feat: solution for 'Экзамен: RAG-агент с ChromaDB и веб-поиском'

README.md

@@ -1,110 +1,73 @@
 # RAG Agent with ChromaDB and Web Search
 
-This project implements a Retrieval-Augmented Generation (RAG) agent that uses a local ChromaDB vector store for document retrieval and falls back to DuckDuckGo web search when the local store does not provide sufficient context.
+This project demonstrates a Retrieval-Augmented Generation (RAG) agent built with **LangChain 1.x**, **ChromaDB** as the vector store, and **SerpAPI** for web search integration.
 
 ## Features
 
-- **Local Retrieval** – Store and query embeddings in a persistent ChromaDB collection.
+- Stores documents in ChromaDB and generates embeddings using OpenAI.
-- **Web Search Fallback** – If local retrieval fails to find relevant context, the agent performs a DuckDuckGo search and uses the snippets.
+- Retrieves relevant documents via a vector store tool.
-- **OpenAI Integration** – Uses OpenAI embeddings (`text-embedding-ada-002`) and the `gpt-3.5-turbo` model for generation.
+- Performs live web searches with SerpAPI.
-- **CLI** – Simple command line interface for ingesting documents and asking questions.
+- Combines both sources to answer user queries.
 
 ## Prerequisites
 
-- Python 3.9+
+- Node.js v18+ (ES modules support)
-- An OpenAI API key
+- A running ChromaDB instance (default: `localhost:8000`)
-- (Optional) Internet access for web search
+- OpenAI API key
+- SerpAPI key
 
-## Installation
+## Setup
 
-```bash
+1. **Clone the repository**
-# Clone the repository
-git clone https://git.brojs.ru/kuzakhmetovartur/ekzamen-rag-agent-s-chromadb-i-veb-poisk.git
-cd ekzamen-rag-agent-s-chromadb-i-veb-poisk
 
-# Create a virtual environment (recommended)
+   ```bash
-python -m venv .venv
+   git clone https://github.com/your-username/rag-agent-chromadb-websearch.git
-source .venv/bin/activate   # On Windows use `.venv\Scripts\activate`
+   cd rag-agent-chromadb-websearch
+   ```
 
-# Install dependencies
+2. **Install dependencies**
-pip install -r requirements.txt
-```
 
-`requirements.txt` contains:
+   ```bash
+   npm install
+   ```
+
+3. **Configure environment variables**
+
+   Create a `.env` file in the project root:
+
+   ```dotenv
+   OPENAI_API_KEY=your_openai_api_key
+   CHROMA_HOST=localhost
+   CHROMA_PORT=8000
+   SERPAPI_KEY=your_serpapi_key
+   ```
+
+4. **Run the agent**
+
+   ```bash
+   npm start
+   ```
+
+   The agent will add sample documents to ChromaDB, then answer a sample query using both the vector store and web search.
+
+## Project Structure
 
 ```
-openai
+src/
-chromadb
+├── index.js        # Entry point
-duckduckgo-search
+├── agent.js        # Agent construction
-beautifulsoup4
+├── vectorStore.js  # ChromaDB interactions
-requests
+└── webSearch.js    # SerpAPI web search
 ```
 
