HADOOP-12384. Add '-direct' flag option for fs copy so that user can choose not to create '._COPYING_' file (Contributed by J.Andreina)

(cherry picked from commit 090d26652c)

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -258,6 +258,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12358. Add -safely flag to rm to prompt when deleting many files.
     (xyao via wang)
 
+    HADOOP-12384. Add "-direct" flag option for fs copy so that user can choose
+    not to create "._COPYING_" file (J.Andreina via vinayakumarb)
+
   OPTIMIZATIONS
 
     HADOOP-11785. Reduce the number of listStatus operation in distcp

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

@@ -61,6 +61,7 @@ abstract class CommandWithDestination extends FsCommand {
   private boolean verifyChecksum = true;
   private boolean writeChecksum = true;
   private boolean lazyPersist = false;
+  private boolean direct = false;
 
   /**
    * The name of the raw xattr namespace. It would be nice to use
@@ -95,6 +96,10 @@ abstract class CommandWithDestination extends FsCommand {
     writeChecksum = flag;
   }
 
+  protected void setDirectWrite(boolean flag) {
+    direct = flag;
+  }
+
   /**
    * If true, the last modified time, last access time,
    * owner, group and permission information of the source
@@ -372,9 +377,11 @@ abstract class CommandWithDestination extends FsCommand {
   }
 
   /**
-   * Copies the stream contents to a temporary file.  If the copy is
+   * If direct write is disabled ,copies the stream contents to a temporary
+   * file "<target>._COPYING_". If the copy is
    * successful, the temporary file will be renamed to the real path,
    * else the temporary file will be deleted.
+   * if direct write is enabled , then creation temporary file is skipped.
    * @param in the input stream for the copy
    * @param target where to store the contents of the stream
    * @throws IOException if copy fails
@@ -386,10 +393,12 @@ abstract class CommandWithDestination extends FsCommand {
     }
     TargetFileSystem targetFs = new TargetFileSystem(target.fs);
     try {
-      PathData tempTarget = target.suffix("._COPYING_");
+      PathData tempTarget = direct ? target : target.suffix("._COPYING_");
       targetFs.setWriteChecksum(writeChecksum);
-      targetFs.writeStreamToFile(in, tempTarget, lazyPersist);
+      targetFs.writeStreamToFile(in, tempTarget, lazyPersist, direct);
+      if (!direct) {
         targetFs.rename(tempTarget, target);
+      }
     } finally {
       targetFs.close(); // last ditch effort to ensure temp file is removed
     }
@@ -459,10 +468,11 @@ abstract class CommandWithDestination extends FsCommand {
     }
 
     void writeStreamToFile(InputStream in, PathData target,
-                           boolean lazyPersist) throws IOException {
+        boolean lazyPersist, boolean direct)
+        throws IOException {
       FSDataOutputStream out = null;
       try {
-        out = create(target, lazyPersist);
+        out = create(target, lazyPersist, direct);
         IOUtils.copyBytes(in, out, getConf(), true);
       } finally {
         IOUtils.closeStream(out); // just in case copyBytes didn't
@@ -470,7 +480,8 @@ abstract class CommandWithDestination extends FsCommand {
     }
     
     // tag created files as temp files
-    FSDataOutputStream create(PathData item, boolean lazyPersist)
+    FSDataOutputStream create(PathData item, boolean lazyPersist,
+        boolean direct)
         throws IOException {
       try {
         if (lazyPersist) {
@@ -488,9 +499,11 @@ abstract class CommandWithDestination extends FsCommand {
           return create(item.path, true);
         }
       } finally { // might have been created but stream was interrupted
+        if (!direct) {
           deleteOnExit(item.path);
         }
       }
+    }
 
     void rename(PathData src, PathData target) throws IOException {
       // the rename method with an option to delete the target is deprecated

