/*
* 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.cassandra.net;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.net.SocketException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.zip.Checksum;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import net.jpountz.lz4.LZ4BlockOutputStream;
import net.jpountz.lz4.LZ4Compressor;
import net.jpountz.lz4.LZ4Factory;
import net.jpountz.xxhash.XXHashFactory;
import org.apache.cassandra.tracing.TraceState;
import org.apache.cassandra.tracing.Tracing;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.cassandra.utils.UUIDGen;
import org.xerial.snappy.SnappyOutputStream;
import org.apache.cassandra.config.Config;
import org.apache.cassandra.config.DatabaseDescriptor;
import com.google.common.util.concurrent.Uninterruptibles;
public class OutboundTcpConnection extends Thread
{
private static final Logger logger = LoggerFactory.getLogger(OutboundTcpConnection.class);
private static final MessageOut CLOSE_SENTINEL = new MessageOut(MessagingService.Verb.INTERNAL_RESPONSE);
private volatile boolean isStopped = false;
private static final int OPEN_RETRY_DELAY = 100; // ms between retries
private static final int WAIT_FOR_VERSION_MAX_TIME = 5000;
private static final int NO_VERSION = Integer.MIN_VALUE;
static final int LZ4_HASH_SEED = 0x9747b28c;
private final BlockingQueue<QueuedMessage> backlog = new LinkedBlockingQueue<>();
private final OutboundTcpConnectionPool poolReference;
private DataOutputStream out;
private Socket socket;
private volatile long completed;
private final AtomicLong dropped = new AtomicLong();
private volatile int currentMsgBufferCount = 0;
private int targetVersion;
public OutboundTcpConnection(OutboundTcpConnectionPool pool)
{
super("WRITE-" + pool.endPoint());
this.poolReference = pool;
}
private static boolean isLocalDC(InetAddress targetHost)
{
String remoteDC = DatabaseDescriptor.getEndpointSnitch().getDatacenter(targetHost);
String localDC = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getBroadcastAddress());
return remoteDC.equals(localDC);
}
public void enqueue(MessageOut<?> message, int id)
{
if (backlog.size() > 1024)
expireMessages();
try
{
backlog.put(new QueuedMessage(message, id));
}
catch (InterruptedException e)
{
throw new AssertionError(e);
}
}
void closeSocket(boolean destroyThread)
{
backlog.clear();
isStopped = destroyThread; // Exit loop to stop the thread
enqueue(CLOSE_SENTINEL, -1);
}
void softCloseSocket()
{
enqueue(CLOSE_SENTINEL, -1);
}
public int getTargetVersion()
{
return targetVersion;
}
public void run()
{
// keeping list (batch) size small for now; that way we don't have an unbounded array (that we never resize)
final List<QueuedMessage> drainedMessages = new ArrayList<>(128);
outer:
while (true)
{
if (backlog.drainTo(drainedMessages, drainedMessages.size()) == 0)
{
try
{
drainedMessages.add(backlog.take());
}
catch (InterruptedException e)
{
throw new AssertionError(e);
}
}
currentMsgBufferCount = drainedMessages.size();
int count = drainedMessages.size();
for (QueuedMessage qm : drainedMessages)
{
try
{
MessageOut<?> m = qm.message;
if (m == CLOSE_SENTINEL)
{
disconnect();
if (isStopped)
break outer;
continue;
}
if (qm.timestamp < System.currentTimeMillis() - m.getTimeout())
dropped.incrementAndGet();
else if (socket != null || connect())
writeConnected(qm, count == 1 && backlog.size() == 0);
else
// clear out the queue, else gossip messages back up.
