feat(Postgres Chat Memory Node): Implement Postgres Chat Memory node (#10071)

packages/@n8n/nodes-langchain/nodes/memory/MemoryPostgresChat/MemoryPostgresChat.node.ts

@@ -0,0 +1,103 @@
+/* eslint-disable n8n-nodes-base/node-dirname-against-convention */
+import type { IExecuteFunctions, INodeType, INodeTypeDescription, SupplyData } from 'n8n-workflow';
+import { NodeConnectionType } from 'n8n-workflow';
+import { BufferMemory } from 'langchain/memory';
+import { PostgresChatMessageHistory } from '@langchain/community/stores/message/postgres';
+import type pg from 'pg';
+import { configurePostgres } from 'n8n-nodes-base/dist/nodes/Postgres/v2/transport';
+import type { PostgresNodeCredentials } from 'n8n-nodes-base/dist/nodes/Postgres/v2/helpers/interfaces';
+import { postgresConnectionTest } from 'n8n-nodes-base/dist/nodes/Postgres/v2/methods/credentialTest';
+import { logWrapper } from '../../../utils/logWrapper';
+import { getConnectionHintNoticeField } from '../../../utils/sharedFields';
+import { sessionIdOption, sessionKeyProperty } from '../descriptions';
+import { getSessionId } from '../../../utils/helpers';
+
+export class MemoryPostgresChat implements INodeType {
+	description: INodeTypeDescription = {
+		displayName: 'Postgres Chat Memory',
+		name: 'memoryPostgresChat',
+		icon: 'file:postgres.svg',
+		group: ['transform'],
+		version: [1],
+		description: 'Stores the chat history in Postgres table.',
+		defaults: {
+			name: 'Postgres Chat Memory',
+		},
+		credentials: [
+			{
+				name: 'postgres',
+				required: true,
+				testedBy: 'postgresConnectionTest',
+			},
+		],
+		codex: {
+			categories: ['AI'],
+			subcategories: {
+				AI: ['Memory'],
+			},
+			resources: {
+				primaryDocumentation: [
+					{
+						url: 'https://docs.n8n.io/integrations/builtin/cluster-nodes/sub-nodes/n8n-nodes-langchain.memorypostgreschat/',
+					},
+				],
+			},
+		},
+		// eslint-disable-next-line n8n-nodes-base/node-class-description-inputs-wrong-regular-node
+		inputs: [],
+		// eslint-disable-next-line n8n-nodes-base/node-class-description-outputs-wrong
+		outputs: [NodeConnectionType.AiMemory],
+		outputNames: ['Memory'],
+		properties: [
+			getConnectionHintNoticeField([NodeConnectionType.AiAgent]),
+			sessionIdOption,
+			sessionKeyProperty,
+			{
+				displayName: 'Table Name',
+				name: 'tableName',
+				type: 'string',
+				default: 'n8n_chat_histories',
+				description:
+					'The table name to store the chat history in. If table does not exist, it will be created.',
+			},
+		],
+	};
+
+	methods = {
+		credentialTest: {
+			postgresConnectionTest,
+		},
+	};
+
+	async supplyData(this: IExecuteFunctions, itemIndex: number): Promise<SupplyData> {
+		const credentials = (await this.getCredentials('postgres')) as PostgresNodeCredentials;
+		const tableName = this.getNodeParameter('tableName', itemIndex, 'n8n_chat_histories') as string;
+		const sessionId = getSessionId(this, itemIndex);
+
+		const pgConf = await configurePostgres.call(this, credentials);
+		const pool = pgConf.db.$pool as unknown as pg.Pool;
+
+		const pgChatHistory = new PostgresChatMessageHistory({
+			pool,
+			sessionId,
+			tableName,
+		});
+
+		const memory = new BufferMemory({
+			memoryKey: 'chat_history',
+			chatHistory: pgChatHistory,
+			returnMessages: true,
+			inputKey: 'input',
+			outputKey: 'output',
+		});
+
+		async function closeFunction() {
+			void pool.end();
+		}
+
+		return {
+			closeFunction,
+			response: logWrapper(memory, this),
+		};
+	}
+}

