add az.namespace to Azure AI Inference spans (Azure#48022)

Author: Liudmila Molkova

sdk/ai/Azure.AI.Inference/src/Telemetry/OpenTelemetryConstants.cs

@@ -11,6 +11,8 @@ internal class OpenTelemetryConstants
         // https://github.com/open-telemetry/semantic-conventions/tree/v1.27.0/docs/gen-ai
 
         public const string ErrorTypeKey = "error.type";
+
+        public const string AzNamespaceKey = "az.namespace";
         public const string ServerAddressKey = "server.address";
         public const string ServerPortKey = "server.port";
 
@@ -39,6 +41,8 @@ internal class OpenTelemetryConstants
         public const string GenAiEventContent = "gen_ai.event.content";
         public const string GenAiChoice = "gen_ai.choice";
 
+        public const string AzureRpNamespaceValue = "Microsoft.CognitiveServices";
+
         public const string ClientName = "Azure.AI.Inference.ChatCompletionsClient";
         public const string EnableOpenTelemetrySwitch = "Azure.Experimental.EnableActivitySource";
         public const string TraceContentsSwitch = "Azure.Experimental.TraceGenAIMessageContent";

sdk/ai/Azure.AI.Inference/src/Telemetry/OpenTelemetryScope.cs

@@ -88,6 +88,7 @@ private OpenTelemetryScope(ChatCompletionsOptions requestOptions, Uri endpoint)
             {
                 _activity?.SetTag(kv.Key, kv.Value);
             }
+            _activity?.SetTag(AzNamespaceKey, AzureRpNamespaceValue);
             SetTagMaybe(GenAiRequestMaxTokensKey, requestOptions.MaxTokens);
             SetTagMaybe(GenAiRequestTemperatureKey, requestOptions.Temperature);
             SetTagMaybe(GenAiRequestTopPKey, requestOptions.NucleusSamplingFactor);

sdk/ai/Azure.AI.Inference/tests/Utilities/ValidatingActivityListener.cs

@@ -93,6 +93,7 @@ public void ValidateResponse(RecordedResponse response, string errorType, string
             ValidateTag(activity, GenAiResponseFinishReasonsKey, response.FinishReasons);
             ValidateIntTag(activity, GenAiUsageOutputTokensKey, response.CompletionTokens);
             ValidateIntTag(activity, GenAiUsageInputTokensKey, response.PromptTokens);
+            ValidateTag(activity, AzNamespaceKey, AzureRpNamespaceValue);
 
             HashSet<string> expectedChoices = new HashSet<string>(response.Choices.Select(c => JsonSerializer.Serialize(c, options: s_jsonOptions)));
             for (int i = 0; i < actualChoices.Count; i++)