初始化项目：langgraph 学习笔记与 lg_common 通用组件包

chapter03/01_checkpoint.ipynb

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+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "id": "initial_id",
+   "metadata": {
+    "collapsed": true
+   },
+   "source": [
+    "import os\n",
+    "from langchain.chat_models import init_chat_model\n",
+    "from dotenv import load_dotenv\n",
+    "\n",
+    "load_dotenv(override=True)\n",
+    "\n",
+    "llm = init_chat_model(\n",
+    "    model=\"openai:qwen3.6-flash\",\n",
+    "    base_url=os.getenv(\"BASE_URL\"),\n",
+    "    api_key=os.getenv(\"API_KEY\")\n",
+    ")"
+   ],
+   "outputs": [],
+   "execution_count": null
+  },
+  {
+   "metadata": {},
+   "cell_type": "code",
+   "source": [
+    "from langgraph.graph.message import MessagesState\n",
+    "\n",
+    "\n",
+    "class OverallState(MessagesState):\n",
+    "    output: str\n",
+    "\n",
+    "\n",
+    "def llm_node(state: OverallState) -> OverallState:\n",
+    "    messages = state[\"messages\"]\n",
+    "    res = llm.invoke(messages)\n",
+    "    return {\n",
+    "        \"messages\": [res]\n",
+    "    }\n",
+    "\n",
+    "\n",
+    "def output_node(state: OverallState) -> OverallState:\n",
+    "    return {\n",
+    "        \"output\": state[\"messages\"][-1].content\n",
+    "    }"
+   ],
+   "id": "b443de7fa7929ba2",
+   "outputs": [],
+   "execution_count": null
+  },
+  {
+   "metadata": {},
+   "cell_type": "code",
+   "source": [
+    "from langgraph.graph import StateGraph, START, END\n",
+    "\n",
+    "builder = StateGraph(state_schema=OverallState)\n",
+    "builder.add_node(\"llm_node\", llm_node)\n",
+    "builder.add_node(\"output_node\", output_node)\n",
+    "\n",
+    "builder.add_edge(START, \"llm_node\")\n",
+    "builder.add_edge(\"llm_node\", \"output_node\")\n",
+    "builder.add_edge(\"output_node\", END)"
+   ],
+   "id": "887432b11f020144",
+   "outputs": [],
+   "execution_count": null
+  },
+  {
+   "metadata": {},
+   "cell_type": "code",
+   "source": [
+    "from langgraph.checkpoint.postgres import PostgresSaver\n",
+    "from langchain_core.runnables import RunnableConfig\n",
+    "from rich import print as rp\n",
+    "\n",
+    "with PostgresSaver.from_conn_string(os.getenv(\"LANGGRAPH_DATABASE_URL\")) as checkpointer:\n",
+    "    checkpointer.setup()\n",
+    "    graph = builder.compile(checkpointer=checkpointer)\n",
+    "\n",
+    "    config: RunnableConfig = {\n",
+    "        \"configurable\": {\n",
+    "            \"thread_id\": \"chapter_0804\"\n",
+    "        }\n",
+    "    }\n",
+    "\n",
+    "    messages1 = {\n",
+    "        \"messages\": [\n",
+    "            {\"role\": \"user\", \"content\": \"你好，我是gqt\"}\n",
+    "        ]\n",
+    "    }\n",
+    "    messages2 = {\n",
+    "        \"messages\": [\n",
+    "            {\"role\": \"user\", \"content\": \"你好，我是谁？\"}\n",
+    "        ]\n",
+    "    }\n",
+    "\n",
+    "    res1 = graph.invoke(messages2, config=config)\n",
+    "\n",
+    "\n",
+    "    rp(res1)\n",
+    "    history_checkpoint = list(graph.get_state_history(config=config))\n",
+    "\n",
+    "    # rp(history_checkpoint)"
+   ],
+   "id": "e0f6b05e0dfeb578",
+   "outputs": [],
+   "execution_count": null
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.6"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}