packages/@n8n/nodes-langchain/package.json

@@ -77,6 +77,7 @@
       "dist/nodes/llms/LMOpenHuggingFaceInference/LmOpenHuggingFaceInference.node.js",
       "dist/nodes/memory/MemoryBufferWindow/MemoryBufferWindow.node.js",
       "dist/nodes/memory/MemoryMotorhead/MemoryMotorhead.node.js",
+      "dist/nodes/memory/MemoryPostgresChat/MemoryPostgresChat.node.js",
       "dist/nodes/memory/MemoryRedisChat/MemoryRedisChat.node.js",
       "dist/nodes/memory/MemoryManager/MemoryManager.node.js",
       "dist/nodes/memory/MemoryChatRetriever/MemoryChatRetriever.node.js",
@@ -153,6 +154,7 @@
     "@pinecone-database/pinecone": "2.2.1",
     "@qdrant/js-client-rest": "1.9.0",
     "@supabase/supabase-js": "2.43.4",
+    "@types/pg": "^8.11.3",
     "@xata.io/client": "0.28.4",
     "basic-auth": "2.0.1",
     "cheerio": "1.0.0-rc.12",

packages/@n8n/nodes-langchain/utils/helpers.ts

@@ -10,6 +10,18 @@ import type { BaseOutputParser } from '@langchain/core/output_parsers';
 import type { BaseMessage } from '@langchain/core/messages';
 import { DynamicTool, type Tool } from '@langchain/core/tools';
 import type { BaseLLM } from '@langchain/core/language_models/llms';
+import type { BaseChatMemory } from 'langchain/memory';
+import type { BaseChatMessageHistory } from '@langchain/core/chat_history';
+
+function hasMethods<T>(obj: unknown, ...methodNames: Array<string | symbol>): obj is T {
+	return methodNames.every(
+		(methodName) =>
+			typeof obj === 'object' &&
+			obj !== null &&
+			methodName in obj &&
+			typeof (obj as Record<string | symbol, unknown>)[methodName] === 'function',
+	);
+}
 
 export function getMetadataFiltersValues(
 	ctx: IExecuteFunctions,
@@ -38,8 +50,16 @@ export function getMetadataFiltersValues(
 	return undefined;
 }
 
+export function isBaseChatMemory(obj: unknown) {
+	return hasMethods<BaseChatMemory>(obj, 'loadMemoryVariables', 'saveContext');
+}
+
+export function isBaseChatMessageHistory(obj: unknown) {
+	return hasMethods<BaseChatMessageHistory>(obj, 'getMessages', 'addMessage');
+}
+
 export function isChatInstance(model: unknown): model is BaseChatModel {
-	const namespace = (model as BaseLLM | BaseChatModel)?.lc_namespace ?? [];
+	const namespace = (model as BaseLLM)?.lc_namespace ?? [];
 
 	return namespace.includes('chat_models');
 }

packages/@n8n/nodes-langchain/utils/logWrapper.ts

@@ -4,21 +4,21 @@ import type { ConnectionTypes, IExecuteFunctions, INodeExecutionData } from 'n8n
 import type { Tool } from '@langchain/core/tools';
 import type { BaseMessage } from '@langchain/core/messages';
 import type { InputValues, MemoryVariables, OutputValues } from '@langchain/core/memory';
-import { BaseChatMessageHistory } from '@langchain/core/chat_history';
+import type { BaseChatMessageHistory } from '@langchain/core/chat_history';
 import type { BaseCallbackConfig, Callbacks } from '@langchain/core/callbacks/manager';
 
