Vercel AI SDK - Observability & Analytics

LANGFUSE_SECRET_KEY="sk-lf-..."
LANGFUSE_PUBLIC_KEY="pk-lf-..."
LANGFUSE_BASEURL="https://cloud.langfuse.com" # 🇪🇺 EU region
# LANGFUSE_BASEURL="https://us.cloud.langfuse.com" # 🇺🇸 US region

import { LangfuseExporter } from "langfuse-vercel";
 
new LangfuseExporter({
  secretKey: "sk-lf-...",
  publicKey: "pk-lf-...",
  baseUrl: "https://cloud.langfuse.com", // 🇪🇺 EU region
  // baseUrl: "https://us.cloud.langfuse.com", // 🇺🇸 US region
});

npm install @vercel/otel langfuse-vercel @opentelemetry/api-logs @opentelemetry/instrumentation @opentelemetry/sdk-logs

/** @type {import('next').NextConfig} */
const nextConfig = {
  experimental: {
    instrumentationHook: true,
  },
};
 
module.exports = nextConfig;

import { registerOTel } from "@vercel/otel";
import { LangfuseExporter } from "langfuse-vercel";
 
export function register() {
  registerOTel({
    serviceName: "langfuse-vercel-ai-nextjs-example",
    traceExporter: new LangfuseExporter(),
  });
}

import { openai } from "@ai-sdk/openai";
import { generateText } from "ai";
import { NodeSDK } from "@opentelemetry/sdk-node";
import { getNodeAutoInstrumentations } from "@opentelemetry/auto-instrumentations-node";
import { LangfuseExporter } from "langfuse-vercel";
 
const sdk = new NodeSDK({
  traceExporter: new LangfuseExporter(),
  instrumentations: [getNodeAutoInstrumentations()],
});
 
sdk.start();
 
async function main() {
  const result = await generateText({
    model: openai("gpt-3.5-turbo"),
    maxTokens: 50,
    prompt: "Invent a new holiday and describe its traditions.",
    experimental_telemetry: {
      isEnabled: true,
      functionId: "my-awesome-function",
      metadata: {
        something: "custom",
        someOtherThing: "other-value",
      },
    },
  });
 
  console.log(result.text);
 
  await sdk.shutdown(); // Flushes the trace to Langfuse
}
 
main().catch(console.error);