{"id":5812,"date":"2026-04-11T11:19:41","date_gmt":"2026-04-11T03:19:41","guid":{"rendered":"http:\/\/xinblog.ltd\/?p=5812"},"modified":"2026-04-16T16:42:02","modified_gmt":"2026-04-16T08:42:02","slug":"14-langgraph%e6%90%ad%e5%bb%baagent-%e5%9f%ba%e4%ba%8elcel%e5%ae%9e%e7%8e%b0%e6%b1%87%e7%8e%87%e5%85%91%e6%8d%a2","status":"publish","type":"post","link":"http:\/\/xinblog.ltd\/?p=5812","title":{"rendered":"14.LangGraph\u642d\u5efaAgent-\u57fa\u4e8eLCEL\u5b9e\u73b0\u6c47\u7387\u5151\u6362"},"content":{"rendered":"

LangGraph\u5982\u4f55\u642d\u5efaAgent<\/p>\n

\u5bf9\u4e8eLangChain\uff0c\u60f3\u5fc5\u8bf8\u5982\u5e76\u4e0d\u964c\u751f\uff0c\u4e4b\u524d\u6211\u4eec\u4e5f\u8bb2\u8fc7LangChain\u76f8\u5173\u6846\u67b6\u7684\u4f7f\u7528\u3002<\/p>\n

LangChain\u65e9\u671f\u662f\u5927\u6a21\u578b\u5f00\u53d1\u6846\u67b6\uff0c\u5176\u5c06\u63d0\u793a\u8bcd\uff0c\u6a21\u578b\uff0c\u5de5\u5177\uff0cRAG\u7b49\u6a21\u5757\u8fdb\u884c\u7ec4\u5408\uff0c\u8ba9\u5f00\u53d1\u8005\u53ef\u4ee5\u6e05\u6670\u7684\u7ec4\u5408\u8fd9\u4e9b\u7ec4\u4ef6\uff0c\u8fdb\u884c\u5e94\u7528\u6784\u5efa\u3002<\/p>\n

\u4f46\u662f\u540e\u7eedLangChain\u66b4\u9732\u4e86\u95ee\u9898: 1. \u4e0d\u65b9\u4fbf\u8c03\u8bd5\uff0c\u6ca1\u6709\u66b4\u9732\u4e2d\u95f4\u65e5\u5fd7 2. \u7f3a\u4e4f\u5e76\u53d1\u548c\u5206\u652f\u63a7\u5236 3. Agent \u96be\u4ee5\u63a7\u5236<\/p>\n

\u540e\u7eed\u5c31\u662fLangChain\u56e2\u961f\u63a8\u51fa\u4e86LCEL\u8fd9\u4e2a\u65b0\u7684\u5f00\u53d1\u8bed\u8a00\uff0c\u57fa\u4e8e\u66f4\u52a0\u660e\u786e\u7684\u8bed\u6cd5\u7ec4\u7ec7\u8c03\u7528\u903b\u8f91\uff0c\u5c06\u6d41\u7a0b\u53d8\u6210\u4e00\u4e2a\u58f0\u660e\u5f0f\u7684\u6570\u636e\u6d41\u56fe\uff0cLCEL\u8ba9\u5f00\u53d1\u8005\u50cf\u662f\u642d\u5efa\u79ef\u6728\u4e00\u6837\u6784\u5efa\u6a21\u5757\u5316\uff0c\u6e05\u6670\u53ef\u63a7\u7684\u6d41\u7a0b\u56fe\u3002<\/p>\n

\u5e76\u540e\u7eed\u57fa\u4e8e\u8fd9\u4e2a\u5f00\u53d1\u8bed\u8a00\uff0c\u63a8\u51fa\u4e86LLM\u5e94\u7528\u7f16\u6392\u6846\u67b6LangGraph\u3002<\/p>\n

\u5229\u7528LCEL\u5b9a\u4e49\u5355\u4e2a\u8282\u70b9\u7684\u8c03\u7528\u903b\u8f91\uff0c\u5229\u7528LangGraph\u6765\u7f16\u6392\u591a\u4e2a\u8282\u70b9\uff0c\u63a7\u5236\u6574\u4e2a\u5de5\u4f5c\u6d41\u7684\u8c03\u5ea6\u3002<\/p>\n

\u5e76\u8fdb\u4e00\u6b65\uff0c\u8ba9LangGraph\u548c\u6d4b\u8bd5\u8f85\u52a9\u5e73\u53f0LangSmith\u8fdb\u884c\u642d\u914d\u4f7f\u7528\uff0c\u8fdb\u4e00\u6b65\u5b9e\u73b0\u9519\u8bef\u8ddf\u8e2a\u548c\u6027\u80fd\u5206\u6790\u3002<\/p>\n

\u90a3\u4e48\u6211\u4eec\u5c31\u9996\u5148\u6784\u5efa\u4e00\u4e2a\u6700\u7b80\u5316\u7248\u672c\u7684LangGraph Agent\uff0c\u7528\u4e8e\u6c47\u7387\u5151\u6362\u3002<\/p>\n

\u5728\u6700\u521d\u7248\u7684Agent\u4e4b\u4e2d\uff0c\u6211\u4eec\u5148\u4e0d\u4f7f\u7528AI\u80fd\u529b\uff0c\u800c\u662f\u5229\u7528\u786c\u7f16\u7801\u7684\u65b9\u5f0f\u53bb\u5b9e\u73b0\u4e00\u4e2aAgent\u3002<\/p>\n

