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langgraph-learning/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
}