Skip to content

Tuning the application's entry point

Note

This change is an optional change. If you don't have any unpredictable components to alter, like, time, scheduler, etc... Or if you don't want to have full observability over Kafka you can leave the main function as is. But, still we recommend this change, as you might have components to change in the future.

Let's say the application has a standard main function, here how we will change it:

@SpringBootApplication
class ExampleApplication

fun main(args: Array<String>) { runApplication<ExampleApplication>(*args) }

@SpringBootApplication
class ExampleApplication

fun main(args: Array<String>) { run(args) }

fun run(
     args: Array<String>,
     init: SpringApplication.() -> Unit = {},
  ): ConfigurableApplicationContext {
        return runApplication<ExampleApplication>(*args, init = init)
    }

As you can see from before-after sections, we have divided the application main function into two parts.

run(args, init) method is the important point for the testing configuration. init allows us to override any dependency from the testing side that is being time related or configuration related. Spring itself opens this configuration higher order function to the outside.