\u9996\u5148\u662f\u5bfc\u5165\u76f8\u5173\u7684\u5e93<\/p>\n\n\n\n
import os<\/p>\n

import httpx<\/p>\n

from typing import TypedDict, Annotated<\/p>\n

from dotenv import load_dotenv<\/p>\n

from langchain_core.messages import HumanMessage, AIMessage<\/p>\n

from langchain_core.tools import tool<\/p>\n

from langchain_google_genai import ChatGoogleGenerativeAI<\/p>\n

from langgraph.graph import StateGraph, END<\/p>\n

from langgraph.checkpoint.memory import MemorySaver<\/p>\n

# \u52a0\u8f7d\u73af\u5883\u53d8\u91cf<\/p>\n

load_dotenv()<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e4b\u540e\u662f\u58f0\u660e\u4e00\u4e2a\u7c7b\uff0c\u4f5c\u4e3a\u6570\u636e\u5b58\u50a8\u7c7b\uff0c\u5e76\u4e14\u5728\u7c7b\u5916\u5b9a\u4e49\u4e00\u4e2a\u51fd\u6570\u4f5c\u4e3a\u5de5\u5177<\/p>\n\n\n\n
class CurrencyState(TypedDict):<\/p>\n

“””\u6c47\u7387\u8f6c\u6362\u72b6\u6001”””<\/p>\n

messages: Annotated[list, “\u5bf9\u8bdd\u6d88\u606f\u5217\u8868”]<\/p>\n

exchange_data: Annotated[dict, “\u6c47\u7387\u6570\u636e”]<\/p>\n

@tool<\/p>\n

def get_exchange_rate(currency_from: str = ‘USD’, currency_to: str = ‘CNY’) -> dict:<\/p>\n

“””\u83b7\u53d6\u6c47\u7387\u4fe1\u606f<\/p>\n

\u53c2\u6570:<\/p>\n

currency_from: \u6e90\u8d27\u5e01\u4ee3\u7801 (\u4f8b\u5982: “USD”, “CNY”)<\/p>\n

currency_to: \u76ee\u6807\u8d27\u5e01\u4ee3\u7801 (\u4f8b\u5982: “EUR”, “JPY”)<\/p>\n

\u8fd4\u56de:<\/p>\n

\u5305\u542b\u6c47\u7387\u6570\u636e\u7684\u5b57\u5178<\/p>\n

“””<\/p>\n

try:<\/p>\n

response = httpx.get(<\/p>\n

f’https:\/\/api.frankfurter.app\/latest’,<\/p>\n

params={‘from’: currency_from, ‘to’: currency_to},<\/p>\n

timeout=10.0<\/p>\n

)<\/p>\n

response.raise_for_status()<\/p>\n

return response.json()<\/p>\n

except Exception as e:<\/p>\n

return {‘error’: f’\u83b7\u53d6\u6c47\u7387\u5931\u8d25: {e}’}<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u4e4b\u540e\u6211\u4eec\u6784\u5efaAgent<\/p>\n

\u5728\u8fd9\u4e2aAgent\u7c7b\u4e4b\u4e2d\uff0c\u6211\u4eec\u4e3b\u8981\u5b9a\u4e49\u4e09\u4e2a\u51fd\u6570\uff0c\u5bf9\u5e94\u7684\u662f\u7528\u6237\u610f\u56fe\u8bc6\u522b process_query\uff0c\u6c47\u7387\u83b7\u53d6get_rate\uff0c\u54cd\u5e94\u751f\u6210respond\u4e09\u90e8\u5206\u3002<\/p>\n\n\n\n
class SimpleCurrencyAgent:<\/p>\n

“””\u6781\u7b80\u6c47\u7387Agent”””<\/p>\n

def __init__(self):<\/p>\n

“””\u521d\u59cb\u5316Agent”””<\/p>\n

# \u914d\u7f6eLLM<\/p>\n

self.llm = ChatGoogleGenerativeAI(<\/p>\n

model=’gemini-2.0-flash’,<\/p>\n

api_key=os.getenv(‘GOOGLE_API_KEY’)<\/p>\n

)<\/p>\n

# \u521b\u5efa\u56fe<\/p>\n

self.graph = self._create_graph()<\/p>\n

def _process_query(self, state: CurrencyState) -> CurrencyState:<\/p>\n

“””\u5904\u7406\u7528\u6237\u67e5\u8be2”””<\/p>\n

# \u83b7\u53d6\u7528\u6237\u6d88\u606f<\/p>\n

user_message = state[“messages”][-1].content<\/p>\n

# \u7b80\u5355\u7684\u5173\u952e\u8bcd\u5339\u914d<\/p>\n

currencies = {<\/p>\n

‘\u7f8e\u5143’: ‘USD’, ‘\u4eba\u6c11\u5e01’: ‘CNY’, ‘\u6b27\u5143’: ‘EUR’, ‘\u65e5\u5143’: ‘JPY’,<\/p>\n

‘\u82f1\u9551’: ‘GBP’, ‘\u6fb3\u5143’: ‘AUD’, ‘\u6e2f\u5e01’: ‘HKD’, ‘\u97e9\u5143’: ‘KRW’<\/p>\n

