content: /**
   * 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 com.alibaba.jstorm.hdfs.blobstore;
  
  import backtype.storm.Config;
  import com.alibaba.jstorm.blobstore.BlobStoreFile;
  import com.alibaba.jstorm.utils.JStormUtils;
  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.fs.permission.FsPermission;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.FileNotFoundException;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Timer;
  import java.util.TimerTask;
  
  /**
   * HDFS blob store impl.
   */
  public class HdfsBlobStoreImpl {
      private static final Logger LOG = LoggerFactory.getLogger(HdfsBlobStoreImpl.class);
  
      private static final long FULL_CLEANUP_FREQ = 60 * 60 * 1000l;
      private static final int BUCKETS = 1024;
      private static final Timer timer = new Timer("HdfsBlobStore cleanup thread", true);
      private static final String BLOBSTORE_DATA = "data";
  
      public class KeyInHashDirIterator implements Iterator<String> {
          private int currentBucket = 0;
          private Iterator<String> it = null;
          private String next = null;
  
          public KeyInHashDirIterator() throws IOException {
              primeNext();
          }
  
          private void primeNext() throws IOException {
              while (it == null && currentBucket < BUCKETS) {
                  String name = String.valueOf(currentBucket);
                  Path dir = new Path(_fullPath, name);
                  try {
                      it = listKeys(dir);
                  } catch (FileNotFoundException e) {
                      it = null;
                  }
                  if (it == null || !it.hasNext()) {
                      it = null;
                      currentBucket++;
                  } else {
                      next = it.next();
                  }
              }
          }
  
          @Override
          public boolean hasNext() {
              return next != null;
          }
  
          @Override
          public String next() {
              if (!hasNext()) {
                  throw new NoSuchElementException();
              }
              String current = next;
              next = null;
              if (it != null) {
                  if (!it.hasNext()) {
                      it = null;
                      currentBucket++;
                      try {
                          primeNext();
                      } catch (IOException e) {
                          throw new RuntimeException(e);
                      }
                  } else {
                      next = it.next();
                  }
              }
              return current;
          }
  
          @Override
          public void remove() {
              throw new UnsupportedOperationException("Delete Not Supported");
          }
      }
  
  
      private Path _fullPath;
      private FileSystem _fs;
      private TimerTask _cleanup = null;
      private Configuration _hadoopConf;
  
      // blobstore directory is private!
      final public static FsPermission BLOBSTORE_DIR_PERMISSION =
              FsPermission.createImmutable((short) 0755); // rwxr-xr-x
  
      public HdfsBlobStoreImpl(Path path, Map<String, Object> conf) throws IOException {
          this(path, conf, new Configuration());
      }
  
      public HdfsBlobStoreImpl(Path path, Map<String, Object> conf,
                               Configuration hconf) throws IOException {
          LOG.info("Blob store based in {}", path);
          _fullPath = path;
          _hadoopConf = hconf;
  
          String hdfsHostName = (String) conf.get(Config.BLOBSTORE_HDFS_HOSTNAME);
          Integer hdfsPort = JStormUtils.parseInt(conf.get(Config.BLOBSTORE_HDFS_PORT));
          String defaultFS = (String) conf.get(Config.BLOBSTORE_HDFS_DEFAULT_FS);
          if ((hdfsHostName == null || hdfsPort == null) && defaultFS == null) {
              throw new RuntimeException("<blobstore.hdfs.hostname, blobstore.hdfs.port> and blobstore.hdfs.defaultFS " +
                      "is empty. You must specify an HDFS location! ");
          }
          if (defaultFS == null) {
              defaultFS = String.format("hdfs://%s:%d", hdfsHostName, hdfsPort);
          }
          LOG.info("HDFS blob store, using defaultFS: {}", defaultFS);
          _hadoopConf.set("fs.defaultFS", defaultFS);
  
          String keyPrefix = "blobstore.hdfs.";
          for (Map.Entry<String, Object> confEntry : conf.entrySet()) {
              String key = confEntry.getKey();
              Object value = confEntry.getValue();
              if (key.startsWith(keyPrefix) && value != null) {
                  key = key.substring(keyPrefix.length(), key.length());
                  LOG.info("adding \"{}={}\" to hadoop conf", key, value);
                  _hadoopConf.set(key, value.toString());
              }
          }
  
          _fs = path.getFileSystem(_hadoopConf);
  
          if (!_fs.exists(_fullPath)) {
              FsPermission perms = new FsPermission(BLOBSTORE_DIR_PERMISSION);
              boolean success = false;
              try {
                  success = _fs.mkdirs(_fullPath, perms);
              } catch (IOException e) {
                  LOG.error("fs mkdir ", e);
              }
              if (!success) {
                  throw new IOException("Error creating blobstore directory: " + _fullPath);
              }
          }
  
          Object shouldCleanup = conf.get(Config.BLOBSTORE_CLEANUP_ENABLE);
          if (JStormUtils.parseBoolean(shouldCleanup, false)) {
              LOG.debug("Starting hdfs blobstore cleaner");
              _cleanup = new TimerTask() {
                  @Override
                  public void run() {
                      try {
                          fullCleanup(FULL_CLEANUP_FREQ);
                      } catch (IOException e) {
                          LOG.error("Error trying to cleanup", e);
                      }
                  }
              };
              timer.scheduleAtFixedRate(_cleanup, 0, FULL_CLEANUP_FREQ);
          }
      }
  
