kube-derive: yaml vs. rust question

[webern]

Is the correct workflow to maintain a CRD spec both as a YAML file and as a Rust struct with the CustomResource derive? Or can the YAML be generated from the Rust struct (or the Rust struct from the YAML)? Or can the CRD be applied to the cluster by a Rust program that skips the YAML formatting altogether?

Thanks. I'm just getting started. I hope the question is clear. I'm trying to understand the developer workflow for keeping

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  name: mycrd

in sync with

#[derive(CustomResource, Serialize, Deserialize, Debug, PartialEq, Clone, JsonSchema)]
#[kube(
    group = "example.com",
    version = "v1",
    kind = "MyCrd",
    plural = "mycrds",
    derive = "PartialEq",
    namespaced
)]
#[kube(status = "MyCrdStatus")]
pub struct MyCrdSpec {
  // ...
}

[clux]

Is the correct workflow to maintain a CRD spec both as a YAML file and as a Rust struct with the CustomResource derive? Or can the YAML be generated from the Rust struct (or the Rust struct from the YAML)?

You can generate the yaml from the rust struct (not the other way around), and you should commit that generated file, because the definition is usually applied out of band (crd write perms are usually cluster admin type permissions, and you generally don't want your controller to have it).

I recommend a small bin entry point to generate this file like crdgen in controller-rs.

Or can the CRD be applied to the cluster by a Rust program that skips the YAML formatting altogether?

You can do this, but for the permission issue, this is generally not good practice.

[webern]

Very helpful, thank you!

[webern]

I have an additional, related question. I was looking for pattern constraints like this:

some_pattern:
  type: string
  pattern: '^\d{3}-\d{2}-\d{4}$'

My guess is that this PR GREsau/schemars#78 might make this possible in the future with kube-derive?
Am I understanding correctly that kube-derive is using schemars to generate a JSON schema then transforming it to produce OpenAPIv3?

[clux]

Yeah, that's all correct. There are some ongoing discussions in onwards from #129 (comment) about this, but waiting for nice sugar. You can at least get around validation limitations by manually doing implementations of Schema. The crd_derive example is good here.

[p-alik]

crdgen.rs of controller-rs generates YAML for the DocumentSpec.
Is it possible to generate vice versa struct DocumentSpec from YAML?

[clux]

yep! see https://github.com/kube-rs/kopium