追踪 LangGraph 应用 - LangChain中文版文档

LangSmith 与 LangGraph（Python 和 JS）无缝集成，帮助您追踪智能体，无论您使用的是 LangChain 模块还是其他 SDK。

使用 LangChain

如果您在 LangGraph 中使用 LangChain 模块，只需设置几个环境变量即可启用追踪。本指南将演示一个基础示例。有关配置的更多详细信息，请参阅使用 LangChain 进行追踪指南。

1. 安装

安装 LangGraph 库以及 Python 和 JS 的 OpenAI 集成（以下代码片段使用 OpenAI 集成）。有关可用包的完整列表，请参阅 LangChain Python 文档和 LangChain JS 文档。

pip install langchain_openai langgraph

yarn add @langchain/openai @langchain/langgraph

npm install @langchain/openai @langchain/langgraph

pnpm add @langchain/openai @langchain/langgraph

2. 配置环境

export LANGSMITH_TRACING=true
export LANGSMITH_API_KEY=<your-api-key>
# 此示例使用 OpenAI，但您可以选择任何 LLM 提供商
export OPENAI_API_KEY=<your-openai-api-key>
# 对于关联到多个工作空间的 LangSmith API 密钥，设置 LANGSMITH_WORKSPACE_ID 环境变量以指定使用哪个工作空间。
export LANGSMITH_WORKSPACE_ID=<your-workspace-id>

如果您在非无服务器环境中使用 LangChain.js 和 LangSmith，我们还建议显式设置以下变量以减少延迟：export LANGCHAIN_CALLBACKS_BACKGROUND=true如果您在无服务器环境中，建议设置相反的值，以便在函数结束前完成追踪：export LANGCHAIN_CALLBACKS_BACKGROUND=false更多信息请参阅此 LangChain.js 指南。

3. 记录追踪

设置好环境后，您可以正常调用 LangChain 可运行对象。LangSmith 将推断出正确的追踪配置：

from typing import Literal
from langchain.messages import HumanMessage
from langchain_openai import ChatOpenAI
from langchain.tools import tool
from langgraph.prebuilt import ToolNode
from langgraph.graph import StateGraph, MessagesState

@tool
def search(query: str):
    """调用以浏览网页。"""
    if "sf" in query.lower() or "san francisco" in query.lower():
        return "天气是 60 华氏度，有雾。"
    return "天气是 90 华氏度，晴朗。"

tools = [search]
tool_node = ToolNode(tools)

model = ChatOpenAI(model="gpt-4.1", temperature=0).bind_tools(tools)

def should_continue(state: MessagesState) -> Literal["tools", "__end__"]:
    messages = state['messages']
    last_message = messages[-1]
    if last_message.tool_calls:
        return "tools"
    return "__end__"

def call_model(state: MessagesState):
    messages = state['messages']
    # 调用 `model` 将自动推断正确的追踪上下文
    response = model.invoke(messages)
    return {"messages": [response]}

workflow = StateGraph(MessagesState)
workflow.add_node("agent", call_model)
workflow.add_node("tools", tool_node)
workflow.add_edge("__start__", "agent")
workflow.add_conditional_edges(
    "agent",
    should_continue,
)
workflow.add_edge("tools", 'agent')

app = workflow.compile()

final_state = app.invoke(
    {"messages": [HumanMessage(content="what is the weather in sf")]},
    config={"configurable": {"thread_id": 42}}
)

final_state["messages"][-1].content

import { HumanMessage, AIMessage } from "@langchain/core/messages";
import { tool } from "@langchain/core/tools";
import { z } from "zod";
import { ChatOpenAI } from "@langchain/openai";
import { StateGraph, StateGraphArgs } from "@langchain/langgraph";
import { ToolNode } from "@langchain/langgraph/prebuilt";

interface AgentState {
  messages: HumanMessage[];
}

const graphState: StateGraphArgs<AgentState>["channels"] = {
  messages: {
    reducer: (x: HumanMessage[], y: HumanMessage[]) => x.concat(y),
  },
};

const searchTool = tool(async ({ query }: { query: string }) => {
  if (query.toLowerCase().includes("sf") || query.toLowerCase().includes("san francisco")) {
    return "天气是 60 华氏度，有雾。"
  }
  return "天气是 90 华氏度，晴朗。"
}, {
  name: "search",
  description:
    "调用以浏览网页。",
  schema: z.object({
    query: z.string().describe("搜索中使用的查询。"),
  }),
});

const tools = [searchTool];
const toolNode = new ToolNode<AgentState>(tools);

