Enhance LLMNode error handling for structured output parsing

- Wrapped the result processing loop in a try-except block to catch OutputParserError exceptions.
- Raised a custom LLMNodeError with a descriptive message when parsing fails, improving error reporting and debugging capabilities.

api/core/workflow/nodes/llm/node.py

@@ -8,6 +8,7 @@ from typing import TYPE_CHECKING, Any, Optional, cast
 from core.app.entities.app_invoke_entities import ModelConfigWithCredentialsEntity
 from core.file import FileType, file_manager
 from core.helper.code_executor import CodeExecutor, CodeLanguage
+from core.llm_generator.output_parser.errors import OutputParserError
 from core.llm_generator.output_parser.structured_output import invoke_llm_with_structured_output
 from core.memory.token_buffer_memory import TokenBufferMemory
 from core.model_manager import ModelInstance, ModelManager
@@ -340,12 +341,16 @@ class LLMNode(BaseNode[LLMNodeData]):
         usage = LLMUsage.empty_usage()
         finish_reason = None
         full_text_buffer = io.StringIO()
+        # Consume the invoke result and handle generator exception
+        try:
             for result in invoke_result:
                 if isinstance(result, LLMResultChunk):
                     contents = result.delta.message.content
                     for text_part in self._save_multimodal_output_and_convert_result_to_markdown(contents):
                         full_text_buffer.write(text_part)
-                    yield RunStreamChunkEvent(chunk_content=text_part, from_variable_selector=[self.node_id, "text"])
+                        yield RunStreamChunkEvent(
+                            chunk_content=text_part, from_variable_selector=[self.node_id, "text"]
+                        )
 
                     # Update the whole metadata
                     if not model and result.model:
@@ -360,6 +365,8 @@ class LLMNode(BaseNode[LLMNodeData]):
                         finish_reason = result.delta.finish_reason
                 elif isinstance(result, LLMStructuredOutput):
                     yield result
+        except OutputParserError as e:
+            raise LLMNodeError(f"Failed to parse structured output: {e}")
 
         yield ModelInvokeCompletedEvent(text=full_text_buffer.getvalue(), usage=usage, finish_reason=finish_reason)