Let's user define how he wants to log his routes (eg. JSON, key value, or something else) (#1553) (#1555)

README.md

@@ -58,6 +58,7 @@ Gin is a web framework written in Go (Golang). It features a martini-like API wi
     - [Bind form-data request with custom struct](#bind-form-data-request-with-custom-struct)
     - [Try to bind body into different structs](#try-to-bind-body-into-different-structs)
     - [http2 server push](#http2-server-push)
+    - [Define format for the log of routes](#define-format-for-the-log-of-routes)
 - [Testing](#testing)
 - [Users](#users)
 
@@ -1836,6 +1837,49 @@ func main() {
 }
 ```
 
+### Define format for the log of routes
+
+The default log of routes is:
+```
+[GIN-debug] POST   /foo                      --> main.main.func1 (3 handlers)
+[GIN-debug] GET    /bar                      --> main.main.func2 (3 handlers)
+[GIN-debug] GET    /status                   --> main.main.func3 (3 handlers)
+```
+
+If you want to log this information in given format (e.g. JSON, key values or something else), then you can define this format with `gin.DebugPrintRouteFunc`.
+In the example below, we log all routes with standard log package but you can use another log tools that suits of your needs.
+```go
+import (
+	"log"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func main() {
+	r := gin.Default()
+	gin.DebugPrintRouteFunc = func(httpMethod, absolutePath, handlerName string, nuHandlers int) {
+		log.Printf("endpoint %v %v %v %v\n", httpMethod, absolutePath, handlerName, nuHandlers)
+	}
+
+	r.POST("/foo", func(c *gin.Context) {
+		c.JSON(http.StatusOK, "foo")
+	})
+
+	r.GET("/bar", func(c *gin.Context) {
+		c.JSON(http.StatusOK, "bar")
+	})
+
+	r.GET("/status", func(c *gin.Context) {
+		c.JSON(http.StatusOK, "ok")
+	})
+
+	// Listen and Server in http://0.0.0.0:8080
+	r.Run()
+}
+```
+
+
 ## Testing
 
 The `net/http/httptest` package is preferable way for HTTP testing.

debug.go

@@ -20,11 +20,17 @@ func IsDebugging() bool {
 	return ginMode == debugCode
 }
 
+var DebugPrintRouteFunc func(httpMethod, absolutePath, handlerName string, nuHandlers int)
+
 func debugPrintRoute(httpMethod, absolutePath string, handlers HandlersChain) {
 	if IsDebugging() {
 		nuHandlers := len(handlers)
 		handlerName := nameOfFunction(handlers.Last())
+		if DebugPrintRouteFunc == nil {
 			debugPrint("%-6s %-25s --> %s (%d handlers)\n", httpMethod, absolutePath, handlerName, nuHandlers)
+		} else {
+			DebugPrintRouteFunc(httpMethod, absolutePath, handlerName, nuHandlers)
+		}
 	}
 }