It’s a very very basic presentation about how to use interfaces, what is it and why you need it.
When you work with gRPC you work with an auto-generated code which contains Go structures. If your app has a strong separation between business logic and transport level most likely your business logins has it’s own set of structures. The issue here is for Go two structure types with different names and even with equal set of fields are different types, i.e. in order to publish result from BL level to gRPC endpoint you have to convert one structure type into another, field-by-field or you can generate such kind of transformations and I’m going to explain how to achieve it.