 import { Embeddings } from '@langchain/core/embeddings';
 import { VectorStore } from '@langchain/core/vectorstores';
 import type { Document } from '@langchain/core/documents';
 import { TextSplitter } from '@langchain/textsplitters';
-import { BaseChatMemory } from '@langchain/community/memory/chat_memory';
+import type { BaseChatMemory } from '@langchain/community/memory/chat_memory';
 import { BaseRetriever } from '@langchain/core/retrievers';
 import { BaseOutputParser, OutputParserException } from '@langchain/core/output_parsers';
 import { isObject } from 'lodash';
 import type { BaseDocumentLoader } from 'langchain/dist/document_loaders/base';
 import { N8nJsonLoader } from './N8nJsonLoader';
 import { N8nBinaryLoader } from './N8nBinaryLoader';
-import { logAiEvent, isToolsInstance } from './helpers';
+import { logAiEvent, isToolsInstance, isBaseChatMemory, isBaseChatMessageHistory } from './helpers';
 
 const errorsMap: { [key: string]: { message: string; description: string } } = {
 	'You exceeded your current quota, please check your plan and billing details.': {
@@ -125,7 +125,7 @@ export function logWrapper(
 		get: (target, prop) => {
 			let connectionType: ConnectionTypes | undefined;
 			// ========== BaseChatMemory ==========
-			if (originalInstance instanceof BaseChatMemory) {
+			if (isBaseChatMemory(originalInstance)) {
 				if (prop === 'loadMemoryVariables' && 'loadMemoryVariables' in target) {
 					return async (values: InputValues): Promise<MemoryVariables> => {
 						connectionType = NodeConnectionType.AiMemory;
@@ -177,7 +177,7 @@ export function logWrapper(
 			}
 
 			// ========== BaseChatMessageHistory ==========
-			if (originalInstance instanceof BaseChatMessageHistory) {
+			if (isBaseChatMessageHistory(originalInstance)) {
 				if (prop === 'getMessages' && 'getMessages' in target) {
 					return async (): Promise<BaseMessage[]> => {
 						connectionType = NodeConnectionType.AiMemory;

pnpm-lock.yaml

@@ -337,6 +337,9 @@ importers:
       '@supabase/supabase-js':
         specifier: 2.43.4
         version: 2.43.4
+      '@types/pg':
+        specifier: ^8.11.3
+        version: 8.11.6
       '@xata.io/client':
         specifier: 0.28.4
         version: 0.28.4(typescript@5.5.2)
@@ -5354,6 +5357,9 @@ packages:
   '@types/normalize-package-data@2.4.1':
     resolution: {integrity: sha512-Gj7cI7z+98M282Tqmp2K5EIsoouUEzbBJhQQzDE3jSIRk6r9gsz0oUokqIUR4u1R3dMHo0pDHM7sNOHyhulypw==}
 
+  '@types/pg@8.11.6':
+    resolution: {integrity: sha512-/2WmmBXHLsfRqzfHW7BNZ8SbYzE8OSk7i3WjFYvfgRHj7S1xj+16Je5fUKv3lVdVzk/zn9TXOqf+avFCFIE0yQ==}
+
   '@types/phoenix@1.6.4':
     resolution: {integrity: sha512-B34A7uot1Cv0XtaHRYDATltAdKx0BvVKNgYNqE4WjtPUa4VQJM7kxeXcVKaH+KS+kCmZ+6w+QaUdcljiheiBJA==}
 
@@ -10433,6 +10439,9 @@ packages:
     resolution: {integrity: sha512-aU6xnDFYT3x17e/f0IiiwlGPTy2jzMySGfUB4fq6z7CV8l85CWHDk5ErhyhpfDHhrOMwGFhSQkhMGHaIotA6Ng==}
     engines: {node: '>= 0.4'}
 
