I'm trying to write a tool for batch data upload using Akka HTTP 2.0-M2.
But I'm facing akka.stream.OverflowStrategy$Fail$BufferOverflowException: Exceeded configured max-open-requests value of [32] error.
I tried to isolate a problem and here is the sample code which also fails:
public class TestMaxRequests {
private static final class Router extends HttpApp {
@Override
public Route createRoute() {
return route(
path("test").route(
get(handleWith(ctx -> ctx.complete("OK")))
)
);
}
}
public static void main(String[] args) {
ActorSystem actorSystem = ActorSystem.create();
Materializer materializer = ActorMaterializer.create(actorSystem);
Router router = new Router();
router.bindRoute("127.0.0.1", 8082, actorSystem);
LoggingAdapter log = Logging.getLogger(actorSystem, new Object());
for (int i = 0; i < 100; i++) {
final int reqNum = i;
Http.get(actorSystem).singleRequest(HttpRequest.create().withUri("http://127.0.0.1:8082/test"), materializer)
.onComplete(new OnComplete<HttpResponse>() {
@Override
public void onComplete(Throwable failure, HttpResponse response) throws Throwable {
if (failure != null) {
log.error(failure, "Failed: {}", reqNum);
} else {
log.info("Success: {}, consuming stream...", reqNum);
response.entity().getDataBytes().runWith(Sink.ignore(), materializer);
log.info("Success: {}, consumed stream", reqNum);
}
}
}, actorSystem.dispatcher());
}
}
}
It fails with:
[2015-12-15 16:17:32,609] [ INFO] [] [] a.e.s.Slf4jLogger: Slf4jLogger started
[2015-12-15 16:17:32,628] [ DEBUG] [main] [EventStream(akka://default)] a.e.EventStream: logger log1-Slf4jLogger started
[2015-12-15 16:17:32,636] [ DEBUG] [main] [EventStream(akka://default)] a.e.EventStream: Default Loggers started
[2015-12-15 16:17:33,531] [ DEBUG] [spatcher-3] [akka://default/system/IO-TCP/selectors/$a/0] a.i.TcpListener: Successfully bound to /127.0.0.1:8082
[2015-12-15 16:17:33,624] [ DEBUG] [spatcher-7] [akka://default/user/PoolInterfaceActor-0] a.h.i.e.c.PoolInterfaceActor: (Re-)starting host connection pool to 127.0.0.1:8082
[2015-12-15 16:17:33,736] [ DEBUG] [spatcher-8] [akka://default/user/SlotProcessor-0] a.h.i.e.c.PoolSlot$SlotProcessor: become unconnected, from subscriber pending
[2015-12-15 16:17:33,748] [ DEBUG] [patcher-11] [akka://default/user/SlotProcessor-3] a.h.i.e.c.PoolSlot$SlotProcessor: become unconnected, from subscriber pending
[2015-12-15 16:17:33,758] [ DEBUG] [spatcher-9] [akka://default/user/SlotProcessor-2] a.h.i.e.c.PoolSlot$SlotProcessor: become unconnected, from subscriber pending
[2015-12-15 16:17:33,762] [ DEBUG] [spatcher-9] [akka://default/user/SlotProcessor-1] a.h.i.e.c.PoolSlot$SlotProcessor: become unconnected, from subscriber pending
[2015-12-15 16:17:33,779] [ ERROR] [patcher-11] [Object(akka://default)] j.l.Object: Failed: 36
akka.stream.OverflowStrategy$Fail$BufferOverflowException: Exceeded configured max-open-requests value of [32]
at akka.http.impl.engine.client.PoolInterfaceActor$$anonfun$receive$1.applyOrElse(PoolInterfaceActor.scala:120) ~[akka-http-core-experimental_2.11-2.0-M2.jar:na]
at akka.actor.Actor$class.aroundReceive(Actor.scala:480) ~[akka-actor_2.11-2.4.0.jar:na]
at akka.http.impl.engine.client.PoolInterfaceActor.akka$stream$actor$ActorSubscriber$$super$aroundReceive(PoolInterfaceActor.scala:48) ~[akka-http-core-experimental_2.11-2.0-M2.jar:na]
at akka.stream.actor.ActorSubscriber$class.aroundReceive(ActorSubscriber.scala:201) ~[akka-stream-experimental_2.11-2.0-M2.jar:na]
at akka.http.impl.engine.client.PoolInterfaceActor.akka$stream$actor$ActorPublisher$$super$aroundReceive(PoolInterfaceActor.scala:48) ~[akka-http-core-experimental_2.11-2.0-M2.jar:na]
at akka.stream.actor.ActorPublisher$class.aroundReceive(ActorPublisher.scala:309) ~[akka-stream-experimental_2.11-2.0-M2.jar:na]
at akka.http.impl.engine.client.PoolInterfaceActor.aroundReceive(PoolInterfaceActor.scala:48) ~[akka-http-core-experimental_2.11-2.0-M2.jar:na]
at akka.actor.ActorCell.receiveMessage(ActorCell.scala:525) [akka-actor_2.11-2.4.0.jar:na]
at akka.actor.ActorCell.invoke(ActorCell.scala:494) [akka-actor_2.11-2.4.0.jar:na]
at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257) [akka-actor_2.11-2.4.0.jar:na]
at akka.dispatch.Mailbox.run(Mailbox.scala:224) [akka-actor_2.11-2.4.0.jar:na]
at akka.dispatch.Mailbox.exec(Mailbox.scala:234) [akka-actor_2.11-2.4.0.jar:na]
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) [scala-library-2.11.7.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) [scala-library-2.11.7.jar:na]
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) [scala-library-2.11.7.jar:na]
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107) [scala-library-2.11.7.jar:na]
[2015-12-15 16:17:33,780] [ ERROR] [patcher-20] [Object(akka://default)] j.l.Object: Failed: 48
I guess that's because I'm trying to create a lot of Futures and execute them all at once. But isn't Akka supposed to enable backpressure? I guess I'm using it wrong. I tried superPool methods but nothing changed because, as I understand, Http.singleRequest has same pool inside. I also tried to reuse Http instance instead of calling Http.get() in the loop but it also did not help.
What is the correct way of firing a batch of requests? I am planning to execute batches of 10 000 - 100 000 requests.
Ramon J Romero y Vigil
Akka absolutely enables backpressure, you're just not taking advantage of it. Instead of dispatching multiple single requests, you can use a single Flow to send all of your requests through. From the documentation:
final Flow<HttpRequest, HttpResponse, Future<OutgoingConnection>> connectionFlow =
Http.get(actorSystem).outgoingConnection("127.0.0.1", 8082);
You can then use this Flow to process your HttpRequest objects:
HttpRequest httpRequest = HttpRequest.GET("/test")
//imitates your for-loop example of 100 requests
Source.from(() -> Collections.nCopies(100, httpRequest).iterator())
.via(connectionFlow)
.runForeach(...)
来源：https://stackoverflow.com/questions/34293113/how-to-properly-call-akka-http-client-for-multiple-10k-100k-requests