Node.of(construct).uniqueId is not strictly compatible with the K8s labels

[foriequal0]

Description of the feature or enhancement:

I can find some usages of Node.of(construct).uniqueId across the codebase and examples. However, it is bound to CloudFormation's resource name rules and it isn't strictly compatable with Kubernetes' name/labels rules.
It might be compatible if the resource name is short enough to be within k8s' length limitations, but you still bear the fact that Node.of(construct).uniqueId gives you a uniqueidbutwithbarelyreadablebecauseitlacksofseparatorcharactorsA8322FCE when you use a snake-case for resources names.

There is already Names.toDnsLabel and Chart.generateObjectName using it. However, labels are superset of dns labels.

Use Case:

I can find uniqueId in 8 files:

Potentially invalid

https://github.com/awslabs/cdk8s/blob/d863232e4bf8a6dfcdd11e32b18b03586a4b766d/packages/cdk8s-plus/src/deployment.ts#L208
They are examples, but it should be changed considering the fact that people are blindfoldingly conpy-paste them.
https://github.com/awslabs/cdk8s/blob/85cf6313c20771b718c19ee6085afc23cd787311/examples/typescript/podinfo/lib/deployment.ts#L92-L95
https://github.com/awslabs/cdk8s/blob/85cf6313c20771b718c19ee6085afc23cd787311/examples/typescript/web-service/web-service.ts#L33
https://github.com/awslabs/cdk8s/blob/0f70a4fa0a471b27b3c75e25d0609935060b44ed/docs/getting-started/typescript.md#L285

It would be better to be changed for the readibility

https://github.com/awslabs/cdk8s/blob/2ae890a92cf67be1e1a5478102dd6003e446440f/packages/cdk8s/src/app.ts#L51
https://github.com/awslabs/cdk8s/blob/2ae890a92cf67be1e1a5478102dd6003e446440f/packages/cdk8s/src/dependency.ts#L160
Okay-ish for internal use
https://github.com/awslabs/cdk8s/blob/2ae890a92cf67be1e1a5478102dd6003e446440f/packages/cdk8s/src/dependency.ts#L26-L32

Proposed Solution:

It would be better to have a separate function for the label.

...
const MAX_LABEL_LEN = 63;
const INVALIDATE_LABEL = /[^0-9a-zA-Z-_.]/
...
export class Names {
...
    public static toLabel(path: string, delim: string = '-', maxLen: number = MAX_LABEL_LEN) {
        if (maxLen < HASH_LEN) {
          throw new Error(`minimum max length for label is ${HASH_LEN} (required for hash)`);
        }

        if (INVALIDATE_LABEL.test(delim)) {
          throw new Error(`delim should not contain '[^0-9a-zA-Z-_.]'`);
        }

        let components = path.split('/');

        // special case: if we only have one component in our path and it adheres to DNS_NAME, we don't decorate it
        if (components.length === 1 && !INVALIDATE_LABEL.test(components[0]) && components[0].length <= maxLen) {
          return components[0];
        }

        components = components.map(normalizeToLabel);

        components.push(calcHash(path, HASH_LEN));

        return components
          .reverse()
          .filter(omitDuplicates)
          .join('/')
          .slice(0, 63)
          .split('/')
          .reverse()
          .filter(x => x)
          .join(delim);
    }
...
}

function normalizeToLabel(c: string) {
    return c
        .replace(/[^0-9a-zA-Z-_.]/g, ''); // remove non-allowed characters
}
...

And I think it is cumbersome to use

Names.toLabel(Node.of(construct).path);

Names.toDnsLabel(Node.of(construct).path)
// which is
Chart.of(construct).generateObjectName(construct);

Overloading them would be helpful?

...
    public static toDnsLabel(pathOrConstruct: string | IConstruct, maxLen?: number): string {
        ...
        const path = typeof pathOrConstruct === "string" ? pathOrConstruct : Node.of(pathOrConstruct).path;
        let components = path.split(".");
...

Other:

Relative issue: aws/constructs#250

Short question: Why normalizeToDnsName limits components to maxLen? https://github.com/awslabs/cdk8s/blob/473b5ef7f442b932e9c4c4356945b91e8e1bc4e4/packages/cdk8s/src/names.ts#L79

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

---

This is a 🚀 Feature Request