+  obuf@1.1.2:
+    resolution: {integrity: sha512-PX1wu0AmAdPqOL1mWhqmlOd8kOIZQwGZw6rh7uby9fTc5lhaOWFLX3I6R1hrF9k3zUY40e6igsLGkDXK92LJNg==}
+
   on-finished@2.4.1:
     resolution: {integrity: sha512-oVlzkg3ENAhCk2zdv7IJwd/QUD4z2RxRwpkcGY8psCVcCYZNq4wYnVWALHM+brtuJjePWiYF/ClmuDr8Ch5+kg==}
     engines: {node: '>= 0.8'}
@@ -10720,6 +10729,10 @@ packages:
     resolution: {integrity: sha512-1KdmFGGTP6jplJoI8MfvRlfvMiyBivMRP7/ffh4a11RUFJ7kC2J0ZHlipoKiH/1hz+DVgceon9U2qbaHpPeyPg==}
     engines: {node: '>=8.0'}
 
+  pg-numeric@1.0.2:
+    resolution: {integrity: sha512-BM/Thnrw5jm2kKLE5uJkXqqExRUY/toLHda65XgFTBTFYZyopbKjBe29Ii3RbkvlsMoFwD+tHeGaCjjv0gHlyw==}
+    engines: {node: '>=4'}
+
   pg-pool@3.6.1:
     resolution: {integrity: sha512-jizsIzhkIitxCGfPRzJn1ZdcosIt3pz9Sh3V01fm1vZnbnCMgmGl5wvGGdNN2EL9Rmb0EcFoCkixH4Pu+sP9Og==}
     peerDependencies:
@@ -10736,6 +10749,10 @@ packages:
     resolution: {integrity: sha512-qTAAlrEsl8s4OiEQY69wDvcMIdQN6wdz5ojQiOy6YRMuynxenON0O5oCpJI6lshc6scgAY8qvJ2On/p+CXY0GA==}
     engines: {node: '>=4'}
 
+  pg-types@4.0.2:
+    resolution: {integrity: sha512-cRL3JpS3lKMGsKaWndugWQoLOCoP+Cic8oseVcbr0qhPzYD5DWXK+RZ9LY9wxRf7RQia4SCwQlXk0q6FCPrVng==}
+    engines: {node: '>=10'}
+
   pg@8.11.3:
     resolution: {integrity: sha512-+9iuvG8QfaaUrrph+kpF24cXkH1YOOUeArRNYIxq1viYHZagBxrTno7cecY1Fa44tJeZvaoG+Djpkc3JwehN5g==}
     engines: {node: '>= 8.0.0'}
@@ -10870,18 +10887,37 @@ packages:
     resolution: {integrity: sha512-VpZrUqU5A69eQyW2c5CA1jtLecCsN2U/bD6VilrFDWq5+5UIEVO7nazS3TEcHf1zuPYO/sqGvUvW62g86RXZuA==}
     engines: {node: '>=4'}
 
+  postgres-array@3.0.2:
+    resolution: {integrity: sha512-6faShkdFugNQCLwucjPcY5ARoW1SlbnrZjmGl0IrrqewpvxvhSLHimCVzqeuULCbG0fQv7Dtk1yDbG3xv7Veog==}
+    engines: {node: '>=12'}
+
   postgres-bytea@1.0.0:
     resolution: {integrity: sha512-xy3pmLuQqRBZBXDULy7KbaitYqLcmxigw14Q5sj8QBVLqEwXfeybIKVWiqAXTlcvdvb0+xkOtDbfQMOf4lST1w==}
     engines: {node: '>=0.10.0'}
 
+  postgres-bytea@3.0.0:
+    resolution: {integrity: sha512-CNd4jim9RFPkObHSjVHlVrxoVQXz7quwNFpz7RY1okNNme49+sVyiTvTRobiLV548Hx/hb1BG+iE7h9493WzFw==}
+    engines: {node: '>= 6'}
+
   postgres-date@1.0.7:
     resolution: {integrity: sha512-suDmjLVQg78nMK2UZ454hAG+OAW+HQPZ6n++TNDUX+L0+uUlLywnoxJKDou51Zm+zTCjrCl0Nq6J9C5hP9vK/Q==}
     engines: {node: '>=0.10.0'}
 
