chore: Do not send api request when session does not have events

PiperOrigin-RevId: 775423356

src/google/adk/memory/vertex_ai_memory_bank_service.py

@@ -78,12 +78,15 @@ class VertexAiMemoryBankService(BaseMemoryService):
         },
     }
 
-    api_response = await api_client.async_request(
-        http_method='POST',
-        path=f'reasoningEngines/{self._agent_engine_id}/memories:generate',
-        request_dict=request_dict,
-    )
-    logger.info(f'Generate memory response: {api_response}')
+    if events:
+      api_response = await api_client.async_request(
+          http_method='POST',
+          path=f'reasoningEngines/{self._agent_engine_id}/memories:generate',
+          request_dict=request_dict,
+      )
+      logger.info(f'Generate memory response: {api_response}')
+    else:
+      logger.info('No events to add to memory.')
 
   @override
   async def search_memory(self, *, app_name: str, user_id: str, query: str):

tests/unittests/memory/test_vertex_ai_memory_bank_service.py

@@ -48,6 +48,13 @@ MOCK_SESSION = Session(
     ],
 )
 
+MOCK_SESSION_WITH_EMPTY_EVENTS = Session(
+    app_name=MOCK_APP_NAME,
+    user_id=MOCK_USER_ID,
+    id='444',
+    last_update_time=22333,
+)
+
 
 RETRIEVE_MEMORIES_REGEX = r'^reasoningEngines/([^/]+)/memories:retrieve$'
 GENERATE_MEMORIES_REGEX = r'^reasoningEngines/([^/]+)/memories:generate$'
@@ -136,6 +143,15 @@ async def test_add_session_to_memory(mock_get_api_client):
   )
 
 
+@pytest.mark.asyncio
+@pytest.mark.usefixtures('mock_get_api_client')
+async def test_add_empty_session_to_memory(mock_get_api_client):
+  memory_service = mock_vertex_ai_memory_bank_service()
+  await memory_service.add_session_to_memory(MOCK_SESSION_WITH_EMPTY_EVENTS)
+
+  mock_get_api_client.async_request.assert_not_called()
+
+
 @pytest.mark.asyncio
 @pytest.mark.usefixtures('mock_get_api_client')
 async def test_search_memory(mock_get_api_client):