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Python

"""
LLM 服务
"""
import logging
from typing import AsyncGenerator, Dict, List, Optional
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from ai_platform.providers import (
BaseLLMProvider,
LLMConfig,
LLMMessage,
LLMResponse,
ProviderRegistry,
)
from ai_platform.providers.base import LLMStreamChunk, ToolDefinition
logger = logging.getLogger(__name__)
class LLMService:
"""
LLM 服务
统一管理 LLM 调用,支持多种提供商
"""
def __init__(self, db: Optional[AsyncSession] = None):
self._provider_cache: Dict[str, BaseLLMProvider] = {}
self._db = db
@staticmethod
def _is_missing_model_id(model_id: Optional[str]) -> bool:
if model_id is None:
return True
return str(model_id).strip().lower() in {"", "none", "null", "undefined"}
async def resolve_chat_model_id(self, model_id: Optional[str]) -> str:
"""解析 chat 模型。未指定时使用当前启用的默认 chat 模型。"""
if not self._is_missing_model_id(model_id):
return str(model_id)
if not self._db:
raise ValueError("未找到可用的 chat 模型,请先在模型配置中启用一个模型")
from ai_platform.models import LLMModel, LLMProvider
result = await self._db.execute(
select(LLMModel)
.join(LLMProvider, LLMProvider.id == LLMModel.provider_id)
.where(
LLMModel.is_deleted == False,
LLMModel.is_active == True,
LLMModel.model_type == "chat",
LLMProvider.is_deleted == False,
LLMProvider.is_active == True,
)
.order_by(LLMModel.sort.desc(), LLMModel.sys_create_datetime.desc())
)
model = result.scalars().first()
if not model:
raise ValueError("未找到可用的 chat 模型,请先在模型配置中启用一个模型")
logger.info("No model_id supplied, fallback to default chat model %s", model.id)
return str(model.id)
@staticmethod
def _run_async_sync(coro):
import asyncio
import concurrent.futures
try:
loop = asyncio.get_event_loop()
except RuntimeError:
return asyncio.run(coro)
if loop.is_running():
with concurrent.futures.ThreadPoolExecutor() as executor:
return executor.submit(asyncio.run, coro).result()
return loop.run_until_complete(coro)
def resolve_chat_model_id_sync(self, model_id: Optional[str]) -> str:
"""同步解析 chat 模型,供同步节点和流式生成器复用。"""
return self._run_async_sync(self.resolve_chat_model_id(model_id))
async def _get_provider_async(self, model_id: str) -> tuple:
"""
异步获取模型对应的提供商实例
Args:
model_id: 模型 ID
Returns:
(provider, model_name)
"""
from ai_platform.models import LLMModel, LLMProvider
if not self._db:
raise ValueError("数据库会话未初始化")
model_id = await self.resolve_chat_model_id(model_id)
# 查询模型
result = await self._db.execute(
select(LLMModel).where(
LLMModel.id == model_id,
LLMModel.is_active == True,
LLMModel.is_deleted == False
)
)
model = result.scalar_one_or_none()
if not model:
raise ValueError(f'模型不存在或已禁用: {model_id}')
# 查询提供商
provider_result = await self._db.execute(
select(LLMProvider).where(LLMProvider.id == model.provider_id)
)
provider = provider_result.scalar_one_or_none()
if not provider or not provider.is_active:
raise ValueError(f'提供商不存在或已禁用')
# 缓存提供商实例
cache_key = str(provider.id)
if cache_key not in self._provider_cache:
provider_instance = ProviderRegistry.create_instance(
provider_type=provider.provider_type,
api_key=provider.api_key,
api_base=provider.api_base or "",
ollama_host=provider.ollama_host or "",
)
if not provider_instance:
raise ValueError(f'不支持的提供商类型: {provider.provider_type}')
self._provider_cache[cache_key] = provider_instance
provider_instance = self._provider_cache[cache_key]
setattr(provider_instance, 'config_name', provider.name or provider.provider_type)
setattr(provider_instance, 'config_id', str(provider.id))
setattr(provider_instance, 'config_api_base', provider.api_base or '')
return provider_instance, model.model_name
def _get_provider_sync(self, model_id: str, model_data: dict) -> tuple:
"""
同步获取提供商实例(使用预加载的数据)
Args:
model_id: 模型 ID
model_data: 预加载的模型和提供商数据
Returns:
(provider, model_name)
"""
provider_type = model_data.get('provider_type')
api_key = model_data.get('api_key', '')
api_base = model_data.get('api_base', '')
ollama_host = model_data.get('ollama_host', '')
model_name = model_data.get('model_name', '')
