Investigate and support Next.js instrumentation

[dario-piotrowicz]

Next.js 15 introduced a loadInstrumentationModule methods that appears in our bundled worker which caused our workers to fail at runtime.

We're solved such issue by replacing the content of the loadInstrumentationModule methods with a no-op implementation (see: #169), this was the simplest and quickest way to work around the issue and unblock Next.js 15 for us, it is however most likely not the correct solution and almost certainly breaks Next.js' instrumentation.

So this issue is for investigating and understanding if and how we support instrumentation, and if we don't support it (which most likely we don't) find a way to do so.

[nopsled]

As I understand, this adapter does support Next.js 15.1 now?

[dario-piotrowicz]

Yes it does 🙂

Although we don't support all Next.js 15 features (like instrumentation), I don't even think we have investigated all features and understood the extent of our support

@vicb might be able to shed some light here 🙂

[hitsthings]

Apologies if this is noise, but just a vote here for prioritizing this and some context in case that is helpful.

We are having a hell of a time with instrumentation for next-on-pages and are holding out hope that OpenNext will soon solve our problems. Observability is pretty important to use in our production services and we currently aren't able to see all Sentry errors (which is a huge problem!). We are looking at workarounds with logpush and setting up alerting on our logs, but given the edge runtime requirement for next-on-pages, our other options are slim unless we move to Vercel (which I really don't want to do!) We need to know when things fail before we can ship this to customers.

Thanks for listening and for all you're doing on OpenNext!

[vicb]

I took a quick look here.

What we say in the patch

opennextjs-cloudflare/packages/cloudflare/src/cli/build/patches/to-investigate/patch-load-instrumentation-module.ts

Lines 6 to 7 in 642c3d2

	* The `loadInstrumentationModule` method (source: https://github.com/vercel/next.js/blob/5b7833e3/packages/next/src/server/next-server.ts#L301)
	* calls `module.findSourceMap` (https://nodejs.org/api/module.html#modulefindsourcemappath) which we haven't implemented causing a runtime error.

is outdated as findSourceMap was implemented in unjs/unenv#349

The real issue here is a dynamicRequire