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

@@ -133,7 +133,8 @@ class CopyCommands {
 
   static class Cp extends CommandWithDestination {
     public static final String NAME = "cp";
-    public static final String USAGE = "[-f] [-p | -p[topax]] <src> ... <dst>";
+    public static final String USAGE =
+        "[-f] [-p | -p[topax]] [-d] <src> ... <dst>";
     public static final String DESCRIPTION =
       "Copy files that match the file pattern <src> to a " +
       "destination.  When copying multiple files, the destination " +
@@ -147,13 +148,15 @@ class CopyCommands {
       "if (1) they are supported (HDFS only) and, (2) all of the source and " +
       "target pathnames are in the /.reserved/raw hierarchy. raw namespace " +
       "xattr preservation is determined solely by the presence (or absence) " +
-      "of the /.reserved/raw prefix and not by the -p option.\n";
+        "of the /.reserved/raw prefix and not by the -p option. Passing -d "+
+        "will skip creation of temporary file(<dst>._COPYING_).\n";
 
     @Override
     protected void processOptions(LinkedList<String> args) throws IOException {
       popPreserveOption(args);
-      CommandFormat cf = new CommandFormat(2, Integer.MAX_VALUE, "f");
+      CommandFormat cf = new CommandFormat(2, Integer.MAX_VALUE, "f", "d");
       cf.parse(args);
+      setDirectWrite(cf.getOpt("d"));
       setOverwrite(cf.getOpt("f"));
       // should have a -r option
       setRecursive(true);
@@ -215,7 +218,8 @@ class CopyCommands {
    */
   public static class Put extends CommandWithDestination {
     public static final String NAME = "put";
-    public static final String USAGE = "[-f] [-p] [-l] <localsrc> ... <dst>";
+    public static final String USAGE =
+        "[-f] [-p] [-l] [-d] <localsrc> ... <dst>";
     public static final String DESCRIPTION =
       "Copy files from the local file system " +
       "into fs. Copying fails if the file already " +
@@ -225,15 +229,18 @@ class CopyCommands {
       "  -f : Overwrites the destination if it already exists.\n" +
       "  -l : Allow DataNode to lazily persist the file to disk. Forces\n" +
       "       replication factor of 1. This flag will result in reduced\n" +
-      "       durability. Use with care.\n";
+      "       durability. Use with care.\n" +
+        "  -d : Skip creation of temporary file(<dst>._COPYING_).\n";
 
     @Override
     protected void processOptions(LinkedList<String> args) throws IOException {
-      CommandFormat cf = new CommandFormat(1, Integer.MAX_VALUE, "f", "p", "l");
+      CommandFormat cf =
+          new CommandFormat(1, Integer.MAX_VALUE, "f", "p", "l", "d");
       cf.parse(args);
       setOverwrite(cf.getOpt("f"));
       setPreserve(cf.getOpt("p"));
       setLazyPersist(cf.getOpt("l"));
+      setDirectWrite(cf.getOpt("d"));
       getRemoteDestination(args);
       // should have a -r option
       setRecursive(true);

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFsShellCopy.java

@@ -485,6 +485,52 @@ public class TestFsShellCopy {
     checkPath(dstPath, false);
   }
   