const model = new ChatOpenAI({
  model: "gpt-4.1",
  temperature: 0,
}).bindTools(tools);

function shouldContinue(state: AgentState) {
  const messages = state.messages;
  const lastMessage = messages[messages.length - 1] as AIMessage;
  if (lastMessage.tool_calls?.length) {
    return "tools";
  }
  return "__end__";
}

async function callModel(state: AgentState) {
  const messages = state.messages;
  // 调用 `model` 将自动推断正确的追踪上下文
  const response = await model.invoke(messages);
  return { messages: [response] };
}

const workflow = new StateGraph<AgentState>({ channels: graphState })
  .addNode("agent", callModel)
  .addNode("tools", toolNode)
  .addEdge("__start__", "agent")
  .addConditionalEdges("agent", shouldContinue)
  .addEdge("tools", "agent");

const app = workflow.compile();

const finalState = await app.invoke(
  { messages: [new HumanMessage("what is the weather in sf")] },
  { configurable: { thread_id: "42" } }
);

finalState.messages[finalState.messages.length - 1].content;

查看追踪

详细信息视图 点击追踪，并在右上角切换到 详细信息 视图。您在 LangSmith 中的追踪应看起来像这样。 消息视图 LangSmith UI 中的消息视图显示了用户与智能体之间的简化对话历史。此视图从顶层追踪（包括用户的初始请求、工具调用和智能体的最终响应）中提取消息，并以类似聊天的格式呈现。

不使用 LangChain

如果您在 LangGraph 中使用其他 SDK 或自定义函数，您将需要适当地包装或装饰它们（在 Python 中使用 @traceable 装饰器，在 JS 中使用 traceable 函数，或类似 wrap_openai 的方法）。如果这样做，LangSmith 将自动嵌套来自这些包装方法的追踪。以下是一个示例。您也可以查看此页面获取更多信息。

1. 安装

安装 LangGraph 库以及 Python 和 JS 的 OpenAI SDK（以下代码片段使用 OpenAI 集成）。

pip install openai langsmith langgraph

yarn add openai langsmith @langchain/langgraph

npm install openai langsmith @langchain/langgraph

pnpm add openai langsmith @langchain/langgraph

2. 配置环境

export LANGSMITH_TRACING=true
export LANGSMITH_API_KEY=<your-api-key>
# 此示例使用 OpenAI，但您可以选择任何 LLM 提供商
export OPENAI_API_KEY=<your-openai-api-key>

3. 记录追踪

设置好环境后，包装或装饰您想要追踪的自定义函数/SDK。LangSmith 随后将推断出正确的追踪配置：

import json
import openai
import operator
from langsmith import traceable
from langsmith.wrappers import wrap_openai
from typing import Annotated, Literal, TypedDict
from langgraph.graph import StateGraph

class State(TypedDict):
    messages: Annotated[list, operator.add]

tool_schema = {
    "type": "function",
    "function": {
        "name": "search",
        "description": "调用以浏览网页。",
        "parameters": {
            "type": "object",
            "properties": {"query": {"type": "string"}},
            "required": ["query"],
        },
    },
}

# 装饰工具函数将自动使用正确的上下文进行追踪
@traceable(run_type="tool", name="Search Tool")
def search(query: str):
    """调用以浏览网页。"""
    if "sf" in query.lower() or "san francisco" in query.lower():
        return "天气是 60 华氏度，有雾。"
    return "天气是 90 华氏度，晴朗。"

tools = [search]

def call_tools(state):
    function_name_to_function = {"search": search}
    messages = state["messages"]
    tool_call = messages[-1]["tool_calls"][0]
    function_name = tool_call["function"]["name"]
    function_arguments = tool_call["function"]["arguments"]
    arguments = json.loads(function_arguments)
    function_response = function_name_to_function[function_name](**arguments)
    tool_message = {
        "tool_call_id": tool_call["id"],
        "role": "tool",
        "name": function_name,
        "content": function_response,
    }
    return {"messages": [tool_message]}

wrapped_client = wrap_openai(openai.Client())

def should_continue(state: State) -> Literal["tools", "__end__"]:
    messages = state["messages"]
    last_message = messages[-1]
    if last_message["tool_calls"]:
        return "tools"
    return "__end__"

