HADOOP-15428. s3guard bucket-info will create s3guard table if FS is set to do this automatically. (Contributed by Gabor Bota)

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

@@ -1061,7 +1061,7 @@ public abstract class S3GuardTool extends Configured implements Tool {
         + "\t" + PURPOSE + "\n\n"
         + "Common options:\n"
         + "  -" + GUARDED_FLAG + " - Require S3Guard\n"
-        + "  -" + UNGUARDED_FLAG + " - Require S3Guard to be disabled\n"
+        + "  -" + UNGUARDED_FLAG + " - Force S3Guard to be disabled\n"
         + "  -" + AUTH_FLAG + " - Require the S3Guard mode to be \"authoritative\"\n"
         + "  -" + NONAUTH_FLAG + " - Require the S3Guard mode to be \"non-authoritative\"\n"
         + "  -" + MAGIC_FLAG + " - Require the S3 filesystem to be support the \"magic\" committer\n"
@@ -1092,6 +1092,15 @@ public abstract class S3GuardTool extends Configured implements Tool {
         throw invalidArgs("No bucket specified");
       }
       String s3Path = paths.get(0);
+      CommandFormat commands = getCommandFormat();
+
+      // check if UNGUARDED_FLAG is passed and use NullMetadataStore in
+      // config to avoid side effects like creating the table if not exists
+      if (commands.getOpt(UNGUARDED_FLAG)) {
+        LOG.debug("Unguarded flag is passed to command :" + this.getName());
+        getConf().set(S3_METADATA_STORE_IMPL, S3GUARD_METASTORE_NULL);
+      }
+
       S3AFileSystem fs = (S3AFileSystem) FileSystem.newInstance(
           toUri(s3Path), getConf());
       setFilesystem(fs);
@@ -1128,7 +1137,6 @@ public abstract class S3GuardTool extends Configured implements Tool {
               "none");
       printOption(out, "\tInput seek policy", INPUT_FADVISE, INPUT_FADV_NORMAL);
 
-      CommandFormat commands = getCommandFormat();
       if (usingS3Guard) {
         if (commands.getOpt(UNGUARDED_FLAG)) {
           throw badState("S3Guard is enabled for %s", fsUri);

hadoop-tools/hadoop-aws/src/site/markdown/tools/hadoop-aws/s3guard.md

@@ -505,7 +505,7 @@ Options
 | argument | meaning |
 |-----------|-------------|
 | `-guarded` | Require S3Guard to be enabled |
-| `-unguarded` | Require S3Guard to be disabled |
+| `-unguarded` | Force S3Guard to be disabled |
 | `-auth` | Require the S3Guard mode to be "authoritative" |
 | `-nonauth` | Require the S3Guard mode to be "non-authoritative" |
 | `-magic` | Require the S3 filesystem to be support the "magic" committer |

hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/s3a/s3guard/AbstractS3GuardToolTestBase.java

@@ -316,6 +316,24 @@ public abstract class AbstractS3GuardToolTestBase extends AbstractS3ATestBase {
         S3GuardTool.SetCapacity.WRITE_CAP_INVALID, () -> cmdW.run(argsW));
   }
 
+  @Test
+  public void testBucketInfoUnguarded() throws Exception {
+    final Configuration conf = getConfiguration();
+    conf.set(S3GUARD_DDB_TABLE_CREATE_KEY, Boolean.FALSE.toString());
+    conf.set(S3GUARD_DDB_TABLE_NAME_KEY,
+        "testBucketInfoUnguarded-" + UUID.randomUUID());
+
+    // run a bucket info command and look for
+    // confirmation that it got the output from DDB diags
+    S3GuardTool.BucketInfo infocmd = new S3GuardTool.BucketInfo(conf);
+    String info = exec(infocmd, S3GuardTool.BucketInfo.NAME,
+        "-" + S3GuardTool.BucketInfo.UNGUARDED_FLAG,
+        getFileSystem().getUri().toString());
+
+    assertTrue("Output should contain information about S3A client " + info,
+        info.contains("S3A Client"));
+  }
+
   @Test
   public void testSetCapacityFailFastIfNotGuarded() throws Exception{
     Configuration conf = getConfiguration();