An attempt to fix flaky SecureReactorNetty4HttpServerTransportTests (opensearch-project#18680)

Signed-off-by: Andriy Redko <[email protected]>

Author: reta

plugins/transport-reactor-netty4/src/main/java/org/opensearch/http/reactor/netty4/ReactorNetty4HttpServerTransport.java

@@ -243,6 +243,7 @@ protected HttpServerChannel bind(InetSocketAddress socketAddress) throws Excepti
                 .runOn(sharedGroup.getLowLevelGroup())
                 .bindAddress(() -> socketAddress)
                 .compress(true)
+                .http2Settings(spec -> spec.maxHeaderListSize(maxHeaderSize.bytesAsInt()))
                 .httpRequestDecoder(
                     spec -> spec.maxChunkSize(maxChunkSize.bytesAsInt())
                         .h2cMaxContentLength(h2cMaxContentLength.bytesAsInt())

plugins/transport-reactor-netty4/src/test/java/org/opensearch/http/reactor/netty4/ReactorHttpClient.java

@@ -25,6 +25,7 @@
 import java.io.UncheckedIOException;
 import java.net.InetSocketAddress;
 import java.nio.charset.StandardCharsets;
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
@@ -56,6 +57,8 @@
 import reactor.netty.http.Http2SslContextSpec;
 import reactor.netty.http.HttpProtocol;
 import reactor.netty.http.client.HttpClient;
+import reactor.netty.http.client.PrematureCloseException;
+import reactor.util.retry.Retry;
 
 import static io.netty.handler.codec.http.HttpHeaderNames.HOST;
 import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
@@ -255,6 +258,7 @@ private FullHttpResponse sendRequestStream(
                             )
                         )
                 )
+                .retryWhen(Retry.backoff(3, Duration.ofSeconds(1)).filter(throwable -> throwable instanceof PrematureCloseException))
                 .blockLast();
 
         } finally {
@@ -283,7 +287,7 @@ private HttpClient createClient(final InetSocketAddress remoteAddress, final Nio
                                 .configure(s -> s.clientAuth(ClientAuth.NONE).trustManager(InsecureTrustManagerFactory.INSTANCE))
                             : Http2SslContextSpec.forClient()
                                 .configure(s -> s.clientAuth(ClientAuth.NONE).trustManager(InsecureTrustManagerFactory.INSTANCE))
-                    )
+                    ).handshakeTimeout(Duration.ofSeconds(30))
                 );
         } else {
             return client.protocol(