Unable to consume more than 4MB from pubsub

[mahendra-sawarkar-exa]

We are using below dependencies in out project:

"com.google.cloud" % "google-cloud-pubsub" % "1.105.1" exclude("io.grpc", "grpc-alts"),
"io.grpc" % "grpc-alts" % "1.29.0",
"com.lightbend.akka" %% "akka-stream-alpakka-google-cloud-pub-sub-grpc" % "3.0.4"

below is the akka code:

val pubsubSubscription = Helper.getSubscriptionPath(customerName)
val pubsubConfig = PullRequest()
  .withSubscription(pubsubSubscription)
  .withReturnImmediately(true)
  .withMaxMessages(1000)

  GooglePubSub.subscribePolling(pubsubConfig, 500.millis)
  .map { pubsubMessage => print(s"I got message $pubsubMessage") )
  ......

but i am getting following error while consuming data from pubsub

Error to processing messages for Code Code(testUser).
io.grpc.StatusRuntimeException: RESOURCE_EXHAUSTED: gRPC message exceeds maximum size 4194304: 4910368
at io.grpc.Status.asRuntimeException(Status.java:533)
at akka.grpc.internal.UnaryCallAdapter.onClose(UnaryCallAdapter.scala:40)
at io.grpc.internal.ClientCallImpl.closeObserver(ClientCallImpl.java:413)
at io.grpc.internal.ClientCallImpl.access$500(ClientCallImpl.java:66)
at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInternal(ClientCallImpl.java:742)
at io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1StreamClosed.runInContext(ClientCallImpl.java:721)
at io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
at io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:123)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Jan 03, 2023 12:16:07 PM io.grpc.internal.AbstractClientStream$TransportState inboundDataReceived
INFO: Received data on closed stream

please guide, thanks in advance!

[gkatzioura]

I had the same limitation on this one.
I ended up swapping the SubscriberClient on the GrpcSubscriber with a custom one using reflection.
A pr tackling this would be more suitable.

[mahendra-sawarkar-exa]

@gkatzioura
Thanks for suggestion :)
is this error per pubsub message or for batch of messages?