-## Environment Variables
+## Customization
 
-| Variable | Description | Example |
+- **Adding Documents**: Use `addDocuments` from `vectorStore.js` to add your own documents.
-|----------|-------------|---------|
+- **Changing LLM**: Replace `OpenAI` with another LLM provider supported by LangChain.
-| `OPENAI_API_KEY` | Your OpenAI API key | `sk-...` |
+- **Adjusting Retrieval**: Modify the number of results returned by the vector store or web search.
-| `CHROMA_DB_PATH` | Directory where ChromaDB stores data | `./chromadb` |
-| `CHROMA_COLLECTION_NAME` | Name of the collection | `rag_collection` |
-| `TOP_K` | Number of top documents to retrieve | `5` |
-| `SIMILARITY_THRESHOLD` | Minimum similarity to consider a document relevant | `0.5` |
-| `WEB_SEARCH_MAX_RESULTS` | Max number of web snippets to fetch | `3` |
-
-Set them in your shell or create a `.env` file and load with `dotenv` (optional).
-
-## Usage
-
-### Ingest Documents
-
-Place your plain text files (`.txt`) in a folder, then run:
-
-```bash
-python src/index.py ingest /path/to/text/files
-```
-
-The script will read all `.txt` files, split them into chunks, embed them, and store them in ChromaDB.
-
-### Ask a Question
-
-```bash
-python src/index.py ask "What is the capital of France?"
-```
-
-The agent will:
-
-1. Query the local vector store for relevant passages.
-2. If none are found above the similarity threshold, perform a DuckDuckGo search.
-3. Combine the retrieved context into a prompt.
-4. Call OpenAI’s `gpt-3.5-turbo` to generate an answer.
-
-## Example
-
-```bash
-$ python src/index.py ingest ./data
-INFO:root:Added 12 documents to collection 'rag_collection'.
-
-$ python src/index.py ask "Explain the theory of relativity."
-Answer:
-The theory of relativity, developed by Albert Einstein, consists of two parts: special relativity and general relativity. ...
-```
-
-## Testing
-
-Unit tests are provided in the `tests/` directory. To run them:
-
-```bash
-pytest tests/
-```
-
-(If you don't have `pytest` installed, run `pip install pytest`.)
-
-## Troubleshooting
-
-- **No documents ingested** – Ensure the folder path is correct and contains `.txt` files.
-- **OpenAI errors** – Verify that `OPENAI_API_KEY` is set and that you have sufficient quota.
-- **Web search fails** – Check your internet connection and that DuckDuckGo is reachable.
 
 ## License
 
 MIT License
+--- 
+Happy coding!

package.json

@@ -1,16 +1,17 @@
 {
   "name": "rag-agent-chromadb-websearch",
   "version": "1.0.0",
-  "description": "RAG agent using ChromaDB and OpenAI API with web search",
+  "description": "RAG agent using ChromaDB and web search with LangChain 1.x",
   "main": "src/index.js",
-  "type": "commonjs",
+  "type": "module",
   "scripts": {
     "start": "node src/index.js"
   },
   "dependencies": {
     "chromadb": "^1.0.0",
-    "dotenv": "^16.4.5",
+    "dotenv": "^16.0.3",
-    "node-fetch": "^2.6.7",
+    "langchain": "^1.0.0",
-    "openai": "^4.12.0"
+    "openai": "^3.3.0",
+    "serpapi": "^2.0.0"
   }
 }

src/agent.js

@@ -1,37 +1,54 @@
-const { OpenAI } = require('openai');
+import { OpenAI } from 'langchain/llms/openai';
-const dotenv = require('dotenv');
+import { Tool } from 'langchain/tools';
-dotenv.config();
+import { AgentExecutor } from 'langchain/agents';
+import { query } from './vectorStore.js';
+import { webSearch } from './webSearch.js';
 
-const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
+const llm = new OpenAI({
+  temperature: 0,
+  openAIApiKey: process.env.OPENAI_API_KEY,
+});
 
-class Agent {
+/**
-  constructor(vectorStore) {
+ * Tool that retrieves relevant documents from ChromaDB.
-    this.vectorStore = vectorStore;
+ */
-  }
+const vectorStoreTool = new Tool({
+  name: 'VectorStore',
+  description: 'Retrieve relevant documents from the vector store.',
+  func: async (input) => {
+    const result = await query(input);
+    if (!result.documents || result.documents.length === 0) {
+      return 'No relevant documents found.';
+    }
+    return result.documents.map((doc, idx) => `(${idx + 1}) ${doc}`).join('\n');
+  },
+});
 
-  async ask(question) {
+/**
-    const contextDocs = await this.vectorStore.query(question, 5);
+ * Tool that performs a web search.
-    const context = contextDocs.join('\n\n');
+ */
-    const prompt = `
+const webSearchTool = new Tool({
-You are a helpful assistant. Use the following context to answer the question. If the context does not contain the answer, say you don't know.
+  name: 'WebSearch',
+  description: 'Search the web for up-to-date information.',
+  func: async (input) => {
+    const results = await webSearch(input);
+    if (!results || results.length === 0) {
+      return 'No web results found.';
+    }
+    return results
+      .map((r, idx) => `(${idx + 1}) ${r.title}: ${r.link}`)
+      .join('\n');
+  },
+});
 
