apm: address OTLP resource naming review

Keep legacy V1 naming unchanged and register url.template as a semantic concept for V2 lookups.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 6b3ce287-79dc-4a9b-b16d-26179119b3d9

Author: niharikag09

pkg/trace/api/otlp.go

@@ -741,7 +741,7 @@ func (o *OTLPReceiver) convertSpan(res pcommon.Resource, lib pcommon.Instrumenta
 		if transform.OperationAndResourceNameV2Enabled(o.conf) {
 			span.Resource = transform.GetOTelResourceV2(in, res)
 		} else {
-			if r := resourceFromTags(span.Meta, in.Kind()); r != "" {
+			if r := resourceFromTags(span.Meta); r != "" {
 				span.Resource = r
 			} else {
 				span.Resource = in.Name()
@@ -756,16 +756,11 @@ func (o *OTLPReceiver) convertSpan(res pcommon.Resource, lib pcommon.Instrumenta
 
 // resourceFromTags attempts to deduce a more accurate span resource from the given list of tags meta.
 // If this is not possible, it returns an empty string.
-func resourceFromTags(meta map[string]string, spanKind ptrace.SpanKind) string {
+func resourceFromTags(meta map[string]string) string {
 	// `http.method` was renamed to `http.request.method` in the HTTP stabilization from v1.23.
 	// See https://opentelemetry.io/docs/specs/semconv/http/migration-guide/#summary-of-changes
 	if _, m := transform.GetFirstFromMap(meta, "http.request.method", "http.method"); m != "" {
-		if spanKind == ptrace.SpanKindClient {
-			if template := meta["url.template"]; template != "" {
-				return m + " " + template
-			}
-			return m
-		}
+		// use the HTTP method + route (if available)
 		if _, route := transform.GetFirstFromMap(meta, string(semconv.HTTPRouteKey), "grpc.path"); route != "" {
 			return m + " " + route
 		}

pkg/trace/api/otlp_test.go

@@ -1612,9 +1612,8 @@ func TestOTLPHelpers(t *testing.T) {
 
 	t.Run("resourceFromTags", func(t *testing.T) {
 		for _, tt := range []struct {
-			meta     map[string]string
-			spanKind ptrace.SpanKind
-			out      string
+			meta map[string]string
+			out  string
 		}{
 			{
 				meta: nil,
@@ -1628,16 +1627,6 @@ func TestOTLPHelpers(t *testing.T) {
 				meta: map[string]string{"http.method": "POST", "http.route": "/settings"},
 				out:  "POST /settings",
 			},
-			{
-				meta:     map[string]string{"http.method": "POST", "url.template": "/settings/{section}"},
-				spanKind: ptrace.SpanKindClient,
-				out:      "POST /settings/{section}",
-			},
-			{
-				meta:     map[string]string{"http.method": "POST", "http.route": "/settings"},
-				spanKind: ptrace.SpanKindClient,
-				out:      "POST",
-			},
 			{
 				meta: map[string]string{"http.method": "POST", "grpc.path": "/settings"},
 				out:  "POST /settings",
@@ -1679,7 +1668,7 @@ func TestOTLPHelpers(t *testing.T) {
 				out:  "query myQuery",
 			},
 		} {
-			assert.Equal(t, tt.out, resourceFromTags(tt.meta, tt.spanKind))
+			assert.Equal(t, tt.out, resourceFromTags(tt.meta))
 		}
 	})
 

pkg/trace/otel/traceutil/otel_util_test.go

@@ -432,7 +432,7 @@ func TestGetOTelResource(t *testing.T) {
 			name:       "HTTP client method and URL template resource",
 			sattrs:     map[string]string{"http.request.method": "GET", "url.template": "/users/{user_id}"},
 			spanKind:   ptrace.SpanKindClient,
-			expectedV1: "GET /users/{user_id}",
+			expectedV1: "GET",
 			expectedV2: "GET /users/{user_id}",
 		},
 		{

pkg/trace/semantics/mappings.json

@@ -316,6 +316,16 @@
         }
       ]
     },
+    "url.template": {
+      "canonical": "url.template",
+      "fallbacks": [
+        {
+          "name": "url.template",
+          "provider": "otel",
+          "type": "string"
+        }
+      ]
+    },
     "http.status_code": {
       "canonical": "http.status_code",
       "fallbacks": [

pkg/trace/semantics/semantics.go

@@ -58,6 +58,7 @@ const (
 	ConceptHTTPStatusCode Concept = "http.status_code"
 	ConceptHTTPMethod     Concept = "http.method"
 	ConceptHTTPRoute      Concept = "http.route"
+	ConceptURLTemplate    Concept = "url.template"
 	ConceptGRPCStatusCode Concept = "rpc.grpc.status_code"
 	ConceptSpanKind       Concept = "span.kind"
 	ConceptDDBaseService  Concept = "_dd.base_service"

pkg/trace/transform/otelutil.go

@@ -292,12 +292,9 @@ func GetOTelResourceV1(span ptrace.Span, res pcommon.Resource) (resName string)
 	resName = GetOTelAttrValInResAndSpanAttrs(span, res, false, "resource.name")
 	if resName == "" {
 		if m := GetOTelAttrValInResAndSpanAttrs(span, res, false, "http.request.method", string(semconv.HTTPMethodKey)); m != "" {
+			// use the HTTP method + route (if available)
 			resName = m
-			if span.Kind() == ptrace.SpanKindClient {
-				if template := GetOTelAttrValInResAndSpanAttrs(span, res, false, "url.template"); template != "" {
-					resName = resName + " " + template
-				}
-			} else if route := GetOTelAttrValInResAndSpanAttrs(span, res, false, string(semconv.HTTPRouteKey)); route != "" {
+			if route := GetOTelAttrValInResAndSpanAttrs(span, res, false, string(semconv.HTTPRouteKey)); route != "" {
 				resName = resName + " " + route
 			}
 		} else if m := GetOTelAttrValInResAndSpanAttrs(span, res, false, string(semconv.MessagingOperationKey)); m != "" {
@@ -349,7 +346,7 @@ func getOTelResourceV2[A semantics.Accessor](span ptrace.Span, accessor A) (resN
 		}
 		resName = m
 		if span.Kind() == ptrace.SpanKindClient {
-			if template := accessor.GetString("url.template"); template != "" {
+			if template := lookupString(accessor, semantics.ConceptURLTemplate, false); template != "" {
 				resName = resName + " " + template
 			}
 		} else if span.Kind() == ptrace.SpanKindServer {