Separating non-core functionality into separate modules

[eutkin]

Problem

ScaleCube Services has supporting subsystems that allow it to be self-contained. For now, I want to highlight two subsystems:

• subsystem IoC (DI): @Inject, etc;
• subsystem Security: @Principal, Authenticator, etc.

These subsystems are hardcoded into the project, which prevents ScaleCube Services from integrating with third-party implementations of IoC/Security frameworks: Spring IoC, Guice, Spring Security, Okta, etc.

Problems that prevent integration:

• duplication of functionality;
• conflict of namespaces of different frameworks: the same for annotations @Principal, @Inject ;
• cyclical dependence in ScaleCube IoC between instance service and instance Microservices;
• a mechanism for solving the type of parameter corresponding to the user's profile in the service method.

Solution

I propose the following algorithm:

1. to separate the subsystems described above into separate modules;
2. to replace them with SPI interfaces;
3. to connect modules from item 1 as default implementations
4. write modules implementation using popular frameworks (I can take over completely).

Motivation

I faced this problem when integrating the project with the Spring Framework. Integration is possible, but it looks redundant and crooked.