common/src/java/org/apache/hadoop/fs/Trash.java - hadoop - Git at Google

 /**
  * 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.fs;

 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;

 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
 import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.util.StringUtils;

 /** Provides a <i>trash</i> feature.  Files are moved to a user's trash
  * directory, a subdirectory of their home directory named ".Trash".  Files are
  * initially moved to a <i>current</i> sub-directory of the trash directory.
  * Within that sub-directory their original path is preserved.  Periodically
  * one may checkpoint the current trash and remove older checkpoints.  (This
  * design permits trash management without enumeration of the full trash
  * content, without date support in the filesystem, and without clock
  * synchronization.)
  */
 @InterfaceAudience.Public
 @InterfaceStability.Stable
 public class Trash extends Configured {
   private static final Log LOG =
     LogFactory.getLog(Trash.class);

   private static final Path CURRENT = new Path("Current");
   private static final Path TRASH = new Path(".Trash/");
   private static final Path HOMES = new Path("/user/");

   private static final FsPermission PERMISSION =
     new FsPermission(FsAction.ALL, FsAction.NONE, FsAction.NONE);

   private static final DateFormat CHECKPOINT = new SimpleDateFormat("yyMMddHHmm");
   private static final int MSECS_PER_MINUTE = 60*1000;

   private final FileSystem fs;
   private final Path trash;
   private final Path current;
   private final long interval;

   /** Construct a trash can accessor.
    * @param conf a Configuration
    */
   public Trash(Configuration conf) throws IOException {
     this(FileSystem.get(conf), conf);
   }

   /**
    * Construct a trash can accessor for the FileSystem provided.
    */
   public Trash(FileSystem fs, Configuration conf) throws IOException {
     super(conf);
     this.fs = fs;
     this.trash = new Path(fs.getHomeDirectory(), TRASH);
     this.current = new Path(trash, CURRENT);
     this.interval = conf.getLong("fs.trash.interval", 60) * MSECS_PER_MINUTE;
   }

   private Trash(Path home, Configuration conf) throws IOException {
     super(conf);
     this.fs = home.getFileSystem(conf);
     this.trash = new Path(home, TRASH);
     this.current = new Path(trash, CURRENT);
     this.interval = conf.getLong("fs.trash.interval", 60) * MSECS_PER_MINUTE;
   }

   private Path makeTrashRelativePath(Path basePath, Path rmFilePath) {
     return new Path(basePath + rmFilePath.toUri().getPath());
   }

   /** Move a file or directory to the current trash directory.
    * @return false if the item is already in the trash or trash is disabled
    */
   public boolean moveToTrash(Path path) throws IOException {
     if (interval == 0)
       return false;

     if (!path.isAbsolute())                       // make path absolute
       path = new Path(fs.getWorkingDirectory(), path);

     if (!fs.exists(path))                         // check that path exists
       throw new FileNotFoundException(path.toString());

     String qpath = path.makeQualified(fs).toString();

     if (qpath.startsWith(trash.toString())) {
       return false;                               // already in trash
     }

     if (trash.getParent().toString().startsWith(qpath)) {
       throw new IOException("Cannot move \"" + path +
                             "\" to the trash, as it contains the trash");
     }

     Path trashPath = makeTrashRelativePath(current, path);
     Path baseTrashPath = makeTrashRelativePath(current, path.getParent());

     IOException cause = null;

     // try twice, in case checkpoint between the mkdirs() & rename()
     for (int i = 0; i < 2; i++) {
       try {
         if (!fs.mkdirs(baseTrashPath, PERMISSION)) {      // create current
           LOG.warn("Can't create(mkdir) trash directory: "+baseTrashPath);
           return false;
         }
       } catch (IOException e) {
         LOG.warn("Can't create trash directory: "+baseTrashPath);
         cause = e;
         break;
       }
       try {
         //
         // if the target path in Trash already exists, then append with
         // a current time in millisecs.
         //
         String orig = trashPath.toString();

         while(fs.exists(trashPath)) {
           trashPath = new Path(orig + System.currentTimeMillis());
         }

         if (fs.rename(path, trashPath))           // move to current trash
           return true;
       } catch (IOException e) {
         cause = e;
       }
     }
     throw (IOException)
       new IOException("Failed to move to trash: "+path).initCause(cause);
   }