}<\/p>\n

# \u68c0\u67e5\u662f\u5426\u5305\u542b\u8d27\u5e01\u76f8\u5173\u5173\u952e\u8bcd<\/p>\n

currency_keywords = [‘\u6c47\u7387’, ‘\u5151’, ‘\u6362’, ‘\u7f8e\u5143’, ‘\u4eba\u6c11\u5e01’, ‘\u6b27\u5143’, ‘\u65e5\u5143’, ‘\u82f1\u9551’, ‘\u6fb3\u5143’, ‘\u6e2f\u5e01’, ‘\u97e9\u5143’]<\/p>\n

is_currency_query = any(keyword in user_message for keyword in currency_keywords)<\/p>\n

if not is_currency_query:<\/p>\n

# \u975e\u8d27\u5e01\u67e5\u8be2<\/p>\n

state[“exchange_data”] = {<\/p>\n

“error”: “\u62b1\u6b49\uff0c\u6211\u53ea\u80fd\u534f\u52a9\u8d27\u5e01\u8f6c\u6362\u548c\u6c47\u7387\u67e5\u8be2\u3002\u8bf7\u8be2\u95ee\u6c47\u7387\u76f8\u5173\u7684\u95ee\u9898\u3002”<\/p>\n

}<\/p>\n

return state<\/p>\n

# \u8d27\u5e01\u67e5\u8be2\u5904\u7406<\/p>\n

found_currencies = []<\/p>\n

for cn_name, code in currencies.items():<\/p>\n

if cn_name in user_message:<\/p>\n

found_currencies.append(code)<\/p>\n

# \u8bbe\u7f6e\u9ed8\u8ba4\u8d27\u5e01\u5bf9<\/p>\n

if len(found_currencies) >= 2:<\/p>\n

from_currency = found_currencies[0]<\/p>\n

to_currency = found_currencies[1]<\/p>\n

elif len(found_currencies) == 1:<\/p>\n

# \u5982\u679c\u53ea\u627e\u5230\u4e00\u4e2a\u8d27\u5e01\uff0c\u6839\u636e\u67e5\u8be2\u5185\u5bb9\u5224\u65ad<\/p>\n

if ‘\u5151\u4eba\u6c11\u5e01’ in user_message or ‘\u6362\u4eba\u6c11\u5e01’ in user_message:<\/p>\n

from_currency = found_currencies[0]<\/p>\n

to_currency = ‘CNY’<\/p>\n

elif ‘\u4eba\u6c11\u5e01\u5151’ in user_message or ‘\u4eba\u6c11\u5e01\u6362’ in user_message:<\/p>\n

from_currency = ‘CNY’<\/p>\n

to_currency = found_currencies[0]<\/p>\n

else:<\/p>\n

# \u9ed8\u8ba4\u67e5\u8be2\u8be5\u8d27\u5e01\u5151\u4eba\u6c11\u5e01<\/p>\n

from_currency = found_currencies[0]<\/p>\n

to_currency = ‘CNY’<\/p>\n

else:<\/p>\n

# \u6ca1\u6709\u627e\u5230\u8d27\u5e01\uff0c\u4f7f\u7528\u9ed8\u8ba4<\/p>\n

from_currency = ‘USD’<\/p>\n

to_currency = ‘CNY’<\/p>\n

# \u907f\u514d\u76f8\u540c\u8d27\u5e01\u7684API\u8c03\u7528<\/p>\n

if from_currency == to_currency:<\/p>\n

state[“exchange_data”] = {<\/p>\n

“error”: f”\u65e0\u6cd5\u67e5\u8be2{from_currency}\u5151{to_currency}\u7684\u6c47\u7387\uff0c\u56e0\u4e3a\u5b83\u4eec\u662f\u540c\u4e00\u79cd\u8d27\u5e01\u3002”<\/p>\n

}<\/p>\n

return state<\/p>\n

state[“exchange_data”] = {<\/p>\n

“from_currency”: from_currency,<\/p>\n

“to_currency”: to_currency,<\/p>\n

“user_query”: user_message<\/p>\n

}<\/p>\n

return state<\/p>\n

def _get_rate(self, state: CurrencyState) -> CurrencyState:<\/p>\n

“””\u83b7\u53d6\u6c47\u7387\u6570\u636e”””<\/p>\n

exchange_data = state[“exchange_data”]<\/p>\n

# \u5982\u679c\u5df2\u7ecf\u6709\u9519\u8bef\u4fe1\u606f\uff0c\u76f4\u63a5\u8fd4\u56de<\/p>\n

if “error” in exchange_data:<\/p>\n

return state<\/p>\n

# \u8c03\u7528\u6c47\u7387\u5de5\u5177<\/p>\n

rate_data = get_exchange_rate.invoke({<\/p>\n

“currency_from”: exchange_data[“from_currency”],<\/p>\n

“currency_to”: exchange_data[“to_currency”]<\/p>\n

})<\/p>\n

exchange_data.update(rate_data)<\/p>\n

return state<\/p>\n

def _respond(self, state: CurrencyState) -> CurrencyState:<\/p>\n

“””\u751f\u6210\u54cd\u5e94”””<\/p>\n

exchange_data = state[“exchange_data”]<\/p>\n

if “error” in exchange_data:<\/p>\n

response_content = f”\u62b1\u6b49\uff0c\u83b7\u53d6\u6c47\u7387\u65f6\u51fa\u73b0\u9519\u8bef\uff1a{exchange_data[‘error’]}”<\/p>\n

