| /** |
| * 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; |
| |
| import java.io.Closeable; |
| import java.net.Socket; |
| import java.net.SocketAddress; |
| |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map.Entry; |
| |
| import java.io.IOException; |
| import com.google.common.base.Preconditions; |
| import com.google.common.collect.LinkedListMultimap; |
| import org.apache.commons.logging.Log; |
| import org.apache.hadoop.HadoopIllegalArgumentException; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.hdfs.protocol.datatransfer.IOStreamPair; |
| import org.apache.hadoop.io.IOUtils; |
| import org.apache.hadoop.util.Daemon; |
| import org.apache.hadoop.util.StringUtils; |
| import org.apache.hadoop.util.Time; |
| |
| /** |
| * A cache of input stream sockets to Data Node. |
| */ |
| class SocketCache { |
| private static final Log LOG = LogFactory.getLog(SocketCache.class); |
| |
| @InterfaceAudience.Private |
| static class SocketAndStreams implements Closeable { |
| public final Socket sock; |
| public final IOStreamPair ioStreams; |
| long createTime; |
| |
| public SocketAndStreams(Socket s, IOStreamPair ioStreams) { |
| this.sock = s; |
| this.ioStreams = ioStreams; |
| this.createTime = Time.monotonicNow(); |
| } |
| |
| @Override |
| public void close() { |
| if (ioStreams != null) { |
| IOUtils.closeStream(ioStreams.in); |
| IOUtils.closeStream(ioStreams.out); |
| } |
| IOUtils.closeSocket(sock); |
| } |
| |
| public long getCreateTime() { |
| return this.createTime; |
| } |
| } |
| |
| private Daemon daemon; |
| /** A map for per user per datanode. */ |
| private static LinkedListMultimap<SocketAddress, SocketAndStreams> multimap = |
| LinkedListMultimap.create(); |
| private static int capacity; |
| private static long expiryPeriod; |
| private static SocketCache scInstance = new SocketCache(); |
| private static boolean isInitedOnce = false; |
| |
| public static synchronized SocketCache getInstance(int c, long e) { |
| // capacity is only initialized once |
| if (isInitedOnce == false) { |
| capacity = c; |
| expiryPeriod = e; |
| |
| if (capacity == 0 ) { |
| LOG.info("SocketCache disabled."); |
| } |
| else if (expiryPeriod == 0) { |
| throw new IllegalStateException("Cannot initialize expiryPeriod to " + |
| expiryPeriod + "when cache is enabled."); |
| } |
| isInitedOnce = true; |
| } else { //already initialized once |
| if (capacity != c || expiryPeriod != e) { |
| LOG.info("capacity and expiry periods already set to " + capacity + |
| " and " + expiryPeriod + " respectively. Cannot set it to " + c + |
| " and " + e); |
| } |
| } |
| |
| return scInstance; |
| } |
| |
| private boolean isDaemonStarted() { |
| return (daemon == null)? false: true; |
| } |
| |
| private synchronized void startExpiryDaemon() { |
| // start daemon only if not already started |
| if (isDaemonStarted() == true) { |
| return; |
| } |
| |
| daemon = new Daemon(new Runnable() { |
| @Override |
| public void run() { |
| try { |
| SocketCache.this.run(); |
| } catch(InterruptedException e) { |
| //noop |
| } finally { |
| SocketCache.this.clear(); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return String.valueOf(SocketCache.this); |
| } |
| }); |
| daemon.start(); |
| } |
| |
| /** |
| * Get a cached socket to the given address. |
| * @param remote Remote address the socket is connected to. |
| * @return A socket with unknown state, possibly closed underneath. Or null. |
| */ |
| public synchronized SocketAndStreams get(SocketAddress remote) { |
| |
| if (capacity <= 0) { // disabled |
| return null; |
| } |
| |
| List<SocketAndStreams> sockStreamList = multimap.get(remote); |
| if (sockStreamList == null) { |
| return null; |
| } |
| |
| Iterator<SocketAndStreams> iter = sockStreamList.iterator(); |
| while (iter.hasNext()) { |
| SocketAndStreams candidate = iter.next(); |
| iter.remove(); |
| if (!candidate.sock.isClosed()) { |
| return candidate; |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Give an unused socket to the cache. |
| * @param sock socket not used by anyone. |
| */ |
| public synchronized void put(Socket sock, IOStreamPair ioStreams) { |
| |
| Preconditions.checkNotNull(sock); |
| SocketAndStreams s = new SocketAndStreams(sock, ioStreams); |
| if (capacity <= 0) { |
| // Cache disabled. |
| s.close(); |
| return; |
| } |
| |
| startExpiryDaemon(); |
| |
| SocketAddress remoteAddr = sock.getRemoteSocketAddress(); |
| if (remoteAddr == null) { |
| LOG.warn("Cannot cache (unconnected) socket with no remote address: " + |
| sock); |
| IOUtils.closeSocket(sock); |
| return; |
| } |
| |
| if (capacity == multimap.size()) { |
| evictOldest(); |
| } |
| multimap.put(remoteAddr, s); |
| } |
| |
| public synchronized int size() { |
| return multimap.size(); |
| } |
| |
| /** |
| * Evict and close sockets older than expiry period from the cache. |
| */ |
| private synchronized void evictExpired(long expiryPeriod) { |
| while (multimap.size() != 0) { |
| Iterator<Entry<SocketAddress, SocketAndStreams>> iter = |
| multimap.entries().iterator(); |
| Entry<SocketAddress, SocketAndStreams> entry = iter.next(); |
| // if oldest socket expired, remove it |
| if (entry == null || |
| Time.monotonicNow() - entry.getValue().getCreateTime() < |
| expiryPeriod) { |
| break; |
| } |
| iter.remove(); |
| SocketAndStreams s = entry.getValue(); |
| s.close(); |
| } |
| } |
| |
| /** |
| * Evict the oldest entry in the cache. |
| */ |
| private synchronized void evictOldest() { |
| Iterator<Entry<SocketAddress, SocketAndStreams>> iter = |
| multimap.entries().iterator(); |
| if (!iter.hasNext()) { |
| throw new IllegalStateException("Cannot evict from empty cache! " + |
| "capacity: " + capacity); |
| } |
| Entry<SocketAddress, SocketAndStreams> entry = iter.next(); |
| iter.remove(); |
| SocketAndStreams s = entry.getValue(); |
| s.close(); |
| } |
| |
| /** |
| * Periodically check in the cache and expire the entries |
| * older than expiryPeriod minutes |
| */ |
| private void run() throws InterruptedException { |
| for(long lastExpiryTime = Time.monotonicNow(); |
| !Thread.interrupted(); |
| Thread.sleep(expiryPeriod)) { |
| final long elapsed = Time.monotonicNow() - lastExpiryTime; |
| if (elapsed >= expiryPeriod) { |
| evictExpired(expiryPeriod); |
| lastExpiryTime = Time.monotonicNow(); |
| } |
| } |
| clear(); |
| throw new InterruptedException("Daemon Interrupted"); |
| } |
| |
| /** |
| * Empty the cache, and close all sockets. |
| */ |
| private synchronized void clear() { |
| for (SocketAndStreams sockAndStream : multimap.values()) { |
| sockAndStream.close(); |
| } |
| multimap.clear(); |
| } |
| |
| } |