nimbus VS kubit

> These same feelings extend to other proprietary config languages like HCL for Terraform, ASL for AWS Step Functions, etc. It's fine that you want a declarative API, but let me generate my declaration programatically.

Yeah, I've had the same sort of opinion since the bad old AWS CloudFormation days. I wrote an experimental CloudFormation generator 4 years ago where all of the resources and Python type hints were generated from a JSON file that AWS published and it worked really well (https://github.com/weberc2/nimbus/blob/master/examples/src/n...).

> Config declared in and generated by code has been a superior experience. It's one of the things that AWS CDK got absolutely right.

Is that how CDK works? I've only dabbled with it, but it was pretty far from the "generate cloudformation" experience that I had built; I guess I never "saw the light" for CDK. It felt like trading YAML/templating problems for inheritance/magic problems. I'd really like to hear from more people who have used AWS CDK, Terraform's CDK, and/or Pulumi.

oh yeah; operators are great and sometimes they are necessary.

On the other hand, most operators I've seen are just k8s manifest templates implemented in Go.

I often end up preferring using Jsonnet to deal with that instead of doing the same stuff in Go.

Jsonnet is much more close to the underlying datamodel (the k8s manifest Json/Yaml document) and comes with some useful functionality out of the box, such "overlays".

It has downsides too! It's untyped, debugging tools are lacking, people are unfamiliar with it and don't care to learn it. So I totally get why one would entertain the possibility of writing your "templates" using a better language.

However, an operator is often too much freedom. It's not just using Go or Rust or Typescript to "generate" some Json manifests, but it also contains the code to interact with the API server, setup watches, and reactions etc.

I often wish there was a better way to separate those two concerns

I'm a fan of metacontroller [1], which is a tool that allows you to write operators without actually writing a lot of imperative code that interacts with the k8s API, but instead just provide a general JSON->JSON transformer, which you could write in any langue (Go, Python, Rust, Javascript, .... and also Jsonnet if you want).

I recently implemented something similar but much tailored to just "installing" stuff, called Kubit. An OCI artifact contains some abitrary tarball (generally containing some template sources) and a reference to a docker image containing an "engine" and runs the engine with your provided tarball + some parameters passed in a CRD. The OCI artifact could contain a helm chart and the template engine could contain the helm binary, or the template engine could be kubecfg and the OCI artifact could contain a bunch of jsonnet files. Or you could write your own stuff in python or typescript. The kubit operator then just runs your code, gathers the output and applies with with kubectl apply-set.

1. https://metacontroller.github.io/metacontroller/intro.html

2. https://github.com/kubecfg/kubit