Merging back PR #2882

.changes/next-release/bugfix-nettynioclient-0fb07b2.json

@@ -0,0 +1,6 @@
+{
+    "category": "Netty NIO HTTP Client", 
+    "contributor": "", 
+    "type": "bugfix", 
+    "description": "Ensure initial channel used for protocol detection is released before re-acquiring"
+}

http-clients/netty-nio-client/src/main/java/software/amazon/awssdk/http/nio/netty/internal/http2/HttpOrHttp2ChannelPool.java

@@ -17,6 +17,7 @@
 
 import static software.amazon.awssdk.http.nio.netty.internal.ChannelAttributeKey.PROTOCOL_FUTURE;
 import static software.amazon.awssdk.http.nio.netty.internal.utils.NettyUtils.doInEventLoop;
+import static software.amazon.awssdk.http.nio.netty.internal.utils.NettyUtils.runOrPropagate;
 
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoop;
@@ -140,7 +141,7 @@ private void completeProtocolConfiguration(Channel newChannel, Protocol protocol
                 closeAndRelease(newChannel, new IllegalStateException("Pool closed"));
             } else {
                 try {
-                    protocolImplPromise.setSuccess(configureProtocol(newChannel, protocol));
+                    configureProtocol(newChannel, protocol);
                 } catch (Throwable e) {
                     closeAndRelease(newChannel, e);
                 }
@@ -154,7 +155,7 @@ private void closeAndRelease(Channel newChannel, Throwable e) {
         protocolImplPromise.setFailure(e);
     }
 
-    private ChannelPool configureProtocol(Channel newChannel, Protocol protocol) {
+    private void configureProtocol(Channel newChannel, Protocol protocol) {
         if (Protocol.HTTP1_1 == protocol) {
             // For HTTP/1.1 we use a traditional channel pool without multiplexing
             SdkChannelPool idleConnectionMetricChannelPool = new IdleConnectionCountingChannelPool(eventLoop, delegatePool);
@@ -180,8 +181,10 @@ private ChannelPool configureProtocol(Channel newChannel, Protocol protocol) {
                                                  .build();
         }
         // Give the channel back so it can be acquired again by protocolImpl
-        delegatePool.release(newChannel);
-        return protocolImpl;
+        // Await the release completion to ensure we do not unnecessarily acquire a second channel
+        delegatePool.release(newChannel).addListener(runOrPropagate(protocolImplPromise, () -> {
+            protocolImplPromise.trySuccess(protocolImpl);
+        }));
     }
 
     @Override

http-clients/netty-nio-client/src/main/java/software/amazon/awssdk/http/nio/netty/internal/utils/NettyUtils.java

@@ -29,6 +29,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import javax.net.ssl.SSLEngine;
 import javax.net.ssl.SSLParameters;
@@ -221,4 +222,48 @@ private static void configureSslEngine(SSLEngine sslEngine) {
         sslParameters.setEndpointIdentificationAlgorithm("HTTPS");
         sslEngine.setSSLParameters(sslParameters);
     }
+
+    /**
+     * Create a {@link GenericFutureListener} that will propagate any failures or cancellations to the provided {@link Promise},
+     * or invoke the provided {@link Consumer} with the result of a successful operation completion. This is useful for chaining
+     * together multiple futures that may depend upon each other but that may not have the same return type.
+     * <p>
+     * Note that if you do not need the value returned by a successful completion (or if it returns {@link Void}) you may use
+     * {@link #runOrPropagate(Promise, Runnable)} instead.
+     *
+     * @param destination the Promise to notify upon failure or cancellation
+     * @param onSuccess   the Consumer to invoke upon success
+     */
+    public static <T> GenericFutureListener<Future<T>> consumeOrPropagate(Promise<?> destination, Consumer<T> onSuccess) {
+        return f -> {
+            if (f.isSuccess()) {
+                T result = f.getNow();
+                onSuccess.accept(result);
+            } else if (f.isCancelled()) {
+                destination.cancel(false);
+            } else {
+                destination.tryFailure(f.cause());
+            }
+        };
+    }
+
+    /**
+     * Create a {@link GenericFutureListener} that will propagate any failures or cancellations to the provided {@link Promise},
+     * or invoke the provided {@link Runnable} upon successful operation completion. This is useful for chaining together multiple
+     * futures that may depend upon each other but that may not have the same return type.
+     *
+     * @param destination the Promise to notify upon failure or cancellation
+     * @param onSuccess   the Runnable to invoke upon success
+     */
+    public static <T> GenericFutureListener<Future<T>> runOrPropagate(Promise<?> destination, Runnable onSuccess) {
+        return f -> {
+            if (f.isSuccess()) {
+                onSuccess.run();
+            } else if (f.isCancelled()) {
+                destination.cancel(false);
+            } else {
+                destination.tryFailure(f.cause());
+            }
+        };
+    }
 }

