com.github.netty.core.util.ChunkedWriteHandler Maven / Gradle / Ivy
package com.github.netty.core.util;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufHolder;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.stream.ChunkedInput;
import io.netty.util.ReferenceCountUtil;
import java.io.Flushable;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ClosedChannelException;
import java.util.*;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.LongSupplier;
/**
* A {@link ChannelHandler} that adds support for writing a large data stream
* asynchronously neither spending a lot of memory nor getting
* {@link OutOfMemoryError}. Large data streaming such as file
* transfer requires complicated state management in a {@link ChannelHandler}
* implementation. {@link ChunkedWriteHandler} manages such complicated states
* so that you can send a large data stream without difficulties.
*
* To use {@link ChunkedWriteHandler} in your application, you have to insert
* a new {@link ChunkedWriteHandler} instance:
*
* {@link ChannelPipeline} p = ...;
* p.addLast("streamer", new {@link ChunkedWriteHandler}());
* p.addLast("handler", new MyHandler());
*
* Once inserted, you can write a {@link ChunkedInput} so that the
* {@link ChunkedWriteHandler} can pick it up and fetch the content of the
* stream chunk by chunk and write the fetched chunk downstream:
*
* {@link Channel} ch = ...;
* ch.write(new {@link io.netty.handler.stream.ChunkedFile}(new File("video.mkv"));
*
*
* Sending a stream which generates a chunk intermittently
*
* Some {@link ChunkedInput} generates a chunk on a certain event or timing.
* Such {@link ChunkedInput} implementation often returns {@code null} on
* {@link ChunkedInput#readChunk(ByteBufAllocator)}, resulting in the indefinitely suspended
* transfer. To resume the transfer when a new chunk is available, you have to
* call {@link #resumeTransfer()}.
*/
public class ChunkedWriteHandler extends ChannelDuplexHandler {
private static final LoggerX LOGGER =
LoggerFactoryX.getLogger(ChunkedWriteHandler.class);
private final Queue queue;
private final AtomicBoolean flushIng = new AtomicBoolean(false);
private final AtomicLong unFlushBytes = new AtomicLong();
private /*volatile*/ ChannelHandlerContext ctx;
/**
* output stream maxBufferBytes
* Each buffer accumulate the maximum number of bytes (default 1M)
*/
private LongSupplier maxBufferBytes;
public ChunkedWriteHandler(LongSupplier maxBufferBytes) {
this(new ArrayDeque(), maxBufferBytes);
}
public ChunkedWriteHandler(Queue queue, LongSupplier maxBufferBytes) {
this.queue = queue;
this.maxBufferBytes = maxBufferBytes;
}
private static void handleEndOfInputFuture(ChannelFuture future, PendingWrite currentWrite, ChunkedInput input) {
if (!future.isSuccess()) {
closeInput(input);
currentWrite.fail(future.cause());
} else {
// read state of the input in local variables before closing it
long inputProgress = input.progress();
long inputLength = input.length();
closeInput(input);
currentWrite.progress(inputProgress, inputLength);
currentWrite.success(inputLength);
}
}
private static void closeInput(ChunkedInput chunks) {
try {
chunks.close();
} catch (Throwable t) {
if (LOGGER.isWarnEnabled()) {
LOGGER.warn("Failed to close a chunked input.", t);
}
}
}
public Collection getUnFlushList() {
return Collections.unmodifiableCollection(queue);
}
public long getMaxBufferBytes() {
return maxBufferBytes.getAsLong();
}
public void setMaxBufferBytes(LongSupplier maxBufferBytes) {
this.maxBufferBytes = maxBufferBytes;
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
this.ctx = ctx;
}
/**
* Continues to fetch the chunks from the input.
