fix(cli): detailed error message on sse stream specifying stacktrack (error type on client side as well)

Merge #4248

Co-authored-by: Xuan Yang <xygoogle@google.com>
PiperOrigin-RevId: 940627393

Author: 2 people

src/google/adk/cli/api_server.py

@@ -26,6 +26,7 @@
 import os
 import re
 import sys
+import time
 import traceback
 import typing
 from typing import Any
@@ -1603,7 +1604,18 @@ async def event_generator():
                 yield f"data: {sse_event}\n\n"
           except Exception as e:
             logger.exception("Error in event_generator: %s", e)
-            yield f"data: {json.dumps({'error': str(e)})}\n\n"
+            error_details = {
+                "error_type": type(e).__name__,
+                "error_message": str(e),
+                "timestamp": time.time(),
+            }
+            if logger.isEnabledFor(logging.DEBUG):
+              error_details["stacktrace"] = traceback.format_exc()
+
+            yield (
+                "data:"
+                f" {json.dumps({'error': f'{type(e).__name__}: {e}', 'error_details': error_details})}\n\n"
+            )
 
       # Returns a streaming response with the proper media type for SSE
       return StreamingResponse(

tests/unittests/cli/test_fast_api.py

@@ -1645,7 +1645,7 @@ async def run_async_with_artifact_delta(
 def test_agent_run_sse_yields_error_object_on_exception(
     test_app, create_test_session, monkeypatch
 ):
-  """Test /run_sse streams an error object if streaming raises."""
+  """Test /run_sse streams structured error details on exception."""
   info = create_test_session
 
   async def run_async_raises(self, **kwargs):
@@ -1662,15 +1662,42 @@ async def run_async_raises(self, **kwargs):
       "streaming": True,
   }
 
-  response = test_app.post("/run_sse", json=payload)
-  assert response.status_code == 200
-
-  sse_events = [
-      json.loads(line.removeprefix("data: "))
-      for line in response.text.splitlines()
-      if line.startswith("data: ")
-  ]
-  assert sse_events == [{"error": "boom"}]
+  # 1. Test without DEBUG enabled
+  with patch(
+      "google.adk.cli.api_server.logger.isEnabledFor", return_value=False
+  ):
+    response = test_app.post("/run_sse", json=payload)
+    assert response.status_code == 200
+    sse_events = [
+        json.loads(line.removeprefix("data: "))
+        for line in response.text.splitlines()
+        if line.startswith("data: ")
+    ]
+    assert len(sse_events) == 1
+    error_event = sse_events[0]
+    assert error_event["error"] == "ValueError: boom"
+    assert "error_details" in error_event
+    assert error_event["error_details"]["error_type"] == "ValueError"
+    assert error_event["error_details"]["error_message"] == "boom"
+    assert "stacktrace" not in error_event["error_details"]
+    assert "timestamp" in error_event["error_details"]
+
+  # 2. Test with DEBUG enabled
+  with patch(
+      "google.adk.cli.api_server.logger.isEnabledFor", return_value=True
+  ):
+    response = test_app.post("/run_sse", json=payload)
+    assert response.status_code == 200
+    sse_events = [
+        json.loads(line.removeprefix("data: "))
+        for line in response.text.splitlines()
+        if line.startswith("data: ")
+    ]
+    assert len(sse_events) == 1
+    error_event = sse_events[0]
+    assert error_event["error"] == "ValueError: boom"
+    assert "stacktrace" in error_event["error_details"]
+    assert "ValueError: boom" in error_event["error_details"]["stacktrace"]
 
 
 def test_list_artifact_names(test_app, create_test_session):