   /** Create a trash checkpoint. */
   public void checkpoint() throws IOException {
     if (!fs.exists(current))                      // no trash, no checkpoint
       return;

     Path checkpoint;
     synchronized (CHECKPOINT) {
       checkpoint = new Path(trash, CHECKPOINT.format(new Date()));
     }

     if (fs.rename(current, checkpoint)) {
       LOG.info("Created trash checkpoint: "+checkpoint.toUri().getPath());
     } else {
       throw new IOException("Failed to checkpoint trash: "+checkpoint);
     }
   }

   /** Delete old checkpoints. */
   public void expunge() throws IOException {
     FileStatus[] dirs = null;

     try {
       dirs = fs.listStatus(trash);            // scan trash sub-directories
     } catch (FileNotFoundException fnfe) {
       return;
     }

     long now = System.currentTimeMillis();
     for (int i = 0; i < dirs.length; i++) {
       Path path = dirs[i].getPath();
       String dir = path.toUri().getPath();
       String name = path.getName();
       if (name.equals(CURRENT.getName()))         // skip current
         continue;

       long time;
       try {
         synchronized (CHECKPOINT) {
           time = CHECKPOINT.parse(name).getTime();
         }
       } catch (ParseException e) {
         LOG.warn("Unexpected item in trash: "+dir+". Ignoring.");
         continue;
       }

       if ((now - interval) > time) {
         if (fs.delete(path, true)) {
           LOG.info("Deleted trash checkpoint: "+dir);
         } else {
           LOG.warn("Couldn't delete checkpoint: "+dir+" Ignoring.");
         }
       }
     }
   }

   //
   // get the current working directory
   //
   Path getCurrentTrashDir() {
     return current;
   }

   /** Return a {@link Runnable} that periodically empties the trash of all
    * users, intended to be run by the superuser.  Only one checkpoint is kept
    * at a time.
    */
   public Runnable getEmptier() throws IOException {
     return new Emptier(getConf());
   }

   private class Emptier implements Runnable {

     private Configuration conf;
     private long interval;

     Emptier(Configuration conf) throws IOException {
       this.conf = conf;
       this.interval = conf.getLong("fs.trash.interval", 0) * MSECS_PER_MINUTE;
     }

     public void run() {
       if (interval == 0)
         return;                                   // trash disabled

       long now = System.currentTimeMillis();
       long end;
       while (true) {
         end = ceiling(now, interval);
         try {                                     // sleep for interval
           Thread.sleep(end - now);
         } catch (InterruptedException e) {
           break;                                  // exit on interrupt
         }

         try {
           now = System.currentTimeMillis();
           if (now >= end) {

             FileStatus[] homes = null;
             try {
               homes = fs.listStatus(HOMES);         // list all home dirs
             } catch (IOException e) {
               LOG.warn("Trash can't list homes: "+e+" Sleeping.");
               continue;
             }

             for (FileStatus home : homes) {         // dump each trash
               if (!home.isDirectory())
                 continue;
               try {
                 Trash trash = new Trash(home.getPath(), conf);
                 trash.expunge();
                 trash.checkpoint();
               } catch (IOException e) {
                 LOG.warn("Trash caught: "+e+". Skipping "+home.getPath()+".");
               }
             }
           }
         } catch (Exception e) {
           LOG.warn("RuntimeException during Trash.Emptier.run() " +
                    StringUtils.stringifyException(e));
         }
       }
       try {
         fs.close();
       } catch(IOException e) {
         LOG.warn("Trash cannot close FileSystem. " +
             StringUtils.stringifyException(e));
       }
     }

     private long ceiling(long time, long interval) {
       return floor(time, interval) + interval;
     }
     private long floor(long time, long interval) {
       return (time / interval) * interval;
     }

   }

   /** Run an emptier.*/
   public static void main(String[] args) throws Exception {
     new Trash(new Configuration()).getEmptier().run();
   }