provider_id = model_data.get('provider_id', '')
# 缓存提供商实例
cache_key = str(provider_id)
if cache_key not in self._provider_cache:
provider_instance = ProviderRegistry.create_instance(
provider_type=provider_type,
api_key=api_key,
api_base=api_base,
ollama_host=ollama_host,
)
if not provider_instance:
raise ValueError(f'不支持的提供商类型: {provider_type}')
self._provider_cache[cache_key] = provider_instance
provider_instance = self._provider_cache[cache_key]
setattr(provider_instance, 'config_name', model_data.get('provider_name') or provider_type)
setattr(provider_instance, 'config_id', str(provider_id))
setattr(provider_instance, 'config_api_base', api_base or '')
return provider_instance, model_name
@staticmethod
def _extract_upstream_message(error_text: str) -> str:
import re
for pattern in (
r"'message'\s*:\s*'([^']+)'",
r'"message"\s*:\s*"([^"]+)"',
):
match = re.search(pattern, error_text)
if match:
return match.group(1)
return error_text[:240]
def _format_provider_error(
self,
exc: Exception,
provider: Optional[BaseLLMProvider] = None,
model_name: str = '',
) -> str:
error_text = str(exc)
lower_text = error_text.lower()
provider_name = (
getattr(provider, 'config_name', '')
or getattr(provider, 'provider_name', '')
or '未知提供商'
)
model_text = model_name or '未知模型'
if (
'401' in lower_text
or 'unauthorized' in lower_text
or 'invalid api key' in lower_text
or 'incorrect api key' in lower_text
or '无效的令牌' in error_text
or '鉴权' in error_text
):
reason = '上游模型鉴权失败,API Key 无效或已过期'
elif (
'404' in lower_text
or 'model_not_found' in lower_text
or 'model not found' in lower_text
or 'does not exist' in lower_text
):
reason = '上游模型不存在或当前账号无权访问该模型'
elif 'timeout' in lower_text or 'timed out' in lower_text or '超时' in error_text:
reason = '上游模型请求超时'
elif 'rate limit' in lower_text or '429' in lower_text or 'quota' in lower_text:
reason = '上游模型限流或额度不足'
else:
reason = '上游模型调用失败'
upstream_message = self._extract_upstream_message(error_text)
return (
f'{reason}:提供商 {provider_name},模型 {model_text}'
f'请在 AI 平台的模型提供商配置中检查 Base URL、API Key 和模型名称。'
f'上游返回:{upstream_message}'
)
def chat_with_provider(
self,
provider: BaseLLMProvider,
model_name: str,
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
) -> LLMResponse:
"""
使用指定提供商进行同步对话
Args:
provider: 提供商实例
model_name: 模型名称
messages: 消息列表 [{"role": "user", "content": "..."}]
temperature: 温度参数
max_tokens: 最大 Token
tools: 工具定义列表 [{"name": "...", "description": "...", "parameters": {...}}]
tool_choice: 工具选择策略 (auto, none, required, 或具体工具名)
**kwargs: 其他参数
Returns:
LLMResponse
"""
llm_messages = self._convert_messages(messages)
# 转换工具定义
tool_definitions = None
if tools:
tool_definitions = [
ToolDefinition(
name=t['name'],
description=t.get('description', ''),
parameters=t.get('parameters', {}),
)
for t in tools
]
config = LLMConfig(
model=model_name,
temperature=temperature,
max_tokens=max_tokens,
tools=tool_definitions,
tool_choice=tool_choice,
**kwargs
)
try:
return provider.chat(llm_messages, config)
except Exception as exc:
raise RuntimeError(self._format_provider_error(exc, provider, model_name)) from exc
def chat(
self,
model_id: Optional[str],
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
) -> LLMResponse:
"""
同步对话入口。
旧节点仍会调用该方法;这里统一走 provider 解析和默认 chat 模型兜底,
避免不同节点各自处理 model_id 为空的情况。
"""
provider, model_name = self._run_async_sync(self._get_provider_async(model_id))
return self.chat_with_provider(
provider=provider,
model_name=model_name,
messages=messages,
temperature=temperature,
max_tokens=max_tokens,
tools=tools,
tool_choice=tool_choice,
**kwargs,
)
def _convert_messages(self, messages: List[Dict]) -> List[LLMMessage]:
"""转换消息格式,支持 tool 消息"""
llm_messages = []
for m in messages:
msg = LLMMessage(
role=m['role'],
content=m.get('content', ''),
name=m.get('name'),
tool_calls=m.get('tool_calls'),
tool_call_id=m.get('tool_call_id'),
)
llm_messages.append(msg)
return llm_messages
async def chat_async(
self,
model_id: str,
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
) -> LLMResponse:
"""
异步对话
Args:
model_id: 模型 ID
