move CRT creation logic to client factory

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/DefaultS3ClientFactory.java

@@ -85,6 +85,11 @@ public class DefaultS3ClientFactory extends Configured
   protected static final Logger LOG =
       LoggerFactory.getLogger(DefaultS3ClientFactory.class);
 
+  /**
+   * A one-off log stating whether S3 CRT client is enabled
+   */
+  private static final LogExactlyOnce LOG_S3_CRT_ENABLED = new LogExactlyOnce(LOG);
+
 
   /** Exactly once log to inform about ignoring the AWS-SDK Warnings for CSE. */
   private static final LogExactlyOnce IGNORE_CSE_WARN = new LogExactlyOnce(LOG);
@@ -118,7 +123,17 @@ public S3Client createS3Client(
   }
 
   @Override
-  public S3AsyncClient createS3AsyncClient(
+  public S3AsyncClient createS3AsyncClient(final URI uri,
+      final S3ClientCreationParameters parameters) throws IOException {
+    if (parameters.isCrtEnabled()) {
+      LOG_S3_CRT_ENABLED.info("The S3 CRT client is enabled");
+      return createS3CrtAsyncClient(uri, parameters);
+    } else {
+      return createJavaAsyncClient(uri, parameters);
+    }
+  }
+
+  public S3AsyncClient createJavaAsyncClient(
       final URI uri,
       final S3ClientCreationParameters parameters) throws IOException {
 
@@ -148,8 +163,7 @@ public S3AsyncClient createS3AsyncClient(
     return s3AsyncClientBuilder.build();
   }
 
-  @Override
-  public S3AsyncClient createS3CrtClient(URI uri, S3ClientCreationParameters parameters)
+  private S3AsyncClient createS3CrtAsyncClient(URI uri, S3ClientCreationParameters parameters)
       throws IOException {
     Configuration conf = getConf();
     String bucket = uri.getHost();

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3ClientFactory.java

@@ -82,8 +82,6 @@ S3AsyncClient createS3AsyncClient(URI uri,
       S3ClientCreationParameters parameters) throws IOException;
 
 
-  S3AsyncClient createS3CrtClient(URI uri, S3ClientCreationParameters parameters) throws IOException;
-
   /**
    * Creates a new {@link S3TransferManager}.
    *

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/impl/ClientManagerImpl.java

@@ -60,10 +60,6 @@ public class ClientManagerImpl
 
   public static final Logger LOG = LoggerFactory.getLogger(ClientManagerImpl.class);
 
-  /**
-   * A one-off log stating whether S3 CRT client is enabled
-   */
-  private static final LogExactlyOnce LOG_S3_CRT_ENABLED = new LogExactlyOnce(LOG);
 
   /**
    * Client factory to invoke.
@@ -148,15 +144,9 @@ private CallableRaisingIOE<S3Client> createS3Client() {
    * @return a callable which will create the client.
    */
   private CallableRaisingIOE<S3AsyncClient> createAsyncClient() {
-    return trackDurationOfOperation(durationTrackerFactory, STORE_CLIENT_CREATION.getSymbol(),
-        () -> {
-          if (clientCreationParameters.isCrtEnabled()) {
-            LOG_S3_CRT_ENABLED.info("S3 CRT client is enabled");
-            return clientFactory.createS3CrtClient(getUri(), clientCreationParameters);
-          } else {
-            return clientFactory.createS3AsyncClient(getUri(), clientCreationParameters);
-          }
-        });
+    return trackDurationOfOperation(durationTrackerFactory,
+        STORE_CLIENT_CREATION.getSymbol(),
+        () -> clientFactory.createS3AsyncClient(getUri(), clientCreationParameters));
   }
 
 

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/index.md

@@ -1775,10 +1775,9 @@ enhanced connection pool management, and can provide higher transfer from and to
 ability to split PUT requests into MPU, and GETs into multiple byte-ranged GETs. More information
 can be found [here](https://aws.amazon.com/blogs/developer/introducing-crt-based-s3-client-and-the-s3-transfer-manager-in-the-aws-sdk-for-java-2-x/).
 
-While S3A does not benefit directly from all these features, since when writing files S3A
-implements its own MPU is used, the enhanced connection pool management can help when making 
-many parallel GET requests to ensure load is evenly distributed across S3, as happens in the
-Analytics input stream. 
+Using CRT ensures load is evenly distributed across S3, as happens in the
+Analytics input stream when making multiple parallel GET requests, due to the enhanced connection 
+pool management.
 
 The CRT client can be enabled as follows:
 

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/MockS3ClientFactory.java

@@ -62,13 +62,6 @@ public S3AsyncClient createS3AsyncClient(URI uri, final S3ClientCreationParamete
     return s3;
   }
 
-  @Override
-  public S3AsyncClient createS3CrtClient(URI uri, S3ClientCreationParameters parameters)
-      throws IOException {
-    S3AsyncClient s3 = mock(S3AsyncClient.class);
-    return s3;
-  }
-
   @Override
   public S3TransferManager createS3TransferManager(S3AsyncClient s3AsyncClient) {
     S3TransferManager tm = mock(S3TransferManager.class);

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/test/StubS3ClientFactory.java

@@ -90,14 +90,6 @@ public S3AsyncClient createS3AsyncClient(final URI uri,
     return asyncClient;
   }
 
-  @Override
-  public S3AsyncClient createS3CrtClient(URI uri, S3ClientCreationParameters parameters)
-      throws IOException {
-    asyncClientCreationCount.incrementAndGet();
-    launcher.apply();
-    return asyncClient;
-  }
-
   @Override
   public S3TransferManager createS3TransferManager(final S3AsyncClient s3AsyncClient) {
     transferManagerCreationCount.incrementAndGet();