 }
	/**
	* 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.fs;

	import java.io.FileNotFoundException;
	import java.io.IOException;
	import java.text.DateFormat;
	import java.text.ParseException;
	import java.text.SimpleDateFormat;
	import java.util.Date;

	import org.apache.commons.logging.Log;
	import org.apache.commons.logging.LogFactory;
	import org.apache.hadoop.classification.InterfaceAudience;
	import org.apache.hadoop.classification.InterfaceStability;
	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.conf.Configured;
	import org.apache.hadoop.fs.permission.FsAction;
	import org.apache.hadoop.fs.permission.FsPermission;
	import org.apache.hadoop.util.StringUtils;

	/** Provides a <i>trash</i> feature. Files are moved to a user's trash
	* directory, a subdirectory of their home directory named ".Trash". Files are
	* initially moved to a <i>current</i> sub-directory of the trash directory.
	* Within that sub-directory their original path is preserved. Periodically
	* one may checkpoint the current trash and remove older checkpoints. (This
	* design permits trash management without enumeration of the full trash
	* content, without date support in the filesystem, and without clock
	* synchronization.)
	*/
	@InterfaceAudience.Public
	@InterfaceStability.Stable
	public class Trash extends Configured {
	private static final Log LOG =
	LogFactory.getLog(Trash.class);

	private static final Path CURRENT = new Path("Current");
	private static final Path TRASH = new Path(".Trash/");
	private static final Path HOMES = new Path("/user/");

	private static final FsPermission PERMISSION =
	new FsPermission(FsAction.ALL, FsAction.NONE, FsAction.NONE);

	private static final DateFormat CHECKPOINT = new SimpleDateFormat("yyMMddHHmm");
	private static final int MSECS_PER_MINUTE = 60*1000;

	private final FileSystem fs;
	private final Path trash;
	private final Path current;
	private final long interval;

	/** Construct a trash can accessor.
	* @param conf a Configuration
	*/
	public Trash(Configuration conf) throws IOException {
	this(FileSystem.get(conf), conf);
	}

	/**
	* Construct a trash can accessor for the FileSystem provided.
	*/
	public Trash(FileSystem fs, Configuration conf) throws IOException {
	super(conf);
	this.fs = fs;
	this.trash = new Path(fs.getHomeDirectory(), TRASH);
	this.current = new Path(trash, CURRENT);
	this.interval = conf.getLong("fs.trash.interval", 60) * MSECS_PER_MINUTE;
	}

	private Trash(Path home, Configuration conf) throws IOException {
	super(conf);
	this.fs = home.getFileSystem(conf);
	this.trash = new Path(home, TRASH);
	this.current = new Path(trash, CURRENT);
	this.interval = conf.getLong("fs.trash.interval", 60) * MSECS_PER_MINUTE;
	}

	private Path makeTrashRelativePath(Path basePath, Path rmFilePath) {
	return new Path(basePath + rmFilePath.toUri().getPath());
	}

	/** Move a file or directory to the current trash directory.
	* @return false if the item is already in the trash or trash is disabled
	*/
	public boolean moveToTrash(Path path) throws IOException {
	if (interval == 0)
	return false;

	if (!path.isAbsolute()) // make path absolute
	path = new Path(fs.getWorkingDirectory(), path);

	if (!fs.exists(path)) // check that path exists
	throw new FileNotFoundException(path.toString());

	String qpath = path.makeQualified(fs).toString();

	if (qpath.startsWith(trash.toString())) {
	return false; // already in trash
	}

	if (trash.getParent().toString().startsWith(qpath)) {
	throw new IOException("Cannot move \"" + path +
	"\" to the trash, as it contains the trash");
	}

	Path trashPath = makeTrashRelativePath(current, path);
	Path baseTrashPath = makeTrashRelativePath(current, path.getParent());

	IOException cause = null;

	// try twice, in case checkpoint between the mkdirs() & rename()
	for (int i = 0; i < 2; i++) {
	try {
	if (!fs.mkdirs(baseTrashPath, PERMISSION)) { // create current
	LOG.warn("Can't create(mkdir) trash directory: "+baseTrashPath);
	return false;
	}
	} catch (IOException e) {
	LOG.warn("Can't create trash directory: "+baseTrashPath);
	cause = e;
	break;
	}
	try {
	//
	// if the target path in Trash already exists, then append with
	// a current time in millisecs.
	//
	String orig = trashPath.toString();

	while(fs.exists(trashPath)) {
	trashPath = new Path(orig + System.currentTimeMillis());
	}

	if (fs.rename(path, trashPath)) // move to current trash
	return true;
	} catch (IOException e) {
	cause = e;
	}
	}
	throw (IOException)
	new IOException("Failed to move to trash: "+path).initCause(cause);
	}