+  @Test
+  public void testDirectCopy() throws Exception {
+    Path testRoot = new Path(testRootDir, "testPutFile");
+    lfs.delete(testRoot, true);
+    lfs.mkdirs(testRoot);
+
+    Path target_COPYING_File = new Path(testRoot, "target._COPYING_");
+    Path target_File = new Path(testRoot, "target");
+    Path srcFile = new Path(testRoot, new Path("srcFile"));
+    lfs.createNewFile(srcFile);
+
+    // If direct write is false , then creation of "file1" ,will delete file
+    // (file1._COPYING_) if already exist.
+    checkDirectCopy(srcFile, target_File, target_COPYING_File, false);
+    shell.run(new String[] { "-rm", target_File.toString() });
+
+    // If direct write is true , then creation of "file1", will not create a
+    // temporary file and will not delete (file1._COPYING_) if already exist.
+    checkDirectCopy(srcFile, target_File, target_COPYING_File, true);
+  }
+
+  private void checkDirectCopy(Path srcFile, Path target_File,
+      Path target_COPYING_File,boolean direct) throws Exception {
+    int directWriteExitCode = direct ? 0 : 1;
+    shell
+        .run(new String[] { "-copyFromLocal", srcFile.toString(),
+        target_COPYING_File.toString() });
+    int srcFileexist = shell
+        .run(new String[] { "-cat", target_COPYING_File.toString() });
+    assertEquals(0, srcFileexist);
+
+    if (!direct) {
+      shell.run(new String[] { "-copyFromLocal", srcFile.toString(),
+          target_File.toString() });
+    } else {
+      shell.run(new String[] { "-copyFromLocal", "-d", srcFile.toString(),
+          target_File.toString() });
+    }
+    // cat of "target._COPYING_" will return exitcode :
+    // as 1(file does not exist), if direct write is false.
+    // as 0, if direct write is true.
+    srcFileexist = shell.run(new String[] { "-cat",
+        target_COPYING_File.toString() });
+    assertEquals(directWriteExitCode, srcFileexist);
+  }
+
   private void createFile(Path ... paths) throws IOException {
     for (Path path : paths) {
       FSDataOutputStream out = lfs.create(path);

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

@@ -336,7 +336,7 @@
       <comparators>
         <comparator>
           <type>RegexpComparator</type>
-          <expected-output>^-cp \[-f\] \[-p \| -p\[topax\]\] &lt;src&gt; \.\.\. &lt;dst&gt; :\s*</expected-output>
+          <expected-output>^-cp \[-f\] \[-p \| -p\[topax\]\] \[-d\] &lt;src&gt; \.\.\. &lt;dst&gt; :\s*</expected-output>
         </comparator>
         <comparator>
           <type>RegexpComparator</type>
@@ -376,7 +376,11 @@
         </comparator>
         <comparator>
             <type>RegexpComparator</type>
-            <expected-output>^\s*\(or absence\) of the \/\.reserved\/raw prefix and not by the -p option.( )*</expected-output>
+          <expected-output>^\s*\(or absence\) of the \/\.reserved\/raw prefix and not by the -p option\. Passing -d( )*</expected-output>
+        </comparator>
+        <comparator>
+            <type>RegexpComparator</type>
+            <expected-output>^\s*will skip creation of temporary file\(&lt;dst&gt;\._COPYING_\)\.( )*</expected-output>
         </comparator>
       </comparators>
     </test>
@@ -472,7 +476,7 @@
       <comparators>
         <comparator>
           <type>RegexpComparator</type>
-          <expected-output>^-put \[-f\] \[-p\] \[-l\] &lt;localsrc&gt; \.\.\. &lt;dst&gt; :( )*</expected-output>
+          <expected-output>^-put \[-f\] \[-p\] \[-l\] \[-d\] &lt;localsrc&gt; \.\.\. &lt;dst&gt; :( )*</expected-output>
         </comparator>
         <comparator>
           <type>RegexpComparator</type>
@@ -506,6 +510,10 @@
           <type>RegexpComparator</type>
           <expected-output>^\s*durability. Use with care.( )*</expected-output>
         </comparator>
+        <comparator>
+          <type>RegexpComparator</type>
+          <expected-output>^\s*-d  Skip creation of temporary file\(&lt;dst&gt;\._COPYING_\).( )*</expected-output>
+        </comparator>
       </comparators>
     </test>
 
@@ -519,7 +527,7 @@
       <comparators>
         <comparator>
           <type>RegexpComparator</type>
-          <expected-output>^-copyFromLocal \[-f\] \[-p\] \[-l\] &lt;localsrc&gt; \.\.\. &lt;dst&gt; :\s*</expected-output>
+          <expected-output>^-copyFromLocal \[-f\] \[-p\] \[-l\] \[-d\] &lt;localsrc&gt; \.\.\. &lt;dst&gt; :\s*</expected-output>
         </comparator>
         <comparator>
           <type>RegexpComparator</type>