-Context:
+const tools = [vectorStoreTool, webSearchTool];
-${context}
 
-Question:
+/**
-${question}
+ * Create and return a LangChain 1.x AgentExecutor.
-Answer:
+ */
-`;
+export async function createAgent() {
-
+  const agent = await AgentExecutor.fromLLMAndTools(llm, tools, {
-    const completion = await openai.chat.completions.create({
+    verbose: true,
-      model: 'gpt-3.5-turbo',
+  });
-      messages: [{ role: 'user', content: prompt }],
+  return agent;
-      temperature: 0.2,
-      max_tokens: 300,
-    });
-
-    return completion.choices[0].message.content.trim();
-  }
 }
-
-module.exports = Agent;

src/index.js

@@ -1,54 +1,28 @@
-const readline = require('readline');
+import dotenv from 'dotenv';
-const VectorStore = require('./vectorStore');
-const Agent = require('./agent');
-const { searchAndChunk } = require('./webSearch');
-const dotenv = require('dotenv');
 dotenv.config();
 
+import { createAgent } from './agent.js';
+import { addDocuments } from './vectorStore.js';
+
 async function main() {
-  console.log('Initializing RAG agent...');
+  // Add sample documents to the vector store
-  const vectorStore = new VectorStore();
+  const sampleDocs = [
-
+    'LangChain is a framework for building applications powered by language models.',
-  // Example URLs to index
+    'ChromaDB is an open-source vector database that stores embeddings.',
-  const urls = [
+    'Web search can provide up-to-date information that may not be in the vector store.',
-    'https://en.wikipedia.org/wiki/Artificial_intelligence',
-    'https://en.wikipedia.org/wiki/ChromaDB',
-    'https://en.wikipedia.org/wiki/OpenAI',
   ];
+  await addDocuments(sampleDocs);
 
-  console.log('Fetching and indexing web pages...');
+  const agent = await createAgent();
-  const chunks = await searchAndChunk(urls);
-  await vectorStore.addDocuments(chunks);
-  console.log(`Indexed ${chunks.length} chunks.`);
 
-  const agent = new Agent(vectorStore);
+  const query = 'Explain how LangChain can use ChromaDB and web search together.';
+  const result = await agent.invoke({ input: query });
 
-  const rl = readline.createInterface({
+  console.log('\n=== Agent Response ===\n');
-    input: process.stdin,
+  console.log(result.output);
-    output: process.stdout,
-  });
-
-  const askQuestion = () => {
-    rl.question('\nEnter your question (or type "exit" to quit): ', async (answer) => {
-      if (answer.trim().toLowerCase() === 'exit') {
-        rl.close();
-        return;
-      }
-      console.log('\nGenerating answer...');
-      try {
-        const response = await agent.ask(answer);
-        console.log(`\nAnswer:\n${response}`);
-      } catch (err) {
-        console.error('Error generating answer:', err);
-      }
-      askQuestion();
-    });
-  };
-
-  askQuestion();
 }
 
 main().catch((err) => {
-  console.error('Fatal error:', err);
+  console.error('Error running the agent:', err);
   process.exit(1);
 });

src/vectorStore.js

@@ -1,52 +1,58 @@
-const chromadb = require('chromadb');
+import { ChromaClient } from 'chromadb';
-const { OpenAI } = require('openai');
+import { OpenAIEmbeddings } from 'langchain/embeddings/openai';
-const dotenv = require('dotenv');
-dotenv.config();
 
-const openai = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });
+const chroma = new ChromaClient({
+  host: process.env.CHROMA_HOST || 'localhost',
+  port: parseInt(process.env.CHROMA_PORT, 10) || 8000,
+});
 
-class VectorStore {
+const embeddings = new OpenAIEmbeddings({
-  constructor() {
+  openAIApiKey: process.env.OPENAI_API_KEY,
-    this.client = new chromadb.Client({ path: './chromadb' });
+});
-    this.collection = this.client.getCollection('rag_collection');
-  }
 
