feat: integrate Langfuse for LLM observability (#66)

* feat: integrate Langfuse for LLM observability

- Add instrumentation.ts with Langfuse OpenTelemetry exporter
- Enable experimental telemetry on streamText calls
- Add instrumentationHook to Next.js config
- Install required dependencies (@vercel/otel, langfuse-vercel, etc.)

* feat: add optional Langfuse observability integration

- Add session tracking with unique sessionId per conversation
- Add user tracking via IP address (x-forwarded-for header)
- Make telemetry conditional - only enabled if LANGFUSE_PUBLIC_KEY is set
- Add environment variable validation in instrumentation.ts
- Add sessionId validation (type check + 200 char limit)
- Update env.example with Langfuse configuration docs
- Remove unused langfuse-vercel and @vercel/otel packages

* fix: remove deprecated instrumentationHook (enabled by default in Next.js 15)
This commit is contained in:
Dayuan Jiang
2025-12-04 00:23:09 +09:00
committed by GitHub
parent 39322c2793
commit fa1b02ad78
6 changed files with 383 additions and 3 deletions

View File

@@ -41,3 +41,9 @@ AI_MODEL=global.anthropic.claude-sonnet-4-5-20250929-v1:0
# DeepSeek Configuration
# DEEPSEEK_API_KEY=sk-...
# DEEPSEEK_BASE_URL=https://api.deepseek.com/v1 # Optional: Custom endpoint
# Langfuse Observability (Optional)
# Enable LLM tracing and analytics - https://langfuse.com
# LANGFUSE_PUBLIC_KEY=pk-lf-...
# LANGFUSE_SECRET_KEY=sk-lf-...
# LANGFUSE_BASEURL=https://cloud.langfuse.com # EU region, use https://us.cloud.langfuse.com for US