] Fix issue with unit-tests

---
 middleware/logger/logger_test.go | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index d165c66e97..5975060a6c 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -173,18 +173,18 @@ func Test_Logger_Done(t *testing.T) {
 
 func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()
-	app := fiber.New()
-
-	// Create a logging middleware that filters logs to only include 404 status codes
-	app.Use(New(Config{
-		Filter: func(c fiber.Ctx) bool {
-			return c.Response().StatusCode() == fiber.StatusNotFound
-		},
-	}))
 
 	// Log only 404 status codes
 	t.Run("Test Not Found", func(t *testing.T) {
 		t.Parallel()
+		app := fiber.New()
+
+		// Create a logging middleware that filters logs to only include 404 status codes
+		app.Use(New(Config{
+			Filter: func(c fiber.Ctx) bool {
+				return c.Response().StatusCode() == fiber.StatusNotFound
+			},
+		}))
 
 		logOutput := bytes.Buffer{}
 
@@ -204,6 +204,14 @@ func Test_Logger_Filter(t *testing.T) {
 	// Subtest for 200 status code
 	t.Run("Test OK", func(t *testing.T) {
 		t.Parallel()
+		app := fiber.New()
+
+		// Create a logging middleware that filters logs to only include 404 status codes
+		app.Use(New(Config{
+			Filter: func(c fiber.Ctx) bool {
+				return c.Response().StatusCode() == fiber.StatusNotFound
+			},
+		}))
 
 		logOutput := bytes.Buffer{}
 

From b60018323c4198c36475cfb8a316da1d3f9815b3 Mon Sep 17 00:00:00 2001
From: Juan Calderon-Perez <835733+gaby@users.noreply.github.com>
Date: Thu, 27 Feb 2025 09:25:36 -0500
Subject: [PATCH 11/16] Update middleware/logger/logger_test.go

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
---
 middleware/logger/logger_test.go | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index 5975060a6c..58920adc6e 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -174,22 +174,17 @@ func Test_Logger_Done(t *testing.T) {
 func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()
 
-	// Log only 404 status codes
 	t.Run("Test Not Found", func(t *testing.T) {
 		t.Parallel()
 		app := fiber.New()
 
-		// Create a logging middleware that filters logs to only include 404 status codes
+		logOutput := bytes.Buffer{}
+
+		// Create a single logging middleware with both filter and output capture
 		app.Use(New(Config{
 			Filter: func(c fiber.Ctx) bool {
 				return c.Response().StatusCode() == fiber.StatusNotFound
 			},
-		}))
-
-		logOutput := bytes.Buffer{}
-
-		// Redirect log output to the logOutput buffer
-		app.Use(New(Config{
 			Output: &logOutput,
 		}))
 
@@ -198,38 +193,33 @@ func Test_Logger_Filter(t *testing.T) {
 		require.Equal(t, fiber.StatusNotFound, resp.StatusCode)
 
 		// Verify the log output contains the "404" message
-		require.Contains(t, logOutput.String(), "404") // Check if the log contains "404"
+		require.Contains(t, logOutput.String(), "404")
 	})
 
-	// Subtest for 200 status code
 	t.Run("Test OK", func(t *testing.T) {
 		t.Parallel()
 		app := fiber.New()
 
-		// Create a logging middleware that filters logs to only include 404 status codes
+		logOutput := bytes.Buffer{}
+
+		// Create a single logging middleware with both filter and output capture
 		app.Use(New(Config{
 			Filter: func(c fiber.Ctx) bool {
 				return c.Response().StatusCode() == fiber.StatusNotFound
 			},
+			Output: &logOutput,
 		}))
 
-		logOutput := bytes.Buffer{}
-
 		app.Get("/", func(c fiber.Ctx) error {
 			return c.SendStatus(fiber.StatusOK)
 		})
 
-		// Redirect log output to the logOutput buffer
-		app.Use(New(Config{
-			Output: &logOutput,
-		}))
-
 		resp, err := app.Test(httptest.NewRequest(fiber.MethodGet, "/", nil))
 		require.NoError(t, err)
 		require.Equal(t, fiber.StatusOK, resp.StatusCode)
 
 		// Verify the log output does not contain the "200" message
-		require.NotContains(t, logOutput.String(), "200") // Check if the log does not contain "200"
+		require.NotContains(t, logOutput.String(), "200")
 	})
 }
 

From 2154baf7513a53ecdf7631af4c329bc1b4d6142b Mon Sep 17 00:00:00 2001
From: Juan Calderon-Perez <835733+gaby@users.noreply.github.com>
Date: Sat, 1 Mar 2025 14:20:22 -0500
Subject: [PATCH 12/16] Apply logger filter as soon as possible

---
 middleware/logger/default_logger.go | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/middleware/logger/default_logger.go b/middleware/logger/default_logger.go
index 168ce7411d..14ad6a1a1c 100644
--- a/middleware/logger/default_logger.go
+++ b/middleware/logger/default_logger.go
@@ -15,6 +15,11 @@ import (
 
