Unmarshalling fails for Scale object if 'replicas' is set to 0

[mariozel]

Hey there.
I have some code that looks like this:

def scaleDeployment(namespace: String, name: String, newScale: Int): Future[Scale] = {
  skuber.usingNamespace(namespace).getScale[Deployment](name).flatMap { scale =>
    val downscale = scale.withSpecReplicas(newScale)
    skuber.usingNamespace(namespace).updateScale[Deployment](name, downscale)
  }
}

calling this method with non-zero values in newScale works just fine. However, if I need to scale the deployment to 0 then Unmarshalling fails with the following error:

e => JsError(List((/spec/replicas,List(JsonValidationError(List(error.path.missing),WrappedArray())))))
akka.http.scaladsl.server.RejectionError
	at skuber.json.PlayJsonSupportForAkkaHttp.$anonfun$unmarshaller$1(PlayJsonSupportForAkkaHttp.scala:79)
	at play.api.libs.json.JsError.recoverTotal(JsResult.scala:91)
	at skuber.json.PlayJsonSupportForAkkaHttp.read$1(PlayJsonSupportForAkkaHttp.scala:76)
	at skuber.json.PlayJsonSupportForAkkaHttp.$anonfun$unmarshaller$2(PlayJsonSupportForAkkaHttp.scala:83)
	at akka.http.scaladsl.util.FastFuture$.$anonfun$map$1(FastFuture.scala:23)
	at akka.http.scaladsl.util.FastFuture$.strictTransform$1(FastFuture.scala:41)
	at akka.http.scaladsl.util.FastFuture$.transformWith$extension1(FastFuture.scala:45)
	at akka.http.scaladsl.util.FastFuture$.map$extension(FastFuture.scala:23)
	at akka.http.scaladsl.unmarshalling.Unmarshaller.$anonfun$map$3(Unmarshaller.scala:26)
	at akka.http.scaladsl.unmarshalling.Unmarshaller.$anonfun$transform$3(Unmarshaller.scala:23)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$$anon$1.apply(Unmarshaller.scala:58)
	at akka.http.scaladsl.unmarshalling.LowerPriorityGenericUnmarshallers.$anonfun$messageUnmarshallerFromEntityUnmarshaller$3(GenericUnmarshallers.scala:25)
	at akka.http.scaladsl.unmarshalling.Unmarshaller$$anon$1.apply(Unmarshaller.scala:58)
	at akka.http.scaladsl.unmarshalling.Unmarshal.to(Unmarshal.scala:25)
	at skuber.api.client.impl.KubernetesClientImpl.$anonfun$toKubernetesResponse$1(KubernetesClientImpl.scala:651)
	at scala.concurrent.Future.$anonfun$flatMap$1(Future.scala:307)
	at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:91)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:85)
	at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:91)
	at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:40)
	at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:44)
	at akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
	at akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
	at akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
	at akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

It seems that k8s is omitting the 0 value in replicas which invalidates the Json object for Skuber.

Is this a known issue (perhaps related to #48 )? Is there a workaround?

Thanks in advance
M

[mzeljkovic]

PR up with a proposed fix.

Apologies for using a different account. (same user as the person logging the issue)