Files
LangBot/src/langbot/pkg/workflow/nodes/llm_call.py
Typer_Body 6609bebeec platfrom
2026-06-04 03:13:32 +08:00

842 lines
34 KiB
Python

"""LLM Call Node - invoke large language model with Agent capabilities.
Supports:
- Primary model with fallback models
- Knowledge base retrieval with reranking
- Max round context control
- Streaming output
"""
from __future__ import annotations
import json
import logging
import re
import time
from typing import Any, AsyncGenerator
import langbot_plugin.api.entities.builtin.provider.message as provider_message
import langbot_plugin.api.entities.builtin.rag.context as rag_context
from langbot_plugin.api.entities.builtin.workflow.entities import ExecutionContext
from ..node import WorkflowNode, workflow_node
from .. import monitoring_helper
logger = logging.getLogger(__name__)
# Pre-compiled regex patterns for CoT content removal (performance optimization)
_THINK_PATTERNS = [
re.compile(r'<think>.*?</think>', re.DOTALL | re.IGNORECASE),
re.compile(r'<thought>.*?</thought>', re.DOTALL | re.IGNORECASE),
re.compile(r'<reasoning>.*?</reasoning>', re.DOTALL | re.IGNORECASE),
re.compile(r'<\u601d\u8003>.*?</\u601d\u8003>', re.DOTALL | re.IGNORECASE),
re.compile(r'<\u63a8\u7406>.*?</\u63a8\u7406>', re.DOTALL | re.IGNORECASE),
]
# Template variable regex
_TEMPLATE_VAR_RE = re.compile(r'\{\{([^}]+)\}\}')
@workflow_node('llm_call')
class LLMCallNode(WorkflowNode):
"""LLM call node - invoke large language model"""
category = 'process'
def _resolve_template(self, template: str, inputs: dict[str, Any], context: ExecutionContext) -> str:
"""Resolve {{variable}} placeholders in a template string."""
if not template:
return ''
unresolved_vars = []
def replacer(match: re.Match) -> str:
expr = match.group(1).strip()
# Try inputs first
if expr in inputs:
return str(inputs[expr])
# Try context variables
if expr.startswith('variables.'):
var_name = expr[len('variables.'):]
return str(context.variables.get(var_name, ''))
# Try message context
if expr.startswith('message.') and context.message_context:
attr = expr[len('message.'):]
return str(getattr(context.message_context, attr, ''))
unresolved_vars.append(expr)
return match.group(0) # leave unresolved
result = _TEMPLATE_VAR_RE.sub(replacer, template)
# Log warning for unresolved variables
if unresolved_vars:
logger.warning(
f'LLM call node {self.node_id}: unresolved template variables: {unresolved_vars}'
)
return result
def _remove_think_content(self, text: str) -> str:
"""Remove CoT (Chain of Thought) thinking content from response."""
if not text:
return text
result = text
for pattern in _THINK_PATTERNS:
result = pattern.sub('', result)
return result.strip()
def _apply_content_filter(self, text: str) -> tuple[str, bool, str]:
"""Apply content safety filter to text.
Returns:
(filtered_text, is_blocked, user_notice)
"""
if not text or not self.ap:
return text, False, ''
# Check if content filter is enabled
safety_config = getattr(self.ap, 'pipeline_cfg', None)
if not safety_config:
return text, False, ''
# Check sensitive words
sensitive_words = []
try:
if hasattr(self.ap, 'sensitive_meta') and hasattr(self.ap.sensitive_meta, 'data'):
sensitive_words = self.ap.sensitive_meta.data.get('words', [])
except Exception as e:
logger.warning("Failed to load sensitive words from sensitive_meta: %s", e)
sensitive_words = []
if not sensitive_words:
return text, False, ''
found = False
filtered_text = text
for word in sensitive_words:
try:
matches = re.findall(word, filtered_text, re.IGNORECASE)
if matches:
found = True
mask_word = ''
mask = '*'
try:
if hasattr(self.ap, 'sensitive_meta') and hasattr(self.ap.sensitive_meta, 'data'):
mask_word = self.ap.sensitive_meta.data.get('mask_word', '')
mask = self.ap.sensitive_meta.data.get('mask', '*')
except Exception as e:
