HDFS-13960. hdfs dfs -checksum command should optionally show block size in output. Contributed by Lokesh Jain.

Signed-off-by: Wei-Chiu Chuang <weichiu@apache.org>

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/Display.java

@@ -175,7 +175,7 @@ class Display extends FsCommand {
   
   public static class Checksum extends Display {
     public static final String NAME = "checksum";
-    public static final String USAGE = "<src> ...";
+    public static final String USAGE = "[-v] <src> ...";
     public static final String DESCRIPTION =
       "Dump checksum information for files that match the file " +
       "pattern <src> to stdout. Note that this requires a round-trip " +
@@ -184,6 +184,16 @@ class Display extends FsCommand {
       "file depends on its content, block size and the checksum " +
       "algorithm and parameters used for creating the file.";
 
+    private boolean displayBlockSize;
+
+    @Override
+    protected void processOptions(LinkedList<String> args)
+        throws IOException {
+      CommandFormat cf = new CommandFormat(1, Integer.MAX_VALUE, "v");
+      cf.parse(args);
+      displayBlockSize = cf.getOpt("v");
+    }
+
     @Override
     protected void processPath(PathData item) throws IOException {
       if (item.stat.isDirectory()) {
@@ -191,14 +201,15 @@ class Display extends FsCommand {
       }
 
       FileChecksum checksum = item.fs.getFileChecksum(item.path);
-      if (checksum == null) {
-        out.printf("%s\tNONE\t%n", item.toString());
+      String outputChecksum = checksum == null ? "NONE" :
+          String.format("%s\t%s", checksum.getAlgorithmName(), StringUtils
+              .byteToHexString(checksum.getBytes(), 0, checksum.getLength()));
+      if (displayBlockSize) {
+        FileStatus fileStatus = item.fs.getFileStatus(item.path);
+        out.printf("%s\t%s\tBlockSize=%s%n", item.toString(), outputChecksum,
+            fileStatus != null ? fileStatus.getBlockSize() : "NONE");
       } else {
-        String checksumString = StringUtils.byteToHexString(
-            checksum.getBytes(), 0, checksum.getLength());
-        out.printf("%s\t%s\t%s%n",
-            item.toString(), checksum.getAlgorithmName(),
-            checksumString);
+        out.printf("%s\t%s%n", item.toString(), outputChecksum);
       }
     }
   }

hadoop-common-project/hadoop-common/src/site/markdown/FileSystemShell.md

@@ -73,10 +73,14 @@ Returns 0 on success and -1 on error.
 checksum
 --------
 
-Usage: `hadoop fs -checksum URI`
+Usage: `hadoop fs -checksum [-v] URI`
 
 Returns the checksum information of a file.
 
+Options
+
+* The `-v` option displays blocks size for the file.
+
 Example:
 
 * `hadoop fs -checksum hdfs://nn1.example.com/file1`

hadoop-common-project/hadoop-common/src/test/resources/testConf.xml

@@ -714,7 +714,7 @@
       <comparators>
         <comparator>
           <type>RegexpComparator</type>
-          <expected-output>^-checksum &lt;src&gt; \.\.\. :\s*</expected-output>
+          <expected-output>^-checksum \[-v\] &lt;src&gt; \.\.\. :\s*</expected-output>
         </comparator>
         <comparator>
           <type>RegexpComparator</type>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java

@@ -71,6 +71,7 @@ import org.junit.rules.Timeout;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Rule;
+import org.junit.Assert;
 
 import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_TRASH_INTERVAL_KEY;
 import static org.apache.hadoop.fs.permission.AclEntryScope.ACCESS;
@@ -1121,6 +1122,31 @@ public class TestDFSShell {
     }
   }
 
+  @Test (timeout = 30000)
+  public void testChecksum() throws Exception {
+    PrintStream printStream = System.out;
+    try {
+      ByteArrayOutputStream out = new ByteArrayOutputStream();
+      System.setOut(new PrintStream(out));
+      FsShell shell = new FsShell(dfs.getConf());
+      final Path filePath = new Path("/testChecksum/file1");
+      writeFile(dfs, filePath);
+      FileStatus fileStatus = dfs.getFileStatus(filePath);
+      FileChecksum checksum = dfs.getFileChecksum(filePath);
+      String[] args = {"-checksum", "-v", filePath.toString()};
+      assertEquals(0, shell.run(args));
+      // verify block size is printed in the output
+      assertTrue(out.toString()
+          .contains(String.format("BlockSize=%s", fileStatus.getBlockSize())));
+      // verify checksum is printed in the output
+      assertTrue(out.toString().contains(StringUtils
+          .byteToHexString(checksum.getBytes(), 0, checksum.getLength())));
+    } finally {
+      Assert.assertNotNull(printStream);
+      System.setOut(printStream);
+    }
+  }
+
   @Test (timeout = 30000)
   public void testCopyToLocal() throws IOException {
     FsShell shell = new FsShell(dfs.getConf());