| /** |
| * 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.text.*; |
| import java.io.*; |
| import java.net.URI; |
| import java.util.Date; |
| |
| import org.apache.commons.logging.*; |
| |
| import org.apache.hadoop.conf.*; |
| |
| /** Provides a <i>trash</i> feature. Files may be moved to a trash directory. |
| * They're initially stored in 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.) |
| */ |
| public class Trash extends Configured { |
| private static final Log LOG = |
| LogFactory.getLog("org.apache.hadoop.fs.Trash"); |
| |
| private static final String CURRENT = "Current"; |
| private static final DateFormat CHECKPOINT = new SimpleDateFormat("yyMMddHHmm"); |
| private static final int MSECS_PER_MINUTE = 60*1000; |
| |
| private FileSystem fs; |
| private Path root; |
| private Path current; |
| private long interval; |
| |
| /** Construct a trash can accessor. |
| * @param conf a Configuration |
| */ |
| public Trash(Configuration conf) throws IOException { |
| super(conf); |
| |
| Path root = new Path(conf.get("fs.trash.root", "/tmp/Trash")); |
| |
| this.fs = root.getFileSystem(conf); |
| |
| if (!root.isAbsolute()) |
| root = new Path(fs.getWorkingDirectory(), root); |
| |
| this.root = root; |
| this.current = new Path(root, CURRENT); |
| this.interval = conf.getLong("fs.trash.interval", 60) * MSECS_PER_MINUTE; |
| } |
| |
| /** 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()); |
| |
| URI rootUri = root.toUri(); |
| String dirPath = path.toUri().getPath(); |
| |
| if (dirPath.startsWith(rootUri.getPath())) { // already in trash |
| return false; |
| } |
| |
| Path trashPath = // create path in current |
| new Path(rootUri.getScheme(), rootUri.getAuthority(), |
| current.toUri().getPath()+dirPath); |
| |
| IOException cause = null; |
| |
| // try twice, in case checkpoint between the mkdirs() & rename() |
| for (int i = 0; i < 2; i++) { |
| Path trashDir = trashPath.getParent(); |
| if (!fs.mkdirs(trashDir)) { // make parent directory |
| throw new IOException("Failed to create trash directory: "+trashDir); |
| } |
| try { |
| // |
| // if the target path in Trash already exists, then append with |
| // a number. Start from 1. |
| // |
| String orig = trashPath.toString(); |
| for (int j = 1; fs.exists(trashPath); j++) { |
| trashPath = new Path(orig + "." + j); |
| } |
| 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(root, CHECKPOINT.format(new Date())); |
| } |
| |
| if (fs.rename(current, checkpoint)) { |
| LOG.info("Created trash checkpoint: "+checkpoint); |
| } else { |
| throw new IOException("Failed to checkpoint trash: "+checkpoint); |
| } |
| } |
| |
| /** Delete old checkpoints. */ |
| public void expunge() throws IOException { |
| Path[] dirs = fs.listPaths(root); // scan trash sub-directories |
| long now = System.currentTimeMillis(); |
| for (int i = 0; i < dirs.length; i++) { |
| Path dir = dirs[i]; |
| String name = dir.getName(); |
| if (name.equals(CURRENT)) // 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(dir)) { |
| 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. |
| * Only one checkpoint is kept at a time. |
| */ |
| public Runnable getEmptier() { |
| return new Emptier(); |
| } |
| |
| private class Emptier implements Runnable { |
| |
| public void run() { |
| if (interval == 0) |
| return; // trash disabled |
| |
| long now = System.currentTimeMillis(); |
| long end = ceiling(now, interval); |
| while (true) { |
| try { // sleep for interval |
| Thread.sleep(end - now); |
| } catch (InterruptedException e) { |
| return; // exit on interrupt |
| } |
| |
| now = System.currentTimeMillis(); |
| if (now >= end) { |
| |
| try { |
| expunge(); |
| } catch (IOException e) { |
| LOG.warn("Trash expunge caught: "+e+". Ignoring."); |
| } |
| |
| try { |
| checkpoint(); |
| } catch (IOException e) { |
| LOG.warn("Trash checkpoint caught: "+e+". Ignoring."); |
| } |
| |
| end = ceiling(now, interval); |
| } |
| } |
| } |
| |
| 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(); |
| } |
| |
| } |