# Keep default mask settings when sensitive metadata is unavailable or malformed.
logger.debug(
f'LLM call node {self.node_id}: failed to read sensitive mask config, using defaults: {e}'
)
for m in matches:
if mask_word:
filtered_text = filtered_text.replace(m, mask_word)
else:
filtered_text = filtered_text.replace(m, mask * len(m))
except re.error:
# Invalid regex pattern, skip
continue
if found:
return filtered_text, False, '消息中存在不合适的内容, 请修改'
return text, False, ''
# RAG combined prompt template (same as localagent.py)
RAG_COMBINED_PROMPT_TEMPLATE = """
The following are relevant context entries retrieved from the knowledge base.
Please use them to answer the user's message.
Respond in the same language as the user's input.
<context>
{rag_context}
</context>
<user_message>
{user_message}
</user_message>
"""
def _build_system_prompt_with_format(self, base_prompt: str, output_format: str, json_schema: str) -> str:
"""Build system prompt with output format instructions."""
prompt = base_prompt
if output_format == 'json':
prompt += '\n\nPlease respond in valid JSON format.'
if json_schema:
prompt += f'\nFollow this JSON schema:\n{json_schema}'
elif output_format == 'markdown':
prompt += '\n\nPlease respond in Markdown format.'
return prompt
def _build_messages_from_prompt_array(
self,
prompt_array: list[dict],
inputs: dict[str, Any],
context: ExecutionContext,
output_format: str,
json_schema: str,
) -> list[provider_message.Message]:
"""Build messages list from prompt array (same format as pipeline).
Each item in prompt_array is {role: str, content: str}.
Resolves template variables in content.
"""
messages: list[provider_message.Message] = []
for item in prompt_array:
role = item.get('role', 'user')
content = item.get('content', '')
# Resolve template variables in content
resolved_content = self._resolve_template(content, inputs, context)
# Apply format instructions to system prompt
if role == 'system':
resolved_content = self._build_system_prompt_with_format(
resolved_content, output_format, json_schema
)
messages.append(provider_message.Message(role=role, content=resolved_content))
return messages
async def _get_model_candidates(self, model_uuid: str, fallback_models: list) -> list:
"""Build ordered list of models to try: primary model + fallback models."""
candidates = []
# Primary model
if model_uuid:
try:
primary = await self.ap.model_mgr.get_model_by_uuid(model_uuid)
candidates.append(primary)
except ValueError:
logger.warning(f'[LLM:{self.node_id}] Primary model {model_uuid} not found')
# Fallback models
for fb_uuid in fallback_models:
try:
fb_model = await self.ap.model_mgr.get_model_by_uuid(fb_uuid)
candidates.append(fb_model)
except ValueError:
logger.warning(f'[LLM:{self.node_id}] Fallback model {fb_uuid} not found, skipping')
return candidates
async def _invoke_with_fallback(
self,
candidates: list,
messages: list,
funcs: list | None,
extra_args: dict,
) -> tuple[Any, Any, dict]:
"""Try non-streaming invocation with sequential fallback. Returns (message, model_used, usage_info)."""
last_error = None
for model in candidates:
try:
result = await model.provider.invoke_llm(
query=None,
model=model,
messages=messages,
funcs=funcs if model.model_entity.abilities.__contains__('func_call') else [],
extra_args=extra_args,
)
# invoke_llm returns (message, usage_info) tuple
if isinstance(result, tuple) and len(result) == 2:
msg, usage_info = result
else:
msg = result
usage_info = {}
return msg, model, usage_info
except Exception as e:
last_error = e
logger.warning(f'[LLM:{self.node_id}] Model {model.model_entity.name} failed: {e}, trying next...')
raise last_error or RuntimeError('No model candidates available')
async def _retrieve_knowledge(
self,
user_message_text: str,
knowledge_bases: list[str],
rerank_model_uuid: str,
rerank_top_k: int,
) -> str:
"""Retrieve from knowledge bases and optionally rerank results.