*/
public void resumeTransfer() {
final ChannelHandlerContext ctx = this.ctx;
if (ctx == null) {
return;
}
if (ctx.executor().inEventLoop()) {
resumeTransfer0(ctx);
} else {
// let the transfer resume on the next event loop round
ctx.executor().execute(() -> resumeTransfer0(ctx));
}
}
private void resumeTransfer0(ChannelHandlerContext ctx) {
try {
doFlush(ctx);
} catch (Exception e) {
LOGGER.warn("Unexpected exception while sending chunks.", e);
}
}
private PendingWrite removeFirst() {
PendingWrite remove = queue.poll();
if (remove != null) {
unFlushBytes.addAndGet(-remove.bytes);
}
return remove;
}
private void add(PendingWrite pendingWrite) {
queue.add(pendingWrite);
unFlushBytes.addAndGet(pendingWrite.bytes);
}
@Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
add(PendingWrite.newInstance(msg, promise));
if (unFlushBytes.get() >= maxBufferBytes.getAsLong()) {
doFlush(ctx);
}
}
@Override
public void flush(ChannelHandlerContext ctx) throws Exception {
doFlush(ctx);
}
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
doFlush(ctx);
ctx.fireChannelInactive();
}
@Override
public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {
if (ctx.channel().isWritable()) {
// channel is writable again try to continue flushing
doFlush(ctx);
}
ctx.fireChannelWritabilityChanged();
}
public int unWriteSize() {
return queue.size();
}
public void discard(Throwable cause) {
List responseList = new ArrayList<>();
PendingWrite currentWrite;
for (; ; ) {
currentWrite = removeFirst();
if (currentWrite == null) {
break;
}
Object message = currentWrite.msg;
if (message instanceof ChunkedInput) {
ChunkedInput in = (ChunkedInput) message;
boolean endOfInput;
long inputLength;
try {
endOfInput = in.isEndOfInput();
inputLength = in.length();
closeInput(in);
} catch (Exception e) {
closeInput(in);
currentWrite.fail(e);
if (LOGGER.isWarnEnabled()) {
LOGGER.warn(ChunkedInput.class.getSimpleName() + " failed", e);
}
continue;
}
if (!endOfInput) {
if (cause == null) {
cause = new ClosedChannelException();
}
currentWrite.fail(cause);
} else {
currentWrite.success(inputLength);
}
} else if (message instanceof HttpResponse) {
responseList.add(currentWrite);
} else {
if (cause == null) {
cause = new ClosedChannelException();
}
currentWrite.fail(cause);
}
}
for (PendingWrite httpResponse : responseList) {
add(httpResponse);
}
}
private void doFlush(final ChannelHandlerContext ctx) {
if (queue.isEmpty()) {
ctx.flush();
return;
}
if (flushIng.compareAndSet(false, true)) {
try {
doFlush0(ctx);
} finally {
flushIng.set(false);
}
}
}
private void doFlush0(final ChannelHandlerContext ctx) {
final Channel channel = ctx.channel();
if (!channel.isActive()) {
discard(null);
return;
}
boolean requiresFlush = true;
ByteBufAllocator allocator = ctx.alloc();
while (channel.isWritable()
// || unFlushBytes.longValue() >= 0
) {
final PendingWrite currentWrite = queue.peek();
if (currentWrite == null) {
break;
}
if (currentWrite.promise.isDone()) {
// This might happen e.g. in the case when a write operation
// failed, but there're still unconsumed chunks left.
// Most chunked input sources would stop generating chunks
// and report end of input, but this doesn't work with any
// source wrapped in HttpChunkedInput.
// Note, that we're not trying to release the message/chunks
// as this had to be done already by someone who resolved the
// promise (using ChunkedInput.close method).
// See https://github.com/netty/netty/issues/8700.
removeFirst();
continue;
}
final Object pendingMessage = currentWrite.msg;
if (pendingMessage instanceof ChunkedInput) {
final ChunkedInput chunks = (ChunkedInput) pendingMessage;
boolean endOfInput;
boolean suspend;
Object message = null;
try {
message = chunks.readChunk(allocator);
endOfInput = chunks.isEndOfInput();
if (message == null) {
// No need to suspend when reached at the end.
suspend = !endOfInput;
} else {
suspend = false;
}
} catch (final Throwable t) {
removeFirst();
if (message != null) {
ReferenceCountUtil.release(message);
}
closeInput(chunks);
currentWrite.fail(t);
break;
}
if (suspend) {
// ChunkedInput.nextChunk() returned null and it has
// not reached at the end of input. Let's wait until
// more chunks arrive. Nothing to write or notify.
break;
}
if (message == null) {
// If message is null write an empty ByteBuf.