else:<\/p>\n

rates = exchange_data.get(‘rates’, {})<\/p>\n

base = exchange_data.get(‘base’, ‘EUR’)<\/p>\n

date = exchange_data.get(‘date’, ‘latest’)<\/p>\n

if rates:<\/p>\n

rate_info = []<\/p>\n

for currency, rate in rates.items():<\/p>\n

rate_info.append(f”{base} -> {currency}: {rate}”)<\/p>\n

response_content = f”\u6c47\u7387\u4fe1\u606f ({date}):\\n” + “\\n”.join(rate_info)<\/p>\n

else:<\/p>\n

response_content = “\u65e0\u6cd5\u83b7\u53d6\u6c47\u7387\u4fe1\u606f”<\/p>\n

# \u521b\u5efaAI\u54cd\u5e94<\/p>\n

ai_message = AIMessage(content=response_content)<\/p>\n

state[“messages”].append(ai_message)<\/p>\n

return state<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728\u4ee3\u7801\u4e4b\u4e2d\uff0c\u5e76\u6ca1\u6709\u53bb\u5b9e\u9645\u4f7f\u7528\u5927\u6a21\u578b\u80fd\u529b\uff0c\u800c\u662f\u901a\u8fc7\u7b80\u5355\u7684\u5b57\u7b26\u4e32\u5339\u914d\u7684\u65b9\u5f0f\u83b7\u53d6\u8981\u4e0d\u8981\u5904\u7406\u6c47\u7387\u95ee\u9898\u3002<\/p>\n

\u5e76\u4e14\u6700\u540e\u901a\u8fc7respond\u51fd\u6570\u8fdb\u884c\u8fd4\u56de<\/p>\n

\u4e09\u4e2a\u51fd\u6570\u4e4b\u95f4\u901a\u8fc7CurrencyState\u4f5c\u4e3a\u4e0a\u4e0b\u6587\u8fdb\u884c\u6d88\u606f\u4f20\u9012\u3002<\/p>\n

\u5728\u4e09\u4e2a\u51fd\u6570\u4e0b\u9762\uff0c\u5219\u662f\u4e00\u4e2a\u91cd\u8981\u7684\u521b\u5efa\u56fe\u7684\u51fd\u6570\uff0c\u5c06\u4e0a\u9762\u51e0\u4e2a\u5de5\u4f5c\u7528\u7684\u51fd\u6570\u4e32\u8d77\u6765\u3002<\/p>\n\n\n\n
def _create_graph(self):<\/p>\n

“””\u521b\u5efaLangGraph\u5de5\u4f5c\u6d41”””<\/p>\n

# \u521b\u5efa\u5185\u5b58\u68c0\u67e5\u70b9<\/p>\n

memory = MemorySaver()<\/p>\n

# \u521b\u5efa\u5de5\u4f5c\u6d41\u56fe<\/p>\n

workflow = StateGraph(CurrencyState)<\/p>\n

# \u6dfb\u52a0\u8282\u70b9<\/p>\n

workflow.add_node(“process_query”, self._process_query)<\/p>\n

workflow.add_node(“get_rate”, self._get_rate)<\/p>\n

workflow.add_node(“respond”, self._respond)<\/p>\n

# \u8bbe\u7f6e\u5165\u53e3\u70b9<\/p>\n

workflow.set_entry_point(“process_query”)<\/p>\n

# \u6dfb\u52a0\u8fb9<\/p>\n

workflow.add_edge(“process_query”, “get_rate”)<\/p>\n

workflow.add_edge(“get_rate”, “respond”)<\/p>\n

workflow.add_edge(“respond”, END)<\/p>\n

# \u7f16\u8bd1\u56fe<\/p>\n

return workflow.compile(checkpointer=memory)<\/p>\n

def process_query(self, query: str, session_id: str = “default”) -> dict:<\/p>\n

“””\u5904\u7406\u7528\u6237\u67e5\u8be2”””<\/p>\n

# \u521d\u59cb\u5316\u72b6\u6001<\/p>\n

initial_state = {<\/p>\n

“messages”: [HumanMessage(content=query)],<\/p>\n

“exchange_data”: {}<\/p>\n

}<\/p>\n

# \u914d\u7f6e\u4f1a\u8bdd<\/p>\n

config = {‘configurable’: {‘thread_id’: session_id}}<\/p>\n

try:<\/p>\n

# \u6267\u884c\u5de5\u4f5c\u6d41<\/p>\n

result = self.graph.invoke(initial_state, config)<\/p>\n

# \u83b7\u53d6\u6700\u7ec8\u54cd\u5e94<\/p>\n

if result[“messages”]:<\/p>\n

content = result[“messages”][-1].content<\/p>\n

else:<\/p>\n

content = “\u65e0\u6cd5\u5904\u7406\u8bf7\u6c42”<\/p>\n

# \u786e\u5b9a\u4efb\u52a1\u72b6\u6001<\/p>\n

is_complete = “error” not in result[“exchange_data”]<\/p>\n

return {<\/p>\n

‘is_task_complete’: is_complete,<\/p>\n

‘require_user_input’: not is_complete,<\/p>\n

‘content’: content,<\/p>\n

‘session_id’: session_id<\/p>\n

}<\/p>\n

except Exception as e:<\/p>\n

return {<\/p>\n

‘is_task_complete’: False,<\/p>\n

‘require_user_input’: True,<\/p>\n

‘content’: f”\u5904\u7406\u8bf7\u6c42\u65f6\u51fa\u73b0\u9519\u8bef: {str(e)}”,<\/p>\n

