Removing reliance on SDK

Turns out last SDK upgrade broke something it shouldn't and proved how
brittle some parts of this code base are. One thing that's not brittle
is the endpoint we make requests to. Endpoint seems to be quite easy to
generate, thus we're moving away from using the SDK in a "nice" way and
we're doing it for ourselves, since it's easier to understand what's
happening (and it's 1 line of code).

Author: Bogdan Stolojan

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

@@ -21,12 +21,12 @@
 import javax.annotation.Nonnull;
 
 import com.amazonaws.arn.Arn;
-import com.amazonaws.regions.RegionUtils;
 
 /**
  * Represents an Arn Resource, this can be an accesspoint or bucket.
  */
 public final class ArnResource {
+  private final static String ACCESSPOINT_ENDPOINT_FORMAT = "s3-accesspoint.%s.amazonaws.com";
 
   /**
    * Resource name.
@@ -106,11 +106,7 @@ public String getFullArn() {
    * @return resource endpoint.
    */
   public String getEndpoint() {
-    return RegionUtils.getRegion(accessPointRegionKey)
-        .getServiceEndpoint("s3")
-        // There's a slight issue with getServiceEndpoint which breaks an endpoint related to
-        // access points, i.e. the correct one starts with "s3-accesspoint."
-        .replace("s3.accesspoint-", "s3-accesspoint.");
+    return String.format(ACCESSPOINT_ENDPOINT_FORMAT, region);
   }
 
   /**

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

@@ -39,39 +39,43 @@
 public class TestArnResource extends HadoopTestBase {
   private final static Logger LOG = LoggerFactory.getLogger(TestArnResource.class);
 
+  private final static String MOCK_ACCOUNT = "123456789101";
+
   @Test
   public void parseAccessPointFromArn() throws IllegalArgumentException {
     describe("Parse AccessPoint ArnResource from arn string");
 
     String accessPoint = "testAp";
-    String accountId = "123456789101";
     String[][] regionPartitionEndpoints = new String[][] {
-        {Regions.EU_WEST_1.getName(), "aws", "s3-accesspoint.eu-west-1.amazonaws.com"},
-        {Regions.US_GOV_EAST_1.getName(), "aws-us-gov",
-            "s3-accesspoint.us-gov-east-1.amazonaws.com"},
-        {Regions.CN_NORTH_1.getName(), "aws-cn", "s3-accesspoint.cn-north-1.amazonaws.com"},
+        {Regions.EU_WEST_1.getName(), "aws"},
+        {Regions.US_GOV_EAST_1.getName(), "aws-us-gov"},
+        {Regions.CN_NORTH_1.getName(), "aws-cn"},
     };
 
     for (String[] testPair : regionPartitionEndpoints) {
       String region = testPair[0];
       String partition = testPair[1];
-      String endpoint = testPair[2];
-
-      // arn:partition:service:region:account-id:resource-type/resource-id
-      String arn = String.format("arn:%s:s3:%s:%s:accesspoint/%s", partition, region, accountId,
-          accessPoint);
 
-      ArnResource resource = ArnResource.accessPointFromArn(arn);
-      assertEquals("Arn does not match", arn, resource.getFullArn());
+      ArnResource resource = getArnResourceFrom(partition, region, MOCK_ACCOUNT, accessPoint);
       assertEquals("Access Point name does not match", accessPoint, resource.getName());
-      assertEquals("Account Id does not match", accountId, resource.getOwnerAccountId());
+      assertEquals("Account Id does not match", MOCK_ACCOUNT, resource.getOwnerAccountId());
       assertEquals("Region does not match", region, resource.getRegion());
-      Assertions.assertThat(resource.getEndpoint())
-          .describedAs("Endpoint does not match")
-          .contains(endpoint);
     }
   }
 
+  @Test
+  public void makeSureEndpointHasTheCorrectFormat() {
+    // Access point (AP) endpoints are different from S3 bucket endpoints, thus when using APs the
+    // endpoints for the client are modified. This test makes sure endpoint is set up correctly.
+    ArnResource accessPoint = getArnResourceFrom("aws", "eu-west-1", MOCK_ACCOUNT,
+        "test");
+    String expected = "s3-accesspoint.eu-west-1.amazonaws.com";
+
+    Assertions.assertThat(accessPoint.getEndpoint())
+        .describedAs("Endpoint has invalid format. Access Point requests will not work")
+        .isEqualTo(expected);
+  }
+
   @Test
   public void invalidARNsMustThrow() throws Exception {
     describe("Using an invalid ARN format must throw when initializing an ArnResource.");
@@ -80,6 +84,23 @@ public void invalidARNsMustThrow() throws Exception {
         ArnResource.accessPointFromArn("invalid:arn:resource"));
   }
 
+  /**
+   * Create an {@link ArnResource} from string components
+   * @param partition - partition for ARN
+   * @param region - region for ARN
+   * @param accountId - accountId for ARN
+   * @param resourceName - ARN resource name
+   * @return ArnResource described by its properties
+   */
+  private ArnResource getArnResourceFrom(String partition, String region, String accountId,
+      String resourceName) {
+    // arn:partition:service:region:account-id:resource-type/resource-id
+    String arn = String.format("arn:%s:s3:%s:%s:accesspoint/%s", partition, region, accountId,
+        resourceName);
+
+    return ArnResource.accessPointFromArn(arn);
+  }
+
   private void describe(String message) {
     LOG.info(message);
   }