langfuse-migration-deep-dive

# Langfuse Migration Deep Dive ## Current State !`npm list langfuse @langfuse/client 2>/dev/null | head -5 || echo 'No langfuse packages'` ## Overview Comprehensive guide for complex migrations: cloud-to-self-hosted, LangSmith-to-Langfuse, cross-instance data migration, and zero-downtime dual-write patterns. ## Prerequisites - Understanding of source and target Langfuse instances - API keys for both source and target - Git branch for migration work - Rollback plan documented ## Migration Scenarios | Scenario | Complexity | Downtime | Data Loss Risk | |----------|-----------|----------|----------------| | Cloud to Cloud (different project) | Low | None | None | | Cloud to Self-hosted | Medium | Minutes | Low | | Self-hosted to Cloud | Medium | Minutes | Low | | LangSmith to Langfuse | High | Hours | Medium | | SDK v3 to v4+ (no data migration) | Low | None | None | ## Instructions ### Step 1: Export Data from Source Instance ```typescript // scripts/export-langfuse.ts import { LangfuseClient } from "@langfuse/client"; import { writeFileSync, mkdirSync } from "fs"; const source = new LangfuseClient({ publicKey: process.env.SOURCE_LANGFUSE_PUBLIC_KEY, secretKey: process.env.SOURCE_LANGFUSE_SECRET_KEY, baseUrl: process.env.SOURCE_LANGFUSE_BASE_URL, }); async function exportAll(outputDir: string) { mkdirSync(outputDir, { recursive: true }); // Export traces let page = 1; let allTraces: any[] = []; let hasMore = true; console.log("Exporting traces...")...