‘session_id’: session_id<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5176\u4e2dMemorySaver\u662f\u4f7f\u7528\u5185\u5b58\u578b\u68c0\u67e5\u70b9\uff0c\u6765\u8bb0\u5f55\u6bcf\u4e00\u6b65\u7684\u72b6\u6001\u6570\u636e\u3002<\/p>\n

\u7136\u540eStateGraph\u521b\u5efa\u4e00\u4e2a\u6709\u72b6\u6001\u56fe\u3002<\/p>\n

\u4e4b\u540e\u5c06\u4e09\u4e2a\u51fd\u6570\u901a\u8fc7add_node\u6dfb\u52a0\u8fdb\u53bb\u3002\u5e76\u5229\u7528set_entry_point\u6765\u8bbe\u7f6e\u6d41\u7a0b\u8d77\u59cb\u70b9 _process_query\uff0c\u5229\u7528add_edge\u6765\u660e\u786e\u8282\u70b9\u4e4b\u95f4\u7684\u8f6c\u79fb\u8def\u5f84\u3002<\/p>\n

\u6700\u540e\u8c03\u7528compile\u51fd\u6570\u5c06\u5176\u7f16\u8bd1\u4e3a\u53ef\u8fd0\u884c\u7684LangGraph\u5de5\u4f5c\u6d41\u5bf9\u8c61\u3002<\/p>\n

\u5728\u4e0a\u9762\u8868\u683c\u4e2d\uff0c\u9664\u4e86create_graph\u51fd\u6570\u5916\uff0c\u8fd8\u6709\u4e00\u4e2a\u4e13\u95e8\u5bf9\u5916\u66b4\u9732\u7684\u51fd\u6570 process_query<\/p>\n

\u8fd9\u4e2a\u51fd\u6570\u548c_process_query\u4e0d\u4e00\u6837\uff0c\u8fd9\u662f\u4e00\u4e2a\u4e13\u95e8\u5bf9\u5916\u7684\u51fd\u6570\uff0c\u65b9\u4fbf\u88ab\u8c03\u7528\u89e6\u53d1\u3002<\/p>\n

invoke\u5bf9\u5e94\u7684LangGraph\u6d41\u7a0b\uff0c\u8fd4\u56de\u4e00\u4e2a\u7ed3\u6784\u5316\u7684\u5b57\u5178\uff0c\u5176\u4e2d\u5305\u542b\u662f\u5426\u6210\u529f\u3002\u662f\u5426\u9700\u8981\u8fdb\u4e00\u6b65\u8f93\u51fa\u3002<\/p>\n

\u5230\u6b64\u4e3a\u6b62\uff0c\u4e00\u4e2a\u7b80\u5355\u7684LangGraph\u667a\u80fd\u4f53\u5c31\u642d\u5efa\u597d\u4e86\u3002<\/p>\n

\u4e0a\u9762\u7684\u5de5\u4f5c\u6d41\u867d\u7136\u6e05\u6670\uff0c\u4f46\u662f\u6ca1\u6709\u7528\u5230\u4efb\u4f55AI\u80fd\u529b\uff0c\u6240\u4ee5\u6211\u4eec\u589e\u52a0\u4e00\u4e9b\u5c0f\u529f\u80fd\uff0c\u5bf9process_query\u7684\u8bbe\u8ba1\u8fdb\u884c\u5206\u53c9\uff0c\u5728\u5c0f\u529f\u80fd\u5185\u90e8\uff0c\u5229\u7528LLM\u6765\u8fdb\u884c\u610f\u56fe\u8bc6\u522b\u3002\u5224\u65ad\u8981\u4e0d\u8981\u8fdb\u5165\u6c47\u7387\u8ba1\u7b97\u3002<\/p>\n

\u9996\u5148\u662f\u67b6\u6784\u4e0a\u7684\u4fee\u6539<\/p>\n\n\n\n
# \u521b\u5efa\u5de5\u4f5c\u6d41\u56fe<\/p>\n

workflow = StateGraph(CurrencyState)<\/p>\n

# \u6dfb\u52a0\u8282\u70b9<\/p>\n

workflow.add_node(“process_query”, self._process_query)<\/p>\n

workflow.add_node(“get_rate”, self._get_rate)<\/p>\n

workflow.add_node(“respond”, self._respond)<\/p>\n

workflow.add_node(“respond_irrelevant”, self._respond_irrelevant)<\/p>\n

# \u8bbe\u7f6e\u5165\u53e3\u70b9<\/p>\n

workflow.set_entry_point(“process_query”)<\/p>\n

# \u6dfb\u52a0\u6761\u4ef6\u8fb9<\/p>\n

workflow.add_conditional_edges(<\/p>\n

“process_query”,<\/p>\n

self._should_get_rate,<\/p>\n

{<\/p>\n

“get_rate”: “get_rate”,<\/p>\n

“respond_irrelevant”: “respond_irrelevant”<\/p>\n

}<\/p>\n

)<\/p>\n

# \u6dfb\u52a0\u666e\u901a\u8fb9<\/p>\n

workflow.add_edge(“get_rate”, “respond”)<\/p>\n

workflow.add_edge(“respond”, END)<\/p>\n

workflow.add_edge(“respond_irrelevant”, END)<\/p>\n

# \u7f16\u8bd1\u56fe<\/p>\n

return workflow.compile(checkpointer=memory)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728\u5176\u4e2dset_entry_point\u4e4b\u540e\uff0c\u5229\u7528add_conditional_edges\u6765\u6dfb\u52a0\u4e86\u6761\u4ef6\u8fb9\uff0c\u5229\u7528should_get_rate\u51fd\u6570\u6765\u5206\u53c9\u5230\u4e0d\u540c\u8def\u5f84\u3002<\/p>\n