+  postgres-date@2.1.0:
+    resolution: {integrity: sha512-K7Juri8gtgXVcDfZttFKVmhglp7epKb1K4pgrkLxehjqkrgPhfG6OO8LHLkfaqkbpjNRnra018XwAr1yQFWGcA==}
+    engines: {node: '>=12'}
+
   postgres-interval@1.2.0:
     resolution: {integrity: sha512-9ZhXKM/rw350N1ovuWHbGxnGh/SNJ4cnxHiM0rxE4VN41wsg8P8zWn9hv/buK00RP4WvlOyr/RBDiptyxVbkZQ==}
     engines: {node: '>=0.10.0'}
 
+  postgres-interval@3.0.0:
+    resolution: {integrity: sha512-BSNDnbyZCXSxgA+1f5UU2GmwhoI0aU5yMxRGO8CdFEcY2BQF9xm/7MqKnYoM1nJDk8nONNWDk9WeSmePFhQdlw==}
+    engines: {node: '>=12'}
+
+  postgres-range@1.1.4:
+    resolution: {integrity: sha512-i/hbxIE9803Alj/6ytL7UHQxRvZkI9O4Sy+J3HGc4F4oo/2eQAjTSNJ0bfxyse3bH0nuVesCk+3IRLaMtG3H6w==}
+
   posthog-node@3.2.1:
     resolution: {integrity: sha512-ofNX3TPfZPlWErVc2EDk66cIrfp9EXeKBsXFxf8ISXK57b10ANwRnKAlf5rQjxjRKqcUWmV0d3ZfOeVeYracMw==}
     engines: {node: '>=15.0.0'}
@@ -18629,6 +18665,12 @@ snapshots:
 
   '@types/normalize-package-data@2.4.1': {}
 
+  '@types/pg@8.11.6':
+    dependencies:
+      '@types/node': 18.16.16
+      pg-protocol: 1.6.0
+      pg-types: 4.0.2
+
   '@types/phoenix@1.6.4': {}
 
   '@types/pretty-hrtime@1.0.1': {}
@@ -24623,6 +24665,8 @@ snapshots:
       define-properties: 1.2.1
       es-abstract: 1.22.5
 
+  obuf@1.1.2: {}
+
   on-finished@2.4.1:
     dependencies:
       ee-first: 1.1.1
@@ -24925,6 +24969,8 @@ snapshots:
 
   pg-minify@1.6.2: {}
 
+  pg-numeric@1.0.2: {}
+
   pg-pool@3.6.1(pg@8.11.3):
     dependencies:
       pg: 8.11.3
@@ -24952,6 +24998,16 @@ snapshots:
       postgres-date: 1.0.7
       postgres-interval: 1.2.0
 
+  pg-types@4.0.2:
+    dependencies:
+      pg-int8: 1.0.1
+      pg-numeric: 1.0.2
+      postgres-array: 3.0.2
+      postgres-bytea: 3.0.0
+      postgres-date: 2.1.0
+      postgres-interval: 3.0.0
+      postgres-range: 1.1.4
+
   pg@8.11.3:
     dependencies:
       buffer-writer: 2.0.0
@@ -25075,14 +25131,26 @@ snapshots:
 
   postgres-array@2.0.0: {}
 
+  postgres-array@3.0.2: {}
+
   postgres-bytea@1.0.0: {}
 
+  postgres-bytea@3.0.0:
+    dependencies:
+      obuf: 1.1.2
+
   postgres-date@1.0.7: {}
 
+  postgres-date@2.1.0: {}
+
   postgres-interval@1.2.0:
     dependencies:
       xtend: 4.0.2
 
+  postgres-interval@3.0.0: {}
+
+  postgres-range@1.1.4: {}
+
   posthog-node@3.2.1:
     dependencies:
       axios: 1.6.7(debug@3.2.7)