feat: Add Cohere reranking capability to vector stores (#16014)

Co-authored-by: Yiorgis Gozadinos <yiorgis@n8n.io>
Co-authored-by: Mutasem Aldmour <mutasem@n8n.io>

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

@@ -6,6 +6,7 @@ import { Embeddings } from '@langchain/core/embeddings';
 import type { InputValues, MemoryVariables, OutputValues } from '@langchain/core/memory';
 import type { BaseMessage } from '@langchain/core/messages';
 import { BaseRetriever } from '@langchain/core/retrievers';
+import { BaseDocumentCompressor } from '@langchain/core/retrievers/document_compressors';
 import type { StructuredTool, Tool } from '@langchain/core/tools';
 import { VectorStore } from '@langchain/core/vectorstores';
 import { TextSplitter } from '@langchain/textsplitters';
@@ -18,7 +19,12 @@ import type {
 	ITaskMetadata,
 	NodeConnectionType,
 } from 'n8n-workflow';
-import { NodeOperationError, NodeConnectionTypes, parseErrorMetadata } from 'n8n-workflow';
+import {
+	NodeOperationError,
+	NodeConnectionTypes,
+	parseErrorMetadata,
+	deepCopy,
+} from 'n8n-workflow';
 
 import { logAiEvent, isToolsInstance, isBaseChatMemory, isBaseChatMessageHistory } from './helpers';
 import { N8nBinaryLoader } from './N8nBinaryLoader';
@@ -102,6 +108,7 @@ export function logWrapper<
 		| BaseChatMemory
 		| BaseChatMessageHistory
 		| BaseRetriever
+		| BaseDocumentCompressor
 		| Embeddings
 		| Document[]
 		| Document
@@ -297,6 +304,32 @@ export function logWrapper<
 				}
 			}
 
+			// ========== Rerankers ==========
+			if (originalInstance instanceof BaseDocumentCompressor) {
+				if (prop === 'compressDocuments' && 'compressDocuments' in target) {
+					return async (documents: Document[], query: string): Promise<Document[]> => {
+						connectionType = NodeConnectionTypes.AiReranker;
+						const { index } = executeFunctions.addInputData(connectionType, [
+							[{ json: { query, documents } }],
+						]);
+
+						const response = (await callMethodAsync.call(target, {
+							executeFunctions,
+							connectionType,
+							currentNodeRunIndex: index,
+							method: target[prop],
+							// compressDocuments mutates the original object
+							// messing up the input data logging
+							arguments: [deepCopy(documents), query],
+						})) as Document[];
+
+						logAiEvent(executeFunctions, 'ai-document-reranked', { query });
+						executeFunctions.addOutputData(connectionType, index, [[{ json: { response } }]]);
+						return response;
+					};
+				}
+			}
+
 			// ========== N8n Loaders Process All ==========
 			if (
 				originalInstance instanceof N8nJsonLoader ||