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The Java operations layer for the MongoDB Java Driver. Third parties can ' +
'wrap this layer to provide custom higher-level APIs
/*
* Copyright 2008-present MongoDB, Inc.
*
* Licensed 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.mongodb.connection.netty;
import com.mongodb.MongoClientException;
import com.mongodb.MongoException;
import com.mongodb.MongoInternalException;
import com.mongodb.MongoInterruptedException;
import com.mongodb.MongoSocketException;
import com.mongodb.MongoSocketOpenException;
import com.mongodb.MongoSocketReadTimeoutException;
import com.mongodb.ServerAddress;
import com.mongodb.annotations.ThreadSafe;
import com.mongodb.connection.AsyncCompletionHandler;
import com.mongodb.connection.SocketSettings;
import com.mongodb.connection.SslSettings;
import com.mongodb.connection.Stream;
import com.mongodb.lang.Nullable;
import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.CompositeByteBuf;
import io.netty.buffer.PooledByteBufAllocator;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.ssl.SslHandler;
import io.netty.handler.timeout.ReadTimeoutException;
import org.bson.ByteBuf;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLEngine;
import javax.net.ssl.SSLParameters;
import java.io.IOException;
import java.net.SocketAddress;
import java.security.NoSuchAlgorithmException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledFuture;
import static com.mongodb.assertions.Assertions.assertNotNull;
import static com.mongodb.assertions.Assertions.isTrueArgument;
import static com.mongodb.internal.connection.SslHelper.enableHostNameVerification;
import static com.mongodb.internal.connection.SslHelper.enableSni;
import static java.util.Optional.ofNullable;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
/**
* A Stream implementation based on Netty 4.0.
* Just like it is for the {@link java.nio.channels.AsynchronousSocketChannel},
* concurrent pending1 readers
* (whether {@linkplain #read(int, int) synchronous} or {@linkplain #readAsync(int, AsyncCompletionHandler) asynchronous})
* are not supported by {@link NettyStream}.
* However, this class does not have a fail-fast mechanism checking for such situations.
*
* 1We cannot simply say that read methods are not allowed be run concurrently because strictly speaking they are allowed,
* as explained below.
* {@code
* NettyStream stream = ...;
* stream.readAsync(1, new AsyncCompletionHandler() {//inv1
* @Override
* public void completed(ByteBuf o) {
* stream.readAsync(//inv2
* 1, ...);//ret2
* }
*
* @Override
* public void failed(Throwable t) {
* }
* });//ret1
* }
* Arrows on the diagram below represent happens-before relations.
* {@code
* int1 -> inv2 -> ret2
* \--------> ret1
* }
* As shown on the diagram, the method {@link #readAsync(int, AsyncCompletionHandler)} runs concurrently with
* itself in the example above. However, there are no concurrent pending readers because the second operation
* is invoked after the first operation has completed reading despite the method has not returned yet.
*/
final class NettyStream implements Stream {
private static final byte NO_SCHEDULE_TIME = 0;
private final ServerAddress address;
private final SocketSettings settings;
private final SslSettings sslSettings;
private final EventLoopGroup workerGroup;
private final Class socketChannelClass;
private final ByteBufAllocator allocator;
@Nullable
private final SslContext sslContext;
private boolean isClosed;
private volatile Channel channel;
private final LinkedList pendingInboundBuffers = new LinkedList<>();
/* The fields pendingReader, pendingException are always written/read inside synchronized blocks
* that use the same NettyStream object, so they can be plain.*/
private PendingReader pendingReader;
private Throwable pendingException;
/* The fields readTimeoutTask, readTimeoutMillis are each written only in the ChannelInitializer.initChannel method
* (in addition to the write of the default value and the write by variable initializers),
* and read only when NettyStream users read data, or Netty event loop handles incoming data.
