Upload stream

LargeUpload.java

import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Duration;
import java.util.Arrays;
import java.util.concurrent.ExecutorService;

import io.helidon.common.configurable.ThreadPoolSupplier;
import io.helidon.common.http.DataChunk;
import io.helidon.common.http.Http;
import io.helidon.common.http.MediaType;
import io.helidon.common.reactive.IoMulti;
import io.helidon.media.jsonp.JsonpSupport;
import io.helidon.media.multipart.MultiPartSupport;
import io.helidon.webclient.WebClient;
import io.helidon.webserver.Routing;
import io.helidon.webserver.WebServer;

public class LargeUpload {
    
    public static void main(String[] args) {
        ExecutorService executor = ThreadPoolSupplier.create("upload-thread-pool").get();

        WebServer server = WebServer.builder(Routing.builder()
                        .post("/streamUpload", (req, res) -> req.content()
                                .map(DataChunk::data)
                                .flatMapIterable(Arrays::asList)
                                .to(IoMulti.writeToFile(createFile(req.queryParams().first("fileName").orElse("bigFile.mkv")))
                                        .executor(executor)
                                        .build())

                                .onError(res::send)
                                .onComplete(() -> {
                                    res.status(Http.Status.ACCEPTED_202);
                                    res.send();
                                }).ignoreElement())
                        .build())
                .port(8080)
                .build()
                .start()
                .await(Duration.ofSeconds(10));

        // Server started - do upload

        //several gigs file
        Path file = Path.of("/home/kec/helidon-kafka.mkv");


        try (FileInputStream fis = new FileInputStream(file.toFile())) {

            WebClient.builder()
                    .baseUri("http://localhost:8080")
                    .build()
                    .post()
                    .path("/streamUpload")
                    .queryParam("fileName", "bigFile_" + System.currentTimeMillis() + ".mkv")
                    .contentType(MediaType.APPLICATION_OCTET_STREAM)
                    .submit(IoMulti.multiFromByteChannelBuilder(fis.getChannel())
                            .bufferCapacity(1024 * 1024 * 4)
                            .build()
                            .map(DataChunk::create)
                    )
                    .await(Duration.ofMinutes(10));
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        executor.shutdown();
        server.shutdown()
                .await(Duration.ofSeconds(10));
    }

    static Path createFile(String path) {
        try {
            Path filePath = Path.of("/home/kec/tmp/" + path);
            System.out.println("Creating " + filePath);
            return Files.createFile(filePath);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}