 // default logger for fiber
 func defaultLoggerInstance(c fiber.Ctx, data *Data, cfg Config) error {
+	// Check if Filter is defined and call it
+	if cfg.Filter != nil && !cfg.Filter(c) {
+		return nil // Skip logging if Filter returns false
+	}
+
 	// Alias colors
 	colors := c.App().Config().ColorScheme
 
@@ -90,11 +95,6 @@ func defaultLoggerInstance(c fiber.Ctx, data *Data, cfg Config) error {
 			buf.WriteString("\n")
 		}
 
-		// Check if Filter is defined and call it
-		if cfg.Filter != nil && !cfg.Filter(c) {
-			return nil // Skip logging if Filter returns false
-		}
-
 		// Write buffer to output
 		writeLog(cfg.Output, buf.Bytes())
 

From 6528b9f02f30258e45efbece1dd0fa936c1fe088 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Mon, 3 Mar 2025 09:43:02 +0800
Subject: [PATCH 13/16] =?UTF-8?q?=F0=9F=93=9A=20Doc:=20Add=20logger=20filt?=
 =?UTF-8?q?er=20configuration=20example=20to=20whats=5Fnew.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/whats_new.md | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/docs/whats_new.md b/docs/whats_new.md
index 5c3dd6ac9a..33b5a39e6f 100644
--- a/docs/whats_new.md
+++ b/docs/whats_new.md
@@ -940,6 +940,26 @@ The Healthcheck middleware has been enhanced to support more than two routes, wi
 
 Refer to the [healthcheck middleware migration guide](./middleware/healthcheck.md) or the [general migration guide](#-migration-guide) to review the changes.
 
+### Filter
+
+The `Filter` is a function that is called before the log string for a request is written to Output. If it returns true, the log will be written; otherwise, it will be skipped.
+
+```go
+app.Use(logger.New(logger.Config{
+    Filter: func(c fiber.Ctx) bool {
+        // Skip logging for 404 requests
+        return c.Response().StatusCode() == fiber.StatusNotFound
+    },
+}))
+
+app.Use(logger.New(logger.Config{
+    Filter: func(c fiber.Ctx) bool {
+        // Only log requests with status code 200
+        return c.Response().StatusCode() == fiber.StatusOK
+    },
+}))
+```
+
 ## 🔌 Addons
 
 In v3, Fiber introduced Addons. Addons are additional useful packages that can be used in Fiber.

From 288edb2611c64976c9e54eaf79de82d2caefee65 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Mon, 3 Mar 2025 22:32:28 +0800
Subject: [PATCH 14/16] =?UTF-8?q?=F0=9F=93=9A=20Doc:=20Update=20logger=20f?=
 =?UTF-8?q?ilter=20documentation=20in=20whats=5Fnew.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/whats_new.md | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/docs/whats_new.md b/docs/whats_new.md
index 33b5a39e6f..6bb64c7192 100644
--- a/docs/whats_new.md
+++ b/docs/whats_new.md
@@ -912,6 +912,29 @@ func main() {
 
 </details>
 
+The `Filter` is a function that is called before the log string for a request is written to Output. If it returns true, the log will be written; otherwise, it will be skipped.
+
+<details>
+<summary>Example</summary>
+
+```go
+app.Use(logger.New(logger.Config{
+    Filter: func(c fiber.Ctx) bool {
+        // Skip logging for 404 requests
+        return c.Response().StatusCode() == fiber.StatusNotFound
+    },
+}))
+
+app.Use(logger.New(logger.Config{
+    Filter: func(c fiber.Ctx) bool {
+        // Only log requests with status code 200
+        return c.Response().StatusCode() == fiber.StatusOK
+    },
+}))
+```
+
+</details>
+
 ### Filesystem
 
 We've decided to remove filesystem middleware to clear up the confusion between static and filesystem middleware.
@@ -940,26 +963,6 @@ The Healthcheck middleware has been enhanced to support more than two routes, wi
 
 Refer to the [healthcheck middleware migration guide](./middleware/healthcheck.md) or the [general migration guide](#-migration-guide) to review the changes.
 
-### Filter
-
-The `Filter` is a function that is called before the log string for a request is written to Output. If it returns true, the log will be written; otherwise, it will be skipped.
-
-```go
-app.Use(logger.New(logger.Config{
-    Filter: func(c fiber.Ctx) bool {
-        // Skip logging for 404 requests
-        return c.Response().StatusCode() == fiber.StatusNotFound
-    },
-}))
-
-app.Use(logger.New(logger.Config{
-    Filter: func(c fiber.Ctx) bool {
-        // Only log requests with status code 200
-        return c.Response().StatusCode() == fiber.StatusOK
-    },
-}))
-```
-
 ## 🔌 Addons
 
 In v3, Fiber introduced Addons. Addons are additional useful packages that can be used in Fiber.