http-clients/netty-nio-client/src/test/java/software/amazon/awssdk/http/nio/netty/internal/http2/HttpOrHttp2ChannelPoolTest.java

@@ -16,6 +16,7 @@
 package software.amazon.awssdk.http.nio.netty.internal.http2;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Matchers.any;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
@@ -241,7 +242,9 @@ public void incompleteProtocolFutureDelaysMetricsDelegationAndForwardsSuccessFor
 
     public void incompleteProtocolFutureDelaysMetricsDelegationAndForwardsSuccessForProtocol(Protocol protocol) throws Exception {
         Promise<Channel> acquirePromise = eventLoopGroup.next().newPromise();
+        Promise<Void> releasePromise = eventLoopGroup.next().newPromise();
         when(mockDelegatePool.acquire()).thenReturn(acquirePromise);
+        when(mockDelegatePool.release(any(Channel.class))).thenReturn(releasePromise);
 
         // startConnection
         httpOrHttp2ChannelPool.acquire();
@@ -258,6 +261,7 @@ public void incompleteProtocolFutureDelaysMetricsDelegationAndForwardsSuccessFor
         eventLoopGroup.register(channel);
         channel.attr(PROTOCOL_FUTURE).set(CompletableFuture.completedFuture(protocol));
         acquirePromise.setSuccess(channel);
+        releasePromise.setSuccess(null);
 
         metricsFuture.join();
         MetricCollection metrics = metricCollector.collect();
@@ -267,4 +271,31 @@ public void incompleteProtocolFutureDelaysMetricsDelegationAndForwardsSuccessFor
         assertThat(metrics.metricValues(HttpMetric.AVAILABLE_CONCURRENCY).get(0)).isBetween(0, 1);
         assertThat(metrics.metricValues(HttpMetric.LEASED_CONCURRENCY).get(0)).isBetween(0, 1);
     }
+
+    @Test(timeout = 5_000)
+    public void protocolFutureAwaitsReleaseFuture() throws Exception {
+        Promise<Channel> delegateAcquirePromise = eventLoopGroup.next().newPromise();
+        Promise<Void> releasePromise = eventLoopGroup.next().newPromise();
+        when(mockDelegatePool.acquire()).thenReturn(delegateAcquirePromise);
+        when(mockDelegatePool.release(any(Channel.class))).thenReturn(releasePromise);
+
+        MockChannel channel = new MockChannel();
+        eventLoopGroup.register(channel);
+        channel.attr(PROTOCOL_FUTURE).set(CompletableFuture.completedFuture(Protocol.HTTP1_1));
+
+        // Acquire a new connection and save the returned future
+        Future<Channel> acquireFuture = httpOrHttp2ChannelPool.acquire();
+
+        // Return a successful connection from the delegate pool
+        delegateAcquirePromise.setSuccess(channel);
+
+        // The returned future should not complete until the release completes
+        assertThat(acquireFuture.isDone()).isFalse();
+
+        // Complete the release
+        releasePromise.setSuccess(null);
+
+        // Assert the returned future completes (within the test timeout)
+        acquireFuture.await();
+    }
 }

http-clients/netty-nio-client/src/test/java/software/amazon/awssdk/http/nio/netty/internal/utils/NettyUtilsTest.java