backlog.clear();
}
catch (Exception e)
{
// really shouldn't get here, as exception handling in writeConnected() is reasonably robust
// but we want to catch anything bad we don't drop the messages in the current batch
logger.error("error processing a message intended for {}", poolReference.endPoint(), e);
}
currentMsgBufferCount = --count;
}
drainedMessages.clear();
}
}
public int getPendingMessages()
{
return backlog.size() + currentMsgBufferCount;
}
public long getCompletedMesssages()
{
return completed;
}
public long getDroppedMessages()
{
return dropped.get();
}
private boolean shouldCompressConnection()
{
// assumes version >= 1.2
return DatabaseDescriptor.internodeCompression() == Config.InternodeCompression.all
|| (DatabaseDescriptor.internodeCompression() == Config.InternodeCompression.dc && !isLocalDC(poolReference.endPoint()));
}
private void writeConnected(QueuedMessage qm, boolean flush)
{
try
{
byte[] sessionBytes = qm.message.parameters.get(Tracing.TRACE_HEADER);
if (sessionBytes != null)
{
UUID sessionId = UUIDGen.getUUID(ByteBuffer.wrap(sessionBytes));
TraceState state = Tracing.instance.get(sessionId);
String message = String.format("Sending message to %s", poolReference.endPoint());
// session may have already finished; see CASSANDRA-5668
if (state == null)
{
TraceState.trace(ByteBuffer.wrap(sessionBytes), message, -1);
}
else
{
state.trace(message);
if (qm.message.verb == MessagingService.Verb.REQUEST_RESPONSE)
Tracing.instance.stopNonLocal(state);
}
}
writeInternal(qm.message, qm.id, qm.timestamp);
completed++;
if (flush)
out.flush();
}
catch (Exception e)
{
disconnect();
if (e instanceof IOException)
{
if (logger.isDebugEnabled())
logger.debug("error writing to {}", poolReference.endPoint(), e);
// if the message was important, such as a repair acknowledgement, put it back on the queue
// to retry after re-connecting. See CASSANDRA-5393
if (qm.shouldRetry())
{
try
{
backlog.put(new RetriedQueuedMessage(qm));
}
catch (InterruptedException e1)
{
throw new AssertionError(e1);
}
}
}
else
{
// Non IO exceptions are likely a programming error so let's not silence them
logger.error("error writing to {}", poolReference.endPoint(), e);
}
}
}
private void writeInternal(MessageOut message, int id, long timestamp) throws IOException
{
out.writeInt(MessagingService.PROTOCOL_MAGIC);
if (targetVersion < MessagingService.VERSION_20)
out.writeUTF(String.valueOf(id));
else
out.writeInt(id);
// int cast cuts off the high-order half of the timestamp, which we can assume remains
// the same between now and when the recipient reconstructs it.
out.writeInt((int) timestamp);
message.serialize(out, targetVersion);
}
private static void writeHeader(DataOutputStream out, int version, boolean compressionEnabled) throws IOException
{
// 2 bits: unused. used to be "serializer type," which was always Binary
// 1 bit: compression
// 1 bit: streaming mode
// 3 bits: unused
// 8 bits: version
// 15 bits: unused
int header = 0;
if (compressionEnabled)
header |= 4;
header |= (version << 8);
out.writeInt(header);
}
private void disconnect()
{
if (socket != null)
{
try
{
socket.close();
}
catch (IOException e)
{
if (logger.isTraceEnabled())
logger.trace("exception closing connection to " + poolReference.endPoint(), e);
}
out = null;
socket = null;
}
}
private boolean connect()
{
if (logger.isDebugEnabled())
logger.debug("attempting to connect to {}", poolReference.endPoint());
long start = System.nanoTime();
long timeout = TimeUnit.MILLISECONDS.toNanos(DatabaseDescriptor.getRpcTimeout());
while (System.nanoTime() - start < timeout)
{
targetVersion = MessagingService.instance().getVersion(poolReference.endPoint());
try
{
socket = poolReference.newSocket();
socket.setKeepAlive(true);
if (isLocalDC(poolReference.endPoint()))
{
socket.setTcpNoDelay(true);
}
else
{
socket.setTcpNoDelay(DatabaseDescriptor.getInterDCTcpNoDelay());
}
if (DatabaseDescriptor.getInternodeSendBufferSize() != null)
{
try
{
socket.setSendBufferSize(DatabaseDescriptor.getInternodeSendBufferSize());
}
catch (SocketException se)
{