Returns the enhanced user message text with RAG context, or original text if no results.
"""
if not knowledge_bases or not user_message_text:
return user_message_text
all_results: list[rag_context.RetrievalResultEntry] = []
# Retrieve from each knowledge base
for kb_uuid in knowledge_bases:
try:
kb = await self.ap.rag_mgr.get_knowledge_base_by_uuid(kb_uuid)
if not kb:
logger.warning(f'[LLM:{self.node_id}] Knowledge base {kb_uuid} not found, skipping')
continue
result = await kb.retrieve(user_message_text, settings={})
if result:
all_results.extend(result)
except Exception as e:
logger.warning(f'[LLM:{self.node_id}] Failed to retrieve from KB {kb_uuid}: {e}')
# Rerank step: re-score results using a rerank model if configured
if all_results and rerank_model_uuid:
try:
rerank_model = await self.ap.model_mgr.get_rerank_model_by_uuid(rerank_model_uuid)
doc_texts = []
for entry in all_results:
text = ' '.join(c.text for c in entry.content if c.type == 'text' and c.text)
doc_texts.append(text)
doc_texts_capped = doc_texts[:64] # Cap for reranker input
scores = await rerank_model.provider.invoke_rerank(
model=rerank_model,
query=user_message_text,
documents=doc_texts_capped,
)
scored = sorted(scores, key=lambda x: x.get('relevance_score', 0), reverse=True)
top_indices = [s['index'] for s in scored[:rerank_top_k] if s['index'] < len(all_results)]
all_results = [all_results[i] for i in top_indices]
logger.info(
f'[LLM:{self.node_id}] Rerank complete: {len(doc_texts)} docs -> top {len(all_results)} kept (top_k={rerank_top_k})'
)
except ValueError:
logger.warning(f'[LLM:{self.node_id}] Rerank model {rerank_model_uuid} not found, skipping rerank')
except Exception as e:
logger.warning(f'[LLM:{self.node_id}] Rerank failed, using original order: {e}')
# Build RAG context text
if all_results:
texts = []
idx = 1
for entry in all_results:
for content in entry.content:
if content.type == 'text' and content.text is not None:
texts.append(f'[{idx}] {content.text}')
idx += 1
rag_context_text = '\n\n'.join(texts)
return self.RAG_COMBINED_PROMPT_TEMPLATE.format(
rag_context=rag_context_text,
user_message=user_message_text,
)
return user_message_text
def _build_messages_with_history(
self,
system_prompt: str,
user_message_text: str,
context: ExecutionContext,
max_round: int,
) -> list[provider_message.Message]:
"""Build messages list with conversation history up to max_round."""
messages: list[provider_message.Message] = []
# Add system prompt
if system_prompt:
messages.append(provider_message.Message(role='system', content=system_prompt))
# Get conversation history from context
conversation_history = context.variables.get('_conversation_history', [])
# Apply max_round limit (each round = 1 user + 1 assistant message)
if max_round > 0 and conversation_history:
# Keep only the last max_round * 2 messages (user + assistant pairs)
max_messages = max_round * 2
if len(conversation_history) > max_messages:
conversation_history = conversation_history[-max_messages:]
# Add conversation history
for msg in conversation_history:
if isinstance(msg, dict):
role = msg.get('role', 'user')
content = msg.get('content', '')
messages.append(provider_message.Message(role=role, content=content))
elif hasattr(msg, 'role') and hasattr(msg, 'content'):
messages.append(provider_message.Message(role=msg.role, content=msg.content))
# Add current user message
messages.append(provider_message.Message(role='user', content=user_message_text))
return messages
def _save_to_conversation_history(
self,
context: ExecutionContext,
user_message_text: str,
response_text: str,
max_round: int,
) -> None:
"""Save the exchange to conversation history."""
