npm install @langfuse/tracing @langfuse/otel @langfuse/openai \\
  @opentelemetry/sdk-node \\
  @opentelemetry/exporter-trace-otlp-http \\
  dotenv

import "dotenv/config";

import { NodeSDK } from "@opentelemetry/sdk-node";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-http";
import { LangfuseSpanProcessor } from "@langfuse/otel";

const secretId = process.env.TENCENTCLOUD_SECRET_ID!;
const secretKey = process.env.TENCENTCLOUD_SECRET_KEY!;
const region = process.env.CLS_DEFAULT_REGION!;
const topicId = process.env.CLS_TOPIC_ID!;

const auth = Buffer.from(`${secretId}:${secretKey}`).toString("base64");

export const sdk = new NodeSDK({
  spanProcessors: [
    new LangfuseSpanProcessor({
      exporter: new OTLPTraceExporter({
        url: `https://${region}.cls.tencentcs.com/v1/traces`,
        headers: {
          Authorization: `Basic ${auth}`,
          topic_id: topicId,
        },
      }),
      flushAt: 512,
      flushInterval: 5000,
    }),
  ],
});

sdk.start();

process.on("SIGTERM", async () => {
  await sdk.shutdown();
});

import { sdk } from "./instrumentation";

import OpenAI from "openai";
import { observeOpenAI } from "@langfuse/openai";
import { startActiveObservation, propagateAttributes } from "@langfuse/tracing";

const openai = observeOpenAI(new OpenAI());

async function chat(userMessage: string) {
  return startActiveObservation("chat", async (span) => {
    span.update({ input: [{ role: "user", content: userMessage }] });

    return propagateAttributes(
      { userId: "u-123", sessionId: "s-456", tags: ["model:gpt-4o"] },
      async () => {
        const res = await openai.chat.completions.create({
          model: "gpt-4o",
          messages: [{ role: "user", content: userMessage }],
        });
        span.update({ output: res.choices[0].message });
        return res;
      },
    );
  });
}

await chat("Hello");
await sdk.shutdown();