instrumentation.ts not working in production

[LaurinBrechter]

Summary

I set up custom node instrumentation with opentelemetry. When I run things in development mode, everything works fine and I can also export traces. The build also works fine. When I start the production server, tracing doesn't work anymore.

next.config.ts

// next.config.ts

import type { NextConfig } from "next";
import createMDX from "@next/mdx";

const createNextIntlPlugin = require("next-intl/plugin");

const withNextIntl = createNextIntlPlugin();

const nextConfig: NextConfig = {
  experimental: {
    authInterrupts: true,
    dynamicIO: true,
    reactCompiler: true,
    serverActions: {
      bodySizeLimit: "10mb",
    },
  },
  output: "standalone",
  pageExtensions: ["ts", "tsx", "js", "jsx", "md", "mdx"],
  images: {
    remotePatterns: [
      {
        protocol: "https",
        hostname: "i.ytimg.com",
      },
    ],
  },
};

const withMDX = createMDX({});
const withBundleAnalyzer = require("@next/bundle-analyzer")({
  enabled: process.env.ANALYZE === "true",
});

export default withNextIntl(withMDX(withBundleAnalyzer(nextConfig)));

And this is my instrumentation file

console.log("registering instrumentation", process.env.NEXT_RUNTIME);

export async function register() {
  console.log("registering instrumentation", process.env.NEXT_RUNTIME);
  if (process.env.NEXT_RUNTIME === "nodejs") {
    await import("./instrumentation.node");
  }
}

I added the console.log statements but none of them seem to get run (neither during build or when starting the server). There was already a similar post #68420 but that didn't seem to be resolved.

I also tried running without standalone output but this doesn't work either. I tried this with the latest next canary 15.3.0-canary.31

Additional information

No response

Example

No response

[icyJoseph]

Have you been able to debug this further? Can you maybe comment out the await import("./instrumentation.node")? I am wondering if something is crashing out silently...

[LaurinBrechter]

No that also didn't work. I now just put the contents of the instrumentation.node.ts file in a different file that initializes my s3Client (which runs once on server start in prod). Now the instrumentation works so it couldn't have been the contents of the instrumentation.node.ts file itself.

[icyJoseph]

🤔 could it be the .node in the file name? I don't understand what exactly did you do to get it working?

[LaurinBrechter]

I copied the contents of my instrumentation.node.ts file into another file that runs on server startup (to initialize my s3Client). As I said, I think the instrumentation.ts file just gets ignored completely. Because otherwise, wouldn't I see the output of the console.log("registering instrumentation", process.env.NEXT_RUNTIME); statement outside of the register function at some point?

[icyJoseph]

I built a new app, build for prod and started it:

➜ yarn build; and yarn start --port 3009
yarn run v1.22.22
$ next build
   ▲ Next.js 15.2.4

   Creating an optimized production build ...
 ✓ Compiled successfully
 ✓ Linting and checking validity of types    
 ✓ Collecting page data    
 ✓ Generating static pages (5/5)
 ✓ Collecting build traces    
 ✓ Finalizing page optimization    

Route (app)                                 Size  First Load JS    
┌ ○ /                                    5.57 kB         106 kB
└ ○ /_not-found                            977 B         101 kB
+ First Load JS shared by all             100 kB
  ├ chunks/4bd1b696-5b6c0ccbd3c0c9ab.js  53.2 kB
  ├ chunks/684-c131fa2291503b5d.js       45.3 kB
  └ other shared chunks (total)          1.89 kB


○  (Static)  prerendered as static content

✨  Done in 17.78s.
yarn run v1.22.22
$ next start --port 3009
   ▲ Next.js 15.2.4
   - Local:        http://localhost:3009
   - Network:      http://192.168.1.118:3009

 ✓ Starting...
Register nodejs
 ✓ Ready in 440ms

Register nodejs did kick in... gonna try it out with standalone mode now

Ah, it worked too:

docker run nextjs-docker
   ▲ Next.js 15.2.4
   - Local:        http://localhost:3009
   - Network:      http://0.0.0.0:3009

 ✓ Starting...
Register nodejs
 ✓ Ready in 42ms

I remember once, there was an issue, where a module was hoisted, crashes upon load, and no logs were ever printed.