HDFS-7655. Expose truncate API for Web HDFS. (yliu)

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

@@ -22,7 +22,6 @@
 import java.net.URI;
 import java.util.Random;
 
-
 import org.apache.commons.lang.RandomStringUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.security.token.Token;
@@ -127,28 +126,36 @@ public Path getDefaultWorkingDirectory(FileSystem fSys)
    */
   public static long createFile(FileSystem fSys, Path path, int numBlocks,
       int blockSize, short numRepl, boolean createParent) throws IOException {
-    FSDataOutputStream out = 
-      fSys.create(path, false, 4096, numRepl, blockSize );
+    return createFile(fSys, path, getFileData(numBlocks, blockSize),
+        blockSize, numRepl);
+  }
 
-    byte[] data = getFileData(numBlocks, blockSize);
-    out.write(data, 0, data.length);
-    out.close();
+  public static long createFile(FileSystem fSys, Path path, byte[] data,
+      int blockSize, short numRepl) throws IOException {
+    FSDataOutputStream out = 
+        fSys.create(path, false, 4096, numRepl, blockSize);
+    try {
+      out.write(data, 0, data.length);
+    } finally {
+      out.close();
+    }
     return data.length;
   }
 
-
   public static long createFile(FileSystem fSys, Path path, int numBlocks,
       int blockSize, boolean createParent) throws IOException {
-      return createFile(fSys, path, numBlocks, blockSize, fSys.getDefaultReplication(path), true);
+    return createFile(fSys, path, numBlocks, blockSize,
+        fSys.getDefaultReplication(path), true);
   }
 
   public static long createFile(FileSystem fSys, Path path, int numBlocks,
       int blockSize) throws IOException {
-      return createFile(fSys, path, numBlocks, blockSize, true);
+    return createFile(fSys, path, numBlocks, blockSize, true);
   }
 
   public static long createFile(FileSystem fSys, Path path) throws IOException {
-    return createFile(fSys, path, DEFAULT_NUM_BLOCKS, DEFAULT_BLOCK_SIZE, DEFAULT_NUM_REPL, true);
+    return createFile(fSys, path, DEFAULT_NUM_BLOCKS, DEFAULT_BLOCK_SIZE,
+        DEFAULT_NUM_REPL, true);
   }
 
   public long createFile(FileSystem fSys, String name) throws IOException {

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -306,6 +306,8 @@ Release 2.7.0 - UNRELEASED
 
     HDFS-6673. Add delimited format support to PB OIV tool. (Eddy Xu via wang)
 
+    HDFS-7655. Expose truncate API for Web HDFS. (yliu)
+
   IMPROVEMENTS
 
     HDFS-7055. Add tracing to DFSInputStream (cmccabe)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java

@@ -57,7 +57,7 @@
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsAction;
-import org.apache.hadoop.hdfs.StorageType;
+import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.DirectoryListing;
@@ -614,10 +614,12 @@ public Response postRoot(
       @QueryParam(BufferSizeParam.NAME) @DefaultValue(BufferSizeParam.DEFAULT)
           final BufferSizeParam bufferSize,
       @QueryParam(ExcludeDatanodesParam.NAME) @DefaultValue(ExcludeDatanodesParam.DEFAULT)
-          final ExcludeDatanodesParam excludeDatanodes
+          final ExcludeDatanodesParam excludeDatanodes,
+      @QueryParam(NewLengthParam.NAME) @DefaultValue(NewLengthParam.DEFAULT)
+          final NewLengthParam newLength
       ) throws IOException, InterruptedException {
     return post(ugi, delegation, username, doAsUser, ROOT, op, concatSrcs,
-        bufferSize, excludeDatanodes);
+        bufferSize, excludeDatanodes, newLength);
   }
 
   /** Handle HTTP POST request. */
@@ -641,19 +643,21 @@ public Response post(
       @QueryParam(BufferSizeParam.NAME) @DefaultValue(BufferSizeParam.DEFAULT)
           final BufferSizeParam bufferSize,
       @QueryParam(ExcludeDatanodesParam.NAME) @DefaultValue(ExcludeDatanodesParam.DEFAULT)
-          final ExcludeDatanodesParam excludeDatanodes
+          final ExcludeDatanodesParam excludeDatanodes,
+      @QueryParam(NewLengthParam.NAME) @DefaultValue(NewLengthParam.DEFAULT)
+          final NewLengthParam newLength
       ) throws IOException, InterruptedException {
 
     init(ugi, delegation, username, doAsUser, path, op, concatSrcs, bufferSize,
-        excludeDatanodes);
+        excludeDatanodes, newLength);
 
