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package io.numaproj.numaflow.sessionreducer;
import akka.actor.AbstractActor;
import akka.actor.Props;
import io.grpc.stub.StreamObserver;
import io.numaproj.numaflow.sessionreduce.v1.Sessionreduce;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
/**
* Output actor is a wrapper around the gRPC output stream.
* It ensures synchronized calls to the responseObserver onNext() and invokes onComplete at the end of the stream.
* ALL session reduce responses are sent to the output actor before getting forwarded to the output gRPC stream.
*
* More details about gRPC StreamObserver concurrency: https://grpc.github.io/grpc-java/javadoc/io/grpc/stub/StreamObserver.html
*/
@Slf4j
@AllArgsConstructor
class OutputActor extends AbstractActor {
StreamObserver responseObserver;
public static Props props(
StreamObserver responseObserver) {
return Props.create(OutputActor.class, responseObserver);
}
@Override
public Receive createReceive() {
return receiveBuilder()
.match(ActorResponse.class, this::handleResponse)
.match(String.class, this::handleEOF)
.build();
}
private void handleResponse(ActorResponse actorResponse) {
responseObserver.onNext(actorResponse.getResponse());
if (actorResponse.isLast()) {
this.closeSystem();
}
}
private void handleEOF(String eof) {
this.closeSystem();
}
private void closeSystem() {
// close the output stream.
responseObserver.onCompleted();
// stop the AKKA system right after we close the output stream.
// note: could make more sense if the supervisor actor stops the system,
// but it requires an extra tell.
getContext().getSystem().stop(getSender());
}
}