feat: validate schema only during the user's input unmarshal

[lobkovilya]

Problem

OpenAPI schema has required attribute, for example:

required:
  - port
  - address

But since ValidateSchema accepts Go object as an input, it's not possible to check if the field was set by user. So the user's input:

spec:
  port: 80

is unmarshalled to:

&Spec{
  port: 80,
}

and ValidateSchema returns no errors even though the address was not set.

As a result the validation result is different on K8s and Universal.

Solution

Unmarshal user's input to rawObj := map[string]interface{}{} instead of spec := &Spec{}. In that case if the field is not provided by user there is no key in rawObj map.

Implementation

This PR moves schema validation out of the Resource#Validate() method. Schema is validated only inside the rest.Unmarshal().

Signed-off-by: Ilya Lobkov ilya.lobkov@konghq.com

Checklist prior to review

• Link to docs PR or issue --
• Link to UI issue or PR --
• Is the issue worked on linked? --
• The PR does not hardcode values that might break projects that depend on kuma (e.g. "kumahq" as a image registry) --
• The PR will work for both Linux and Windows, system specific functions like syscall.Mkfifo have equivalent implementation on the other OS --
• Unit Tests --
• E2E Tests --
• Manual Universal Tests --
• Manual Kubernetes Tests --
• Do you need to update UPGRADE.md? --
• Does it need to be backported according to the backporting policy? --
• Do you need to explicitly set a > Changelog: entry here or add a ci/ label to run fewer/more tests?

Changelog: feat(policy): validate schema only during the user's input unmarshal

[lahabana]

This 3x unmarshaling is a little weird but I guess we can always improve on this later.