GH-110 use CRD validation on DNSRecord

[maksymvavilov]

Adding following validation rules on the DNS Record CRD:

Spec

• RootHost limited to 255 characters and must consist of two groups of allowed for URLs characters separated by the .. This is the only check from the Validate() that is feasible to transfer to the CRD validations

HealthCheck Spec

• Endpoint (aka Path) should start with ? or /, contain only allowed for the URLs symbols and end with alphanumeric character or /.
• Port allowed to be set to 80, 443, and from 1024 to 49151 - the range of registered ports.
• Protocol restricted to HTTP or HTTPS
• FailureThreshold must be a positive integer

[mikenairn]

Using Enum would probably make more sense here, and for port see https://github.com/Kuadrant/kuadrant-operator/blob/main/api/v1alpha1/dnspolicy_types.go#L255

Also, all the validations should be the same as https://github.com/Kuadrant/kuadrant-operator/blob/main/api/v1alpha1/dnspolicy_types.go#L246-L261

@philbrookes Why is that duplicated? Would it not make more sense for the DNSPolicy to reference this HealthCheckSpec type?

[philbrookes]

I cannot remember clearly, I suspect the Specs were different from each other at some point, but are aligned now.

[philbrookes]

as the validations in this PR are superior to the validations in Kuadrant-operator, it might be worth a PR to update kuadrant to use this.

[maksymvavilov]

I'd prefer the CEL validations - way nicer error message if things aren't right.

Hmm, would it be a good idea to remove duplication as part of this issue?

[maksymvavilov]

Opened a PR to the kuadrant-operator as well

[philbrookes]

Some small changes to the language used, the regexes look fine.

[philbrookes]

I see @mikenairn has added some tests to cover his validations, which is pretty neat, is that something we could also do here?

[maksymvavilov]

Added test @philbrookes. It is a strange one, but, hopefully, is useful. At least it is cheep to check it.