Inspect (and mutate) L1 properties after initialization

[eladb]

At the moment, these types are immutable. All their properties have to be defined upon initialization. Similarly to the AWS CDK's "cfn resources", we should allow users to mutate these objects to improve authoring experience.

Let's say I want to conditionally determine the value of a couple of fields in an imported k8s object. Today, I would need to do it like this:

new MyKind(this, 'foo', {
  spec: {
    field1: myCondition ? 'valueA' : 'valueB',
    sub: {
      tree: myCondition ? 'valueA' : 'valueB'
    }
  }
});

new YourKind(this, 'your', {
  spec: {
    opt: myCondition ? 10  : 20
  }
});

This feature will allow me to write this code like this:

const my = new MyKind(this, 'my');
const your = new YourKind(this, 'your');

if (myCondition) {
  my.spec.field1 = my.sub.tree = 'valueA';
  your.opt = 10;
} else {
  my.spec.field1 = my.sub.tree = 'valueB';
  your.opt = 20;
}

An issue here is who is responsible to initialize sub-objects such as spec and sub.tree. I'll leave it for the implementer to ponder options.

[ajaegle]

This feature would be great to have so we can import pre-existing yaml resources and transform them according to e.g. the workspace the current chart will be deployed to, adding missing labels or use a common naming scheme.

Is there an alternative way to weakening the immutability of the constructs? Or is cloning for the transformation a bad idea in terms of parent-child relation (scope)?

[gabe-l-hart]

In this proposal, would it be possible to add net-new attributes to the object that were not automatically discovered during import by the validation schema? We're running into issues where we depend on third-party CRDs which we don't directly control which may be fully missing validation schemas, or have crucial missing portions (such as metadata).

My guess is that this would not be possible (at least from the python interface) because those new fields would somehow need to be plumbed through the jsii interface to the node constructs.

[foriequal0]

I've tried to implement similar to this https://github.com/awslabs/cdk8s/issues/178 Originally, I wanted to set app.kubernetes.io/instance as Names.toLabelValue(this), but there were some hassles. JS prevents accessing this before calling super, so I can't simply initialize it with

super(scope, this, {
  labels: {
    [INSTANCE]: Names.toLabelValue(this)
  }
})

But I couldn't neither this.labels[INSTANCE] = Names.toLabelValue(this) since this.labels is an immutable clone. I've tried Lazy.any trick, but Error: can't render non-simple object of type 'Lazy' is thrown while App.synth. I've found overriding labels property works:

get labels() {
  return {
    ...super.labels, 
    [INSTANCE]: Names.toLabelValue(this)
  }
}

[github-actions[bot]]

This issue is now marked as stale because it hasn't seen activity for a while. Add a comment or it will be closed soon.

[github-actions[bot]]

Closing this issue as it hasn't seen activity for a while. Please add a comment @mentioning a maintainer to reopen.

[github-actions[bot]]

This issue has not received any attention in 1 year and will be closed soon. If you want to keep it open, please leave a comment below @mentioning a maintainer.

[shinebayar-g]

bump