Improvements for logger middleware (#1645)

* Add NO_COLOR compatibility.

* Use /dev/stdout as default output stream.

* Fix coloring with custom formats.

* Fix tests.

middleware/logger/config.go

@@ -38,7 +38,7 @@ type Config struct {
 
 	// Output is a writter where logs are written
 	//
-	// Default: os.Stderr
+	// Default: os.Stdout
 	Output io.Writer
 
 	enableColors     bool
@@ -53,7 +53,7 @@ var ConfigDefault = Config{
 	TimeFormat:   "15:04:05",
 	TimeZone:     "Local",
 	TimeInterval: 500 * time.Millisecond,
-	Output:       os.Stderr,
+	Output:       os.Stdout,
 	enableColors: true,
 }
 
@@ -64,11 +64,11 @@ func validCustomFormat(format string) bool {
 		return true
 	}
 	for _, template := range validTemplates {
-		if !strings.Contains(format, template) {
-			return false
+		if strings.Contains(format, template) {
+			return true
 		}
 	}
-	return true
+	return false
 }
 
 // Helper function to set default values

middleware/logger/logger.go

@@ -118,9 +118,9 @@ func New(config ...Config) fiber.Handler {
 
 	// If colors are enabled, check terminal compatibility
 	if cfg.enableColors {
-		cfg.Output = colorable.NewColorableStderr()
-		if os.Getenv("TERM") == "dumb" || (!isatty.IsTerminal(os.Stderr.Fd()) && !isatty.IsCygwinTerminal(os.Stderr.Fd())) {
-			cfg.Output = colorable.NewNonColorable(os.Stderr)
+		cfg.Output = colorable.NewColorableStdout()
+		if os.Getenv("TERM") == "dumb" || os.Getenv("NO_COLOR") == "1" || (!isatty.IsTerminal(os.Stdout.Fd()) && !isatty.IsCygwinTerminal(os.Stdout.Fd())) {
+			cfg.Output = colorable.NewNonColorable(os.Stdout)
 		}
 	}
 	errPadding := 15
@@ -174,7 +174,7 @@ func New(config ...Config) fiber.Handler {
 		buf := bytebufferpool.Get()
 
 		// Default output when no custom Format or io.Writer is given
-		if cfg.enableColors {
+		if cfg.enableColors && cfg.Format == ConfigDefault.Format {
 			// Format error if exist
 			formatErr := ""
 			if chainErr != nil {
@@ -238,12 +238,18 @@ func New(config ...Config) fiber.Handler {
 			case TagRoute:
 				return buf.WriteString(c.Route().Path)
 			case TagStatus:
+				if cfg.enableColors {
+					return buf.WriteString(fmt.Sprintf("%s %3d %s", statusColor(c.Response().StatusCode()), c.Response().StatusCode(), cReset))
+				}
 				return appendInt(buf, c.Response().StatusCode())
 			case TagResBody:
 				return buf.Write(c.Response().Body())
 			case TagQueryStringParams:
 				return buf.WriteString(c.Request().URI().QueryArgs().String())
 			case TagMethod:
+				if cfg.enableColors {
+					return buf.WriteString(fmt.Sprintf("%s %-7s %s", methodColor(c.Method()), c.Method(), cReset))
+				}
 				return buf.WriteString(c.Method())
 			case TagBlack:
 				return buf.WriteString(cBlack)