add span name generator for otelgin option

CHANGELOG.md

@@ -12,6 +12,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 - Add the new `go.opentelemetry.io/contrib/instrgen` package to provide auto-generated source code instrumentation. (#3068)
 - Support [Go 1.20]. (#3372)
+- Add `SpanNameFormatter` option to package `go.opentelemetry.io/contrib/instrumentation/github.com/gin-gonic/gin/otelgin`. (#3343)
 
 ### Changed
 

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

@@ -73,7 +73,12 @@ func Middleware(service string, opts ...Option) gin.HandlerFunc {
 			oteltrace.WithAttributes(httpconv.ServerRequest(service, c.Request)...),
 			oteltrace.WithSpanKind(oteltrace.SpanKindServer),
 		}
-		spanName := c.FullPath()
+		var spanName string
+		if cfg.SpanNameFormatter == nil {
+			spanName = c.FullPath()
+		} else {
+			spanName = cfg.SpanNameFormatter(c.Request)
+		}
 		if spanName == "" {
 			spanName = fmt.Sprintf("HTTP %s route not found", c.Request.Method)
 		} else {

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

@@ -24,15 +24,19 @@ import (
 )
 
 type config struct {
-	TracerProvider oteltrace.TracerProvider
-	Propagators    propagation.TextMapPropagator
-	Filters        []Filter
+	TracerProvider    oteltrace.TracerProvider
+	Propagators       propagation.TextMapPropagator
+	Filters           []Filter
+	SpanNameFormatter SpanNameFormatter
 }
 
 // Filter is a predicate used to determine whether a given http.request should
 // 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
+
 // Option specifies instrumentation configuration options.
 type Option interface {
 	apply(*config)
@@ -76,3 +80,11 @@ func WithFilter(f ...Filter) Option {
 		c.Filters = append(c.Filters, f...)
 	})
 }
+
+// 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 {
+	return optionFunc(func(c *config) {
+		c.SpanNameFormatter = f
+	})
+}

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

@@ -164,6 +164,32 @@ func TestSpanStatus(t *testing.T) {
 	}
 }
 
+func TestSpanName(t *testing.T) {
+	testCases := []struct {
+		requestPath       string
+		spanNameFormatter otelgin.SpanNameFormatter
+		wantSpanName      string
+	}{
+		{"/user/1", nil, "/user/:id"},
+		{"/user/1", func(r *http.Request) string { return r.URL.Path }, "/user/1"},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.requestPath, func(t *testing.T) {
+			sr := tracetest.NewSpanRecorder()
+			provider := sdktrace.NewTracerProvider()
+			provider.RegisterSpanProcessor(sr)
+			router := gin.New()
+			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))
+
+			require.Len(t, sr.Ended(), 1, "should emit a span")
+			assert.Equal(t, sr.Ended()[0].Name(), tc.wantSpanName, "span name not correct")
+		})
+	}
+}
+
 func TestHTML(t *testing.T) {
 	sr := tracetest.NewSpanRecorder()
 	provider := sdktrace.NewTracerProvider(sdktrace.WithSpanProcessor(sr))