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Comment by riwsky | Hacker News Reader

You’re still not getting it. Duck typing comes from the phrase “if it looks like a duck, and quacks like a duck, then it must be a duck”. The Wikipedia page contrasts it with nominative typing that requires a declaration, and calls out that duck typing does not need the adapter pattern. What you are calling duck typing is just “interfaces”.

Also “tasks.create” is morally a route. Eg grpc has web transports and autogenerated CLIs too; even without those, there’s no particular reason why the OBI “client layer” couldn’t just be, say, gRPC under the hood, with the OBI specs just being used to codegen adapters from the source protocol to gRPC. It would then immediately have a much more widely understood and supported client layer, with better performance, while remaining as simple to implement as the adapters to this new custom OBI runtime protocol.

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You're right that what OBI does is structural typing or just interfaces, not duck typing. Transforms and bindings do use the adapter pattern. The critique lands and I can admit it. The duck typing framing was rhetorically appealing but imprecise.

On the gRPC-as-client-layer point, I want to make sure I understand. You're suggesting that between the OBI client SDK and the source service, there should be a gRPC layer, with generated gRPC adapters fronting each source? Or something else?

Worth noting either way: the spec doesn't dictate implementation. It defines operation contracts, binding sources, and the executor role. How an executor actually reaches a service is left open, so gRPC-based routing is a valid strategy within the spec regardless.

Thanks for sticking with this. This is exactly the kind of discussion I was hoping for. I really do appreciate it.

My gRPC point is that it already gives you a language for describing interfaces and support for generating client types from it, and already abstracts the connection management[1]. If OBI just generated a gRPC ClientConn implementation to map the Invoke calls to eg REST paths, it’d inherit the large existing gRPC client ecosystem. That ClientConn interface can already technically capture what OBI calls binding executors. People don’t do this though because it’s not worth it.

[1]: https://github.com/grpc/grpc-go/blob/06fc26a196350499dd0cf2d...

Thanks for the clarification. That's a valid implementation strategy for client consumers that want a gRPC feel. The spec doesn't require any particular client pattern (what's on the site is guidance, not normative), so an OBI-conformant toolchain could be built that way. I went with a less prescriptive approach, but that's a preference, not a mandate, and I think it's the right choice specifically for leaving the door open to alternative client implementation patterns like what you're proposing. I appreciate you sticking with this across the thread.

If you're open to it, I'd be interested in staying in touch as OBI evolves. I know you're not sold on the project, but critical voices willing to engage constructively for this long are rare and valuable regardless. If you ever want to poke at something or tell me where you think it's going wrong, I'm at https://x.com/clevengermatt, and there's the GitHub discussions.

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