feat: add skipper functionality to logger (#80)

- Add skipper usage example in README.md
- Add `skip` field to logger config struct
- Modify `SetLogger` function to use the `skip` field
- Add `skipper` type and `WithSkipper` option function to logger.go
- Add tests for skipper functionality in logger_test.go
- Add `WithSkipper` option function to options.go

Signed-off-by: appleboy <[email protected]>

README.md

@@ -102,6 +102,15 @@ func main() {
     c.String(http.StatusOK, "pong "+fmt.Sprint(time.Now().Unix()))
   })
 
+  // Example of skipper usage
+  r.GET("/health", logger.SetLogger(
+    logger.WithSkipper(func(c *gin.Context) bool {
+      return c.Request.URL.Path == "/health"
+    }),
+  ), func(c *gin.Context) {
+    c.String(http.StatusOK, "pong "+fmt.Sprint(time.Now().Unix()))
+  })
+
   // Listen and Server in 0.0.0.0:8080
   if err := r.Run(":8080"); err != nil {
     log.Fatal().Msg("can' start server with 8080 port")

logger.go

@@ -14,13 +14,19 @@ import (
 
 type Fn func(*gin.Context, zerolog.Logger) zerolog.Logger
 
+// Skipper is a function to skip logs based on provided Context
+type Skipper func(c *gin.Context) bool
+
 // Config defines the config for logger middleware
 type config struct {
 	logger Fn
 	// UTC a boolean stating whether to use UTC time zone or local.
 	utc             bool
 	skipPath        []string
 	skipPathRegexps []*regexp.Regexp
+	// skip is a Skipper that indicates which logs should not be written.
+	// Optional.
+	skip Skipper
 	// Output is a writer where logs are written.
 	// Optional. Default value is gin.DefaultWriter.
 	output io.Writer
@@ -84,7 +90,7 @@ func SetLogger(opts ...Option) gin.HandlerFunc {
 		c.Next()
 		track := true
 
-		if _, ok := skip[path]; ok {
+		if _, ok := skip[path]; ok || (cfg.skip != nil && cfg.skip(c)) {
 			track = false
 		}
 
@@ -112,7 +118,9 @@ func SetLogger(opts ...Option) gin.HandlerFunc {
 				Str("path", path).
 				Str("ip", c.ClientIP()).
 				Dur("latency", latency).
-				Str("user_agent", c.Request.UserAgent()).Logger()
+				Str("user_agent", c.Request.UserAgent()).
+				Int("body_size", c.Writer.Size()).
+				Logger()
 
 			msg := "Request"
 			if len(c.Errors) > 0 {

logger_test.go

@@ -226,6 +226,29 @@ func TestLoggerCustomLevel(t *testing.T) {
 	assert.Contains(t, buffer.String(), "FTL")
 }
 
+func TestLoggerSkipper(t *testing.T) {
+	buffer := new(bytes.Buffer)
+	gin.SetMode(gin.ReleaseMode)
+	r := gin.New()
+	r.Use(SetLogger(
+		WithWriter(buffer),
+		WithSkipper(func(c *gin.Context) bool {
+			return c.Request.URL.Path == "/example2"
+		}),
+	))
+	r.GET("/example", func(c *gin.Context) {})
+	r.GET("/example2", func(c *gin.Context) {})
+
+	performRequest(r, "GET", "/example")
+	assert.Contains(t, buffer.String(), "GET")
+	assert.Contains(t, buffer.String(), "/example")
+
+	buffer.Reset()
+	performRequest(r, "GET", "/example2")
+	assert.NotContains(t, buffer.String(), "GET")
+	assert.NotContains(t, buffer.String(), "/example2")
+}
+
 func BenchmarkLogger(b *testing.B) {
 	gin.SetMode(gin.ReleaseMode)
 	r := gin.New()

options.go

@@ -88,3 +88,12 @@ func WithServerErrorLevel(lvl zerolog.Level) Option {
 		c.serverErrorLevel = lvl
 	})
 }
+
+// WithSkipper set function to skip middleware
+// requests with this function returning true will not have their logs written
+// Default is nil
+func WithSkipper(s Skipper) Option {
+	return optionFunc(func(c *config) {
+		c.skip = s
+	})
+}