if max_round <= 0:
return
history = context.variables.get('_conversation_history', [])
history.append({'role': 'user', 'content': user_message_text})
history.append({'role': 'assistant', 'content': response_text})
# Enforce max_round limit
max_messages = max_round * 2
if len(history) > max_messages:
history = history[-max_messages:]
context.variables['_conversation_history'] = history
async def execute(self, inputs: dict[str, Any], context: ExecutionContext) -> dict[str, Any]:
# Support both new model_config format and legacy model + fallback_models format
model_config = self.get_config('model_config', None)
if model_config and isinstance(model_config, dict):
# New format: {primary: uuid, fallbacks: [uuid1, uuid2, ...]}
model_uuid = model_config.get('primary', '')
fallback_models = model_config.get('fallbacks', [])
else:
# Legacy format: separate model and fallback_models
model_uuid = self.get_config('model', '')
fallback_models = self.get_config('fallback_models', [])
if not model_uuid:
raise ValueError('No model configured for LLM call node')
if not self.ap:
raise RuntimeError('Application instance not available - cannot call LLM')
# Get error handling config
exception_handling = self.get_config('exception_handling', 'show-error')
failure_hint = self.get_config('failure_hint', 'Request failed.')
track_function_calls = self.get_config('track_function_calls', False)
# Get output format and json_schema config
output_format = self.get_config('output_format', 'text')
json_schema = self.get_config('json_schema', '')
# Agent config: knowledge bases, rerank, max_round
# (fallback_models already resolved above from model_config or fallback_models)
knowledge_bases = self.get_config('knowledge_bases', [])
rerank_model = self.get_config('rerank_model', '')
rerank_top_k = self.get_config('rerank_top_k', 5)
max_round = self.get_config('max_round', 10)
# Resolve prompts - support both new prompt array format and legacy format
prompt_array = self.get_config('prompt')
user_prompt = '' # Initialize for later use in _save_to_conversation_history
if prompt_array and isinstance(prompt_array, list):
# New format: prompt array like pipeline
messages = self._build_messages_from_prompt_array(
prompt_array, inputs, context, output_format, json_schema
)
# Get user input text for knowledge retrieval
user_input = inputs.get('input', '')
# Knowledge retrieval: enhance user input with RAG context
user_input = await self._retrieve_knowledge(
user_message_text=user_input,
knowledge_bases=knowledge_bases,
rerank_model_uuid=rerank_model,
rerank_top_k=rerank_top_k,
)
# Track user_prompt for conversation history
user_prompt = user_input
# Add user input as last message
if user_input:
messages.append(provider_message.Message(role='user', content=user_input))
# Apply max_round to conversation history
conversation_history = context.variables.get('_conversation_history', [])
if max_round > 0 and conversation_history:
max_messages = max_round * 2
if len(conversation_history) > max_messages:
conversation_history = conversation_history[-max_messages:]
# Insert conversation history before user input
history_messages = []
for msg in conversation_history:
if isinstance(msg, dict):
role = msg.get('role', 'user')
content = msg.get('content', '')
history_messages.append(provider_message.Message(role=role, content=content))
elif hasattr(msg, 'role') and hasattr(msg, 'content'):
history_messages.append(provider_message.Message(role=msg.role, content=msg.content))
# Insert history before user message
if history_messages and len(messages) > 0:
messages = messages[:-1] + history_messages + [messages[-1]]
else:
# Legacy format: separate system_prompt and user_prompt_template
system_prompt = self._resolve_template(self.get_config('system_prompt') or '', inputs, context)