	/** Create a trash checkpoint. */
	public void checkpoint() throws IOException {
	if (!fs.exists(current)) // no trash, no checkpoint
	return;

	Path checkpoint;
	synchronized (CHECKPOINT) {
	checkpoint = new Path(trash, CHECKPOINT.format(new Date()));
	}

	if (fs.rename(current, checkpoint)) {
	LOG.info("Created trash checkpoint: "+checkpoint.toUri().getPath());
	} else {
	throw new IOException("Failed to checkpoint trash: "+checkpoint);
	}
	}

	/** Delete old checkpoints. */
	public void expunge() throws IOException {
	FileStatus[] dirs = null;

	try {
	dirs = fs.listStatus(trash); // scan trash sub-directories
	} catch (FileNotFoundException fnfe) {
	return;
	}

	long now = System.currentTimeMillis();
	for (int i = 0; i < dirs.length; i++) {
	Path path = dirs[i].getPath();
	String dir = path.toUri().getPath();
	String name = path.getName();
	if (name.equals(CURRENT.getName())) // skip current
	continue;

	long time;
	try {
	synchronized (CHECKPOINT) {
	time = CHECKPOINT.parse(name).getTime();
	}
	} catch (ParseException e) {
	LOG.warn("Unexpected item in trash: "+dir+". Ignoring.");
	continue;
	}

	if ((now - interval) > time) {
	if (fs.delete(path, true)) {
	LOG.info("Deleted trash checkpoint: "+dir);
	} else {
	LOG.warn("Couldn't delete checkpoint: "+dir+" Ignoring.");
	}
	}
	}
	}

	//
	// get the current working directory
	//
	Path getCurrentTrashDir() {
	return current;
	}

	/** Return a {@link Runnable} that periodically empties the trash of all
	* users, intended to be run by the superuser. Only one checkpoint is kept
	* at a time.
	*/
	public Runnable getEmptier() throws IOException {
	return new Emptier(getConf());
	}

	private class Emptier implements Runnable {

	private Configuration conf;
	private long interval;

	Emptier(Configuration conf) throws IOException {
	this.conf = conf;
	this.interval = conf.getLong("fs.trash.interval", 0) * MSECS_PER_MINUTE;
	}

	public void run() {
	if (interval == 0)
	return; // trash disabled

	long now = System.currentTimeMillis();
	long end;
	while (true) {
	end = ceiling(now, interval);
	try { // sleep for interval
	Thread.sleep(end - now);
	} catch (InterruptedException e) {
	break; // exit on interrupt
	}

	try {
	now = System.currentTimeMillis();
	if (now >= end) {

	FileStatus[] homes = null;
	try {
	homes = fs.listStatus(HOMES); // list all home dirs
	} catch (IOException e) {
	LOG.warn("Trash can't list homes: "+e+" Sleeping.");
	continue;
	}

	for (FileStatus home : homes) { // dump each trash
	if (!home.isDirectory())
	continue;
	try {
	Trash trash = new Trash(home.getPath(), conf);
	trash.expunge();
	trash.checkpoint();
	} catch (IOException e) {
	LOG.warn("Trash caught: "+e+". Skipping "+home.getPath()+".");
	}
	}
	}
	} catch (Exception e) {
	LOG.warn("RuntimeException during Trash.Emptier.run() " +
	StringUtils.stringifyException(e));
	}
	}
	try {
	fs.close();
	} catch(IOException e) {
	LOG.warn("Trash cannot close FileSystem. " +
	StringUtils.stringifyException(e));
	}
	}

	private long ceiling(long time, long interval) {
	return floor(time, interval) + interval;
	}
	private long floor(long time, long interval) {
	return (time / interval) * interval;
	}

	}

	/** Run an emptier.*/
	public static void main(String[] args) throws Exception {
	new Trash(new Configuration()).getEmptier().run();
	}

	}