Kustomize Wasm Plugin

[koba1t]

Enhancement Description

• One-line enhancement description (can be used as a release note): Kustomize Wasm Plugin
• Kubernetes Enhancement Proposal: KEP-4944: Kustomize Wasm Plugin #4946
• Discussion Link: https://docs.google.com/document/d/1I1UFGHMDO7mMbDbioQp52DEJXEhk1qymch3qL5-EN10/edit#bookmark=id.da6ykky890fn
• Primary contact (assignee): @koba1t
• Responsible SIGs: sig-cli
• Enhancement target (which target equals to which milestone):
  • Alpha release target (x.y):
  • Beta release target (x.y):
  • Stable release target (x.y):
• Alpha
  • KEP (k/enhancements) update PR(s):
  • Code (k/k) update PR(s):
  • Docs (k/website) update PR(s):

Please keep this description up to date. This will help the Enhancement Team to track the evolution of the enhancement efficiently.

[koba1t]

/sig cli

[sanposhiho]

It just caught my eye. I'm the maintainer of https://github.com/kubernetes-sigs/kube-scheduler-wasm-extension, happy to collaborate if needed.
I believe, compared to the scheduler, the performance requirement here is not that severe, and hence wasm could be a great option to try. Especially, given Golang just supported //go:wasiexport, it could be a good timing since you can seek Golang SDK from the first step. (otherwise you'd need to use TinyGo and make the wasm plugin SDK independent of k/k)

[koba1t]

@sanposhiho
I would appreciate your advice!

Especially, given Golang just supported golang/go#65199, it could be a good timing since you can seek Golang SDK from the first step. (otherwise you'd need to use TinyGo and make the wasm plugin SDK independent of k/k)

Honest, This plugin framework will be in the form of a WASI binary call. This is because the current container/exec plugin uses stdin/stdout as an interface to kustomize, so we are trying to make it easier to migrate users by using stdin/stdout as input/output.

The PoC successfully got the golang code written for the existing exec plugin to work by simply rebuilding it with GOOS=wasip1 GOARCH=wasm.
https://github.com/koba1t/krm-fn-app/blob/a02b656109b48a7924df6d327d857c6746f9b306/Makefile#L8