Neo4j Memory Server

/** * Smart Embedding Manager - Clean Architecture Implementation * Single responsibility: Model lifecycle management with lazy loading * Features: Auto-dimensions, idle timeout, preload option */ import { pipeline } from '@xenova/transformers'; import { getVectorConfig } from '../../config'; import { MCPServiceError, MCPValidationError, MCPErrorCodes } from '../errors'; export interface EmbeddingManager { calculateEmbedding(text: string): Promise<number[]>; getModelDimensions(): Promise<number>; preloadModel(): Promise<void>; calculateSimilarity(vector1: number[], vector2: number[]): number; } export class SmartEmbeddingManager implements EmbeddingManager { private model: any = null; private lastUsed: number = 0; private modelDimensions: number = 0; private cleanupTimer: NodeJS.Timeout | null = null; private loadingPromise: Promise<void> | null = null; private config = getVectorConfig(); constructor() { // Model loading happens only on first use or explicit preload } async preloadModel(): Promise<void> { await this.ensureModel(); } async calculateEmbedding(text: string): Promise<number[]> { if (!text || text.trim() === '') { throw new MCPValidationError( 'Cannot calculate embedding for empty text', MCPErrorCodes.VALIDATION_FAILED ); } const model = await this.ensureModel(); this.resetIdleTimer(); try { const result = await model(text, { pooling: 'mean', normalize: true }); return Array.from(result.data); } catch (error) { // Zero-fallback: Fail with proper error, no console output throw new MCPServiceError( `Embedding calculation failed: ${error instanceof Error ? error.message : String(error)}`, MCPErrorCodes.EMBEDDING_SERVICE_ERROR, { originalError: error instanceof Error ? error.message : String(error) } ); } } async getModelDimensions(): Promise<number> { if (this.modelDimensions === 0) { await this.ensureModel(); } return this.modelDimensions; } calculateSimilarity(vector1: number[], vector2: number[]): number { // Safety checks if (!vector1 || !vector2 || !Array.isArray(vector1) || !Array.isArray(vector2)) { return 0; } // Ensure same length if (vector1.length !== vector2.length) { return 0; } try { let dotProduct = 0; let mag1 = 0; let mag2 = 0; for (let i = 0; i < vector1.length; i++) { if (typeof vector1[i] !== 'number' || typeof vector2[i] !== 'number') { continue; } dotProduct += vector1[i] * vector2[i]; mag1 += vector1[i] * vector1[i]; mag2 += vector2[i] * vector2[i]; } mag1 = Math.sqrt(mag1); mag2 = Math.sqrt(mag2); if (mag1 === 0 || mag2 === 0) { return 0; } return dotProduct / (mag1 * mag2); } catch (error) { throw new MCPServiceError( `Similarity calculation failed: ${error instanceof Error ? error.message : String(error)}`, MCPErrorCodes.EMBEDDING_SERVICE_ERROR, { operation: 'calculateSimilarity' } ); } } private async ensureModel(): Promise<any> { if (this.model) { this.lastUsed = Date.now(); return this.model; } if (this.loadingPromise) { await this.loadingPromise; return this.model; } this.loadingPromise = this.loadModel(); await this.loadingPromise; this.loadingPromise = null; return this.model; } private async loadModel(): Promise<void> { try { // Determine model name for Xenova transformers const modelName = this.config.modelName.startsWith('Xenova/') ? this.config.modelName : `Xenova/${this.config.modelName.replace('sentence-transformers/', '')}`; this.model = await pipeline('feature-extraction', modelName); // Auto-detect dimensions if not specified if (this.config.dimensions === 'auto') { const testEmbedding = await this.model('test'); this.modelDimensions = testEmbedding.data.length; } else { this.modelDimensions = this.config.dimensions as number; } this.lastUsed = Date.now(); } catch (error) { // Zero-fallback: Fail immediately, no console output this.model = null; this.modelDimensions = 0; this.loadingPromise = null; throw new MCPServiceError( `Failed to load embedding model: ${error instanceof Error ? error.message : String(error)}`, MCPErrorCodes.EMBEDDING_SERVICE_ERROR, { model: this.config.modelName, originalError: error instanceof Error ? error.message : String(error) } ); } } private resetIdleTimer(): void { if (this.cleanupTimer) { clearTimeout(this.cleanupTimer); } this.cleanupTimer = setTimeout(() => { if (Date.now() - this.lastUsed >= this.config.idleTimeout) { this.model = null; this.modelDimensions = 0; this.cleanupTimer = null; } }, this.config.idleTimeout); } /** * Clean shutdown - clear timers and free resources */ async shutdown(): Promise<void> { if (this.cleanupTimer) { clearTimeout(this.cleanupTimer); this.cleanupTimer = null; } this.model = null; this.modelDimensions = 0; } }