      /**
       * @return all keys that are available for reading.
       * @throws IOException on any error.
       */
      public Iterator<String> listKeys() throws IOException {
          return new KeyInHashDirIterator();
      }
  
      /**
       * Get an input stream for reading a part.
       *
       * @param key the key of the part to read.
       * @return the where to read the data from.
       * @throws IOException on any error
       */
      public BlobStoreFile read(String key) throws IOException {
          return new HdfsBlobStoreFile(getKeyDir(key), BLOBSTORE_DATA, _hadoopConf);
      }
  
      /**
       * Get an object tied to writing the data.
       *
       * @param key    the key of the part to write to.
       * @param create whether the file needs to be new or not.
       * @return an object that can be used to both write to, but also commit/cancel the operation.
       * @throws IOException on any error
       */
      public BlobStoreFile write(String key, boolean create) throws IOException {
          return new HdfsBlobStoreFile(getKeyDir(key), true, create, _hadoopConf);
      }
  
      /**
       * Check if the key exists in the blob store.
       *
       * @param key the key to check for
       * @return true if it exists else false.
       */
      public boolean exists(String key) {
          Path dir = getKeyDir(key);
          boolean res = false;
          try {
              _fs = dir.getFileSystem(_hadoopConf);
              res = _fs.exists(dir);
          } catch (IOException e) {
              LOG.warn("Exception checking for exists on: " + key);
          }
          return res;
      }
  
      /**
       * Delete a key from the blob store
       *
       * @param key the key to delete
       * @throws IOException on any error
       */
      public void deleteKey(String key) throws IOException {
          Path keyDir = getKeyDir(key);
          HdfsBlobStoreFile pf = new HdfsBlobStoreFile(keyDir, BLOBSTORE_DATA,
                  _hadoopConf);
          pf.delete();
          delete(keyDir);
      }
  
      protected Path getKeyDir(String key) {
          String hash = String.valueOf(Math.abs((long) key.hashCode()) % BUCKETS);
          Path hashDir = new Path(_fullPath, hash);
  
          Path ret = new Path(hashDir, key);
          LOG.debug("{} Looking for {} in {}", new Object[]{_fullPath, key, hash});
          return ret;
      }
  
      public void fullCleanup(long age) throws IOException {
          long cleanUpIfBefore = System.currentTimeMillis() - age;
          Iterator<String> keys = new KeyInHashDirIterator();
          while (keys.hasNext()) {
              String key = keys.next();
              Path keyDir = getKeyDir(key);
              Iterator<BlobStoreFile> i = listBlobStoreFiles(keyDir);
              if (!i.hasNext()) {
                  //The dir is empty, so try to delete it, may fail, but that is OK
                  try {
                      _fs.delete(keyDir, true);
                  } catch (Exception e) {
                      LOG.warn("Could not delete " + keyDir + " will try again later");
                  }
              }
              while (i.hasNext()) {
                  BlobStoreFile f = i.next();
                  if (f.isTmp()) {
                      if (f.getModTime() <= cleanUpIfBefore) {
                          f.delete();
                      }
                  }
              }
          }
      }
  
      protected Iterator<BlobStoreFile> listBlobStoreFiles(Path path) throws IOException {
          ArrayList<BlobStoreFile> ret = new ArrayList<BlobStoreFile>();
          FileStatus[] files = _fs.listStatus(new Path[]{path});
          if (files != null) {
              for (FileStatus sub : files) {
                  try {
                      ret.add(new HdfsBlobStoreFile(sub.getPath().getParent(), sub.getPath().getName(),
                              _hadoopConf));
                  } catch (IllegalArgumentException e) {
                      //Ignored the file did not match
                      LOG.warn("Found an unexpected file in {} {}", path, sub.getPath().getName());
                  }
              }
          }
          return ret.iterator();
      }
  
      protected Iterator<String> listKeys(Path path) throws IOException {
          ArrayList<String> ret = new ArrayList<String>();
          FileStatus[] files = _fs.listStatus(new Path[]{path});
          if (files != null) {
              for (FileStatus sub : files) {
                  try {
                      ret.add(sub.getPath().getName().toString());
                  } catch (IllegalArgumentException e) {
                      //Ignored the file did not match
                      LOG.debug("Found an unexpected file in {} {}", path, sub.getPath().getName());
                  }
              }
          }
          return ret.iterator();
      }
  
      protected int getBlobReplication(String key) throws IOException {
          Path path = getKeyDir(key);
          Path dest = new Path(path, BLOBSTORE_DATA);
          return _fs.getFileStatus(dest).getReplication();
      }
  
      protected int updateBlobReplication(String key, int replication) throws IOException {
          Path path = getKeyDir(key);
          Path dest = new Path(path, BLOBSTORE_DATA);
          _fs.setReplication(dest, (short) replication);
          return _fs.getFileStatus(dest).getReplication();
      }
  
      protected void delete(Path path) throws IOException {
          _fs.delete(path, true);
      }
  
      public void shutdown() {
          if (_cleanup != null) {
              _cleanup.cancel();
              _cleanup = null;
          }
      }
  }
  