HADOOP-17951. Improve S3A checking of S3 Access Point existence (#3516)

Follow-on to HADOOP-17198. Support S3 Access Points

Contributed by Bogdan Stolojan

Change-Id: I0932476c64e1967eb0cb3e0f00060fac5d2bae72

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java

@@ -204,6 +204,7 @@ import static org.apache.hadoop.fs.s3a.impl.CallableSupplier.submit;
 import static org.apache.hadoop.fs.s3a.impl.CallableSupplier.waitForCompletionIgnoringExceptions;
 import static org.apache.hadoop.fs.s3a.impl.ErrorTranslation.isObjectNotFound;
 import static org.apache.hadoop.fs.s3a.impl.ErrorTranslation.isUnknownBucket;
+import static org.apache.hadoop.fs.s3a.impl.InternalConstants.AP_INACCESSIBLE;
 import static org.apache.hadoop.fs.s3a.impl.InternalConstants.AP_REQUIRED_EXCEPTION;
 import static org.apache.hadoop.fs.s3a.impl.InternalConstants.ARN_BUCKET_OPTION;
 import static org.apache.hadoop.fs.s3a.impl.InternalConstants.CSE_PADDING_LENGTH;
@@ -730,7 +731,8 @@ public class S3AFileSystem extends FileSystem implements StreamCapabilities,
                 s3.getBucketAcl(bucket);
               } catch (AmazonServiceException ex) {
                 int statusCode = ex.getStatusCode();
-                if (statusCode == SC_404 || (statusCode == SC_403 && accessPoint != null)) {
+                if (statusCode == SC_404 ||
+                    (statusCode == SC_403 && ex.getMessage().contains(AP_INACCESSIBLE))) {
                   return false;
                 }
               }

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

@@ -143,6 +143,11 @@ public final class InternalConstants {
   public static final String AP_REQUIRED_EXCEPTION = "Access Points usage is required" +
       " but not configured for the bucket.";
 
+  /**
+   * Error message to indicate Access Points are not accessible or don't exist.
+   */
+  public static final String AP_INACCESSIBLE = "Could not access through this access point";
+
   /**
    * AccessPoint ARN for the bucket. When set as a bucket override the requests for that bucket
    * will go through the AccessPoint.