feat(langgraph): Usage attributes on invocation spans (#5211)

Add prompt, response, and total token counts to LangGraph invocation spans.

Contributes to #5170

Author: alexander-alderman-webb

sentry_sdk/integrations/langgraph.py

@@ -62,7 +62,13 @@ def _normalize_langgraph_message(message):
 
     parsed = {"role": getattr(message, "type", None), "content": message.content}
 
-    for attr in ["name", "tool_calls", "function_call", "tool_call_id"]:
+    for attr in [
+        "name",
+        "tool_calls",
+        "function_call",
+        "tool_call_id",
+        "response_metadata",
+    ]:
         if hasattr(message, attr):
             value = getattr(message, attr)
             if value is not None:
@@ -311,14 +317,51 @@ def _extract_tool_calls(messages):
     return tool_calls if tool_calls else None
 
 
+def _set_usage_data(span, messages):
+    # type: (sentry_sdk.tracing.Span, Any) -> None
+    input_tokens = 0
+    output_tokens = 0
+    total_tokens = 0
+
+    for message in messages:
+        response_metadata = message.get("response_metadata")
+        if response_metadata is None:
+            continue
+
+        token_usage = response_metadata.get("token_usage")
+        if not token_usage:
+            continue
+
+        input_tokens += int(token_usage.get("prompt_tokens", 0))
+        output_tokens += int(token_usage.get("completion_tokens", 0))
+        total_tokens += int(token_usage.get("total_tokens", 0))
+
+    if input_tokens > 0:
+        span.set_data(SPANDATA.GEN_AI_USAGE_INPUT_TOKENS, input_tokens)
+
+    if output_tokens > 0:
+        span.set_data(SPANDATA.GEN_AI_USAGE_OUTPUT_TOKENS, output_tokens)
+
+    if total_tokens > 0:
+        span.set_data(
+            SPANDATA.GEN_AI_USAGE_TOTAL_TOKENS,
+            total_tokens,
+        )
+
+
 def _set_response_attributes(span, input_messages, result, integration):
     # type: (Any, Optional[List[Any]], Any, LanggraphIntegration) -> None
-    if not (should_send_default_pii() and integration.include_prompts):
-        return
-
     parsed_response_messages = _parse_langgraph_messages(result)
     new_messages = _get_new_messages(input_messages, parsed_response_messages)
 
+    if new_messages is None:
+        return
+
+    _set_usage_data(span, new_messages)
+
+    if not (should_send_default_pii() and integration.include_prompts):
+        return
+
     llm_response_text = _extract_llm_response_text(new_messages)
     if llm_response_text:
         set_data_normalized(span, SPANDATA.GEN_AI_RESPONSE_TEXT, llm_response_text)