[Feature]: Introduce factory method CreateDependencyWriter for backend storage

[zzzk1]

Requirement

Introduce factory method CreateDependencyWriter for backend storage

Problem

Based on the discussion in this GitHub pull request, I believe that instead of using type assertion to create StorageIntegration.DependencyWriter through dependencystore.Writer, a more effective approach would be to introduce a CreateDependencyWriter() function.

Proposal

1. Introduce CreateDependencyWriter in storage/factory.go of the BaseFactory.

2. storage factory Implement this function(just ES & Cassandra now, the others ignore).

es/factory.go
func (f *Factory) CreateDependencyWriter() (dependencystore.Writer, error) {
// TODO: Implement this feature
return "The Writer Instance", nil
}
es/grpc.go
func (f *Factory) CreateDependencyWriter() (dependencystore.Writer, error) {
return nil, nil
}

3.Add unit tests.

Open questions

No response

[zzzk1]

Hello @yurishkuro I’d love to hear your thoughts on this 😊

[yurishkuro]

Is it going to solve any specific problem? I have two reservations about such change:

1. You're suggesting to introduce it in v1 storage factories, which we are trying to deprecate.
2. By adding it to a factory interface you create the impression that it is a required function, vs the current approach of an optional interface. It's unclean design having a method in an interface which you don't actually need to support. The compiler will require it to be implemented so where it's not possible the option is only either to panic or return not-implemented error. In both cases the caller is required to check if the backend actually supports writing deps, despite implementing said method, so you are not making the caller's life any easier. Thus back to my lead question.

[zzzk1]

Is it going to solve any specific problem? I have two reservations about such change:

1. You're suggesting to introduce it in v1 storage factories, which we are trying to deprecate.
2. By adding it to a factory interface you create the impression that it is a required function, vs the current approach of an optional interface. It's unclean design having a method in an interface which you don't actually need to support. The compiler will require it to be implemented so where it's not possible the option is only either to panic or return not-implemented error. In both cases the caller is required to check if the backend actually supports writing deps, despite implementing said method, so you are not making the caller's life any easier. Thus back to my lead question.

Thanks!