* Since actions done by the ChannelInitializer.initChannel method
* are ordered (in the happens-before order) before user read actions and before event loop actions that handle incoming data,
* these fields can be plain.*/
@Nullable
private ReadTimeoutTask readTimeoutTask;
private long readTimeoutMillis = NO_SCHEDULE_TIME;
NettyStream(final ServerAddress address, final SocketSettings settings, final SslSettings sslSettings, final EventLoopGroup workerGroup,
final Class socketChannelClass, final ByteBufAllocator allocator,
@Nullable final SslContext sslContext) {
this.address = address;
this.settings = settings;
this.sslSettings = sslSettings;
this.workerGroup = workerGroup;
this.socketChannelClass = socketChannelClass;
this.allocator = allocator;
this.sslContext = sslContext;
}
@Override
public ByteBuf getBuffer(final int size) {
return new NettyByteBuf(allocator.buffer(size, size));
}
@Override
public void open() throws IOException {
FutureAsyncCompletionHandler handler = new FutureAsyncCompletionHandler<>();
openAsync(handler);
handler.get();
}
@Override
public void openAsync(final AsyncCompletionHandler handler) {
Queue socketAddressQueue;
try {
socketAddressQueue = new LinkedList<>(address.getSocketAddresses());
} catch (Throwable t) {
handler.failed(t);
return;
}
initializeChannel(handler, socketAddressQueue);
}
private void initializeChannel(final AsyncCompletionHandler handler, final Queue socketAddressQueue) {
if (socketAddressQueue.isEmpty()) {
handler.failed(new MongoSocketException("Exception opening socket", getAddress()));
} else {
SocketAddress nextAddress = socketAddressQueue.poll();
Bootstrap bootstrap = new Bootstrap();
bootstrap.group(workerGroup);
bootstrap.channel(socketChannelClass);
bootstrap.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, settings.getConnectTimeout(MILLISECONDS));
bootstrap.option(ChannelOption.TCP_NODELAY, true);
bootstrap.option(ChannelOption.SO_KEEPALIVE, true);
if (settings.getReceiveBufferSize() > 0) {
bootstrap.option(ChannelOption.SO_RCVBUF, settings.getReceiveBufferSize());
}
if (settings.getSendBufferSize() > 0) {
bootstrap.option(ChannelOption.SO_SNDBUF, settings.getSendBufferSize());
}
bootstrap.option(ChannelOption.ALLOCATOR, allocator);
bootstrap.handler(new ChannelInitializer() {
@Override
public void initChannel(final SocketChannel ch) {
ChannelPipeline pipeline = ch.pipeline();
if (sslSettings.isEnabled()) {
addSslHandler(ch);
}
int readTimeout = settings.getReadTimeout(MILLISECONDS);
if (readTimeout > NO_SCHEDULE_TIME) {
readTimeoutMillis = readTimeout;
/* We need at least one handler before (in the inbound evaluation order) the InboundBufferHandler,
* so that we can fire exception events (they are inbound events) using its context and the InboundBufferHandler
* receives them. SslHandler is not always present, so adding a NOOP handler.*/
pipeline.addLast(new ChannelInboundHandlerAdapter());
readTimeoutTask = new ReadTimeoutTask(pipeline.lastContext());
}
pipeline.addLast(new InboundBufferHandler());
}
});
ChannelFuture channelFuture = bootstrap.connect(nextAddress);
channelFuture.addListener(new OpenChannelFutureListener(socketAddressQueue, channelFuture, handler));
}
}
@Override
public void write(final List buffers) throws IOException {
FutureAsyncCompletionHandler future = new FutureAsyncCompletionHandler<>();
writeAsync(buffers, future);
future.get();
}
@Override
public ByteBuf read(final int numBytes) throws IOException {
return read(numBytes, 0);
}
@Override
public boolean supportsAdditionalTimeout() {
return true;
}
@Override
public ByteBuf read(final int numBytes, final int additionalTimeoutMillis) throws IOException {
isTrueArgument("additionalTimeoutMillis must not be negative", additionalTimeoutMillis >= 0);
FutureAsyncCompletionHandler future = new FutureAsyncCompletionHandler<>();
readAsync(numBytes, future, combinedTimeout(readTimeoutMillis, additionalTimeoutMillis));
return future.get();
}
@Override
public void writeAsync(final List buffers, final AsyncCompletionHandler handler) {
CompositeByteBuf composite = PooledByteBufAllocator.DEFAULT.compositeBuffer();
for (ByteBuf cur : buffers) {
composite.addComponent(true, ((NettyByteBuf) cur).asByteBuf());
}
channel.writeAndFlush(composite).addListener((ChannelFutureListener) future -> {
if (!future.isSuccess()) {
handler.failed(future.cause());
} else {
handler.completed(null);
}
});
}
@Override
public void readAsync(final int numBytes, final AsyncCompletionHandler handler) {
readAsync(numBytes, handler, readTimeoutMillis);
}
/**
* @param numBytes Must be equal to {@link #pendingReader}{@code .numBytes} when called by a Netty channel handler.
* @param handler Must be equal to {@link #pendingReader}{@code .handler} when called by a Netty channel handler.