user_prompt_template = self.get_config('user_prompt_template')
if user_prompt_template is None:
user_prompt_template = '{{input}}'
user_prompt = self._resolve_template(user_prompt_template, inputs, context)
# Build system prompt with format instructions
system_prompt = self._build_system_prompt_with_format(system_prompt, output_format, json_schema)
# Knowledge retrieval: enhance user prompt with RAG context
user_prompt = await self._retrieve_knowledge(
user_message_text=user_prompt,
knowledge_bases=knowledge_bases,
rerank_model_uuid=rerank_model,
rerank_top_k=rerank_top_k,
)
# Build messages with conversation history
messages = self._build_messages_with_history(
system_prompt=system_prompt,
user_message_text=user_prompt,
context=context,
max_round=max_round,
)
# Get model candidates (primary + fallbacks)
candidates = await self._get_model_candidates(model_uuid, fallback_models)
if not candidates:
raise ValueError('No valid model candidates available')
# Build extra args from config
extra_args: dict[str, Any] = {}
temperature = self.get_config('temperature')
if temperature is not None:
extra_args['temperature'] = float(temperature)
max_tokens = self.get_config('max_tokens', 0)
if max_tokens and int(max_tokens) > 0:
extra_args['max_tokens'] = int(max_tokens)
# Track start time for duration calculation
self._llm_start_time = time.time()
# Invoke LLM with fallback
try:
result_message, used_model, llm_usage = await self._invoke_with_fallback(
candidates=candidates,
messages=messages,
funcs=None,
extra_args=extra_args,
)
except Exception as e:
logger.warning(f'[LLM:{self.node_id}] LLM call failed: {e}')
# Handle based on exception handling strategy
if exception_handling == 'show-error':
raise
elif exception_handling == 'show-hint':
return {
'response': failure_hint,
'usage': {
'prompt_tokens': 0,
'completion_tokens': 0,
'total_tokens': 0,
},
'error': str(e),
'error_hint_shown': True,
}
else: # hide
return {
'response': '',
'usage': {
'prompt_tokens': 0,
'completion_tokens': 0,
'total_tokens': 0,
},
'error': str(e),
}
# Extract response text
response_text = ''
if isinstance(result_message.content, str):
response_text = result_message.content
elif isinstance(result_message.content, list):
for elem in result_message.content:
if hasattr(elem, 'text') and elem.text:
response_text += elem.text
elif isinstance(elem, str):
response_text += elem
# Remove CoT content (always remove to avoid leaking internal reasoning)
response_text = self._remove_think_content(response_text)
# Initialize usage default
usage = {
'prompt_tokens': 0,
'completion_tokens': 0,
'total_tokens': 0,
}
# Apply content safety filter
response_text, is_blocked, filter_notice = self._apply_content_filter(response_text)
if is_blocked:
logger.warning(f'[LLM:{self.node_id}] Response blocked by content filter: {filter_notice}')
return {
'response': filter_notice,
'usage': usage,
'blocked_by_filter': True,
}
# Extract usage info from LLM call result
# Priority: llm_usage (from _invoke_with_fallback) > result_message.usage > result_message.token_usage
if llm_usage:
usage = {
'prompt_tokens': llm_usage.get('input_tokens', 0) or llm_usage.get('prompt_tokens', 0),
'completion_tokens': llm_usage.get('output_tokens', 0) or llm_usage.get('completion_tokens', 0),
'total_tokens': llm_usage.get('total_tokens', 0),
}
# Check result_message.usage (set by RuntimeProvider.invoke_llm)
elif hasattr(result_message, 'usage') and result_message.usage:
u = result_message.usage
if isinstance(u, dict):
usage = {
'prompt_tokens': u.get('input_tokens', 0) or u.get('prompt_tokens', 0),
'completion_tokens': u.get('output_tokens', 0) or u.get('completion_tokens', 0),
'total_tokens': u.get('total_tokens', 0),
}
else:
usage = {
