fix: overriding the llama-index function to improve error handling!

utils/query_engine/subquestion_engine.py

@@ -1,3 +1,4 @@
+import logging
 from typing import List, Optional, Sequence, cast
 
 import llama_index.core.instrumentation as instrument
@@ -7,13 +8,14 @@
 from llama_index.core.callbacks.schema import CBEventType, EventPayload
 from llama_index.core.instrumentation.events.query import QueryEndEvent, QueryStartEvent
 from llama_index.core.query_engine import SubQuestionAnswerPair, SubQuestionQueryEngine
-from llama_index.core.question_gen.types import BaseQuestionGenerator
+from llama_index.core.question_gen.types import BaseQuestionGenerator, SubQuestion
 from llama_index.core.response_synthesizers import BaseSynthesizer
 from llama_index.core.schema import NodeWithScore, QueryBundle
 from llama_index.core.tools.query_engine import QueryEngineTool
 from llama_index.core.utils import get_color_mapping, print_text
 
 dispatcher = instrument.get_dispatcher(__name__)
+logger = logging.getLogger(__name__)
 
 
 class CustomSubQuestionQueryEngine(SubQuestionQueryEngine):
@@ -95,3 +97,36 @@ def query(
             QueryEndEvent(query=str_or_query_bundle, response=query_result)
         )
         return query_result, qa_pairs_all
+
+    def _query_subq(
+        self, sub_q: SubQuestion, color: Optional[str] = None
+    ) -> Optional[SubQuestionAnswerPair]:
+        try:
+            with self.callback_manager.event(
+                CBEventType.SUB_QUESTION,
+                payload={EventPayload.SUB_QUESTION: SubQuestionAnswerPair(sub_q=sub_q)},
+            ) as event:
+                question = sub_q.sub_question
+                query_engine = self._query_engines[sub_q.tool_name]
+
+                if self._verbose:
+                    print_text(f"[{sub_q.tool_name}] Q: {question}\n", color=color)
+
+                response = query_engine.query(question)
+                response_text = str(response)
+
+                if self._verbose:
+                    print_text(f"[{sub_q.tool_name}] A: {response_text}\n", color=color)
+
+                qa_pair = SubQuestionAnswerPair(
+                    sub_q=sub_q, answer=response_text, sources=response.source_nodes
+                )
+
+                event.on_end(payload={EventPayload.SUB_QUESTION: qa_pair})
+
+            return qa_pair
+        except Exception as exp:
+            logger.warning(
+                f"[{sub_q.tool_name}] Failed to run {sub_q.sub_question}: {exp}"
+            )
+            return None