HADOOP-16478 tune patch

-review amazon Region.fromValue code and mirror it
-add test for null handling (which comes from the Region code)

Change-Id: Ibf4e72454ad8413b9b7ce4c57ffb6cc23886fe3f

Author: steveloughran

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

@@ -115,13 +115,14 @@ public static void bindSSLChannelMode(Configuration conf,
    * Given an S3 bucket region as returned by a bucket location query,
    * fix it into a form which can be used by other AWS commands.
    * https://forums.aws.amazon.com/thread.jspa?messageID=796829&tstart=0
+   * See also {@code com.amazonaws.services.s3.model.Region.fromValue()}
+   * for its conversion logic.
    * @param region region from S3 call.
    * @return the region to use in DDB etc.
    */
-  public static String fixBucketRegion(String region) {
-    if (region.equals("US")) {
-      region = "us-east-1";
-    }
-    return region;
+  public static String fixBucketRegion(final String region) {
+    return region == null || region.equals("US")
+        ? "us-east-1"
+        : region;
   }
 }

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/s3guard/DynamoDBMetadataStore.java

@@ -400,7 +400,7 @@ public void initialize(FileSystem fs, ITtlTimeProvider ttlTp)
         // access denied here == can't call getBucket. Report meaningfully
         URI uri = owner.getUri();
         String message =
-            "Failed to get bucket location as S3 client role lacks permission "
+            "Failed to get bucket location as client lacks permission "
                 + RolePolicies.S3_GET_BUCKET_LOCATION + " for " + uri;
         LOG.error(message);
         throw (IOException)new AccessDeniedException(message).initCause(e);

hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/s3guard/S3GuardTool.java

@@ -1160,7 +1160,6 @@ public static class BucketInfo extends S3GuardTool {
 
     public static final String PURPOSE = "provide/check S3Guard information"
         + " about a specific bucket";
-
     private static final String USAGE = NAME + " [OPTIONS] s3a://BUCKET\n"
         + "\t" + PURPOSE + "\n\n"
         + "Common options:\n"

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

@@ -30,19 +30,27 @@
  */
 public class TestNeworkBinding extends HadoopTestBase {
 
+  private static final String US_EAST_1 = "us-east-1";
+  private static final String US_WEST_2 = "us-west-2";
+
+  @Test
+  public void testUSEast() {
+    assertRegionFixup(US_EAST_1, US_EAST_1);
+  }
+
   @Test
-  public void testUSEast() throws Throwable {
-    assertRegionFixup("us-east-1", "us-east-1");
+  public void testUSWest() {
+    assertRegionFixup(US_WEST_2, US_WEST_2);
   }
 
   @Test
-  public void testUSWest() throws Throwable {
-    assertRegionFixup("us-west-2", "us-west-2");
+  public void testRegionUStoUSEast() {
+    assertRegionFixup("US", US_EAST_1);
   }
 
   @Test
-  public void testRegionUStoUSEast() throws Throwable {
-    assertRegionFixup("US", "us-east-1");
+  public void testRegionNullToUSEast() {
+    assertRegionFixup(null, US_EAST_1);
   }
 
   private static void assertRegionFixup(String region, String expected) {