From e2295e51073d01c84fdc9a65c0d7309ef967ecca Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Tue, 4 Mar 2025 11:07:01 +0800
Subject: [PATCH 15/16] =?UTF-8?q?=F0=9F=93=9A=20Doc:=20Update=20logger=20f?=
 =?UTF-8?q?ilter=20documentation=20and=20examples?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/middleware/logger.md        |  2 +-
 docs/whats_new.md                | 13 ++++++++++---
 middleware/logger/logger_test.go |  4 +++-
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/docs/middleware/logger.md b/docs/middleware/logger.md
index 3fa390eaeb..68d5955791 100644
--- a/docs/middleware/logger.md
+++ b/docs/middleware/logger.md
@@ -139,7 +139,7 @@ Writing to os.File is goroutine-safe, but if you are using a custom Output that
 | Property         | Type                       | Description                                                                                                                      | Default                                                               |
 |:-----------------|:---------------------------|:---------------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------|
 | Next             | `func(fiber.Ctx) bool`    | Next defines a function to skip this middleware when returned true.                                                              | `nil`                                                                 |
-| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output. | `nil`                                                                 |
+| Filter           | `func(fiber.Ctx) bool` | Filter is a function that is called before the log string for a request is written to Output. If it returns true, the log will be written; otherwise, it will be skipped. | `nil`                                                                 |
 | Done             | `func(fiber.Ctx, []byte)` | Done is a function that is called after the log string for a request is written to Output, and pass the log string as parameter. | `nil`                                                                 |
 | CustomTags       | `map[string]LogFunc`       | tagFunctions defines the custom tag action.                                                                                      | `map[string]LogFunc`                                                  |
 | Format           | `string`                   | Format defines the logging tags.                                                                                                 | `[${time}] ${ip} ${status} - ${latency} ${method} ${path} ${error}\n` |
diff --git a/docs/whats_new.md b/docs/whats_new.md
index 6bb64c7192..ecd147105c 100644
--- a/docs/whats_new.md
+++ b/docs/whats_new.md
@@ -920,15 +920,22 @@ The `Filter` is a function that is called before the log string for a request is
 ```go
 app.Use(logger.New(logger.Config{
     Filter: func(c fiber.Ctx) bool {
-        // Skip logging for 404 requests
+        // log status code >= 400
+        return c.Response().StatusCode() >= fiber.StatusNotFound
+    },
+}))
+
+app.Use(logger.New(logger.Config{
+    Filter: func(c fiber.Ctx) bool {
+        // log status code == 404
         return c.Response().StatusCode() == fiber.StatusNotFound
     },
 }))
 
 app.Use(logger.New(logger.Config{
     Filter: func(c fiber.Ctx) bool {
-        // Only log requests with status code 200
-        return c.Response().StatusCode() == fiber.StatusOK
+        // log status code != 200
+        return c.Response().StatusCode() != fiber.StatusOK
     },
 }))
 ```
diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index 58920adc6e..36b2aef18b 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -183,6 +183,7 @@ func Test_Logger_Filter(t *testing.T) {
 		// Create a single logging middleware with both filter and output capture
 		app.Use(New(Config{
 			Filter: func(c fiber.Ctx) bool {
+				// log status code == 404
 				return c.Response().StatusCode() == fiber.StatusNotFound
 			},
 			Output: &logOutput,
@@ -205,7 +206,8 @@ func Test_Logger_Filter(t *testing.T) {
 		// Create a single logging middleware with both filter and output capture
 		app.Use(New(Config{
 			Filter: func(c fiber.Ctx) bool {
-				return c.Response().StatusCode() == fiber.StatusNotFound
+				// log status code != 200
+				return c.Response().StatusCode() != fiber.StatusOK
 			},
 			Output: &logOutput,
 		}))

From 0ac13c81bf8a1372aff1ec8b053500de47ebc9a4 Mon Sep 17 00:00:00 2001
From: JIeJaitt <498938874@qq.com>
Date: Tue, 4 Mar 2025 11:17:51 +0800
Subject: [PATCH 16/16] =?UTF-8?q?=F0=9F=A9=B9=20Fix:=20improve=20what=5Fne?=
 =?UTF-8?q?w.md?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 docs/whats_new.md                | 2 +-
 middleware/logger/logger_test.go | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/whats_new.md b/docs/whats_new.md
index ecd147105c..29f46b4549 100644
--- a/docs/whats_new.md
+++ b/docs/whats_new.md
@@ -921,7 +921,7 @@ The `Filter` is a function that is called before the log string for a request is
 app.Use(logger.New(logger.Config{
     Filter: func(c fiber.Ctx) bool {
         // log status code >= 400
-        return c.Response().StatusCode() >= fiber.StatusNotFound
+        return c.Response().StatusCode() >= fiber.StatusBadRequest
     },
 }))
 
diff --git a/middleware/logger/logger_test.go b/middleware/logger/logger_test.go
index 36b2aef18b..916f6d9e74 100644
--- a/middleware/logger/logger_test.go
+++ b/middleware/logger/logger_test.go
@@ -171,6 +171,8 @@ func Test_Logger_Done(t *testing.T) {
 	require.Positive(t, buf.Len(), 0)
 }
 
+// Test_Logger_Filter tests the Filter functionality of the logger middleware.
+// It verifies that logs are written or skipped based on the filter condition.
 func Test_Logger_Filter(t *testing.T) {
 	t.Parallel()