Feature: Configuration Injection

[paullatzelsperger]

Feature Request

Implement a feature that enables configuration injection. By annotating certain field values it should be possible to automatically resolve and set config values, for example:

public class SomeExtension extends ServiceExtension {

    @Setting(key = "edc.some.config.value", required = true, defaultValue = "barbaz")
    private String someConfigValue
}

thus, someConfigValue gets assigned the value of edc.some.config.value, or - lacking that - the default value "barbaz".

In addition, it should be able to group config values together in a configuration object, which is basically a POJO:

public class SomeExtension extends ServiceExtension {

    @Configuration
    private SomeConfigObject configObject;

}

public record SomeConfigObject(@Setting(key="...") String stringValue, 
                               @Setting(key="...") Double doubleValue){

}

Which Areas Would Be Affected?

dependency injection, ultimately the entire code base

Why Is the Feature Desired?

ease of use

Solution Proposal

enhance the InjectionPoint implementations, move some responsibility into the FieldInjectionPoint to allow changing the behaviour in other impls.

Subtasks

• Decision-Record docs: decision record about configuration injection #4611
• Implementation of the configuration injection (including runtime metamodel and autodoc)
  • feat: add config injection annotations Runtime-Metamodel#75
  • feat: autodoc parse @Configuration objects GradlePlugins#289
  • feat: implement Configuration Injection #4617
  • feat: improve handling of default values for ValueInjectionPoints #4620
  • feat: improve DependencyGraph and error reporting #4628
• Adapting the code base to utilize this feature
• Update the EDC documentation