\u5728\u8fd9\u4e2a\u51fd\u6570\u4e2d\uff0c\u53ef\u4ee5\u5229\u7528LLM\u6765\u8fdb\u884c\u5224\u65ad<\/p>\n

\u5982\u679c\u5224\u65ad\u6ca1\u6709\u7b26\u5408\u610f\u56fe\uff0c\u5219\u8fdb\u5165_respond_irrelevant\u51fd\u6570<\/p>\n\n\n\n
def _respond_irrelevant(self, state: CurrencyState) -> CurrencyState:<\/p>\n

“””\u751f\u6210\u4e0d\u76f8\u5173\u67e5\u8be2\u7684\u54cd\u5e94”””<\/p>\n

exchange_data = state[“exchange_data”]<\/p>\n

response_content = exchange_data.get(“error”, “\u62b1\u6b49\uff0c\u6211\u53ea\u80fd\u534f\u52a9\u8d27\u5e01\u8f6c\u6362\u548c\u6c47\u7387\u67e5\u8be2\u3002\u8bf7\u8be2\u95ee\u6c47\u7387\u76f8\u5173\u7684\u95ee\u9898\u3002”)<\/p>\n

# \u521b\u5efaAI\u54cd\u5e94<\/p>\n

ai_message = AIMessage(content=response_content)<\/p>\n

state[“messages”].append(ai_message)<\/p>\n

return state<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u901a\u8fc7\u8fd9\u6837\uff0c\u5b9e\u73b0\u4e86\u667a\u80fd\u610f\u56fe\u8bc6\u522b\u7684\u529f\u80fd\u3002<\/p>\n

\u4e4b\u540e\u662f\u5c06\u8fd9\u4e2a\u521b\u5efa\u597d\u7684LangGraph\u6784\u5efa\u7684\u8d27\u5e01\u8f6c\u6362Agent\uff0c\u96c6\u6210\u5230\u4e86A2A\u534f\u8bae\u4e2d\u3002<\/p>\n

\u9996\u5148\u8003\u8651\u5c06LangGraph\u4ee5ReAct\u6a21\u5f0f\u8fdb\u884c\u4fee\u6539\uff0c\u4e3b\u8981\u662f\u5229\u7528\u7cfb\u7edf\u7ea7\u522b\u7684\u63d0\u793a\u8bcd\u6765\u96c6\u6210ReAct\u6a21\u5f0f\u3002<\/p>\n\n\n\n
class CurrencyAgent:<\/p>\n

SYSTEM_INSTRUCTION = (<\/p>\n

‘\u4f60\u662f\u4e13\u95e8\u8fdb\u884c\u8d27\u5e01\u8f6c\u6362\u7684\u52a9\u624b\u3002’<\/p>\n

“\u4f60\u7684\u552f\u4e00\u76ee\u7684\u662f\u4f7f\u7528’get_exchange_rate’\u5de5\u5177\u6765\u56de\u7b54\u6709\u5173\u6c47\u7387\u7684\u95ee\u9898\u3002”<\/p>\n

‘\u5982\u679c\u7528\u6237\u8be2\u95ee\u9664\u8d27\u5e01\u8f6c\u6362\u6216\u6c47\u7387\u4e4b\u5916\u7684\u4efb\u4f55\u5185\u5bb9\uff0c’<\/p>\n

‘\u8bf7\u793c\u8c8c\u5730\u8bf4\u660e\u4f60\u65e0\u6cd5\u5e2e\u52a9\u8be5\u4e3b\u9898\uff0c\u53ea\u80fd\u534f\u52a9\u8d27\u5e01\u76f8\u5173\u7684\u67e5\u8be2\u3002’<\/p>\n

‘\u4e0d\u8981\u5c1d\u8bd5\u56de\u7b54\u4e0d\u76f8\u5173\u7684\u95ee\u9898\u6216\u5c06\u5de5\u5177\u7528\u4e8e\u5176\u4ed6\u76ee\u7684\u3002’<\/p>\n

‘\u5982\u679c\u7528\u6237\u9700\u8981\u63d0\u4f9b\u66f4\u591a\u4fe1\u606f\uff0c\u8bf7\u5c06\u54cd\u5e94\u72b6\u6001\u8bbe\u7f6e\u4e3ainput_required\u3002’<\/p>\n

‘\u5982\u679c\u5728\u5904\u7406\u8bf7\u6c42\u65f6\u51fa\u73b0\u9519\u8bef\uff0c\u8bf7\u5c06\u54cd\u5e94\u72b6\u6001\u8bbe\u7f6e\u4e3aerror\u3002’<\/p>\n

‘\u5982\u679c\u8bf7\u6c42\u5b8c\u6210\uff0c\u8bf7\u5c06\u54cd\u5e94\u72b6\u6001\u8bbe\u7f6e\u4e3acompleted\u3002’<\/p>\n