messages: 消息列表
temperature: 温度参数
max_tokens: 最大 Token
tools: 工具定义列表
tool_choice: 工具选择策略
**kwargs: 其他参数
Returns:
LLMResponse
"""
provider, model_name = await self._get_provider_async(model_id)
llm_messages = self._convert_messages(messages)
# 转换工具定义
tool_definitions = None
if tools:
tool_definitions = [
ToolDefinition(
name=t['name'],
description=t.get('description', ''),
parameters=t.get('parameters', {}),
)
for t in tools
]
config = LLMConfig(
model=model_name,
temperature=temperature,
max_tokens=max_tokens,
tools=tool_definitions,
tool_choice=tool_choice,
**kwargs
)
try:
return await provider.chat_async(llm_messages, config)
except Exception as exc:
raise RuntimeError(self._format_provider_error(exc, provider, model_name)) from exc
async def chat_stream(
self,
model_id: str,
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
) -> AsyncGenerator[LLMStreamChunk, None]:
"""
异步流式对话
Args:
model_id: 模型 ID
messages: 消息列表
temperature: 温度参数
max_tokens: 最大 Token
tools: 工具定义列表
tool_choice: 工具选择策略
**kwargs: 其他参数
Yields:
LLMStreamChunk
"""
provider, model_name = await self._get_provider_async(model_id)
llm_messages = self._convert_messages(messages)
# 转换工具定义
tool_definitions = None
if tools:
tool_definitions = [
ToolDefinition(
name=t['name'],
description=t.get('description', ''),
parameters=t.get('parameters', {}),
)
for t in tools
]
config = LLMConfig(
model=model_name,
temperature=temperature,
max_tokens=max_tokens,
tools=tool_definitions,
tool_choice=tool_choice,
**kwargs
)
try:
async for chunk in provider.chat_stream(llm_messages, config):
yield chunk
except Exception as exc:
raise RuntimeError(self._format_provider_error(exc, provider, model_name)) from exc
def chat_stream_sync(
self,
model_id: str,
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
):
"""
同步流式对话(生成器)
注意:此方法会在内部运行异步代码来获取 provider,
需要确保 LLMService 初始化时传入了 db_session
Args:
model_id: 模型 ID
messages: 消息列表
temperature: 温度参数
max_tokens: 最大 Token
tools: 工具定义列表
tool_choice: 工具选择策略
**kwargs: 其他参数
Yields:
LLMStreamChunk
"""
import asyncio
import concurrent.futures
# 在同步上下文中运行异步代码获取 provider
async def get_provider():
return await self._get_provider_async(model_id)
try:
loop = asyncio.get_event_loop()
except RuntimeError:
provider, model_name = asyncio.run(get_provider())
else:
if loop.is_running():
# 如果已有事件循环在运行,使用线程池
with concurrent.futures.ThreadPoolExecutor() as executor:
future = executor.submit(asyncio.run, get_provider())
provider, model_name = future.result()
else:
provider, model_name = loop.run_until_complete(get_provider())
# 使用获取到的 provider 进行流式调用
yield from self.chat_stream_sync_with_provider(
provider=provider,
model_name=model_name,
messages=messages,
temperature=temperature,
max_tokens=max_tokens,
tools=tools,
tool_choice=tool_choice,
**kwargs
)
def chat_stream_sync_with_provider(
self,
provider: BaseLLMProvider,
model_name: str,
messages: List[Dict[str, str]],
temperature: float = 0.7,
max_tokens: int = 2048,
tools: List[Dict] = None,
tool_choice: str = 'auto',
**kwargs
):
"""
使用指定提供商进行同步流式对话(生成器)
Args:
provider: 提供商实例
model_name: 模型名称
messages: 消息列表
temperature: 温度参数
max_tokens: 最大 Token
tools: 工具定义列表
tool_choice: 工具选择策略
**kwargs: 其他参数
Yields:
LLMStreamChunk
"""
llm_messages = self._convert_messages(messages)
# 转换工具定义
tool_definitions = None
if tools:
tool_definitions = [
ToolDefinition(
name=t['name'],
description=t.get('description', ''),
parameters=t.get('parameters', {}),
)
for t in tools
]
config = LLMConfig(
model=model_name,
temperature=temperature,
max_tokens=max_tokens,
tools=tool_definitions,
tool_choice=tool_choice,
**kwargs
)
try:
for chunk in provider.chat_stream_sync(llm_messages, config):
yield chunk
except Exception as exc:
raise RuntimeError(self._format_provider_error(exc, provider, model_name)) from exc
@staticmethod
def get_available_providers() -> List[Dict]:
"""获取可用的提供商列表"""
return ProviderRegistry.get_all_types()
@staticmethod
def get_default_models(provider_type: str) -> List[Dict]:
"""获取提供商的默认模型列表"""
return ProviderRegistry.get_default_models(provider_type)