Group configuration in quarkus / microprofile

Question

I want to group configuration items in Quarkus and use them as a Map. Something along the lines of the next application.properties:

greeting.names = tom,jane
greeting.tom.message = hello
greeting.tom.name = tom
greeting.jane.message = hi
greeting.jane.name = jane

And have them in the application in a Map, like this:

@ConfigProperties
public class GreetingConfig {

   private String name;
   private String message;

   // getters / setters
}

And use them like this:

private Map<String, GreetingConfig> config;

They are now name indexed, but a List would also be fine (and is what I actually need):

greeting.1.message = hello
greeting.1.name = tom
greeting.2.message = hi
greeting.2.name = jane

Any ideas on how to realize this? I have a programmatic solution, but would prefer a solution by annotation only

Answer 1

I've had a similar problem these days. So I wrote a simple Quarkus extension which helped me with the configuration. You can use the guides from the Quarkus site: Quarkus - Writing Your Own Extension and Quarkus - Building my first extension, but basically these are the steps taken in order to create the configuration:

1. Have some maven multi module project (not the project where the configuration will be consumed).
2. Execute a similar command form the project directory:

mvn io.quarkus:quarkus-maven-plugin:1.4.2.Final:create-extension -N \
    -Dquarkus.artifactIdBase=keycloak-extension \
    -Dquarkus.artifactIdPrefix=otaibe-commons-quarkus- \
    -Dquarkus.nameBase="Keycloak extension"

This will create 'sub multi module' project there with the following modules: runtume and deployment.

3. Go to the runtime module and add and annotate your config class. It should be something similar to this class
4. In runtime module create a producer class which should register the configuration class as CDI bean:

@ApplicationScoped
public class OtaibeKeycloakQuarkusProducer {

    private volatile OtaibeKeycloakConfig otaibeKeycloakConfig;

    void initialize(OtaibeKeycloakConfig config) {
        this.otaibeKeycloakConfig = config;
    }

    @Singleton
    @Produces
    public OtaibeKeycloakConfig otaibeKeycloakConfig() {
        return otaibeKeycloakConfig;
    }

}

5. Create a Recorder class which should initialize the Producer:

@Recorder
public class OtaibeKeycloakRecorder {

    public void initOtaQuarkusProducer(BeanContainer container, OtaibeKeycloakConfig configuration) {
        OtaibeKeycloakQuarkusProducer producer = container.instance(OtaibeKeycloakQuarkusProducer.class);
        producer.initialize(configuration);
    }

}

6. In deployment module you have a Processor class. Go there and register your Producer to be injectable as CDI bean and your Recorder to initialize it. Add the similar code:

    @BuildStep
    AdditionalBeanBuildItem beans() {
        return AdditionalBeanBuildItem.builder().addBeanClasses(OtaibeKeycloakQuarkusProducer.class).build();
    }

    @BuildStep
    @Record(ExecutionTime.RUNTIME_INIT)
    void otaibeKeycloackConfigBuildItem(BeanContainerBuildItem beanContainer,
                                        OtaibeKeycloakConfig otaibeKeycloakConfig,
                                        OtaibeKeycloakRecorder recorder) {
        recorder.initOtaQuarkusProducer(beanContainer.getValue(), otaibeKeycloakConfig);
    }

You can find my implementation here.

7. Now, go to your initial project where the configuration will be consumed and add the runtime module as a dependency.

8. In order to ensure that the configuration is added properly execute the following maven command:

mvn quarkus:generate-config

Now, you can check the file src/main/resources/application.properties.example and verify whether your properties are added there. The property group should start with quarkus. plus the name of your @ConfigRoot annotation. In my case for example it will start with quarkus.otaibe.keycloak

That's it!