Package com.linkedin.venice.listener

Class ServerLoadControllerHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

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

com.linkedin.venice.listener.ServerLoadControllerHandler

All Implemented Interfaces:

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

@Sharable
public class ServerLoadControllerHandler
extends io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.HttpRequest>

This handler is used to control the load on the server by measuring the read latency. If there are many requests, which are suffering from the high latency, the server will start rejecting the requests and return the service overloaded response, so that the clients can back off upon overloaded signals.

Nested Class Summary

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

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
static final io.netty.handler.codec.http.HttpResponseStatus	OVERLOADED_RESPONSE_STATUS
static final String	SERVICE_OVERLOADED_MESSAGE

Constructor Summary

Constructors

Constructor	Description
ServerLoadControllerHandler(VeniceServerConfig serverConfig, ServerLoadStats loadStats)

Method Summary

Modifier and Type	Method	Description
protected void	channelRead0(io.netty.channel.ChannelHandlerContext ctx, io.netty.handler.codec.http.HttpRequest msg)
void	recordLatency(RequestType requestType, double latency, int responseStatusCode)

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

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

Field Details

OVERLOADED_RESPONSE_STATUS

public static final io.netty.handler.codec.http.HttpResponseStatus OVERLOADED_RESPONSE_STATUS

SERVICE_OVERLOADED_MESSAGE

public static final String SERVICE_OVERLOADED_MESSAGE

See Also:

• Constant Field Values

Constructor Details

ServerLoadControllerHandler

public ServerLoadControllerHandler(VeniceServerConfig serverConfig,
 ServerLoadStats loadStats)

Method Details

channelRead0

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

Specified by:

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

Throws:

Exception

recordLatency

public void recordLatency(RequestType requestType,
 double latency,
 int responseStatusCode)