500 Internal Server Error in Akka Scala server - scala

Question

This is my code for the server written using Akka framework:
case class Sentence(data: String)
case class RawTriples(triples: List[String])
trait Protocols extends DefaultJsonProtocol {
implicit val sentenceRequestFormat = jsonFormat1(Sentence)
implicit val rawTriplesFormat = jsonFormat1(RawTriples)
}
trait Service extends Protocols {
implicit val system: ActorSystem
implicit def executor: ExecutionContextExecutor
implicit val materializer: Materializer
val openie = new OpenIE
def config: Config
val logger: LoggingAdapter
lazy val ipApiConnectionFlow: Flow[HttpRequest, HttpResponse, Any] =
Http().outgoingConnection(config.getString("services.ip-api.host"), config.getInt("services.ip-api.port"))
def ipApiRequest(request: HttpRequest): Future[HttpResponse] = Source.single(request).via(ipApiConnectionFlow).runWith(Sink.head)
val routes = {
logRequestResult("akka-http-microservice") {
pathPrefix("openie") {
post {
decodeRequest{
entity(as[Sentence]){ sentence =>
complete {
var rawTriples = openie.extract(sentence.data)
val resp: MutableList[String] = MutableList()
for(rtrip <- rawTriples){
resp += (rtrip.toString())
}
val response: List[String] = resp.toList
println(response)
response
}
}
}
}
}
}
}
}
object AkkaHttpMicroservice extends App with Service {
override implicit val system = ActorSystem()
override implicit val executor = system.dispatcher
override implicit val materializer = ActorMaterializer()
override val config = ConfigFactory.load()
override val logger = Logging(system, getClass)
Http().bindAndHandle(routes, config.getString("http.interface"), config.getInt("http.port"))
}
The server accepts a POST request containing a sentence and returns a json array in return. It works fine but if I am making requests to it too frequently using parallelized code, then it gives 500 Internal server error. I wanted to know is there any parameter which I can set in the server to avoid that (number of ready threads for accepting requests etc).
In log files, the error is logged as:
[ERROR] [05/31/2017 11:48:38.110]
[default-akka.actor.default-dispatcher-6]
[akka.actor.ActorSystemImpl(default)] Error during processing of
request: 'null'. Completing with 500 Internal Server Error response.

Answer 1

The doc on the bindAndHandle method shows what you want:
/**
* Convenience method which starts a new HTTP server at the given endpoint and uses the given `handler`
* [[akka.stream.scaladsl.Flow]] for processing all incoming connections.
*
* The number of concurrently accepted connections can be configured by overriding
* the `akka.http.server.max-connections` setting. Please see the documentation in the reference.conf for more
* information about what kind of guarantees to expect.
*
* To configure additional settings for a server started using this method,
* use the `akka.http.server` config section or pass in a [[akka.http.scaladsl.settings.ServerSettings]] explicitly.
*/
akka.http.server.max-connections is probably what you want. As the doc suggests, you can also dig deeper into the akka.http.server config section.

Answer 2

Add following in application.conf file
akka.http {
server {
server-header = akka-http/${akka.http.version}
idle-timeout = infinite
request-timeout = infinite
}
}