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
@@ -340,26 +341,32 @@ class LLMNode(BaseNode[LLMNodeData]):
         usage = LLMUsage.empty_usage()
         finish_reason = None
         full_text_buffer = io.StringIO()
-        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"])
-
-                # Update the whole metadata
-                if not model and result.model:
-                    model = result.model
-                if len(prompt_messages) == 0:
-                    # TODO(QuantumGhost): it seems that this update has no visable effect.
-                    # What's the purpose of the line below?
-                    prompt_messages = list(result.prompt_messages)
-                if usage.prompt_tokens == 0 and result.delta.usage:
-                    usage = result.delta.usage
-                if finish_reason is None and result.delta.finish_reason:
-                    finish_reason = result.delta.finish_reason
-            elif isinstance(result, LLMStructuredOutput):
-                yield result
+        # 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"]
+                        )
+
+                    # Update the whole metadata
+                    if not model and result.model:
+                        model = result.model
+                    if len(prompt_messages) == 0:
+                        # TODO(QuantumGhost): it seems that this update has no visable effect.
+                        # What's the purpose of the line below?
+                        prompt_messages = list(result.prompt_messages)
+                    if usage.prompt_tokens == 0 and result.delta.usage:
+                        usage = result.delta.usage
+                    if finish_reason is None and result.delta.finish_reason:
+                        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)