added new generic parser interface

[henderiw]

this is the generic parser interface which offloads a set of method implementations from the libraries

[linux-foundation-easycla]

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• ✅ login: henderiw / name: Wim Henderickx (129eab8, 556ee9d, b11c74b, 2d0fc40, 0ca3db3)
• ✅ login: ganchandrasekaran / name: Ganesh Chandrasekaran (7efd812, 941c717, 1717686)

[gvbalaji]

Thanks @henderiw . My initial thinking is the following. I have updated this after seeing how this is consumed in the interface lib. Here are my suggestions.

1. I think it may be simpler to have only helper functions in this base library.

type Entity struct {
Obj *fn.KubeObject
}

• NewFromKubeObject(*fn.KubeObject) (Entity, error)
• NewFromYaml(b []byte) (Entity, error)
• NewFromGoStruct(x any) (Entity, error)
• GostructFromKubeObjectT any (T, err)

This should cover the creation of objects for all entities ( ip, interface etc) and base methods. Then we do not need to implement in the individual libraries.

3. Let the callers directly call get/set/delete methods on the kubeobject. I am saying this because we are not providing any additional processing (for e.g like we did with GetInterface... methods to hide the YAML path from the user).
4. Then in individual libraries only define getters/setters that will do further help like in the interface library GetAttachmentType(), GetNetworkInstanceName() etc. Implement these methods directly on the Entity structure defined above ( in this base library). This will avoid lot of code in each of the libraries.

in interface library

type InterfaceEntity interface {
GetAttachmentType()
GetNetworkInstanceName()
SetNetworkInstanceName()
.
.
.
}

func (r *Entity) GetAttachmentType() string
func (r *Entity) GetNetworkInstanceName() string

Users will first create the entity and then call the methods based on function they are implementing.

In fact we can directly implement methods on the structure without an interface.

[kispaljr]

I agree with @gvbalaji to have only helper functions in the base library.
To help the argument, this: nokia#19 alternative (but functionally equivalent) implementation of the same Parser interface shows, that most of the Parser methods are just aliases of KubeObject methods.

The same implementation also shows that the 4 functions @gvbalaji mentioned, are also mostly aliases to existing upstream SDK functions. So in his proposal we only need conversion functions between Entity and KubeObject. Or, we can just use type Entity fn.KubeObject instead of the type Entity struct {...} to make it trivial.

[gvbalaji]

Thanks @henderiw . In line with our discussion. Added a minor comment about naming.

[gvbalaji]

/lgtm

[nephio-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gvbalaji, henderiw

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[gvbalaji]

/lgtm