Vertx Instance not initialized when using Kotlin Coroutines - kotlin

Question

I am trying to writer an HTTP server using a Vert.x CoroutineVerticle, but I get an error lateinit property vertxInstance has not been initialized. It seems like the init(...) function of CoroutineVerticle is not being called when the verticle is deployed.
package http
import io.vertx.core.DeploymentOptions
import io.vertx.core.Vertx
import io.vertx.ext.web.Router
import io.vertx.kotlin.core.http.listenAwait
import io.vertx.kotlin.coroutines.CoroutineVerticle
class CoTest : CoroutineVerticle() {
private var router = createRouter()
override suspend fun start() {
vertx.createHttpServer()
.requestHandler(router)
.listenAwait(config.getInteger("http.port", 8182))
}
private fun createRouter() = Router.router(vertx).apply {
get("/favicon.ico").handler { req ->
req.response().end("NO")
}
}
}
fun main() {
class V : ServerVertxCo(8182) {}
Vertx.vertx().deployVerticle(CoTest::class.java.canonicalName)
}

Answer 1

The problem is the order you do things in your class.
The order for vertx is:
Create the vertx instance
Deploy a verticle
Verticle class constructor is called (vertx is not "injected" to it yet)
Vertx does some internal initializations
Vertx calls the verticle's start function
You use private var router = createRouter() in the class (outside the start block) and at that point vertx is not "injected" yet to the class so you get an exception.
If you move it to the start block it should work as you expect:
class CoTest : CoroutineVerticle() {
override suspend fun start() {
val router = createRouter()
vertx.createHttpServer()
.requestHandler(router)
.listenAwait(config.getInteger("http.port", 8182))
}
private fun createRouter() = Router.router(vertx).apply {
get("/favicon.ico").handler { req ->
req.response().end("NO")
}
}
}
suspend fun main() {
val vertx = Vertx.vertx()
vertx.deployVerticleAwait(CoTest::class.java.canonicalName)
}