388 lines
16 KiB
JavaScript
388 lines
16 KiB
JavaScript
import { errors } from "@opensearch-project/opensearch";
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import * as uuid from "uuid";
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import { VectorStore } from "@langchain/core/vectorstores";
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import { Document } from "@langchain/core/documents";
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/**
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* Class that provides a wrapper around the OpenSearch service for vector
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* search. It provides methods for adding documents and vectors to the
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* OpenSearch index, searching for similar vectors, and managing the
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* OpenSearch index.
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*/
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export class OpenSearchVectorStore extends VectorStore {
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_vectorstoreType() {
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return "opensearch";
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}
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constructor(embeddings, args) {
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super(embeddings, args);
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Object.defineProperty(this, "client", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "indexName", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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// if true, use the Amazon OpenSearch Serverless service instead of es
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Object.defineProperty(this, "isAoss", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "engine", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "spaceType", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "efConstruction", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "efSearch", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "numberOfShards", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "numberOfReplicas", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "m", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "vectorFieldName", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "textFieldName", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "metadataFieldName", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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this.spaceType = args.vectorSearchOptions?.spaceType ?? "l2";
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this.engine = args.vectorSearchOptions?.engine ?? "nmslib";
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this.m = args.vectorSearchOptions?.m ?? 16;
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this.efConstruction = args.vectorSearchOptions?.efConstruction ?? 512;
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this.efSearch = args.vectorSearchOptions?.efSearch ?? 512;
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this.numberOfShards = args.vectorSearchOptions?.numberOfShards ?? 5;
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this.numberOfReplicas = args.vectorSearchOptions?.numberOfReplicas ?? 1;
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this.vectorFieldName = args.vectorFieldName ?? "embedding";
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this.textFieldName = args.textFieldName ?? "text";
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this.metadataFieldName = args.metadataFieldName ?? "metadata";
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this.client = args.client;
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this.indexName = args.indexName ?? "documents";
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this.isAoss = (args.service ?? "es") === "aoss";
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}
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/**
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* Method to add documents to the OpenSearch index. It first converts the
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* documents to vectors using the embeddings, then adds the vectors to the
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* index.
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* @param documents The documents to be added to the OpenSearch index.
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* @returns Promise resolving to void.
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*/
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async addDocuments(documents) {
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const texts = documents.map(({ pageContent }) => pageContent);
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return this.addVectors(await this.embeddings.embedDocuments(texts), documents);
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}
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/**
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* Method to add vectors to the OpenSearch index. It ensures the index
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* exists, then adds the vectors and associated documents to the index.
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* @param vectors The vectors to be added to the OpenSearch index.
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* @param documents The documents associated with the vectors.
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* @param options Optional parameter that can contain the IDs for the documents.
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* @returns Promise resolving to void.
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*/
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async addVectors(vectors, documents, options) {
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await this.ensureIndexExists(vectors[0].length, this.engine, this.spaceType, this.efSearch, this.efConstruction, this.numberOfShards, this.numberOfReplicas, this.m);
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const documentIds = options?.ids ?? Array.from({ length: vectors.length }, () => uuid.v4());
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const operations = vectors.flatMap((embedding, idx) => {
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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const document = [
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{
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index: {
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_index: this.indexName,
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_id: documentIds[idx],
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},
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},
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{
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[this.vectorFieldName]: embedding,
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[this.textFieldName]: documents[idx].pageContent,
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[this.metadataFieldName]: documents[idx].metadata,
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},
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];
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// aoss does not support document id
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if (this.isAoss) {
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delete document[0].index?._id;
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}
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return document;
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});
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await this.client.bulk({ body: operations });
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// aoss does not support refresh
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if (!this.isAoss) {
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await this.client.indices.refresh({ index: this.indexName });
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}
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}
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/**
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* Method to perform a similarity search on the OpenSearch index using a
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* query vector. It returns the k most similar documents and their scores.
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* @param query The query vector.
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* @param k The number of similar documents to return.
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* @param filter Optional filter for the OpenSearch query.
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* @returns Promise resolving to an array of tuples, each containing a Document and its score.
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*/
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async similaritySearchVectorWithScore(query, k, filter) {
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const search = {
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index: this.indexName,
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body: {
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query: {
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bool: {
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filter: { bool: this.buildMetadataTerms(filter) },
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must: [
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{
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knn: {
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[this.vectorFieldName]: { vector: query, k },
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},
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},
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],
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},
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},
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size: k,
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},
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};
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const { body } = await this.client.search(search);
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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return body.hits.hits.map((hit) => [
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new Document({
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pageContent: hit._source[this.textFieldName],
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metadata: hit._source[this.metadataFieldName],
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}),
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hit._score,
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]);
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}
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/**
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* Static method to create a new OpenSearchVectorStore from an array of
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* texts, their metadata, embeddings, and OpenSearch client arguments.
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* @param texts The texts to be converted into documents and added to the OpenSearch index.
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* @param metadatas The metadata associated with the texts. Can be an array of objects or a single object.
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* @param embeddings The embeddings used to convert the texts into vectors.
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* @param args The OpenSearch client arguments.
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* @returns Promise resolving to a new instance of OpenSearchVectorStore.
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*/
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static fromTexts(texts, metadatas, embeddings, args) {
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const documents = texts.map((text, idx) => {
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const metadata = Array.isArray(metadatas) ? metadatas[idx] : metadatas;
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return new Document({ pageContent: text, metadata });
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});
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return OpenSearchVectorStore.fromDocuments(documents, embeddings, args);
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}
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/**
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* Static method to create a new OpenSearchVectorStore from an array of
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* Documents, embeddings, and OpenSearch client arguments.