// See https://github.com/netty/netty/issues/1671
message = Unpooled.EMPTY_BUFFER;
}
// Flush each chunk to conserve memory
ChannelFuture f = ctx.writeAndFlush(message);
if (endOfInput) {
removeFirst();
if (f.isDone()) {
handleEndOfInputFuture(f, currentWrite, chunks);
} else {
// Register a listener which will close the input once the write is complete.
// This is needed because the Chunk may have some resource bound that can not
// be closed before its not written.
//
// See https://github.com/netty/netty/issues/303
f.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
handleEndOfInputFuture(future, currentWrite, chunks);
}
});
}
} else {
final boolean resume = !channel.isWritable();
if (f.isDone()) {
handleFuture(f, currentWrite, resume);
} else {
f.addListener(new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
handleFuture(future, currentWrite, resume);
}
});
}
}
requiresFlush = false;
} else {
if (pendingMessage instanceof Flushable) {
try {
((Flushable) pendingMessage).flush();
} catch (IOException e) {
LOGGER.warn(pendingMessage.getClass().getSimpleName() + " flush error", e);
}
}
removeFirst();
ctx.write(pendingMessage, currentWrite.promise);
currentWrite.recycle();
requiresFlush = true;
}
if (!channel.isActive()) {
discard(new ClosedChannelException());
break;
}
}
if (requiresFlush) {
ctx.flush();
}
}
private void handleFuture(ChannelFuture future, PendingWrite currentWrite, boolean resume) {
ChunkedInput input = (ChunkedInput) currentWrite.msg;
if (future.isSuccess()) {
currentWrite.progress(input.progress(), input.length());
if (resume && future.channel().isWritable()) {
resumeTransfer();
}
} else {
closeInput(input);
currentWrite.fail(future.cause());
}
}
@Override
public String toString() {
return "ChunkedWriteHandler{" +
"maxBufferBytes=" + maxBufferBytes +
", unFlushBytes=" + unFlushBytes +
", queueSize=" + queue.size() +
", ctx=" + ctx +
'}';
}
private static final class PendingWrite implements Recyclable {
private static final Recycler RECYCLER = new Recycler<>(PendingWrite::new);
Object msg;
ChannelPromise promise;
long bytes;
PendingWrite() {
}
public static PendingWrite newInstance(Object msg, ChannelPromise promise) {
PendingWrite instance = RECYCLER.getInstance();
instance.msg = msg;
instance.promise = promise;
if (msg instanceof ByteBuf) {
instance.bytes = ((ByteBuf) msg).readableBytes();
} else if (msg instanceof ByteBuffer) {
instance.bytes = ((ByteBuffer) msg).remaining();
} else if (msg instanceof ByteBufHolder) {
instance.bytes = ((ByteBufHolder) msg).content().readableBytes();
} else if (msg instanceof ChunkedInput) {
instance.bytes = Math.max(((ChunkedInput) msg).length(), 0);
} else if (msg instanceof FileRegion) {
instance.bytes = ((FileRegion) msg).count() - ((FileRegion) msg).position();
} else {
instance.bytes = 0;
}
return instance;
}
@Override
public String toString() {
return "PendingWrite{" +
"msg=" + msg +
", bytes=" + bytes +
'}';
}
void fail(Throwable cause) {
if (promise.isDone()) {
// No need to notify the progress or fulfill the promise because it's done already.
return;
}
if (promise.tryFailure(cause)) {
ReferenceCountUtil.release(msg);
}
// recycle();
}
void success(long total) {
if (promise.isDone()) {
// No need to notify the progress or fulfill the promise because it's done already.
return;
}
if (promise.trySuccess()) {
progress(total, total);
}
// recycle();
}
void progress(long progress, long total) {
if (promise instanceof ChannelProgressivePromise) {
((ChannelProgressivePromise) promise).tryProgress(progress, total);
}
}
@Override
public void recycle() {
this.msg = null;
this.promise = null;
RECYCLER.recycleInstance(this);
}
}
}