Bunny DNS – A scriptable DNS platform

> I strongly believe that it'd be way better for their clients if the client could just do `export default async function handleDns(event) { ... }`

I'm the tech lead of Cloudflare Workers and you're absolutely right about this. We actually introduced such a syntax as an option a while back and are encouraging people to move to it:

https://blog.cloudflare.com/workers-javascript-modules/

Your argument is exactly one of the reasons for this. The more general version of the argument is that it enables composability: you can take a Worker implementation and incorporate it into a larger codebase without having to modify its code. This helps for testing (incorporating into a test harness), but also lets you do things like take two workers and combine them into one worker with a new top-level event handler that dispatches to one or the other.

The cynic in me says: oh no another scripting platform that can be compromised.

The programmer in me says: what cool stuff can I do with that.

Well dang, that's what I get for taking too long to implement my idea :-D

Seriously this is great. I started building a "scriptable DNS" to make it easy to have a DNS record that always points at the valid K8s nodes in my cluster (and randomizes the order of the IPs each time). Since nodes can come and go very quickly (especially during an upgrade), and their IP changes every time, it's useful to be able to act dynamically.

This is most assuredly better than what I was building though. Mine is rust-based but the "script language" is a very simple DSL. I considered allowing docker containers that receive some command arguments and must write the answer to standard out, but that felt like a brittle interface and I worried about performance (even with offering a cache). I also considered writing it in Elixir and allowing elixir code snippets, but I got scared of how hard it would be to secure that.

Anyway really neat idea! I hope to see more innovations and implementations!

Yeah great question, and I don't fully have an answer yet! For the scenario I need it for, the hostname only does one thing and won't be looked up by the client until it's needed, which helps avoid that problem. Furthermore, thank to K8s nodePort routing, as long as one of the nodes is still alive and answering, the request will be routed even if the first IP is no longer valid. I've also considered as the cluster size grows, only returning the 3 to 5 newest node IPs present since I expect the ones most likely to get killed/recycled will be the older ones (not always true, but often is in my setup).

Has anybody else run into this and solved it? Cloudflare DNS seems to have figured out a decent way to deal with this. I may take a close look at their responses and see what they set for TTL, etc.

When an expert is explaining things to non-experts (like a marketing page would), you use terms that your audience will understand and relate to. The goal is not perfect technical accuracy. The goal is to convey the basic idea so the reader can understand it.