otelgin: add routeName argument to SpanNameFormatter function

CHANGELOG.md

@@ -12,6 +12,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 - The `go.opentelemetry.io/contrib/config` add support to configure periodic reader interval and timeout. (#5661)
 - Add support to configure views when creating MeterProvider using the config package. (#5654)
+- Add `routeName` argument to `SpanNameFormatter` function in `go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin`.
 
 ### Fixed
 

instrumentation/github.com/gin-gonic/gin/otelgin/gintrace.go

@@ -66,7 +66,7 @@ func Middleware(service string, opts ...Option) gin.HandlerFunc {
 		if cfg.SpanNameFormatter == nil {
 			spanName = c.FullPath()
 		} else {
-			spanName = cfg.SpanNameFormatter(c.Request)
+			spanName = cfg.SpanNameFormatter(c.FullPath(), c.Request)
 		}
 		if spanName == "" {
 			spanName = fmt.Sprintf("HTTP %s route not found", c.Request.Method)

instrumentation/github.com/gin-gonic/gin/otelgin/option.go

@@ -23,8 +23,8 @@ type config struct {
 // be traced. A Filter must return true if the request should be traced.
 type Filter func(*http.Request) bool
 
-// SpanNameFormatter is used to set span name by http.request.
-type SpanNameFormatter func(r *http.Request) string
+// SpanNameFormatter is used to set span name by http.Request.
+type SpanNameFormatter func(routeName string, r *http.Request) string
 
 // Option specifies instrumentation configuration options.
 type Option interface {
@@ -70,9 +70,11 @@ func WithFilter(f ...Filter) Option {
 	})
 }
 
-// WithSpanNameFormatter takes a function that will be called on every
-// request and the returned string will become the Span Name.
-func WithSpanNameFormatter(f func(r *http.Request) string) Option {
+// WithSpanNameFormatter specifies a function to use for generating a custom span
+// name. By default, the route name (path template or regexp) is used. The route
+// name is provided so you can use it in the span name without needing to
+// duplicate the logic for extracting it from the request.
+func WithSpanNameFormatter(f func(routeName string, r *http.Request) string) Option {
 	return optionFunc(func(c *config) {
 		c.SpanNameFormatter = f
 	})

instrumentation/github.com/gin-gonic/gin/otelgin/test/gintrace_test.go

@@ -7,6 +7,7 @@ package test
 
 import (
 	"errors"
+	"fmt"
 	"html/template"
 	"net/http"
 	"net/http/httptest"
@@ -160,7 +161,8 @@ func TestSpanName(t *testing.T) {
 		wantSpanName      string
 	}{
 		{"/user/1", nil, "/user/:id"},
-		{"/user/1", func(r *http.Request) string { return r.URL.Path }, "/user/1"},
+		{"/user/1", func(routeName string, r *http.Request) string { return r.URL.Path }, "/user/1"},
+		{"/user/1", func(routeName string, r *http.Request) string { return fmt.Sprintf("%s %s", r.Method, routeName) }, "GET /user/:id"},
 	}
 	for _, tc := range testCases {
 		t.Run(tc.requestPath, func(t *testing.T) {
@@ -171,7 +173,7 @@ func TestSpanName(t *testing.T) {
 			router.Use(otelgin.Middleware("foobar", otelgin.WithTracerProvider(provider), otelgin.WithSpanNameFormatter(tc.spanNameFormatter)))
 			router.GET("/user/:id", func(c *gin.Context) {})
 
-			router.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest("GET", tc.requestPath, nil))
+			router.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, tc.requestPath, nil))
 
 			require.Len(t, sr.Ended(), 1, "should emit a span")
 			assert.Equal(t, sr.Ended()[0].Name(), tc.wantSpanName, "span name not correct")