fix(redis): Add TTL support for redis vector store

libs/langchain-redis/src/tests/vectorstores.test.ts

@@ -6,6 +6,7 @@ import { RedisVectorStore } from "../vectorstores.js";
 
 const createRedisClientMockup = () => {
   const hSetMock = jest.fn();
+  const expireMock = jest.fn();
 
   return {
     ft: {
@@ -20,9 +21,11 @@ const createRedisClientMockup = () => {
       dropIndex: jest.fn(),
     },
     hSet: hSetMock,
+    expire: expireMock,
     multi: jest.fn<any>().mockImplementation(() => ({
       exec: jest.fn(),
       hSet: hSetMock,
+      expire: expireMock,
     })),
   };
 };
@@ -83,6 +86,25 @@ test("RedisVectorStore with generated keys", async () => {
   expect(results).toHaveLength(0);
 });
 
+test("RedisVectorStore with TTL", async () => {
+  const client = createRedisClientMockup();
+  const embeddings = new FakeEmbeddings();
+  const ttl = 10;
+  const store = new RedisVectorStore(embeddings, {
+    redisClient: client as any,
+    indexName: "documents",
+    ttl,
+  });
+
+  expect(store).toBeDefined();
+
+  await store.addDocuments([{ pageContent: "hello", metadata: { a: 1 } }]);
+
+  expect(client.hSet).toHaveBeenCalledTimes(1);
+  expect(client.expire).toHaveBeenCalledTimes(1);
+  expect(client.expire).toHaveBeenCalledWith("doc:documents:0", ttl);
+});
+
 test("RedisVectorStore with filters", async () => {
   const client = createRedisClientMockup();
   const embeddings = new FakeEmbeddings();

libs/langchain-redis/src/vectorstores.ts

@@ -62,7 +62,7 @@ export type RedisVectorStoreIndexOptions = Omit<
 /**
  * Interface for the configuration of the RedisVectorStore. It includes
  * the Redis client, index name, index options, key prefix, content key,
- * metadata key, vector key, and filter.
+ * metadata key, vector key, filter and ttl.
  */
 export interface RedisVectorStoreConfig {
   redisClient:
@@ -76,6 +76,7 @@ export interface RedisVectorStoreConfig {
   metadataKey?: string;
   vectorKey?: string;
   filter?: RedisVectorStoreFilterType;
+  ttl?: number; // ttl in second
 }
 
 /**
@@ -123,6 +124,8 @@ export class RedisVectorStore extends VectorStore {
 
   filter?: RedisVectorStoreFilterType;
 
+  ttl?: number;
+
   _vectorstoreType(): string {
     return "redis";
   }
@@ -144,6 +147,7 @@ export class RedisVectorStore extends VectorStore {
     this.metadataKey = _dbConfig.metadataKey ?? "metadata";
     this.vectorKey = _dbConfig.vectorKey ?? "content_vector";
     this.filter = _dbConfig.filter;
+    this.ttl = _dbConfig.ttl;
     this.createIndexOptions = {
       ON: "HASH",
       PREFIX: this.keyPrefix,
@@ -208,6 +212,10 @@ export class RedisVectorStore extends VectorStore {
         [this.metadataKey]: this.escapeSpecialChars(JSON.stringify(metadata)),
       });
 
+      if (this.ttl) {
+        multi.expire(key, this.ttl);
+      }
+
       // write batch
       if (idx % batchSize === 0) {
         await multi.exec();