[GitHub] mkwhitacre commented on a change in pull request #20: CRUNCH-679: Improvements for usage of DistCp

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mkwhitacre commented on a change in pull request #20: CRUNCH-679: Improvements for usage of DistCp
URL: https://github.com/apache/crunch/pull/20#discussion_r261682765
 
 

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 File path: crunch-core/src/main/java/org/apache/crunch/util/CrunchRenameCopyListing.java
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+/**
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.crunch.util;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.SequenceFile;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.security.Credentials;
+import org.apache.hadoop.tools.CopyListing;
+import org.apache.hadoop.tools.CopyListingFileStatus;
+import org.apache.hadoop.tools.DistCpOptions;
+import org.apache.hadoop.tools.DistCpOptions.FileAttribute;
+import org.apache.hadoop.tools.SimpleCopyListing;
+import org.apache.hadoop.tools.util.DistCpUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Stack;
+
+/**
+ * A custom {@link CopyListing} implementation capable of dynamically renaming
+ * the target paths according to a configured set of values.
+ * <p>
+ * Once https://issues.apache.org/jira/browse/HADOOP-16147 is available, this
+ * class can be significantly simplified.
+ * </p>
+ */
+public class CrunchRenameCopyListing extends SimpleCopyListing {
+  /**
+   * Comma-separated list of original-file:renamed-file path rename pairs.
+   */
+  public static final String DISTCP_PATH_RENAMES = "crunch.distcp.path.renames";
+
+  private static final Logger LOG = LoggerFactory.getLogger(CrunchRenameCopyListing.class);
+  private final Map<String, String> pathRenames;
+
+  private long totalPaths = 0;
+  private long totalBytesToCopy = 0;
+
+  /**
+   * Protected constructor, to initialize configuration.
+   *
+   * @param configuration The input configuration, with which the source/target FileSystems may be accessed.
+   * @param credentials - Credentials object on which the FS delegation tokens are cached. If null
+   * delegation token caching is skipped
+   */
+  protected CrunchRenameCopyListing(Configuration configuration, Credentials credentials) {
+    super(configuration, credentials);
+
+    pathRenames = new HashMap<>();
+
+    String[] pathRenameConf = configuration.getStrings(DISTCP_PATH_RENAMES);
+    if (pathRenameConf == null) {
+      throw new IllegalArgumentException("Missing required configuration: " + DISTCP_PATH_RENAMES);
+    }
+    for (String pathRename : pathRenameConf) {
+      String[] pathRenameParts = pathRename.split(":");
+      if (pathRenameParts.length != 2) {
+        throw new IllegalArgumentException("Invalid path rename format: " + pathRename);
+      }
+      if (pathRenames.put(pathRenameParts[0], pathRenameParts[1]) != null) {
+        throw new IllegalArgumentException("Invalid duplicate path rename: " + pathRenameParts[0]);
+      }
+    }
+    LOG.info("Loaded {} path rename entries", pathRenames.size());
+  }
+
+  @Override
+  public void doBuildListing(SequenceFile.Writer fileListWriter, DistCpOptions options) throws IOException {
+    try {
+      for (Path path : options.getSourcePaths()) {
+        FileSystem sourceFS = path.getFileSystem(getConf());
+        final boolean preserveAcls = options.shouldPreserve(FileAttribute.ACL);
+        final boolean preserveXAttrs = options.shouldPreserve(FileAttribute.XATTR);
+        final boolean preserveRawXAttrs = options.shouldPreserveRawXattrs();
+        path = makeQualified(path);
+
+        FileStatus rootStatus = sourceFS.getFileStatus(path);
+        Path sourcePathRoot = computeSourceRootPath(rootStatus, options);
+
+        FileStatus[] sourceFiles = sourceFS.listStatus(path);
+        boolean explore = (sourceFiles != null && sourceFiles.length > 0);
+        if (!explore || rootStatus.isDirectory()) {
+          CopyListingFileStatus rootCopyListingStatus = DistCpUtils.toCopyListingFileStatus(sourceFS, rootStatus, preserveAcls,
+              preserveXAttrs, preserveRawXAttrs);
+          writeToFileListingRoot(fileListWriter, rootCopyListingStatus, sourcePathRoot, options);
+        }
+        if (explore) {
+          for (FileStatus sourceStatus : sourceFiles) {
+            if (LOG.isDebugEnabled()) {
+              LOG.debug("Recording source-path: " + sourceStatus.getPath() + " for copy.");
+            }
+            CopyListingFileStatus sourceCopyListingStatus = DistCpUtils.toCopyListingFileStatus(sourceFS, sourceStatus,
+                preserveAcls && sourceStatus.isDirectory(), preserveXAttrs && sourceStatus.isDirectory(),
+                preserveRawXAttrs && sourceStatus.isDirectory());
+            writeToFileListing(fileListWriter, sourceCopyListingStatus, sourcePathRoot, options);
+
+            if (isDirectoryAndNotEmpty(sourceFS, sourceStatus)) {
+              if (LOG.isDebugEnabled()) {
+                LOG.debug("Traversing non-empty source dir: " + sourceStatus.getPath());
+              }
+              traverseNonEmptyDirectory(fileListWriter, sourceStatus, sourcePathRoot, options);
+            }
+          }
+        }
+      }
+      fileListWriter.close();
+      fileListWriter = null;
 
 Review comment:
   won't this potentially cause an NPE in the finally block as this reference is being set equal to null?

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