langfuse-upgrade-migration

# Langfuse Upgrade & Migration ## Current State !`npm list langfuse @langfuse/client @langfuse/tracing @langfuse/otel 2>/dev/null | head -10 || echo 'No langfuse packages found'` !`pip show langfuse 2>/dev/null | grep -E "Name|Version" || echo 'Python langfuse not installed'` ## Overview Step-by-step guide for upgrading the Langfuse SDK across major versions. Covers v3 to v4 (OTel rewrite), v4 to v5, breaking changes, and automated codemods. ## Prerequisites - Existing Langfuse integration - Test suite covering traced operations - Git branch for the upgrade ## Version Roadmap | SDK | Package | Architecture | Status | |-----|---------|-------------|--------| | v3 | `langfuse` (single) | Custom, `Langfuse` class | Legacy | | v4 | `@langfuse/client`, `@langfuse/tracing`, `@langfuse/otel` | OpenTelemetry-based | Stable | | v5 | `@langfuse/client`, `@langfuse/tracing`, `@langfuse/otel` | OpenTelemetry + improvements | Latest | ## Instructions ### Step 1: Check Current Version and Plan ```bash set -euo pipefail # Check what you have npm list langfuse @langfuse/client @langfuse/tracing 2>/dev/null # Check latest available npm info @langfuse/client version npm info @langfuse/tracing version npm info langfuse version # Python pip show langfuse 2>/dev/null | grep Version pip index versions langfuse 2>/dev/null | head -3 ``` ### Step 2: v3 to v4 Migration (TypeScript) This is the biggest migration -- v4 rewrites tracing on OpenTelemetry. **2a. Install new packages:** ```bas...