Reading Configuration File

As stated by its documentation, Vert.x provides the vertx-config module to efficiently interact with configuration files. Internally, this module relies on the Config Retriever and Configuration store concepts, defining "a location from where the configuration data is read and also a format (JSON by default)."

As an attempt to simplify this process, Kos made the following design choices:

• it only looks after files named application.yml in the classpath. In case more than one is found, they will be merged before being used.
• it fully executes the above by default, but allows one to change the default behaviour (e.g. using a different Configuration Retriever)
• Once the configuration is read, you will have access to an JsonObject - just like you'd have on a typical Vert.x application.

Reading the configuration object

The easiest way to interaction with the read configuration would be through Dependency Injection. You will have full access to Kos Context, which will expose the read configuration file (Vert.x's JsonObject).

Kotlin

@Singleton
class MyServerConfiguration(
    private val kosContext: KosContext
) {

    val dbHost = kosContext.applicationConfig.getString("db.host", "localhost")
    val dbPort = kosContext.applicationConfig.getString("db.port", "5432")
    val dbUser = kosContext.applicationConfig.getString("db.user", "postgres")
    val dbPass = kosContext.applicationConfig.getString("db.pass", "postgres")
}

Java

@Singleton
class MyServerConfiguration {

    private final KosContext kosContext;

    public MyServerConfiguration(KosContext kosContext){
        this.kosContext = kosContext;
    }

    public String getDbHost() {
        return kosContext.getApplicationConfig().getString("db.host", "localhost");
    }

    public String getDbPort() {
        return kosContext.getApplicationConfig().getString("db.port", "5432");
    }

    public String getDbUser() {
        return kosContext.getApplicationConfig().getString("db.user", "postgres");
    }

    public String getDbPass() {
        return kosContext.getApplicationConfig().getString("db.pass", "postgres");
    }
}

Another option would be listening to Kos' internal events.