)<\/p>\n

def __init__(self):<\/p>\n

self.model = ChatGoogleGenerativeAI(model=’gemini-2.0-flash’)<\/p>\n

self.tools = [get_exchange_rate]<\/p>\n

# \u521b\u5efaReAct Agent<\/p>\n

self.graph = create_react_agent(<\/p>\n

self.model,<\/p>\n

tools=self.tools,<\/p>\n

checkpointer=memory,<\/p>\n

prompt=self.SYSTEM_INSTRUCTION,<\/p>\n

response_format=ResponseFormat,<\/p>\n

)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u540c\u65f6\u4e5f\u662f\u4f7f\u7528tools\u6765\u6ce8\u518c\u5916\u90e8\u5de5\u5177\uff0c\u5de5\u5177\u8c03\u7528\u662fLangGraph Agent\u7684\u6838\u5fc3\u80fd\u529b\uff0c\u901a\u8fc7\u88c5\u9970\u5668\u6765\u5b9e\u73b0<\/p>\n\n\n\n
@tool<\/p>\n

def get_exchange_rate(<\/p>\n

currency_from: str = ‘USD’,<\/p>\n

currency_to: str = ‘EUR’,<\/p>\n

currency_date: str = ‘latest’,<\/p>\n

):<\/p>\n

“””\u4f7f\u7528\u6b64\u5de5\u5177\u83b7\u53d6\u5f53\u524d\u6c47\u7387\u3002<\/p>\n

\u53c2\u6570:<\/p>\n

currency_from: \u8981\u8f6c\u6362\u7684\u8d27\u5e01\uff08\u4f8b\u5982\uff0c”USD”\uff09\u3002<\/p>\n

currency_to: \u8981\u8f6c\u6362\u5230\u7684\u8d27\u5e01\uff08\u4f8b\u5982\uff0c”EUR”\uff09\u3002<\/p>\n

currency_date: \u6c47\u7387\u7684\u65e5\u671f\u6216”latest”\u3002\u9ed8\u8ba4\u4e3a”latest”\u3002<\/p>\n

\u8fd4\u56de:<\/p>\n

\u5305\u542b\u6c47\u7387\u6570\u636e\u7684\u5b57\u5178\uff0c\u5982\u679c\u8bf7\u6c42\u5931\u8d25\u5219\u8fd4\u56de\u9519\u8bef\u6d88\u606f\u3002<\/p>\n

“””<\/p>\n

try:<\/p>\n

response = httpx.get(<\/p>\n

f’https:\/\/api.frankfurter.app\/{currency_date}’,<\/p>\n

params={‘from’: currency_from, ‘to’: currency_to},<\/p>\n

)<\/p>\n

response.raise_for_status()<\/p>\n

data = response.json()<\/p>\n

if ‘rates’ not in data:<\/p>\n

return {‘error’: ‘API\u54cd\u5e94\u683c\u5f0f\u65e0\u6548\u3002’}<\/p>\n

return data<\/p>\n

except httpx.HTTPError as e:<\/p>\n

return {‘error’: f’API\u8bf7\u6c42\u5931\u8d25: {e}’}<\/p>\n

except ValueError:<\/p>\n

return {‘error’: ‘API\u8fd4\u56de\u7684JSON\u54cd\u5e94\u65e0\u6548\u3002’}<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728\u62e5\u6709\u56fa\u5b9a\u7684Agent\u4e4b\u540e\uff0c\u53ef\u4ee5\u5728task manager\u4e4b\u4e2d\u589e\u52a0\u6d41\u5f0f\u7684\u54cd\u5e94\u5904\u7406\u3002<\/p>\n\n\n\n
async def stream(self, query, sessionId) -> AsyncIterable[dict[str, Any]]:<\/p>\n

inputs = {‘messages’: [(‘user’, query)]}<\/p>\n

config = {‘configurable’: {‘thread_id’: sessionId}}<\/p>\n

for item in self.graph.stream(inputs, config, stream_mode=’values’):<\/p>\n

message = item[‘messages’][-1]<\/p>\n

if (<\/p>\n

isinstance(message, AIMessage)<\/p>\n

and message.tool_calls<\/p>\n

and len(message.tool_calls) > 0<\/p>\n

):<\/p>\n

yield {<\/p>\n

‘is_task_complete’: False,<\/p>\n

‘require_user_input’: False,<\/p>\n

‘content’: ‘Looking up the exchange rates…’,<\/p>\n

}<\/p>\n

elif isinstance(message, ToolMessage):<\/p>\n

yield {<\/p>\n

‘is_task_complete’: False,<\/p>\n

‘require_user_input’: False,<\/p>\n

‘content’: ‘Processing the exchange rates..’,<\/p>\n

}<\/p>\n

yield self.get_agent_response(config)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728\u6b64\u8fc7\u7a0b\u4e2d\uff0c\u6d41\u5f0f\u5904\u7406\u673a\u5236\u53ef\u4ee5\u8bc6\u522b\u72b6\u6001\uff0c\u8fdb\u884c\u8fdb\u5ea6\u53cd\u9988\uff0c\u5e76\u8fd4\u56de\u6700\u7ec8\u7ed3\u679c\u3002<\/p>\n

\u8fd9\u4e2a\u6d41\u5f0f\u673a\u5236\u8fd8\u53ef\u4ee5\u548c\u4e0a\u5c42\u7684TaskManager\u76f8\u7ed3\u5408<\/p>\n

