community[minor]: add CassandraKVStore

docs/core_docs/docs/integrations/stores/cassandra_storage.mdx

@@ -0,0 +1,60 @@
+---
+sidebar_class_name: node-only
+---
+
+# Cassandra KV
+
+This example demonstrates how to setup chat history storage using the `CassandraKVStore` `BaseStore` integration. Note there is a `CassandraChatMessageHistory`
+integration which may be easier to use for chat history storage; the `CassandraKVStore` is useful if you want a more general-purpose key-value store with
+prefixable keys.
+
+## Setup
+
+```bash npm2yarn
+npm install cassandra-driver
+```
+
+Depending on your database providers, the specifics of how to connect to the database will vary. We will create a document `configConnection` which will be used as part of the store configuration.
+
+### Apache Cassandra®
+
+Storage Attached Indexes (used by `yieldKeys`) are supported in [Apache Cassandra® 5.0](https://cassandra.apache.org/_/blog/Apache-Cassandra-5.0-Features-Storage-Attached-Indexes.html) and above. You can use a standard connection document, for example:
+
+```typescript
+const configConnection = {
+  contactPoints: ['h1', 'h2'],
+  localDataCenter: 'datacenter1',
+  credentials: {
+    username: <...> as string,
+    password: <...> as string,
+  },
+};
+```
+
+### Astra DB
+
+Astra DB is a cloud-native Cassandra-as-a-Service platform.
+
+1. Create an [Astra DB account](https://astra.datastax.com/register).
+2. Create a [vector enabled database](https://astra.datastax.com/createDatabase).
+3. Create a [token](https://docs.datastax.com/en/astra/docs/manage-application-tokens.html) for your database.
+
+```typescript
+const configConnection = {
+  serviceProviderArgs: {
+    astra: {
+      token: <...> as string,
+      endpoint: <...> as string,
+    },
+  },
+};
+```
+
+Instead of `endpoint:`, you many provide property `datacenterID:` and optionally `regionName:`.
+
+## Usage
+
+import CodeBlock from "@theme/CodeBlock";
+import Example from "@examples/stores/cassandra_storage.ts";
+
+<CodeBlock language="typescript">{Example}</CodeBlock>

examples/src/stores/cassandra_storage.ts

@@ -0,0 +1,82 @@
+import { CassandraKVStore } from "@langchain/community/storage/cassandra";
+import { AIMessage, HumanMessage } from "@langchain/core/messages";
+
+// This document is the Cassandra driver connection document; the example is to AstraDB but
+// any valid Cassandra connection can be used.
+const configConnection = {
+  serviceProviderArgs: {
+    astra: {
+      token: "YOUR_TOKEN_OR_LOAD_FROM_ENV" as string,
+      endpoint: "YOUR_ENDPOINT_OR_LOAD_FROM_ENV" as string,
+    },
+  },
+};
+
+const store = new CassandraKVStore({
+  ...configConnection,
+  keyspace: "test", // keyspace must exist
+  table: "test_kv", // table will be created if it does not exist
+  keyDelimiter: ":", // optional, default is "/"
+});
+
+// Define our encoder/decoder for converting between strings and Uint8Arrays
+const encoder = new TextEncoder();
+const decoder = new TextDecoder();
+
+/**
+ * Here you would define your LLM and chat chain, call
+ * the LLM and eventually get a list of messages.
+ * For this example, we'll assume we already have a list.
+ */
+const messages = Array.from({ length: 5 }).map((_, index) => {
+  if (index % 2 === 0) {
+    return new AIMessage("ai stuff...");
+  }
+  return new HumanMessage("human stuff...");
+});
+
+// Set your messages in the store
+// The key will be prefixed with `message:id:` and end
+// with the index.
+await store.mset(
+  messages.map((message, index) => [
+    `message:id:${index}`,
+    encoder.encode(JSON.stringify(message)),
+  ])
+);
+
+// Now you can get your messages from the store
+const retrievedMessages = await store.mget(["message:id:0", "message:id:1"]);
+// Make sure to decode the values
+console.log(retrievedMessages.map((v) => decoder.decode(v)));
+
+/**
+[
+  '{"id":["langchain","AIMessage"],"kwargs":{"content":"ai stuff..."}}',
+  '{"id":["langchain","HumanMessage"],"kwargs":{"content":"human stuff..."}}'
+]
+ */
+
+// Or, if you want to get back all the keys you can call
+// the `yieldKeys` method.
+// Optionally, you can pass a key prefix to only get back
+// keys which match that prefix.
+const yieldedKeys = [];
+for await (const key of store.yieldKeys("message:id:")) {
+  yieldedKeys.push(key);
+}
+
+// The keys are not encoded, so no decoding is necessary
+console.log(yieldedKeys);
+/**
+[
+  'message:id:2',
+  'message:id:1',
+  'message:id:3',
+  'message:id:0',
+  'message:id:4'
+]
+ */
+
+// Finally, let's delete the keys from the store
+await store.mdelete(yieldedKeys);

libs/langchain-community/.gitignore

@@ -574,6 +574,10 @@ document_transformers/mozilla_readability.cjs
 document_transformers/mozilla_readability.js
 document_transformers/mozilla_readability.d.ts
 document_transformers/mozilla_readability.d.cts
+storage/cassandra.cjs
+storage/cassandra.js
+storage/cassandra.d.ts
+storage/cassandra.d.cts
 storage/convex.cjs
 storage/convex.js
 storage/convex.d.ts

libs/langchain-community/langchain.config.js

@@ -182,6 +182,7 @@ export const config = {
     "document_transformers/mozilla_readability":
       "document_transformers/mozilla_readability",
     // storage
+    "storage/cassandra": "storage/cassandra",
     "storage/convex": "storage/convex",
     "storage/ioredis": "storage/ioredis",
     "storage/upstash_redis": "storage/upstash_redis",
@@ -315,6 +316,7 @@ export const config = {
     "document_transformers/html_to_text",
     "document_transformers/mozilla_readability",
     // storage
+    "storage/cassandra",
     "storage/convex",
     "storage/ioredis",
     "storage/upstash_redis",
@@ -335,7 +337,9 @@ export const config = {
     // memory
     "memory/motorhead_memory",
     "memory/zep",
+    // utils
     "util/convex",
+    "utils/cassandra",
     // indexes
     "indexes/postgres",
     "indexes/sqlite",

libs/langchain-community/package.json

@@ -1809,6 +1809,15 @@
       "import": "./document_transformers/mozilla_readability.js",
       "require": "./document_transformers/mozilla_readability.cjs"
     },
+    "./storage/cassandra": {
+      "types": {
+        "import": "./storage/cassandra.d.ts",
+        "require": "./storage/cassandra.d.cts",
+        "default": "./storage/cassandra.d.ts"
+      },
+      "import": "./storage/cassandra.js",
+      "require": "./storage/cassandra.cjs"
+    },
     "./storage/convex": {
       "types": {
         "import": "./storage/convex.d.ts",
@@ -2650,6 +2659,10 @@
     "document_transformers/mozilla_readability.js",
     "document_transformers/mozilla_readability.d.ts",
     "document_transformers/mozilla_readability.d.cts",
+    "storage/cassandra.cjs",
+    "storage/cassandra.js",
+    "storage/cassandra.d.ts",
+    "storage/cassandra.d.cts",
     "storage/convex.cjs",
     "storage/convex.js",
     "storage/convex.d.ts",