Zep 开源检索器

Zep 是一款面向 AI 助手应用的长期记忆服务。借助 Zep，您可以为 AI 助手提供回忆过去对话的能力，无论对话时间间隔有多长，同时还能减少幻觉、延迟和成本。

有兴趣使用 Zep 云？请参阅 Zep 云安装指南

此示例展示如何在检索链中使用 Zep 检索器从 Zep 开源内存存储中检索文档。

安装

按照 Zep 开源快速入门指南 安装并开始使用 Zep。

设置

提示

参阅 此部分，了解有关安装集成包的一般说明。

npm

npm i @getzep/zep-js @langchain/community

Yarn

yarn add @getzep/zep-js @langchain/community

pnpm

pnpm add @getzep/zep-js @langchain/community

用法

import { ZepRetriever } from "@langchain/community/retrievers/zep";
import { ZepMemory } from "@langchain/community/memory/zep";
import { Memory as MemoryModel, Message } from "@getzep/zep-js";
import { randomUUID } from "crypto";

function sleep(ms: number) {
  // eslint-disable-next-line no-promise-executor-return
  return new Promise((resolve) => setTimeout(resolve, ms));
}

export const run = async () => {
  const zepConfig = {
    url: process.env.ZEP_URL || "http://localhost:8000",
    sessionId: `session_${randomUUID()}`,
  };

  console.log(`Zep Config: ${JSON.stringify(zepConfig)}`);

  const memory = new ZepMemory({
    baseURL: zepConfig.url,
    sessionId: zepConfig.sessionId,
  });

  // Generate chat messages about traveling to France
  const chatMessages = [
    {
      role: "AI",
      message: "Bonjour! How can I assist you with your travel plans today?",
    },
    { role: "User", message: "I'm planning a trip to France." },
    {
      role: "AI",
      message: "That sounds exciting! What cities are you planning to visit?",
    },
    { role: "User", message: "I'm thinking of visiting Paris and Nice." },
    {
      role: "AI",
      message: "Great choices! Are you interested in any specific activities?",
    },
    { role: "User", message: "I would love to visit some vineyards." },
    {
      role: "AI",
      message:
        "France has some of the best vineyards in the world. I can help you find some.",
    },
    { role: "User", message: "That would be great!" },
    { role: "AI", message: "Do you prefer red or white wine?" },
    { role: "User", message: "I prefer red wine." },
    {
      role: "AI",
      message:
        "Perfect! I'll find some vineyards that are known for their red wines.",
    },
    { role: "User", message: "Thank you, that would be very helpful." },
    {
      role: "AI",
      message:
        "You're welcome! I'll also look up some French wine etiquette for you.",
    },
    {
      role: "User",
      message: "That sounds great. I can't wait to start my trip!",
    },
    {
      role: "AI",
      message:
        "I'm sure you'll have a fantastic time. Do you have any other questions about your trip?",
    },
    { role: "User", message: "Not at the moment, thank you for your help!" },
  ];

  const zepClient = await memory.zepClientPromise;
  if (!zepClient) {
    throw new Error("ZepClient is not initialized");
  }

  // Add chat messages to memory
  for (const chatMessage of chatMessages) {
    let m: MemoryModel;
    if (chatMessage.role === "AI") {
      m = new MemoryModel({
        messages: [new Message({ role: "ai", content: chatMessage.message })],
      });
    } else {
      m = new MemoryModel({
        messages: [
          new Message({ role: "human", content: chatMessage.message }),
        ],
      });
    }

    await zepClient.memory.addMemory(zepConfig.sessionId, m);
  }

  // Wait for messages to be summarized, enriched, embedded and indexed.
  await sleep(10000);

  // Simple similarity search
  const query = "Can I drive red cars in France?";
  const retriever = new ZepRetriever({ ...zepConfig, topK: 3 });
  const docs = await retriever.invoke(query);
  console.log("Simple similarity search");
  console.log(JSON.stringify(docs, null, 2));

  // mmr reranking search
  const mmrRetriever = new ZepRetriever({
    ...zepConfig,
    topK: 3,
    searchType: "mmr",
    mmrLambda: 0.5,
  });
  const mmrDocs = await mmrRetriever.invoke(query);
  console.log("MMR reranking search");
  console.log(JSON.stringify(mmrDocs, null, 2));

  // summary search with mmr reranking
  const mmrSummaryRetriever = new ZepRetriever({
    ...zepConfig,
    topK: 3,
    searchScope: "summary",
    searchType: "mmr",
    mmrLambda: 0.5,
  });
  const mmrSummaryDocs = await mmrSummaryRetriever.invoke(query);
  console.log("Summary search with MMR reranking");
  console.log(JSON.stringify(mmrSummaryDocs, null, 2));

  // Filtered search
  const filteredRetriever = new ZepRetriever({
    ...zepConfig,
    topK: 3,
    filter: {
      where: { jsonpath: '$.system.entities[*] ? (@.Label == "GPE")' },
    },
  });
  const filteredDocs = await filteredRetriever.invoke(query);
  console.log("Filtered search");
  console.log(JSON.stringify(filteredDocs, null, 2));
};

API 参考

• ZepRetriever 来自 @langchain/community/retrievers/zep
• ZepMemory 来自 @langchain/community/memory/zep

相关

• 检索器 概念指南
• 检索器 操作指南