draft: add extended-span-chat-model-listener

core/runtime/src/main/java/io/quarkiverse/langchain4j/runtime/listeners/ExtendedSpanChatModelListener.java

@@ -0,0 +1,53 @@
+package io.quarkiverse.langchain4j.runtime.listeners;
+
+import dev.langchain4j.model.chat.listener.ChatModelErrorContext;
+import dev.langchain4j.model.chat.listener.ChatModelRequest;
+import dev.langchain4j.model.chat.listener.ChatModelRequestContext;
+import dev.langchain4j.model.chat.listener.ChatModelResponse;
+import dev.langchain4j.model.chat.listener.ChatModelResponseContext;
+import io.opentelemetry.api.trace.Span;
+
+/** 
+ * extended ChatModelListener adding possibility to add custom attributes to span
+ */
+public interface ExtendedSpanChatModelListener {
+    /**
+     * Allowing extendes Span-Attributes {@link SpanChatModelListener} 
+     *
+     * @param requestContext The request context. It contains the {@link ChatModelRequest} and attributes.
+     *                       The attributes can be used to pass data between methods of this listener
+     *                       or between multiple listeners.
+     * @param currentSpan Span opened by {@link SpanChatModelListener}.
+     */
+    default void onRequest(ChatModelRequestContext requestContext, Span currentSpan) {
+
+    }
+
+    /**
+     * Allowing extendes Span-Attributes {@link SpanChatModelListener} 
+     *
+     * @param responseContext The response context.
+     *                        It contains {@link ChatModelResponse}, corresponding {@link ChatModelRequest} and attributes.
+     *                        The attributes can be used to pass data between methods of this listener
+     *                        or between multiple listeners.
+     * @param currentSpan Span opened by {@link SpanChatModelListener}.
+     */
+    default void onResponse(ChatModelResponseContext responseContext, Span currentSpan) {
+
+    }
+
+    /**
+     * Allowing extendes Span-Attributes {@link SpanChatModelListener} 
+     *
+     * @param errorContext The error context.
+     *                     It contains the error, corresponding {@link ChatModelRequest},
+     *                     partial {@link ChatModelResponse} (if available) and attributes.
+     *                     The attributes can be used to pass data between methods of this listener
+     *                     or between multiple listeners.
+     * @param currentSpan Span opened by {@link SpanChatModelListener}.
+     */
+    default void onError(ChatModelErrorContext errorContext, Span currentSpan) {
+
+    }
+
+}

core/runtime/src/main/java/io/quarkiverse/langchain4j/runtime/listeners/SpanChatModelListener.java

@@ -33,11 +33,13 @@ public class SpanChatModelListener implements ChatModelListener {
 
     private final Tracer tracer;
     private final CostEstimatorService costEstimatorService;
-
+    private final ExtendedSpanChatModelListener extendedSpanChatModelListener;
+
     @Inject
-    public SpanChatModelListener(Tracer tracer, CostEstimatorService costEstimatorService) {
-        this.tracer = tracer;
-        this.costEstimatorService = costEstimatorService;
+    public SpanChatModelListener(Tracer tracer, CostEstimatorService costEstimatorService, ExtendedSpanChatModelListener extendedSpanChatModelListener) {
+            this.tracer = tracer;
+            this.costEstimatorService = costEstimatorService;
+            this.extendedSpanChatModelListener = extendedSpanChatModelListener;
     }
 
     @Override
@@ -53,6 +55,7 @@ public void onRequest(ChatModelRequestContext requestContext) {
         var attributes = requestContext.attributes();
         attributes.put(OTEL_SCOPE_KEY_NAME, scope);
         attributes.put(OTEL_SPAN_KEY_NAME, span);
+        extendedSpanChatModelListener.onRequest(requestContext, span);
     }
 
     @Override
@@ -78,6 +81,7 @@ public void onResponse(ChatModelResponseContext responseContext) {
                     span.setAttribute("gen_ai.client.estimated_cost", costEstimate.toString());
                 }
             }
+            extendedSpanChatModelListener.onResponse(responseContext, span);
             span.end();
         } else {
             // should never happen
@@ -91,6 +95,7 @@ public void onError(ChatModelErrorContext errorContext) {
         var attributes = errorContext.attributes();
         Span span = (Span) attributes.get(OTEL_SPAN_KEY_NAME);
         if (span != null) {
+            extendedSpanChatModelListener.onError(errorContext, span);
             span.recordException(errorContext.error());
         } else {
             // should never happen