'prompt_tokens': getattr(u, 'input_tokens', 0) or getattr(u, 'prompt_tokens', 0),
'completion_tokens': getattr(u, 'output_tokens', 0) or getattr(u, 'completion_tokens', 0),
'total_tokens': getattr(u, 'total_tokens', 0),
}
elif hasattr(result_message, 'token_usage') and result_message.token_usage:
u = result_message.token_usage
if isinstance(u, dict):
usage = {
'prompt_tokens': u.get('prompt_tokens', 0) or 0,
'completion_tokens': u.get('completion_tokens', 0) or 0,
'total_tokens': u.get('total_tokens', 0) or 0,
}
else:
usage = {
'prompt_tokens': getattr(u, 'prompt_tokens', 0) or 0,
'completion_tokens': getattr(u, 'completion_tokens', 0) or 0,
'total_tokens': getattr(u, 'total_tokens', 0) or 0,
}
# Log successful response (matching Pipeline's cut_str behavior)
def _cut_str(s: str) -> str:
s0 = s.split('\n')[0]
if len(s0) > 20 or '\n' in s:
s0 = s0[:20] + '...'
return s0
logger.info(f'[LLM:{self.node_id}] Response: {_cut_str(response_text)}')
# Record LLM call log only (response log is redundant)
try:
if self.ap and context.query:
workflow_id = context.workflow_id or ''
workflow_name = context.variables.get('_workflow_name', 'Workflow')
bot_name = context.variables.get('_bot_name', 'Workflow')
node_name = self.get_config('name', self.node_id)
model_name = used_model.model_entity.name if used_model else 'unknown'
# Calculate duration
duration_ms = 0
if hasattr(self, '_llm_start_time'):
duration_ms = int((time.time() - self._llm_start_time) * 1000)
# Get message_id for LLM call association
message_id = context.variables.get('_monitoring_message_id')
# Record LLM call log with message_id association
await monitoring_helper.WorkflowMonitoringHelper.record_llm_call_log(
ap=self.ap,
query=context.query,
workflow_id=workflow_id,
workflow_name=workflow_name,
node_name=node_name,
model_name=model_name,
input_tokens=usage.get('prompt_tokens', 0),
output_tokens=usage.get('completion_tokens', 0),
duration_ms=duration_ms,
status='success',
bot_name=bot_name,
context_vars=context.variables,
message_id=message_id,
)
except Exception as e:
logger.warning(f'[LLM:{self.node_id}] Failed to record LLM logs: {e}')
# Save to conversation history
self._save_to_conversation_history(
context=context,
user_message_text=user_prompt,
response_text=response_text,
max_round=max_round,
)
# Build result
result: dict[str, Any] = {
'response': response_text,
'usage': usage,
'model_used': used_model.model_entity.name if used_model else None,
'model_uuid': used_model.model_entity.uuid if used_model else None,
}
# Parse JSON output if format is json
if output_format == 'json' and response_text:
try:
result['parsed'] = json.loads(response_text)
except json.JSONDecodeError as e:
logger.warning(f'[LLM:{self.node_id}] Failed to parse JSON: {e}')
result['parsed'] = None
result['parse_error'] = str(e)
# Add function call tracking info if configured
if track_function_calls:
result['function_calls'] = []
return result
async def execute_stream(
self, inputs: dict[str, Any], context: ExecutionContext
) -> AsyncGenerator[str, None]:
"""Execute the LLM call with streaming output.
Yields chunks of response text as they arrive.
Falls back to non-streaming if streaming is not available.
"""
# Support both new model_config format and legacy model + fallback_models format
model_config = self.get_config('model_config', None)
if model_config and isinstance(model_config, dict):
model_uuid = model_config.get('primary', '')
else:
model_uuid = self.get_config('model', '')
if not model_uuid:
raise ValueError('No model configured for LLM call node')
if not self.ap:
raise RuntimeError('Application instance not available - cannot call LLM')
exception_handling = self.get_config('exception_handling', 'show-error')
failure_hint = self.get_config('failure_hint', 'Request failed.')