@@ -23,17 +23,39 @@
 import static org.mockito.Mockito.when;
 
 import io.netty.channel.Channel;
+import io.netty.channel.EventLoopGroup;
+import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.handler.ssl.SslContext;
 import io.netty.handler.ssl.SslContextBuilder;
 import io.netty.handler.ssl.SslHandler;
 import io.netty.util.AttributeKey;
 import io.netty.util.concurrent.EventExecutor;
+import io.netty.util.concurrent.Future;
+import io.netty.util.concurrent.GenericFutureListener;
+import io.netty.util.concurrent.Promise;
 import java.time.Duration;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.net.ssl.SSLEngine;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
 import org.junit.Test;
 import software.amazon.awssdk.http.nio.netty.internal.MockChannel;
 
 public class NettyUtilsTest {
+
+    private static EventLoopGroup eventLoopGroup;
+
+    @BeforeClass
+    public static void setup() {
+        eventLoopGroup = new NioEventLoopGroup(1);
+    }
+
+    @AfterClass
+    public static void teardown() throws InterruptedException {
+        eventLoopGroup.shutdownGracefully().await();
+    }
+
     @Test
     public void testGetOrCreateAttributeKey_calledTwiceWithSameName_returnsSameInstance() {
         String attr = "NettyUtilsTest.Foo";
@@ -77,4 +99,98 @@ public void doInEventLoop_notInEventLoop_submits() {
         NettyUtils.doInEventLoop(mockExecutor, () -> {});
         verify(mockExecutor).submit(any(Runnable.class));
     }
+
+    @Test
+    public void runOrPropagate_success_runs() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+        AtomicBoolean reference = new AtomicBoolean();
+
+        GenericFutureListener<Future<Void>> listener =
+            NettyUtils.runOrPropagate(destination, () -> reference.set(true));
+
+        Promise<Void> source = eventLoopGroup.next().newPromise();
+        source.setSuccess(null);
+        listener.operationComplete(source);
+
+        assertThat(reference.get()).isTrue();
+    }
+
+    @Test
+    public void runOrPropagate_exception_propagates() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+
+        GenericFutureListener<Future<Void>> listener =
+            NettyUtils.runOrPropagate(destination, () -> {
+            });
+
+        Promise<Void> source = eventLoopGroup.next().newPromise();
+        source.setFailure(new RuntimeException("Intentional exception for testing purposes"));
+        listener.operationComplete(source);
+
+        assertThat(destination.cause())
+            .isInstanceOf(RuntimeException.class)
+            .hasMessage("Intentional exception for testing purposes");
+    }
+
+    @Test
+    public void runOrPropagate_cancel_propagates() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+
+        GenericFutureListener<Future<Void>> listener =
+            NettyUtils.runOrPropagate(destination, () -> {
+            });
+
+        Promise<Void> source = eventLoopGroup.next().newPromise();
+        source.cancel(false);
+        listener.operationComplete(source);
+
+        assertThat(destination.isCancelled()).isTrue();
+    }
+
+    @Test
+    public void consumeOrPropagate_success_consumes() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+        AtomicReference<String> reference = new AtomicReference<>();
+
+        GenericFutureListener<Future<String>> listener =
+            NettyUtils.consumeOrPropagate(destination, reference::set);
+
+        Promise<String> source = eventLoopGroup.next().newPromise();
+        source.setSuccess("test");
+        listener.operationComplete(source);
+
+        assertThat(reference.get()).isEqualTo("test");
+    }
+
+    @Test
+    public void consumeOrPropagate_exception_propagates() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+
+        GenericFutureListener<Future<String>> listener =
+            NettyUtils.consumeOrPropagate(destination, s -> {
+            });
+
+        Promise<String> source = eventLoopGroup.next().newPromise();
+        source.setFailure(new RuntimeException("Intentional exception for testing purposes"));
+        listener.operationComplete(source);
+
+        assertThat(destination.cause())
+            .isInstanceOf(RuntimeException.class)
+            .hasMessage("Intentional exception for testing purposes");
+    }
+
+    @Test
+    public void consumeOrPropagate_cancel_propagates() throws Exception {
+        Promise<String> destination = eventLoopGroup.next().newPromise();
+
+        GenericFutureListener<Future<String>> listener =
+            NettyUtils.consumeOrPropagate(destination, s -> {
+            });
+
+        Promise<String> source = eventLoopGroup.next().newPromise();
+        source.cancel(false);
+        listener.operationComplete(source);
+
+        assertThat(destination.isCancelled()).isTrue();
+    }
 }