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* @param docs The documents to be added to the OpenSearch index.
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* @param embeddings The embeddings used to convert the documents into vectors.
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* @param dbConfig The OpenSearch client arguments.
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* @returns Promise resolving to a new instance of OpenSearchVectorStore.
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*/
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static async fromDocuments(docs, embeddings, dbConfig) {
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const store = new OpenSearchVectorStore(embeddings, dbConfig);
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await store.addDocuments(docs).then(() => store);
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return store;
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}
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/**
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* Static method to create a new OpenSearchVectorStore from an existing
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* OpenSearch index, embeddings, and OpenSearch client arguments.
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* @param embeddings The embeddings used to convert the documents into vectors.
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* @param dbConfig The OpenSearch client arguments.
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* @returns Promise resolving to a new instance of OpenSearchVectorStore.
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*/
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static async fromExistingIndex(embeddings, dbConfig) {
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const store = new OpenSearchVectorStore(embeddings, dbConfig);
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await store.client.cat.indices({ index: store.indexName });
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return store;
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}
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async ensureIndexExists(dimension, engine = "nmslib", spaceType = "l2", efSearch = 512, efConstruction = 512, numberOfShards = 5, numberOfReplicas = 1, m = 16) {
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const body = {
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settings: {
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index: {
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number_of_shards: numberOfShards,
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number_of_replicas: numberOfReplicas,
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knn: true,
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"knn.algo_param.ef_search": efSearch,
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},
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},
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mappings: {
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dynamic_templates: [
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{
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// map all metadata properties to be keyword
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[`${this.metadataFieldName}.*`]: {
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match_mapping_type: "string",
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mapping: { type: "keyword" },
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},
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},
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{
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[`${this.metadataFieldName}.loc`]: {
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match_mapping_type: "object",
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mapping: { type: "object" },
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},
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},
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],
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properties: {
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[this.textFieldName]: { type: "text" },
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[this.metadataFieldName]: { type: "object" },
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[this.vectorFieldName]: {
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type: "knn_vector",
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dimension,
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method: {
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name: "hnsw",
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engine,
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space_type: spaceType,
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parameters: { ef_construction: efConstruction, m },
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},
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},
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},
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},
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};
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const indexExists = await this.doesIndexExist();
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if (indexExists)
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return;
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await this.client.indices.create({ index: this.indexName, body });
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}
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/**
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* Builds metadata terms for OpenSearch queries.
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*
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* This function takes a filter object and constructs an array of query terms
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* compatible with OpenSearch 2.x. It supports a variety of query types including
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* term, terms, terms_set, ids, range, prefix, exists, fuzzy, wildcard, and regexp.
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* Reference: https://opensearch.org/docs/latest/query-dsl/term/index/
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*
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* @param {Filter | null} filter - The filter object used to construct query terms.
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* Each key represents a field, and the value specifies the type of query and its parameters.
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*
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* @returns {Array<Record<string, any>>} An array of OpenSearch query terms.
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*
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* @example
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* // Example filter:
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* const filter = {
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* status: { "exists": true },
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* age: { "gte": 30, "lte": 40 },
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* tags: ["tag1", "tag2"],
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* description: { "wildcard": "*test*" },
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*
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* };
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*
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* // Resulting query terms:
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* const queryTerms = buildMetadataTerms(filter);
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* // queryTerms would be an array of OpenSearch query objects.
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*/
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buildMetadataTerms(filter) {
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if (!filter)
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return {};
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const must = [];
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const must_not = [];
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for (const [key, value] of Object.entries(filter)) {
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const metadataKey = `${this.metadataFieldName}.${key}`;
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if (value) {
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if (typeof value === "object" && !Array.isArray(value)) {
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if ("exists" in value) {
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if (value.exists) {
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must.push({ exists: { field: metadataKey } });
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}
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else {
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must_not.push({ exists: { field: metadataKey } });
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}
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}
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else if ("fuzzy" in value) {
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must.push({ fuzzy: { [metadataKey]: value.fuzzy } });
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}
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else if ("ids" in value) {
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must.push({ ids: { values: value.ids } });
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}
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else if ("prefix" in value) {
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must.push({ prefix: { [metadataKey]: value.prefix } });
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}
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else if ("gte" in value ||
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"gt" in value ||
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"lte" in value ||
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"lt" in value) {
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must.push({ range: { [metadataKey]: value } });
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}
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else if ("regexp" in value) {
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must.push({ regexp: { [metadataKey]: value.regexp } });
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}
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else if ("terms_set" in value) {
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must.push({ terms_set: { [metadataKey]: value.terms_set } });
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}
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else if ("wildcard" in value) {
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must.push({ wildcard: { [metadataKey]: value.wildcard } });
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}
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}
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else {
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const aggregatorKey = Array.isArray(value) ? "terms" : "term";
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must.push({ [aggregatorKey]: { [metadataKey]: value } });
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}
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}
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}
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return { must, must_not };
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}
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/**
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* Method to check if the OpenSearch index exists.
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* @returns Promise resolving to a boolean indicating whether the index exists.
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*/
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async doesIndexExist() {
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try {
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await this.client.cat.indices({ index: this.indexName });
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return true;
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}
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catch (err) {
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// eslint-disable-next-line no-instanceof/no-instanceof
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if (err instanceof errors.ResponseError && err.statusCode === 404) {
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return false;
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}
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throw err;
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}
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}
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/**
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* Method to delete the OpenSearch index if it exists.
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* @returns Promise resolving to void.
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*/
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async deleteIfExists() {
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const indexExists = await this.doesIndexExist();
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if (!indexExists)
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return;
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await this.client.indices.delete({ index: this.indexName });
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}
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}
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