-  async getEmbedding(text) {
+const COLLECTION_NAME = 'rag_collection';
-    const response = await openai.embeddings.create({
-      model: 'text-embedding-ada-002',
-      input: text,
-    });
-    return response.data[0].embedding;
-  }
 
-  async addDocuments(chunks) {
+/**
-    const documents = [];
+ * Ensure the collection exists in ChromaDB.
-    const embeddings = [];
+ */
-    const ids = [];
+async function ensureCollection() {
-
+  const collections = await chroma.listCollections();
-    for (const chunk of chunks) {
+  if (!collections.includes(COLLECTION_NAME)) {
-      const embedding = await this.getEmbedding(chunk);
+    await chroma.createCollection({ name: COLLECTION_NAME });
-      documents.push(chunk);
-      embeddings.push(embedding);
-      ids.push(`${Date.now()}-${Math.random()}`);
-    }
-
-    await this.collection.add({
-      documents,
-      embeddings,
-      ids,
-    });
-  }
-
-  async query(queryText, k = 5) {
-    const queryEmbedding = await this.getEmbedding(queryText);
-    const results = await this.collection.query({
-      queryEmbeddings: [queryEmbedding],
-      nResults: k,
-    });
-
-    return results.documents[0];
   }
 }
 
-module.exports = VectorStore;
+/**
+ * Add an array of documents to the vector store.
+ * @param {string[]} docs
+ */
+export async function addDocuments(docs) {
+  await ensureCollection();
+  const ids = docs.map((_, idx) => `doc-${Date.now()}-${idx}`);
+  const embeddingsResult = await embeddings.embedDocuments(docs);
+  await chroma.add({
+    collection_name: COLLECTION_NAME,
+    ids,
+    documents: docs,
+    embeddings: embeddingsResult,
+  });
+}
+
+/**
+ * Query the vector store for the most relevant documents.
+ * @param {string} queryText
+ * @param {number} nResults
+ * @returns {Promise<{documents: string[]}>}
+ */
+export async function query(queryText, nResults = 3) {
+  await ensureCollection();
+  const embedding = await embeddings.embedQuery(queryText);
+  const results = await chroma.query({
+    collection_name: COLLECTION_NAME,
+    query_embeddings: [embedding],
+    n_results: nResults,
+  });
+  // ChromaDB returns an array of objects; extract documents
+  const docs = results.documents || [];
+  return { documents: docs };
+}

src/webSearch.js

@@ -1,42 +1,19 @@
-const fetch = require('node-fetch');
+import { GoogleSearchResults } from 'serpapi';
 
-async function fetchPage(url) {
+/**
-  try {
+ * Perform a web search using SerpAPI.
-    const res = await fetch(url);
+ * @param {string} query
-    if (!res.ok) {
+ * @returns {Promise<Array<{title: string, link: string}>>}
-      console.warn(`Failed to fetch ${url}: ${res.statusText}`);
+ */
-      return '';
+export async function webSearch(query) {
-    }
+  const search = new GoogleSearchResults({
-    const html = await res.text();
+    api_key: process.env.SERPAPI_KEY,
-    // Strip HTML tags
+    engine: 'google',
-    const text = html.replace(/<[^>]*>/g, ' ');
+  });
-    // Collapse whitespace
+  const results = await search.get({ q: query, num: 5 });
-    const cleaned = text.replace(/\s+/g, ' ').trim();
+  // Return only the organic results with title and link
-    return cleaned;
+  return (results.organic_results || []).map((r) => ({
-  } catch (err) {
+    title: r.title,
-    console.error(`Error fetching ${url}:`, err);
+    link: r.link,
-    return '';
+  }));
-  }
 }
-
-function chunkText(text, size = 500) {
-  const chunks = [];
-  for (let i = 0; i < text.length; i += size) {
-    chunks.push(text.slice(i, i + size));
-  }
-  return chunks;
-}
-
-async function searchAndChunk(urls) {
-  const allChunks = [];
-  for (const url of urls) {
-    const pageText = await fetchPage(url);
-    if (pageText) {
-      const chunks = chunkText(pageText);
-      allChunks.push(...chunks);
-    }
-  }
-  return allChunks;
-}
-
-module.exports = { searchAndChunk };