[ASP.NET Core] replace http.target with http.route

src/OpenTelemetry.Instrumentation.AspNetCore/CHANGELOG.md

@@ -6,6 +6,10 @@
   `net.host.name` and `net.host.port` attributes will be populated instead.
   ([#3858](https://github.com/open-telemetry/opentelemetry-dotnet/pull/3858))
 
+* The `http.server.duration` metric's `http.target` attribute is replaced
+with `http.route` attribute.
+([#3903](https://github.com/open-telemetry/opentelemetry-dotnet/pull/3903))
+
 ## 1.0.0-rc9.9
 
 Released 2022-Nov-07

src/OpenTelemetry.Instrumentation.AspNetCore/Implementation/HttpInMetricsListener.cs

@@ -70,19 +70,19 @@ public override void OnEventWritten(string name, object payload)
 
                 TagList tags;
 #if NET6_0_OR_GREATER
-                var target = (context.GetEndpoint() as RouteEndpoint)?.RoutePattern.RawText;
+                var route = (context.GetEndpoint() as RouteEndpoint)?.RoutePattern.RawText;
 
                 // TODO: This is just a minimal set of attributes. See the spec for additional attributes:
                 // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/http-metrics.md#http-server
-                if (!string.IsNullOrEmpty(target))
+                if (!string.IsNullOrEmpty(route))
                 {
                     tags = new TagList
                     {
                         { SemanticConventions.AttributeHttpFlavor, HttpTagHelper.GetFlavorTagValueFromProtocol(context.Request.Protocol) },
                         { SemanticConventions.AttributeHttpScheme, context.Request.Scheme },
                         { SemanticConventions.AttributeHttpMethod, context.Request.Method },
                         { SemanticConventions.AttributeHttpHost, host },
-                        { SemanticConventions.AttributeHttpTarget, target },
+                        { SemanticConventions.AttributeHttpRoute, route },
                         { SemanticConventions.AttributeHttpStatusCode, context.Response.StatusCode.ToString() },
                     };
                 }

test/OpenTelemetry.Instrumentation.AspNetCore.Tests/MetricTests.cs

@@ -120,13 +120,13 @@ public async Task RequestMetricIsCaptured()
             var statusCode = new KeyValuePair<string, object>(SemanticConventions.AttributeHttpStatusCode, "200");
             var flavor = new KeyValuePair<string, object>(SemanticConventions.AttributeHttpFlavor, "1.1");
             var host = new KeyValuePair<string, object>(SemanticConventions.AttributeHttpHost, "localhost");
-            var target = new KeyValuePair<string, object>(SemanticConventions.AttributeHttpTarget, "api/Values");
+            var route = new KeyValuePair<string, object>(SemanticConventions.AttributeHttpRoute, "api/Values");
             Assert.Contains(method, attributes);
             Assert.Contains(scheme, attributes);
             Assert.Contains(statusCode, attributes);
             Assert.Contains(flavor, attributes);
             Assert.Contains(host, attributes);
-            Assert.Contains(target, attributes);
+            Assert.Contains(route, attributes);
             Assert.Equal(6, attributes.Length);
         }