Fix ChannelResolver check for MultiThreadIoEventLoopGroup

Author: davidh44

http-clients/netty-nio-client/src/main/java/software/amazon/awssdk/http/nio/netty/SdkEventLoopGroup.java

@@ -18,6 +18,7 @@
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFactory;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.IoHandlerFactory;
 import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.socket.DatagramChannel;
@@ -125,6 +126,10 @@ public static SdkEventLoopGroup create(EventLoopGroup eventLoopGroup, ChannelFac
      * <p>
      * {@link ChannelFactory} will be resolved based on the type of {@link EventLoopGroup} provided. IllegalArgumentException will
      * be thrown for any unknown EventLoopGroup type.
+     * <p>
+     * If {@link MultiThreadIoEventLoopGroup} is passed in, {@link NioSocketChannel} and {@link NioDatagramChannel} will be
+     * resolved, regardless of the transport {@link IoHandlerFactory} passed in. This is because it is not possible to
+     * determine the type of transport factory from a given {@link MultiThreadIoEventLoopGroup}.
      *
      * @param eventLoopGroup the EventLoopGroup to be used
      * @return a new instance of SdkEventLoopGroup

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

@@ -68,12 +68,12 @@ public static ChannelFactory<? extends Channel> resolveSocketChannelFactory(Even
             return resolveSocketChannelFactory(((DelegatingEventLoopGroup) eventLoopGroup).getDelegate());
         }
 
-        if (isNioGroup(eventLoopGroup)) {
-            return NioSocketChannel::new;
-        }
         if (eventLoopGroup instanceof EpollEventLoopGroup) {
             return EpollSocketChannel::new;
         }
+        if (eventLoopGroup instanceof MultiThreadIoEventLoopGroup) {
+            return NioSocketChannel::new;
+        }
 
         String socketFqcn = KNOWN_EL_GROUPS_SOCKET_CHANNELS.get(eventLoopGroup.getClass().getName());
         if (socketFqcn == null) {
@@ -96,12 +96,12 @@ public static ChannelFactory<? extends DatagramChannel> resolveDatagramChannelFa
             return resolveDatagramChannelFactory(((DelegatingEventLoopGroup) eventLoopGroup).getDelegate());
         }
 
-        if (isNioGroup(eventLoopGroup)) {
-            return NioDatagramChannel::new;
-        }
         if (eventLoopGroup instanceof EpollEventLoopGroup) {
             return EpollDatagramChannel::new;
         }
+        if (eventLoopGroup instanceof MultiThreadIoEventLoopGroup) {
+            return NioDatagramChannel::new;
+        }
 
         String datagramFqcn = KNOWN_EL_GROUPS_DATAGRAM_CHANNELS.get(eventLoopGroup.getClass().getName());
         if (datagramFqcn == null) {
@@ -110,10 +110,4 @@ public static ChannelFactory<? extends DatagramChannel> resolveDatagramChannelFa
 
         return invokeSafely(() -> new ReflectiveChannelFactory(Class.forName(datagramFqcn)));
     }
-
-    private static boolean isNioGroup(EventLoopGroup group) {
-        return group instanceof NioEventLoopGroup ||
-               group instanceof MultiThreadIoEventLoopGroup;
-    }
-
 }

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

@@ -19,11 +19,13 @@
 import static software.amazon.awssdk.http.nio.netty.internal.utils.ChannelResolver.resolveDatagramChannelFactory;
 import static software.amazon.awssdk.http.nio.netty.internal.utils.ChannelResolver.resolveSocketChannelFactory;
 
+import io.netty.channel.MultiThreadIoEventLoopGroup;
 import io.netty.channel.epoll.Epoll;
 import io.netty.channel.epoll.EpollDatagramChannel;
 import io.netty.channel.epoll.EpollEventLoopGroup;
 import io.netty.channel.epoll.EpollSocketChannel;
 import io.netty.channel.nio.NioEventLoopGroup;
+import io.netty.channel.nio.NioIoHandler;
 import io.netty.channel.oio.OioEventLoopGroup;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.channel.socket.nio.NioSocketChannel;
@@ -41,6 +43,12 @@ public void canDetectFactoryForStandardNioEventLoopGroup() {
         assertThat(resolveDatagramChannelFactory(new NioEventLoopGroup()).newChannel()).isInstanceOf(NioDatagramChannel.class);
     }
 
+    @Test
+    public void multiThreadIoEventLoopGroup_returnsNioChannels() {
+        assertThat(resolveSocketChannelFactory(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory())).newChannel()).isInstanceOf(NioSocketChannel.class);
+        assertThat(resolveDatagramChannelFactory(new MultiThreadIoEventLoopGroup(NioIoHandler.newFactory())).newChannel()).isInstanceOf(NioDatagramChannel.class);
+    }
+
     @Test
     public void canDetectEpollEventLoopGroupFactory() {
         Assumptions.assumeTrue(Epoll.isAvailable());