def call_model(state: State):
    messages = state["messages"]
    # 调用包装后的客户端将自动推断正确的追踪上下文
    response = wrapped_client.chat.completions.create(
        messages=messages, model="gpt-4.1-mini", tools=[tool_schema]
    )
    raw_tool_calls = response.choices[0].message.tool_calls
    tool_calls = [tool_call.to_dict() for tool_call in raw_tool_calls] if raw_tool_calls else []
    response_message = {
        "role": "assistant",
        "content": response.choices[0].message.content,
        "tool_calls": tool_calls,
    }
    return {"messages": [response_message]}

workflow = StateGraph(State)
workflow.add_node("agent", call_model)
workflow.add_node("tools", call_tools)
workflow.add_edge("__start__", "agent")
workflow.add_conditional_edges(
    "agent",
    should_continue,
)
workflow.add_edge("tools", 'agent')

app = workflow.compile()

final_state = app.invoke(
    {"messages": [{"role": "user", "content": "what is the weather in sf"}]}
)

final_state["messages"][-1]["content"]

**注意：** 以下示例需要 `langsmith>=0.1.39` 和 `@langchain/langgraph>=0.0.31`

import OpenAI from "openai";
import { StateGraph } from "@langchain/langgraph";
import { wrapOpenAI } from "langsmith/wrappers/openai";
import { traceable } from "langsmith/traceable";

type GraphState = {
  messages: OpenAI.ChatCompletionMessageParam[];
};

const wrappedClient = wrapOpenAI(new OpenAI({}));

const toolSchema: OpenAI.ChatCompletionTool = {
  type: "function",
  function: {
    name: "search",
    description: "使用此工具查询网页。",
    parameters: {
      type: "object",
      properties: {
        query: {
          type: "string",
        },
      },
      required: ["query"],
    }
  }
};

// 包装工具函数将自动使用正确的上下文进行追踪
const search = traceable(async ({ query }: { query: string }) => {
  if (
    query.toLowerCase().includes("sf") ||
    query.toLowerCase().includes("san francisco")
  ) {
    return "天气是 60 华氏度，有雾。";
  }
  return "天气是 90 华氏度，晴朗。";
}, { run_type: "tool", name: "Search Tool" });

const callTools = async ({ messages }: GraphState) => {
  const mostRecentMessage = messages[messages.length - 1];
  const toolCalls = (mostRecentMessage as OpenAI.ChatCompletionAssistantMessageParam).tool_calls;
  if (toolCalls === undefined || toolCalls.length === 0) {
    throw new Error("没有工具调用传递给节点。");
  }
  const toolNameMap = {
    search,
  };
  const functionName = toolCalls[0].function.name;
  const functionArguments = JSON.parse(toolCalls[0].function.arguments);
  const response = await toolNameMap[functionName](functionArguments);
  const toolMessage = {
    tool_call_id: toolCalls[0].id,
    role: "tool",
    name: functionName,
    content: response,
  }
  return { messages: [toolMessage] };
};

const callModel = async ({ messages }: GraphState) => {
  // 调用包装后的客户端将自动推断正确的追踪上下文
  const response = await wrappedClient.chat.completions.create({
    messages,
    model: "gpt-4.1-mini",
    tools: [toolSchema],
  });
  const responseMessage = {
    role: "assistant",
    content: response.choices[0].message.content,
    tool_calls: response.choices[0].message.tool_calls ?? [],
  };
  return { messages: [responseMessage] };
};

const shouldContinue = ({ messages }: GraphState) => {
  const lastMessage =
    messages[messages.length - 1] as OpenAI.ChatCompletionAssistantMessageParam;
  if (
    lastMessage?.tool_calls !== undefined &&
    lastMessage?.tool_calls.length > 0
  ) {
    return "tools";
  }
  return "__end__";
}

const workflow = new StateGraph<GraphState>({
  channels: {
    messages: {
      reducer: (a: any, b: any) => a.concat(b),
    }
  }
});

const graph = workflow
  .addNode("model", callModel)
  .addNode("tools", callTools)
  .addEdge("__start__", "model")
  .addConditionalEdges("model", shouldContinue, {
    tools: "tools",
    __end__: "__end__",
  })
  .addEdge("tools", "model")
  .compile();

await graph.invoke({
  messages: [{ role: "user", content: "what is the weather in sf" }]
});

查看追踪

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​使用 LangChain

​1. 安装

​2. 配置环境

​3. 记录追踪

​查看追踪

​不使用 LangChain

​1. 安装

​2. 配置环境

​3. 记录追踪

​查看追踪

使用 LangChain

1. 安装

2. 配置环境

3. 记录追踪

查看追踪

不使用 LangChain

1. 安装

2. 配置环境

3. 记录追踪

查看追踪