* @param readTimeoutMillis Must be equal to {@link #NO_SCHEDULE_TIME} when called by a Netty channel handler.
* Timeouts may be scheduled only by the public read methods. Taking into account that concurrent pending
* readers are not allowed, there must not be a situation when threads attempt to schedule a timeout
* before the previous one is either cancelled or completed.
*/
private void readAsync(final int numBytes, final AsyncCompletionHandler handler, final long readTimeoutMillis) {
ByteBuf buffer = null;
Throwable exceptionResult = null;
synchronized (this) {
exceptionResult = pendingException;
if (exceptionResult == null) {
if (!hasBytesAvailable(numBytes)) {
if (pendingReader == null) {//called by a public read method
pendingReader = new PendingReader(numBytes, handler, scheduleReadTimeout(readTimeoutTask, readTimeoutMillis));
}
} else {
CompositeByteBuf composite = allocator.compositeBuffer(pendingInboundBuffers.size());
int bytesNeeded = numBytes;
for (Iterator iter = pendingInboundBuffers.iterator(); iter.hasNext();) {
io.netty.buffer.ByteBuf next = iter.next();
int bytesNeededFromCurrentBuffer = Math.min(next.readableBytes(), bytesNeeded);
if (bytesNeededFromCurrentBuffer == next.readableBytes()) {
composite.addComponent(next);
iter.remove();
} else {
next.retain();
composite.addComponent(next.readSlice(bytesNeededFromCurrentBuffer));
}
composite.writerIndex(composite.writerIndex() + bytesNeededFromCurrentBuffer);
bytesNeeded -= bytesNeededFromCurrentBuffer;
if (bytesNeeded == 0) {
break;
}
}
buffer = new NettyByteBuf(composite).flip();
}
}
if (!(exceptionResult == null && buffer == null)//the read operation has completed
&& pendingReader != null) {//we need to clear the pending reader
cancel(pendingReader.timeout);
this.pendingReader = null;
}
}
if (exceptionResult != null) {
handler.failed(exceptionResult);
}
if (buffer != null) {
handler.completed(buffer);
}
}
private boolean hasBytesAvailable(final int numBytes) {
int bytesAvailable = 0;
for (io.netty.buffer.ByteBuf cur : pendingInboundBuffers) {
bytesAvailable += cur.readableBytes();
if (bytesAvailable >= numBytes) {
return true;
}
}
return false;
}
private void handleReadResponse(@Nullable final io.netty.buffer.ByteBuf buffer, @Nullable final Throwable t) {
PendingReader localPendingReader = null;
synchronized (this) {
if (buffer != null) {
pendingInboundBuffers.add(buffer.retain());
} else {
pendingException = t;
}
localPendingReader = pendingReader;
}
if (localPendingReader != null) {
//timeouts may be scheduled only by the public read methods
readAsync(localPendingReader.numBytes, localPendingReader.handler, NO_SCHEDULE_TIME);
}
}
@Override
public ServerAddress getAddress() {
return address;
}
@Override
public synchronized void close() {
isClosed = true;
if (channel != null) {
channel.close();
channel = null;
}
for (Iterator iterator = pendingInboundBuffers.iterator(); iterator.hasNext();) {
io.netty.buffer.ByteBuf nextByteBuf = iterator.next();
iterator.remove();
nextByteBuf.release();
}
}
@Override
public boolean isClosed() {
return isClosed;
}
public SocketSettings getSettings() {
return settings;
}
public SslSettings getSslSettings() {
return sslSettings;
}
public EventLoopGroup getWorkerGroup() {
return workerGroup;
}
public Class getSocketChannelClass() {
return socketChannelClass;
}
public ByteBufAllocator getAllocator() {
return allocator;
}
private void addSslHandler(final SocketChannel channel) {
SSLEngine engine;
if (sslContext == null) {
SSLContext sslContext;
try {
sslContext = ofNullable(sslSettings.getContext()).orElse(SSLContext.getDefault());
} catch (NoSuchAlgorithmException e) {
throw new MongoClientException("Unable to create standard SSLContext", e);
}
engine = sslContext.createSSLEngine(address.getHost(), address.getPort());
} else {
engine = sslContext.newEngine(channel.alloc(), address.getHost(), address.getPort());
}
engine.setUseClientMode(true);
SSLParameters sslParameters = engine.getSSLParameters();
enableSni(address.getHost(), sslParameters);
if (!sslSettings.isInvalidHostNameAllowed()) {
enableHostNameVerification(sslParameters);
}
engine.setSSLParameters(sslParameters);