     return ugi.doAs(new PrivilegedExceptionAction<Response>() {
       @Override
       public Response run() throws IOException, URISyntaxException {
         try {
           return post(ugi, delegation, username, doAsUser,
               path.getAbsolutePath(), op, concatSrcs, bufferSize,
-              excludeDatanodes);
+              excludeDatanodes, newLength);
         } finally {
           reset();
         }
@@ -670,9 +674,11 @@ private Response post(
       final PostOpParam op,
       final ConcatSourcesParam concatSrcs,
       final BufferSizeParam bufferSize,
-      final ExcludeDatanodesParam excludeDatanodes
+      final ExcludeDatanodesParam excludeDatanodes,
+      final NewLengthParam newLength
       ) throws IOException, URISyntaxException {
     final NameNode namenode = (NameNode)context.getAttribute("name.node");
+    final NamenodeProtocols np = getRPCServer(namenode);
 
     switch(op.getValue()) {
     case APPEND:
@@ -684,9 +690,17 @@ private Response post(
     }
     case CONCAT:
     {
-      getRPCServer(namenode).concat(fullpath, concatSrcs.getAbsolutePaths());
+      np.concat(fullpath, concatSrcs.getAbsolutePaths());
       return Response.ok().build();
     }
+    case TRUNCATE:
+    {
+      // We treat each rest request as a separate client.
+      final boolean b = np.truncate(fullpath, newLength.getValue(), 
+          "DFSClient_" + DFSUtil.getSecureRandom().nextLong());
+      final String js = JsonUtil.toJsonString("boolean", b);
+      return Response.ok(js).type(MediaType.APPLICATION_JSON).build();
+    }
     default:
       throw new UnsupportedOperationException(op + " is not supported");
     }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -1160,6 +1160,14 @@ public FSDataOutputStream append(final Path f, final int bufferSize,
     ).run();
   }
 
+  @Override
+  public boolean truncate(Path f, long newLength) throws IOException {
+    statistics.incrementWriteOps(1);
+
+    final HttpOpParam.Op op = PostOpParam.Op.TRUNCATE;
+    return new FsPathBooleanRunner(op, f, new NewLengthParam(newLength)).run();
+  }
+
   @Override
   public boolean delete(Path f, boolean recursive) throws IOException {
     final HttpOpParam.Op op = DeleteOpParam.Op.DELETE;

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/resources/NewLengthParam.java

@@ -0,0 +1,49 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.web.resources;
+
+/** NewLength parameter. */
+public class NewLengthParam extends LongParam {
+  /** Parameter name. */
+  public static final String NAME = "newlength";
+  /** Default parameter value. */
+  public static final String DEFAULT = NULL;
+
+  private static final Domain DOMAIN = new Domain(NAME);
+
+  /**
+   * Constructor.
+   * @param value the parameter value.
+   */
+  public NewLengthParam(final Long value) {
+    super(DOMAIN, value, 0L, null);
+  }
+
+  /**
+   * Constructor.
+   * @param str a string representation of the parameter value.
+   */
+  public NewLengthParam(final String str) {
+    this(DOMAIN.parse(str));
+  }
+
+  @Override
+  public String getName() {
+    return NAME;
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/resources/PostOpParam.java

@@ -27,6 +27,8 @@ public static enum Op implements HttpOpParam.Op {
 
     CONCAT(false, HttpURLConnection.HTTP_OK),
 
+    TRUNCATE(false, HttpURLConnection.HTTP_OK),
+
     NULL(false, HttpURLConnection.HTTP_NOT_IMPLEMENTED);
 
     final boolean doOutputAndRedirect;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/web/TestFSMainOperationsWebHdfs.java

@@ -29,11 +29,13 @@
 
 import org.apache.commons.logging.impl.Log4JLogger;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.ContentSummary;
 import org.apache.hadoop.fs.FSMainOperationsBaseTest;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.hdfs.AppendTestUtil;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
@@ -136,6 +138,33 @@ public void testConcat() throws Exception {
     Assert.assertEquals(1024*4, fileStatus.getLen());
   }
 
+  @Test
+  public void testTruncate() throws Exception {
+    final short repl = 3;
+    final int blockSize = 1024;
+    final int numOfBlocks = 2;
+    Path dir = getTestRootPath(fSys, "test/hadoop");
+    Path file = getTestRootPath(fSys, "test/hadoop/file");
+
+    final byte[] data = getFileData(numOfBlocks, blockSize);
+    createFile(fSys, file, data, blockSize, repl);
+
+    final int newLength = blockSize;
+
+    boolean isReady = fSys.truncate(file, newLength);
+
+    Assert.assertTrue("Recovery is not expected.", isReady);
+
+    FileStatus fileStatus = fSys.getFileStatus(file);
+    Assert.assertEquals(fileStatus.getLen(), newLength);
+    AppendTestUtil.checkFullFile(fSys, file, newLength, data, file.toString());
+
+    ContentSummary cs = fSys.getContentSummary(dir);
+    Assert.assertEquals("Bad disk space usage", cs.getSpaceConsumed(),
+        newLength * repl);
+    Assert.assertTrue("Deleted", fSys.delete(dir, true));
+  }
+
   // Test that WebHdfsFileSystem.jsonParse() closes the connection's input
   // stream.
   // Closing the inputstream in jsonParse will allow WebHDFS to reuse