Fix flaky Netty4Http3IT test suite (second attempt)

modules/transport-netty4/src/internalClusterTest/java/org/opensearch/http/netty4/Netty4Http3IT.java

@@ -76,15 +76,18 @@ protected boolean addMockHttpTransport() {
     public void testThatNettyHttpServerSupportsHttp2OrHttp3Get() throws Exception {
         assumeThat("HTTP/3 is not available on this arch/platform", Http3Utils.isHttp3Available(), is(true));
 
+        ensureGreen();
+        ensureFullyConnectedCluster();
+
         String[] requests = new String[] { "/", "/_nodes/stats", "/", "/_cluster/state", "/" };
         HttpServerTransport httpServerTransport = internalCluster().getInstance(HttpServerTransport.class);
         TransportAddress[] boundAddresses = httpServerTransport.boundAddress().boundAddresses();
         TransportAddress transportAddress = randomFrom(boundAddresses);
 
         @SuppressWarnings("unchecked")
         final Tuple<Netty4HttpClient, String> client = randomFrom(
-            Tuple.tuple(Netty4HttpClient.http3(), "h2="),
-            Tuple.tuple(Netty4HttpClient.https(), "h3=")
+            Tuple.tuple(Netty4HttpClient.http3().withLogger(logger), "h2="),
+            Tuple.tuple(Netty4HttpClient.https().withLogger(logger), "h3=")
         );
 
         try (Netty4HttpClient nettyHttpClient = client.v1()) {
@@ -107,15 +110,18 @@ public void testThatNettyHttpServerSupportsHttp2OrHttp3Get() throws Exception {
     public void testThatNettyHttpServerSupportsHttp2OrHttp3Post() throws Exception {
         assumeThat("HTTP/3 is not available on this arch/platform", Http3Utils.isHttp3Available(), is(true));
 
+        ensureGreen();
+        ensureFullyConnectedCluster();
+
         final List<Tuple<String, CharSequence>> requests = List.of(Tuple.tuple("/_search", "{\"query\":{ \"match_all\":{}}}"));
         HttpServerTransport httpServerTransport = internalCluster().getInstance(HttpServerTransport.class);
         TransportAddress[] boundAddresses = httpServerTransport.boundAddress().boundAddresses();
         TransportAddress transportAddress = randomFrom(boundAddresses);
 
         @SuppressWarnings("unchecked")
         final Tuple<Netty4HttpClient, String> client = randomFrom(
-            Tuple.tuple(Netty4HttpClient.http3(), "h2="),
-            Tuple.tuple(Netty4HttpClient.https(), "h3=")
+            Tuple.tuple(Netty4HttpClient.http3().withLogger(logger), "h2="),
+            Tuple.tuple(Netty4HttpClient.https().withLogger(logger), "h3=")
         );
 
         try (Netty4HttpClient nettyHttpClient = client.v1()) {

modules/transport-netty4/src/main/java/org/opensearch/http/netty4/Netty4Http3ServerTransport.java

@@ -231,6 +231,8 @@ protected void doStart() {
     @Override
     protected HttpServerChannel bind(InetSocketAddress socketAddress) throws Exception {
         ChannelFuture future = bootstrap.bind(socketAddress).sync();
+        logger.info("Bound to {}", socketAddress);
+
         Channel channel = future.channel();
         Netty4HttpServerChannel httpServerChannel = new Netty4HttpServerChannel(channel);
         channel.attr(HTTP_SERVER_CHANNEL_KEY).set(httpServerChannel);

modules/transport-netty4/src/test/java/org/opensearch/http/netty4/Netty4HttpClient.java

@@ -32,6 +32,8 @@
 
 package org.opensearch.http.netty4;
 
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.common.TriFunction;
 import org.opensearch.common.collect.Tuple;
 import org.opensearch.common.settings.Settings;
@@ -117,7 +119,6 @@
  * Tiny helper to send http requests over netty.
  */
 public class Netty4HttpClient implements Closeable {
-
     static Collection<String> returnHttpResponseBodies(Collection<FullHttpResponse> responses) {
         List<String> list = new ArrayList<>(responses.size());
         for (FullHttpResponse response : responses) {
@@ -137,6 +138,7 @@ static Collection<String> returnOpaqueIds(Collection<FullHttpResponse> responses
     private final Bootstrap clientBootstrap;
     private final TriFunction<CountDownLatch, Collection<FullHttpResponse>, Boolean, AwaitableChannelInitializer<?>> handlerFactory;
     private final boolean secure;
+    private Logger logger;
 
     Netty4HttpClient(
         Bootstrap clientBootstrap,
@@ -188,6 +190,11 @@ public static Netty4HttpClient http3() {
         );
     }
 
+    public Netty4HttpClient withLogger(Logger logger) {
+        this.logger = logger;
+        return this;
+    }
+
     public List<FullHttpResponse> get(SocketAddress remoteAddress, String... uris) throws InterruptedException {
         List<HttpRequest> requests = new ArrayList<>(uris.length);
         for (int i = 0; i < uris.length; i++) {
@@ -244,6 +251,7 @@ private synchronized List<FullHttpResponse> sendRequests(final SocketAddress rem
         final List<FullHttpResponse> content = Collections.synchronizedList(new ArrayList<>(requests.size()));
 
         final AwaitableChannelInitializer<?> handler = handlerFactory.apply(latch, content, secure);
+        handler.logger = logger;
         clientBootstrap.handler(handler);
 
         ChannelFuture channelFuture = null;
@@ -341,6 +349,14 @@ public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws E
      *
      */
     private static abstract class AwaitableChannelInitializer<C extends Channel> extends ChannelInitializer<C> {
+        private Logger logger;
+
+        void log(Level level, String message, Object... params) {
+            if (logger != null) {
+                logger.log(level, message, params);
+            }
+        }
+
         void await() {
             // do nothing
         }
@@ -518,6 +534,8 @@ protected void initChannel(DatagramChannel ch) {
 
         @Override
         Channel prepare(Bootstrap clientBootstrap, Channel channel) throws InterruptedException {
+            log(Level.INFO, "[QuicChannel] Connecting to: {}", channel.remoteAddress());
+
             final QuicChannel quicChannel = QuicChannel.newBootstrap(channel)
                 .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 30000) // 30 seconds
                 .handler(new Http3ClientConnectionHandler())