\u5b9e\u73b0\u4efb\u52a1\u72b6\u6001\u7684\u8bb0\u5f55\uff0c\u66f4\u65b0\u548c\u901a\u77e5<\/p>\n\n\n\n
class AgentTaskManager(InMemoryTaskManager):<\/p>\n

def __init__(<\/p>\n

self,<\/p>\n

agent: CurrencyAgent,<\/p>\n

notification_sender_auth: PushNotificationSenderAuth,<\/p>\n

):<\/p>\n

super().__init__()<\/p>\n

self.agent = agent<\/p>\n

self.notification_sender_auth = notification_sender_auth<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5728TaskManager\u4e4b\u4e2d\uff0c\u5c06\u5177\u4f53\u7684CurrencyAgnet\u6ce8\u5165\u5230\u4efb\u52a1\u7ba1\u7406\u5668\u4e2d\uff0c\u4fbf\u4e8e\u4efb\u52a1\u8c03\u5ea6\u5668\u7684\u7edf\u4e00\u8c03\u7528\uff0c\u5b9e\u73b0\u901a\u77e5\u673a\u5236\u3002<\/p>\n

\u5728TaskManager\u4e4b\u4e2d\uff0c\u4e5f\u5229\u7528\u76f8\u5173\u7684\u673a\u5236\u4f7f\u7528\u6d41\u5f0f\u56de\u586b<\/p>\n\n\n\n
async def _run_streaming_agent(self, request: SendTaskStreamingRequest):<\/p>\n

task_send_params: TaskSendParams = request.params<\/p>\n

query = self._get_user_query(task_send_params)<\/p>\n

try:<\/p>\n

async for item in self.agent.stream(<\/p>\n

query, task_send_params.sessionId<\/p>\n

):<\/p>\n

is_task_complete = item[‘is_task_complete’]<\/p>\n

require_user_input = item[‘require_user_input’]<\/p>\n

artifact = None<\/p>\n

message = None<\/p>\n

parts = [{‘type’: ‘text’, ‘text’: item[‘content’]}]<\/p>\n

end_stream = False<\/p>\n

if not is_task_complete and not require_user_input:<\/p>\n

task_state = TaskState.WORKING<\/p>\n

message = Message(role=’agent’, parts=parts)<\/p>\n

elif require_user_input:<\/p>\n

task_state = TaskState.INPUT_REQUIRED<\/p>\n

message = Message(role=’agent’, parts=parts)<\/p>\n

end_stream = True<\/p>\n

else:<\/p>\n

task_state = TaskState.COMPLETED<\/p>\n

artifact = Artifact(parts=parts, index=0, append=False)<\/p>\n

end_stream = True<\/p>\n

task_status = TaskStatus(state=task_state, message=message)<\/p>\n

latest_task = await self.update_store(<\/p>\n

task_send_params.id,<\/p>\n

task_status,<\/p>\n

None if artifact is None else [artifact],<\/p>\n

)<\/p>\n

await self.send_task_notification(latest_task)<\/p>\n

if artifact:<\/p>\n

task_artifact_update_event = TaskArtifactUpdateEvent(<\/p>\n

id=task_send_params.id, artifact=artifact<\/p>\n

)<\/p>\n

await self.enqueue_events_for_sse(<\/p>\n

task_send_params.id, task_artifact_update_event<\/p>\n

)<\/p>\n

task_update_event = TaskStatusUpdateEvent(<\/p>\n

id=task_send_params.id, status=task_status, final=end_stream<\/p>\n

)<\/p>\n

await self.enqueue_events_for_sse(<\/p>\n

task_send_params.id, task_update_event<\/p>\n

)<\/p>\n

except Exception as e:<\/p>\n

logger.error(f’An error occurred while streaming the response: {e}’)<\/p>\n

await self.enqueue_events_for_sse(<\/p>\n

task_send_params.id,<\/p>\n

InternalError(<\/p>\n

message=f’An error occurred while streaming the response: {e}’<\/p>\n

),<\/p>\n

)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u6700\u540e\u5728\u4e3b\u51fd\u6570\u4e4b\u4e2d\uff0c\u901a\u8fc7A2AServer\u6765\u8fdb\u884c\u542f\u52a8\uff0c\u5e76\u5b9e\u73b0Agent\u7684\u4f7f\u7528<\/p>\n\n\n\n
server = A2AServer(<\/p>\n

agent_card=agent_card,<\/p>\n

task_manager=AgentTaskManager(<\/p>\n

agent=CurrencyAgent(),<\/p>\n

notification_sender_auth=notification_sender_auth,<\/p>\n

),<\/p>\n

host=host,<\/p>\n

port=port,<\/p>\n

)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u901a\u8fc7\u4e0a\u8ff0\u6d41\u7a0b\uff0c\u5b9e\u73b0\u4e86\u4eceLangGraph\u6784\u5efa\u5230A2A\u7684\u96c6\u6210\u6d41\u7a0b<\/p>\n","protected":false},"excerpt":{"rendered":"

LangGraph\u5982\u4f55\u642d\u5efaAg […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[],"_links":{"self":[{"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/posts\/5812"}],"collection":[{"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5812"}],"version-history":[{"count":1,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/posts\/5812\/revisions"}],"predecessor-version":[{"id":5813,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=\/wp\/v2\/posts\/5812\/revisions\/5813"}],"wp:attachment":[{"href":"http:\/\/xinblog.ltd\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5812"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5812"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/xinblog.ltd\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5812"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}