Package com.linkedin.davinci.blobtransfer.client

Class P2PFileTransferClientHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.HttpObject>

com.linkedin.davinci.blobtransfer.client.P2PFileTransferClientHandler

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

public class P2PFileTransferClientHandler
extends io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.HttpObject>

The client-side Netty handler to process responses for P2P file transfer. It's not shareable among multiple requests since it maintains the states for a single partition. It's important to note that this handler is operated in a single thread, and it processes file transfers sequentially.

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor	Description
P2PFileTransferClientHandler(String baseDir, CompletionStage<InputStream> inputStreamFuture, String storeName, int version, int partition, BlobTransferUtils.BlobTransferTableFormat tableFormat)

Method Summary

Modifier and Type	Method	Description
void	channelInactive(io.netty.channel.ChannelHandlerContext ctx)	Handles channel deactivation, typically triggered when the server gracefully closes the connection.
protected void	channelRead0(io.netty.channel.ChannelHandlerContext ctx, io.netty.handler.codec.http.HttpObject msg)
void	exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause)
void	userEventTriggered(io.netty.channel.ChannelHandlerContext ctx, Object evt)	Handles idle state events to detect unresponsive server connections during blob transfer.

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Constructor Details

P2PFileTransferClientHandler

public P2PFileTransferClientHandler(String baseDir,
 CompletionStage<InputStream> inputStreamFuture,
 String storeName,
 int version,
 int partition,
 BlobTransferUtils.BlobTransferTableFormat tableFormat)

Method Details

channelRead0

protected void channelRead0(io.netty.channel.ChannelHandlerContext ctx,
 io.netty.handler.codec.http.HttpObject msg)
                     throws Exception

Specified by:

channelRead0 in class io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.HttpObject>

Throws:

Exception

channelInactive

public void channelInactive(io.netty.channel.ChannelHandlerContext ctx)
                     throws Exception

Handles channel deactivation, typically triggered when the server gracefully closes the connection. This is called when the server sends a FIN packet (graceful shutdown), which is different from abrupt termination handled by userEventTriggered(io.netty.channel.ChannelHandlerContext, java.lang.Object). If the transfer was incomplete, this indicates the server shut down unexpectedly during the transfer process, so we complete the input stream future exceptionally for fast failover.

Specified by:

channelInactive in interface io.netty.channel.ChannelInboundHandler

Overrides:

channelInactive in class io.netty.channel.ChannelInboundHandlerAdapter

Parameters:

ctx -

Throws:

Exception

userEventTriggered

public void userEventTriggered(io.netty.channel.ChannelHandlerContext ctx,
 Object evt)
                        throws Exception

Handles idle state events to detect unresponsive server connections during blob transfer. When no data is received within the timeout (READER_IDLE), this method assumes the server is unavailable, completes the transfer future exceptionally, and closes the channel. This enables fast failover to the next available peer instead of waiting for the longer client timeout configured in NettyFileTransferClient#blobReceiveTimeoutInMin. Please note that if traffic is legitimately slow but continuous, it should NOT trigger READER_IDLE. However, if traffic has long gaps, it WILL trigger.

Specified by:

userEventTriggered in interface io.netty.channel.ChannelInboundHandler

Overrides:

userEventTriggered in class io.netty.channel.ChannelInboundHandlerAdapter

Parameters:

ctx - the channel handler context

evt - the user event, expected to be IdleStateEvent for timeout detection

Throws:

Exception

exceptionCaught

public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
 Throwable cause)

Specified by:

exceptionCaught in interface io.netty.channel.ChannelHandler

Specified by:

exceptionCaught in interface io.netty.channel.ChannelInboundHandler

Overrides:

exceptionCaught in class io.netty.channel.ChannelInboundHandlerAdapter