Implement filesystem stores

We want to provide three different storage options, memory, filesystem and database. Currently filesystem is not implemented (e.g. see https://code.fbi.h-da.de/danet/gosdn/-/blob/develop/controller/nucleus/pndStore.go#L40).

This should also be possible with generics, check https://code.fbi.h-da.de/danet/gosdn/-/blob/develop/controller/nucleus/genericStore.go for the in-memory implementation.

This is needed for the following stores:

UUID are unique, that means the store should check that there can't be two. Prototype for this in utils:

func CheckForDuplicateUUIDs[T store.LoadedStorable](objects []T) error {
	var uuids = make(map[uuid.UUID]bool)

	for _, object := range objects {

		_, uuidExists := uuids[object.GetID()]
		if uuidExists {
			return &errors.ErrAlreadyExists{Item: object}
		}

		uuids[object.GetID()] = true
	}

	return nil
}

func CheckForDuplicatePndUUIDs[T store.Storable](objects []T) error {
	var uuids = make(map[uuid.UUID]bool)

	for _, object := range objects {

		_, uuidExists := uuids[object.ID()]
		if uuidExists {
			return &errors.ErrAlreadyExists{Item: object}
		}

		uuids[object.ID()] = true
	}

	return nil
}

• PND
• Device
• SBI
• User
• Role
• Ensure that duplicate uuids are not possible