HADOOP-16505. Add ability to register custom signer with AWS SignerFactory

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AUtils.java

@@ -26,6 +26,8 @@
 import com.amazonaws.SdkBaseException;
 import com.amazonaws.auth.AWSCredentialsProvider;
 import com.amazonaws.auth.EnvironmentVariableCredentialsProvider;
+import com.amazonaws.auth.Signer;
+import com.amazonaws.auth.SignerFactory;
 import com.amazonaws.retry.RetryUtils;
 import com.amazonaws.services.dynamodbv2.model.AmazonDynamoDBException;
 import com.amazonaws.services.dynamodbv2.model.LimitExceededException;
@@ -1239,7 +1241,22 @@ public static void initConnectionSettings(Configuration conf,
     awsConf.setSocketBufferSizeHints(sockSendBuffer, sockRecvBuffer);
     String signerOverride = conf.getTrimmed(SIGNING_ALGORITHM, "");
     if (!signerOverride.isEmpty()) {
-     LOG.debug("Signer override = {}", signerOverride);
+      try {
+        SignerFactory.getSignerByTypeAndService(signerOverride, null);
+      } catch (IllegalArgumentException e) {
+        LOG.debug("{}, preparing to load custom signer : {} ",
+                e.getMessage(), signerOverride);
+        Class<? extends Signer> klass;
+        try {
+          klass = (Class<? extends Signer>) Class.forName(signerOverride);
+        } catch (ClassNotFoundException cnfe) {
+          throw new RuntimeException(
+                  String.format("Signer Class %s not found",
+                          signerOverride), cnfe);
+        }
+        SignerFactory.registerSigner(signerOverride, klass);
+      }
+      LOG.debug("Signer override = {}", signerOverride);
       awsConf.setSignerOverride(signerOverride);
     }
   }

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/S3ATestConstants.java

@@ -207,4 +207,11 @@ public interface S3ATestConstants {
    */
   String S3GUARD_DDB_TEST_TABLE_NAME_KEY =
       "fs.s3a.s3guard.ddb.test.table";
+
+
+  /**
+   * Custom Signer Name to be set in the conf for Test
+   */
+  String S3A_SIGNING_ALGORITHM = "com.amazonaws.services.s3.internal.AWSS3V4Signer";
+
 }

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/TestS3ASigningAlgorithmOverride.java

@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements.  See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership.  The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License.  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package org.apache.hadoop.fs.s3a;
+
+import com.amazonaws.ClientConfiguration;
+import org.apache.hadoop.conf.Configuration;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Objects;
+
+
+/**
+ * Test whether or not Custom Signing Algorithm Override works by turning it on.
+ */
+public class TestS3ASigningAlgorithmOverride extends AbstractS3ATestBase {
+
+  @Override
+  protected Configuration createConfiguration() {
+    // awsConf is instantiated here
+    Configuration conf = super.createConfiguration();
+    conf.set(Constants.SIGNING_ALGORITHM,
+            S3ATestConstants.S3A_SIGNING_ALGORITHM);
+    return conf;
+  }
+
+  @Test
+  public void testCustomSignerOverride() throws AssertionError {
+    assertIsCustomSignerLoaded();
+  }
+
+  private void assertIsCustomSignerLoaded() {
+    final ClientConfiguration awsConf = new ClientConfiguration();
+    Assert.assertEquals(awsConf.getSignerOverride(),
+            S3ATestConstants.S3A_SIGNING_ALGORITHM);
+  }
+}