Operation name mapping for server spans (Azure#23448)

* operation name mapping

* update mapping as per CS

Author: vishweshbankwar

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/TelemetryPartA.cs

@@ -31,9 +31,7 @@ internal class TelemetryPartA
 
         internal static string RoleInstance { get; set; }
 
-#pragma warning disable CA1801 // Review unused parameters
         internal static TelemetryItem GetTelemetryItem(Activity activity, ref TagEnumerationState monitorTags, Resource resource, string instrumentationKey)
-#pragma warning restore CA1801 // Review unused parameters
         {
             TelemetryItem telemetryItem = new TelemetryItem(PartA_Name_Mapping[activity.GetTelemetryType()], FormatUtcTimestamp(activity.StartTimeUtc))
             {
@@ -45,6 +43,13 @@ internal static TelemetryItem GetTelemetryItem(Activity activity, ref TagEnumera
             telemetryItem.Tags[ContextTagKeys.AiCloudRoleInstance.ToString()] = RoleInstance;
             telemetryItem.Tags[ContextTagKeys.AiOperationId.ToString()] = activity.TraceId.ToHexString();
 
+            // we only have mapping for server spans
+            // todo: non-server spans
+            if (activity.Kind == ActivityKind.Server)
+            {
+                telemetryItem.Tags[ContextTagKeys.AiOperationName.ToString()] = GetOperationName(activity, ref monitorTags.PartBTags);
+            }
+
             if (activity.ParentSpanId != default)
             {
                 telemetryItem.Tags[ContextTagKeys.AiOperationParentId.ToString()] = activity.ParentSpanId.ToHexString();
@@ -55,6 +60,17 @@ internal static TelemetryItem GetTelemetryItem(Activity activity, ref TagEnumera
             return telemetryItem;
         }
 
+        private static string GetOperationName(Activity activity, ref AzMonList partBTags)
+        {
+            var httpMethod = AzMonList.GetTagValue(ref partBTags, SemanticConventions.AttributeHttpMethod)?.ToString();
+            if (!string.IsNullOrWhiteSpace(httpMethod))
+            {
+                return $"{httpMethod} {activity.DisplayName}";
+            }
+
+            return activity.DisplayName;
+        }
+
         internal static TelemetryItem GetTelemetryItem(LogRecord logRecord, string instrumentationKey)
         {
             var name = PartA_Name_Mapping[TelemetryType.Message];

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/tests/Azure.Monitor.OpenTelemetry.Exporter.Tests/TelemetryPartATests.cs

@@ -183,7 +183,47 @@ public void GeneratePartAEnvelope_Activity_WithParentSpanId()
             Assert.Equal(activity.ParentSpanId.ToHexString(), telemetryItem.Tags[ContextTagKeys.AiOperationParentId.ToString()]);
         }
 
-        // TODO: GeneratePartAEnvelope_WithActivityParent
+        [Fact]
+        public void HttpMethodAndActivityNameIsUsedForHttpRequestOperationName()
+        {
+            using ActivitySource activitySource = new ActivitySource(ActivitySourceName);
+            using var activity = activitySource.StartActivity(
+                ActivityName,
+                ActivityKind.Server,
+                null,
+                startTime: DateTime.UtcNow);
+            var resource = CreateTestResource();
+
+            activity.DisplayName = "/getaction";
+
+            activity.SetTag(SemanticConventions.AttributeHttpMethod, "GET");
+
+            var monitorTags = AzureMonitorConverter.EnumerateActivityTags(activity);
+
+            var telemetryItem = TelemetryPartA.GetTelemetryItem(activity, ref monitorTags, resource, null);
+
+            Assert.Equal("GET /getaction", telemetryItem.Tags[ContextTagKeys.AiOperationName.ToString()]);
+        }
+
+        [Fact]
+        public void ActivityNameIsUsedByDefaultForRequestOperationName()
+        {
+            using ActivitySource activitySource = new ActivitySource(ActivitySourceName);
+            using var activity = activitySource.StartActivity(
+                ActivityName,
+                ActivityKind.Server,
+                null,
+                startTime: DateTime.UtcNow);
+            var resource = CreateTestResource();
+
+            activity.DisplayName = "displayname";
+
+            var monitorTags = AzureMonitorConverter.EnumerateActivityTags(activity);
+
+            var telemetryItem = TelemetryPartA.GetTelemetryItem(activity, ref monitorTags, resource, null);
+
+            Assert.Equal("displayname", telemetryItem.Tags[ContextTagKeys.AiOperationName.ToString()]);
+        }
 
         /// <summary>
         /// If SERVICE.NAME is not defined, it will fall-back to "unknown_service".