logger.warn("Failed to set send buffer size on internode socket.", se);
}
}
out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream(), 4096));
out.writeInt(MessagingService.PROTOCOL_MAGIC);
writeHeader(out, targetVersion, shouldCompressConnection());
out.flush();
DataInputStream in = new DataInputStream(socket.getInputStream());
int maxTargetVersion = handshakeVersion(in);
if (maxTargetVersion == NO_VERSION)
{
// no version is returned, so disconnect an try again: we will either get
// a different target version (targetVersion < MessagingService.VERSION_12)
// or if the same version the handshake will finally succeed
logger.debug("Target max version is {}; no version information yet, will retry", maxTargetVersion);
disconnect();
continue;
}
if (targetVersion > maxTargetVersion)
{
logger.debug("Target max version is {}; will reconnect with that version", maxTargetVersion);
MessagingService.instance().setVersion(poolReference.endPoint(), maxTargetVersion);
disconnect();
return false;
}
if (targetVersion < maxTargetVersion && targetVersion < MessagingService.current_version)
{
logger.trace("Detected higher max version {} (using {}); will reconnect when queued messages are done",
maxTargetVersion, targetVersion);
MessagingService.instance().setVersion(poolReference.endPoint(), Math.min(MessagingService.current_version, maxTargetVersion));
softCloseSocket();
}
out.writeInt(MessagingService.current_version);
CompactEndpointSerializationHelper.serialize(FBUtilities.getBroadcastAddress(), out);
if (shouldCompressConnection())
{
out.flush();
logger.trace("Upgrading OutputStream to be compressed");
if (targetVersion < MessagingService.VERSION_21)
{
out = new DataOutputStream(new SnappyOutputStream(new BufferedOutputStream(socket.getOutputStream())));
}
else
{
LZ4Compressor compressor = LZ4Factory.fastestInstance().fastCompressor();
Checksum checksum = XXHashFactory.fastestInstance().newStreamingHash32(LZ4_HASH_SEED).asChecksum();
out = new DataOutputStream(new LZ4BlockOutputStream(new BufferedOutputStream(socket.getOutputStream()),
1 << 14, // 16k block size
compressor,
checksum,
true)); // no async flushing
}
}
return true;
}
catch (IOException e)
{
socket = null;
if (logger.isTraceEnabled())
logger.trace("unable to connect to " + poolReference.endPoint(), e);
Uninterruptibles.sleepUninterruptibly(OPEN_RETRY_DELAY, TimeUnit.MILLISECONDS);
}
}
return false;
}
private int handshakeVersion(final DataInputStream inputStream)
{
final AtomicInteger version = new AtomicInteger(NO_VERSION);
final CountDownLatch versionLatch = new CountDownLatch(1);
new Thread("HANDSHAKE-" + poolReference.endPoint())
{
@Override
public void run()
{
try
{
logger.info("Handshaking version with {}", poolReference.endPoint());
version.set(inputStream.readInt());
}
catch (IOException ex)
{
final String msg = "Cannot handshake version with " + poolReference.endPoint();
if (logger.isTraceEnabled())
logger.trace(msg, ex);
else
logger.info(msg);
}
finally
{
//unblock the waiting thread on either success or fail
versionLatch.countDown();
}
}
}.start();
try
{
versionLatch.await(WAIT_FOR_VERSION_MAX_TIME, TimeUnit.MILLISECONDS);
}
catch (InterruptedException ex)
{
throw new AssertionError(ex);
}
return version.get();
}
private void expireMessages()
{
Iterator<QueuedMessage> iter = backlog.iterator();
while (iter.hasNext())
{
QueuedMessage qm = iter.next();
if (qm.timestamp >= System.currentTimeMillis() - qm.message.getTimeout())
return;
iter.remove();
dropped.incrementAndGet();
}
}
/** messages that have not been retried yet */
private static class QueuedMessage
{
final MessageOut<?> message;
final int id;
final long timestamp;
QueuedMessage(MessageOut<?> message, int id)
{
this.message = message;
this.id = id;
this.timestamp = System.currentTimeMillis();
}
boolean shouldRetry()
{
return !MessagingService.DROPPABLE_VERBS.contains(message.verb);
}
}
private static class RetriedQueuedMessage extends QueuedMessage
{
RetriedQueuedMessage(QueuedMessage msg)
{
super(msg.message, msg.id);
}
boolean shouldRetry()
{
return false;
}
}
}