# Resolve prompts - support both new prompt array format and legacy format
prompt_array = self.get_config('prompt')
if prompt_array and isinstance(prompt_array, list):
# New format: prompt array like pipeline
messages = self._build_messages_from_prompt_array(
prompt_array, inputs, context, 'text', '' # No format instructions for streaming
)
# Add user input
user_input = inputs.get('input', '')
if user_input:
messages.append(provider_message.Message(role='user', content=user_input))
else:
# Legacy format
system_prompt = self._resolve_template(self.get_config('system_prompt') or '', inputs, context)
user_prompt_template = self.get_config('user_prompt_template')
if user_prompt_template is None:
user_prompt_template = '{{input}}'
user_prompt = self._resolve_template(user_prompt_template, inputs, context)
# Build messages
messages = []
if system_prompt:
messages.append(provider_message.Message(role='system', content=system_prompt))
messages.append(provider_message.Message(role='user', content=user_prompt))
# Get model
runtime_model = await self.ap.model_mgr.get_model_by_uuid(model_uuid)
# Build extra args
extra_args: dict[str, Any] = {}
temperature = self.get_config('temperature')
if temperature is not None:
extra_args['temperature'] = float(temperature)
max_tokens = self.get_config('max_tokens', 0)
if max_tokens and int(max_tokens) > 0:
extra_args['max_tokens'] = int(max_tokens)
logger.info(f'[LLM:{self.node_id}] Streaming model {model_uuid}')
try:
# Try streaming first
stream = runtime_model.provider.invoke_llm_stream(
query=None,
model=runtime_model,
messages=messages,
funcs=None,
extra_args=extra_args,
)
full_response = ''
in_think_block = False
async for chunk in stream:
chunk_text = ''
if hasattr(chunk, 'content'):
if isinstance(chunk.content, str):
chunk_text = chunk.content
elif isinstance(chunk.content, list):
for elem in chunk.content:
if hasattr(elem, 'text') and elem.text:
chunk_text += elem.text
elif isinstance(elem, str):
chunk_text += elem
if chunk_text:
# Filter <think> blocks in streaming mode
if '<think>' in chunk_text or '<thought>' in chunk_text:
in_think_block = True
if in_think_block:
if '</think>' in chunk_text or '</thought>' in chunk_text:
in_think_block = False
chunk_text = chunk_text.split('</think>')[-1].split('</thought>')[-1]
else:
chunk_text = ''
if chunk_text:
full_response += chunk_text
yield chunk_text
# Store in context for downstream nodes
context.variables['_last_llm_response'] = full_response
except Exception as e:
logger.warning(f'[LLM:{self.node_id}] Streaming failed, falling back - {e}')
# Fallback to non-streaming
try:
result_message = await runtime_model.provider.invoke_llm(
query=None,
model=runtime_model,
messages=messages,
funcs=None,
extra_args=extra_args,
)
response_text = self._extract_response_text(result_message)
# Always remove <think> content in fallback
response_text = self._remove_think_content(response_text)
yield response_text
context.variables['_last_llm_response'] = response_text
except Exception as e2:
logger.error(f'[LLM:{self.node_id}] Fallback also failed - {e2}')
if exception_handling == 'show-hint':
yield failure_hint
elif exception_handling != 'hide':
raise
def _extract_response_text(self, result_message: provider_message.Message) -> str:
"""Extract response text from LLM result message."""
response_text = ''
if isinstance(result_message.content, str):
response_text = result_message.content
elif isinstance(result_message.content, list):
for elem in result_message.content:
if hasattr(elem, 'text') and elem.text:
response_text += elem.text
elif isinstance(elem, str):
response_text += elem
return response_text