SDK conformance harness

[markmandel]

A way for developers who want to develop / bring their own SDK to know that their SDK implementation is compliant with what we need it to do.

Ideally, I think it would not involve a full Kubernetes install, or e2e test, but likely could be run on it's own - maybe as a binary / docker container? Something simple.

We could then integrate this into our CI system to run against existing SDKs, and ensure that they always pass. Right now, this could fail for anything other than our Go sdk.

Would need to have a way to skip tests as well - since we often have SDKs that are partial implementations.

Open to suggestions on what this should look like?

[aLekSer]

As I understand we should generate single GRPC/RestAPI client which would be calling SDK implementations one by one (each with unique hostnames).
One interesting approach which I found is to write golang declarative tests of the API:
example.

[aLekSer]

I made a draft proposal on how the system of SDK harness tests could look like:
https://docs.google.com/document/d/1Qjy-wXA1wsZB8PE_CP_GCgnyWktySm_ytZgRUZ2wtCo/edit?usp=sharing
Basically we could make an adapter from the Unified Test Scenarios language to all other target SDK languages.
Test scenarios would contain the sequence of calls to the SDK and the expected results as they seen from Gameserver Sidecar.

[markmandel]

Added a bunch of notes - PTAL

[aLekSer]

I found an absence of new Allocate() method in Rust (fixed in a PR), CPP and Unreal Engine SDKs.
https://agones.dev/site/docs/guides/client-sdks/#allocate

[markmandel]

Can we close this now? We have the harness after all.

[aLekSer]

Yes, we can close this PR now.

[markmandel]

Closing!