channel.pipeline().addFirst("ssl", new SslHandler(engine, false));
}
private class InboundBufferHandler extends SimpleChannelInboundHandler {
@Override
protected void channelRead0(final ChannelHandlerContext ctx, final io.netty.buffer.ByteBuf buffer) throws Exception {
handleReadResponse(buffer, null);
}
@Override
public void exceptionCaught(final ChannelHandlerContext ctx, final Throwable t) {
if (t instanceof ReadTimeoutException) {
handleReadResponse(null, new MongoSocketReadTimeoutException("Timeout while receiving message", address, t));
} else {
handleReadResponse(null, t);
}
ctx.close();
}
}
private static final class PendingReader {
private final int numBytes;
private final AsyncCompletionHandler handler;
@Nullable
private final ScheduledFuture timeout;
private PendingReader(
final int numBytes, final AsyncCompletionHandler handler, @Nullable final ScheduledFuture timeout) {
this.numBytes = numBytes;
this.handler = handler;
this.timeout = timeout;
}
}
private static final class FutureAsyncCompletionHandler implements AsyncCompletionHandler {
private final CountDownLatch latch = new CountDownLatch(1);
private volatile T t;
private volatile Throwable throwable;
FutureAsyncCompletionHandler() {
}
@Override
public void completed(@Nullable final T t) {
this.t = t;
latch.countDown();
}
@Override
public void failed(final Throwable t) {
this.throwable = t;
latch.countDown();
}
public T get() throws IOException {
try {
latch.await();
if (throwable != null) {
if (throwable instanceof IOException) {
throw (IOException) throwable;
} else if (throwable instanceof MongoException) {
throw (MongoException) throwable;
} else {
throw new MongoInternalException("Exception thrown from Netty Stream", throwable);
}
}
return t;
} catch (InterruptedException e) {
throw new MongoInterruptedException("Interrupted", e);
}
}
}
private class OpenChannelFutureListener implements ChannelFutureListener {
private final Queue socketAddressQueue;
private final ChannelFuture channelFuture;
private final AsyncCompletionHandler handler;
OpenChannelFutureListener(final Queue socketAddressQueue, final ChannelFuture channelFuture,
final AsyncCompletionHandler handler) {
this.socketAddressQueue = socketAddressQueue;
this.channelFuture = channelFuture;
this.handler = handler;
}
@Override
public void operationComplete(final ChannelFuture future) {
synchronized (NettyStream.this) {
if (future.isSuccess()) {
if (isClosed) {
channelFuture.channel().close();
} else {
channel = channelFuture.channel();
channel.closeFuture().addListener((ChannelFutureListener) future1 -> handleReadResponse(null, new IOException("The connection to the server was closed")));
}
handler.completed(null);
} else {
if (isClosed) {
handler.completed(null);
} else if (socketAddressQueue.isEmpty()) {
handler.failed(new MongoSocketOpenException("Exception opening socket", getAddress(), future.cause()));
} else {
initializeChannel(handler, socketAddressQueue);
}
}
}
}
}
private static void cancel(@Nullable final Future f) {
if (f != null) {
f.cancel(false);
}
}
private static long combinedTimeout(final long timeout, final int additionalTimeout) {
if (timeout == NO_SCHEDULE_TIME) {
return NO_SCHEDULE_TIME;
} else {
return Math.addExact(timeout, additionalTimeout);
}
}
@Nullable
private static ScheduledFuture scheduleReadTimeout(@Nullable final ReadTimeoutTask readTimeoutTask, final long timeoutMillis) {
if (timeoutMillis == NO_SCHEDULE_TIME) {
return null;
} else {
return assertNotNull(readTimeoutTask).schedule(timeoutMillis);
}
}
@ThreadSafe
private static final class ReadTimeoutTask implements Runnable {
private final ChannelHandlerContext ctx;
private ReadTimeoutTask(final ChannelHandlerContext timeoutChannelHandlerContext) {
ctx = timeoutChannelHandlerContext;
}
@Override
public void run() {
try {
if (ctx.channel().isOpen()) {
ctx.fireExceptionCaught(ReadTimeoutException.INSTANCE);
ctx.close();
}
} catch (final Throwable t) {
ctx.fireExceptionCaught(t);
}
}
private ScheduledFuture schedule(final long timeoutMillis) {
//assert timeoutMillis > 0 : timeoutMillis;
return ctx.executor().schedule(this, timeoutMillis, MILLISECONDS);
}
}
}